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Table of Content

    25 July 2022, Volume 43 Issue 7 Previous Issue    Next Issue
    Omics & Biotechnology
    Cloning and Identification of NFU Family Genes in Mango and Responsive Analysis to Abiotic Stresses
    LI Youhuan, BAO Zhongqi, GAO Taiping, HUANG Jianfeng, WANG Limin, ZHANG Hongxia, SONG Zhizhong
    2022, 43 (7):  1313-1321.  doi: 10.3969/j.issn.1000-2561.2022.07.001
    Abstract ( 175 )   HTML ( 25 )   PDF (3819KB) ( 128 )  

    Four NFU family genes that involved in Fe-S cluster assembly were isolated and identified from diploid mango ‘Guire82’, which were entitled MiNFU1 to MiNFU4, respectively. MiNFU2 and MiNFU3 proteins had all three typical motifs of NFU family proteins, while MiNFU1 lacks motif 3 and MiNFU4 lacks motif 1 and motif 2. MiNFU1 to MiNFU3 had a similar tertiary structure, while the tertiary structure of MiNFU4 was quite unique and different. There are slight differences in NFU family members among13 different plant families and genera. Three annual herbs of Arabidopsis, Brachypodium, and Thellungiella contain more scaffold proteins, while non-functional scaffold proteins are more likely to be lost in perennial fruit crops, such as mango, strawberry, peach, apple, citrus and grape. According to the phylogenetic tree, plant NFU homologous proteins can be divided into two subfamilies, which have differences in genetic and evolutionary relationships. Among them, NFU homologous proteins from Cruciferae, Gramineae or Rosaceae tend to be closely clustered, respectively, and mango NFU proteins are closely clustered with the corresponding homologs of citrus and tomato. In addition, there were significant differences in the expression levels of NFU family genes in different tissues / organs of mango. The overall expression level of MiNFU2 was the highest in all tested tissues, followed by MiNFU4 and MiNFU1, while the overall expression level of MiNFU3 was the lowest. The expression levels of NFU family genes in seedling leaves were the highest, followed by phloem and full blooming flowers, while the expression levels of NFU family genes in fruits (young and mature fruits) was relatively low. Notably, the transcriptional responses of NFU family genes in mango seedlings to iron depletion, high iron toxicity, NaCl, PEG and low temperature treatments were significantly different. Although the overall expression of MiNFU3 was the lowest, it was not affected by all tested abiotic stresses. MiNFU1 and MiNFU4 were more sensitive to high iron treatment, whose expression levels were significantly increased throughout the whole plant under high iron treatment. In addition, NaCl treatment significantly increased the expression of MiNFU1 in roots. Iron deficiency and PEG treatment tended to reduce the expression levels of responsive NFU genes in roots, while low temperature treatment were prone to reduce the expression levels of responsive NFU genes in leaves. This study provides gene resources to elucidate the molecular mechanisms of Fe-S cluster assembly in mango, and lays a theoretical foundation to reveal Fe nutrition and metabolism in tropical fruit crops.

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    Function of MeUGT14 Gene in Cassava under Biotic Stress
    YE Wei, LUO Qiuxian, CAI Meiqi, ZENG Jian, HU Wei
    2022, 43 (7):  1322-1327.  doi: 10.3969/j.issn.1000-2561.2022.07.002
    Abstract ( 115 )   HTML ( 13 )   PDF (1420KB) ( 90 )  

    Cassava is an important cash crop and food crop in tropical and subtropical regions. It is not only the third source of carbohydrates consumed by nearly one billion people, but also a major source of industrial starch and bioethanol. Glycosyltransferase (GTs) is a ubiquitous modification type that catalyzes modification reactions. GTs add sugar groups to substrate molecules to form more stable natural glycosides or sugar esters. Sugar groups mainly include glucose, rhamnose, xylose, galactose, etc. UDP-glycosyltransferases (UGTs) belongs to GTs, which are found in all plant species. Plant UGTs play important function in many processes, while the most universal one is transfer reaction, leading to multiple crucial consequences, such as activation of secondary metabolites (plant hormones) and change of the solubility of compounds responding to biotic and abiotic stresses. In order to analyze the function of UGT genes in cassava, MeUGT14 was cloned from cassava leaves (SC124) by RT-PCR. The expression of MeUGT14 under different stresses showed that MeUGT14 was significantly induced by biotic stress. Data analysis showed that MeUGT14 was significantly induced by Xanthomonas axonopodis pv. manihotis (Xam) strain. Therefore, virus induced gene silencing (VIGS) vector of MeUGT14 gene was constructed, and the silent fragment was 285 bp. Through gene silencing in cassava leaves, qPCR results showed that MeUGT14 significantly decreased in cassava leaves. The expression levels of MeUGT14 in different transgenic plants decreased by 69%, 45% and 68%, respectively. Subsequently, infection experiments were carried out on cassava leaves, after 6 days of inoculation Xam, results showed that decreased MeUGT14 expression resulted in a significant increase in the number of bacteria on the leaves and phenotypic images of leaves also showed that reduced MeUGT14 expression resulted in more obvious plaque on leaves. These results showed that the downregulation of MeUGT14 expression significantly reduced the resistance to Xam infection. According to the evolutionary relationship between MeUGT14 and UGT76B1/UGT74F1 and the function of UGT76B1/UGT74F1, it was speculated that MeUGT14 may respond to Xam infection by affecting the synthesis of salicylic acid and jasmonic acid. The results indicated that MeUGT14 played a role in cassava resistance to pathogen infection, and provided clues for further study on the mechanism of MeUGT14 in cassava resistance to biotic stress.

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    Cloning and Expression Analysis of an MYB Transcription Factor Gene ScMYB52-1 from Sugarcane
    LIN Yongxu, YU Qing, FENG Meichang, LIN Jiaying, ZHAO Mingming, OU Qiuyue, GUO Jinlong, HUANG Guoqiang
    2022, 43 (7):  1328-1337.  doi: 10.3969/j.issn.1000-2561.2022.07.003
    Abstract ( 105 )   HTML ( 11 )   PDF (5245KB) ( 92 )  

    The MYB transcription factor family members are widely involved in various biological processes in plants and play a vital role in the abiotic stress response. This study aims to isolate the stress response MYB gene from sugarcane and further validate its characteristics and biological function under abiotic stresses. An R2R3-MYB gene, termed ScMYB52-1, was obtained via 3°RACE homologous cloning from the sugarcane variety ROC22 (Saccharum. spp. hybrids. cv. ROC22). The cDNA sequence was 1 072 bp long with a 696 bp open reading frame (ORF), 54 bp 5°-UTR (untranslated region), and 322 bp 3°-UTR. The ORF encoded 231 amino acids with a predicted molecular mass of 26.65 kDa and two repeats of the MYB domain. Phylogenetic analysis of ScMYB52-1 with MYB protein family from Arabidopsis thaliana indicated that ScMYB52-1 was most closely related to AtMYB52 and AtMYB54 from A. thaliana. Multiple sequence alignment of ScMYB52-1, AtMYB52, and AtMYB54 showed that the MYB domain sequences in the N-terminal of the three proteins were highly consistent. Moreover, the protein tertiary structure prediction results showed that they shared very similar structures, suggesting that the functions of ScMYB52-1 might be similar to the other proteins. Real-time fluorescence quantitative PCR (qPCR) analysis showed that the expression of ScMYB52-1 was not sensitive under PEG stress in the root. It was transitorily up-regulated in the leaf at the time point of 3 h only. When treated with ABA or NaCl, ScMYB52-1 was up-regulated rapidly in the leaf. It was 3.35 times and 2.75 times as high as that in the control at 0.5 h, respectively, and kept a higher level than control during the experiment. Conversely, ScMYB52-1 was suppressed under the two treatments in the root at 0.5 h. The expression level was 12% and 40% as much as the control at 24 h, respectively, and generally kept lower than control during the experiment. Subcellular localization analysis showed that the efficient expression of ScMYB52-1-GFP fusion protein was observed, and the fluorescence was mainly located in the nucleus of tobacco cells. The yeast two-hybrid self-activation experiment suggested that the ScMYB52-1 protein did not have transcriptional activation activity. It implied that ScMYB52-1 was involved in sugarcane response to salt stress via ABA signaling pathways and might have different regulatory mechanisms in the leaf and the root. The results would provide preliminary information for understanding the role of ScMYB52-1 in abiotic stress tolerance mechanisms in sugarcane.

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    PhPP2Aa as Reference Gene in Phalaenopsis under Low-temperature Stress
    LIANG Fang, XU Shenping, ZHANG Yan, WANG Mofei, CUI Bo
    2022, 43 (7):  1338-1346.  doi: 10.3969/j.issn.1000-2561.2022.07.004
    Abstract ( 82 )   HTML ( 8 )   PDF (1687KB) ( 69 )  

    Quantitative real-time polymerase chain reaction (qPCR) analysis, with the benefits of simplicity, high sensitivity, accuracy and high-throughput characteristics, has been used in many fields to quantify the transcript levels of target genes. There are many rules that must be followed to ensure the reproducible and accurate expression profiles of target genes using qPCR. Among them, the use of a reliable internal control known as a reference gene for data normalization is the elementary prerequisite for valid results and proper analysis. Numerous studies have suggested that no single reference gene is always expressed stably under any condition. There are no reports on the selection of optimal reference genes for Phalaenopsis under low temperature conditions. Protein phosphatase 2A (PP2A) is a major intracellular serine / threonine protein phosphatase in eukaryotes. A subunit gene of PP2A was cloned by the results of the transcriptome sequencing of Phalaenopsis hybrid under cold stress, which was named PhPP2Aa and the GenBank accession number was MW847782. The coding region (ORF) of PhPP2Aa was 1764 bp, encoding 587 amino acids. Homologous alignment showed that it shared over 80% nucleotide sequence similarity with PP2A in other plants, and that it shared 99.66% amino acid sequence similarity with P. equestris. The phylogenetic tree analysis based on the amino acid suggested that the relationship of PP2A between Phalaenopsis hybrid, P. equestris and Dendrobium catenatum was close, which belonged to the same branch. Three conventional software (geNorm, NormFinder, BestKeeper) were used to analyze the expression stability of 8 candidate reference genes (TUA, TUB, ACTIN, F-box, PP2A, RPL19, RPL36 and RPL41) from Phalaenopsis. The results showed that the most stable reference gene was PP2A, followed by ACTIN. And, the most unstable was F-box, followed by TUA. Using PP2A of Phalaenopsis (PhPP2Aa) as the reference gene to explore transcriptional profile of the target gene PhNAC1, the results demonstrated that the expression pattern of PhNAC1 was consistent with its characterize under cold stress. Therefore, PhPP2Aa can be used as the internal reference gene for the analysis of target gene in Phalaenopsis under low-temperature stress.

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    Germplasm Resources, Genetics & Breeding
    Biological Characteristics of Main Sugarcane Cultivars in China
    LI Rudan, MAO Jun, DAO Jingmei, FAN Xian, YANG Shaolin, DENG Jun, ZHANG Yuebin
    2022, 43 (7):  1347-1356.  doi: 10.3969/j.issn.1000-2561.2022.07.005
    Abstract ( 107 )   HTML ( 13 )   PDF (1320KB) ( 111 )  

    In this study, five main sugarcane varieties in China, ‘Guiliu 05-136’, ‘Guitang 42’, ‘Yunzhe 05-51’, ‘Funong 41’, and ‘ROC22’, were used as the research materials. At early stage of elongation, booming elongation stage, and mature stage, the leaf area index (LAI) of different genotypes of sugarcane, the leaf area of fully expanded green leaves (+1, middle, and base), plant height and stalk diameter were measured. The total number of sugarcane leaves and the number of green leaves were measured at booming elongation stage and mature stage. The quality indicators such as yield, sucrose content, fiber content, and dry matter content were measured at mature stage, and the phenotypic characters were analyzed, and the correlation of sugarcane phenotypic characteristics and mature yield and sugar were also analyzed. The results showed that the growth rate in plant cane at early stage of elongation was higher than that of ratoon cane for all the varieties. ‘Yunzhe 05-51’ had the highest growth rate, ‘Funong 41’ had the highest stalk diameter in both plant and ratoon canes. The leaf LAI showed increasing first and then decreasing, and higher in ratoon cane than plant cane at booming elongation stage. The leaf area was significantly higher in ratoon cane than in plant cane at early elongation stage, and that in plant cane showed increasing first and then decreasing. Ratoon cane had higher green leaf rate than plant cane, and ‘Guiliu 05-136’ had the highest green leaf rate for all time. Cane quality analysis at maturity stage showed that the cane yield was the highest in ‘Yunzhe 05-51’, and the sucrose content was the highest in ‘Guiliu 05-136’, the fiber and dry matter contents were the highest in ‘Guitang 42’. ‘Guitang 42’ produced the highest sugar in plant cane, and ‘Guiliu 05-136’ produced the highest sugar in ratoon cane. Correlation analysis showed that the sucrose content was significantly negatively correlated with plant height, stalk diameter, leaf area at early elongation stage in plant cane, and cane yield was significantly positively correlated with plant height at each growth stage in ratoon cane. According to the results of this study, ‘Guiliu 05-136’ has a better sugar yield in ratoon cane, ‘Guitang 42’ has a higher sugar yield in plant cane, and ‘Yunzhe 05-51’ has a higher cane yield than other cultivars. Different cultivars have different biological characteristics, so suitable varieties should be selected according to local conditions, considering the combination of climatic conditions and cultivation patterns.

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    Quality Evaluation of 23 Species of Clausena lansium (Lour.) Skeels Germplasm Resources Based on Principal Component Analysis and Cluster Analysis
    YU Huaping, ZHAO Zhichang, GAO Aiping, LUO Ruixiong
    2022, 43 (7):  1357-1364.  doi: 10.3969/j.issn.1000-2561.2022.07.006
    Abstract ( 99 )   HTML ( 16 )   PDF (1069KB) ( 95 )  

    In order to lay the foundation for scientific evaluation of fruit quality of wampee germplasms, 11 fruit quality indices including single fruit weight, fruit length, fruit diameter, fruit shape index, edible rate, total soluble solid, vitamin C, protein, soluble sugar, total acid, sugar-acid ratio for the mature fruits of 23 wampee germplasms resources were measured and analyzed using principal component analysis and cluster analysis. Lastly, the representative quality evaluation indexes were selected from indices, 23 wampee germplasms resources were clustered according to the selected indexes. The results showed that the variation of single fruit weight, vitamin C, protein, soluble sugar, total acid and sugar-acid ratio were above 20%, while the variation of fruit diameter and fruit shape index were below 10%. Among them, the variation of sugar-acid ratio of wampee germplasms was the most significant, which was as high as 108.57%, while the variation of fruit shape index was the most non-significant, only 6.98%. This indicated that the content of nutrients varied greatly among different wampee germplasm, with abundant genetic information and diversity, and the appearance and size of them were genetically stable, and had less space for improvement. There were significant or extremely significant correlations among the quality indexes of the germplasm. After standardizing the data, the principal component analysis was carried out, and four representative principal components were extracted, of whom cumulative proportion reached 85.41%. According to the score of the 1st to 4th principal component factor and the comprehensive score of the quality indexes, the first and second principal components played a key role in the comprehensive evaluation of wampee quality, the highest score was A3, and the lowest score was G1. Meanwhile, the six indexes which has great influence and relatively independent on the quality of wampee germplasm resources were single fruit weight, fruit shape index, edible rate, soluble sugar, total acid and sugar-acid ratio. The systematic cluster analysis of fruit quality in wampee by the 6 selected and representative indexes which were standardized showed that the fruit quality from the germplasm resources could be clustered into 4 groups according to Euclidean distance of 15. The 1st group had A3 and Y-2, which were the largest, and had a high edible rate and sugar-acid ratio, with a sweet flavor and excellent quality. The 2nd group had X1, Y-1, G2 and B1, the fruits were larger and diverse in shapes, with high edible rates, but relatively low in soluble sugar and sugar acids, and inferior quality. The 3rd group included 300-1, J2, 300-2, 9-3, H1, A1, Z1, A2 and N-3, which had low fruit size, high edible rate, moderate sour and sweet. The 4th group included A5, N-1, H2, A6, T1, G1, J1, J3, which had small fruit, low edible rate, low soluble sugar, high total acid, low sugar-acid ratio and poor taste.

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    Genetic Diversity and Traits Evaluation of Coix lacryma-jobi Germplasm Resources
    ZHOU Hongcan, YIN Weidan, JIE Hongdong, MA Yushen, ZENG Yi, HE Pengliang, XING Hucheng, JIE Yucheng
    2022, 43 (7):  1365-1374.  doi: 10.3969/j.issn.1000-2561.2022.07.007
    Abstract ( 92 )   HTML ( 13 )   PDF (1344KB) ( 77 )  

    In order to clarify the genetic diversity of Coix lacryma-jobi germplasm resources commonly used in Hunan province, 51 Coix lacryma-jobi germplasm resources were used as the materials to analyze the genetic diversity of phenotypic traits, agronomic traits and nutritional quality. The results showed that the coefficient of variation of agronomic traits and nutritional quality ranged from 5.36% to 26.41%. The genetic diversity index of phenotypic traits ranged from 0.52 to 1.87. Principal component analysis showed that the cumulative contribution rate of the first five principal components was 67.13%. 51 Coix lacryma-jobi germplasms were divided into 4 categories by systematic cluster analysis. The first group includes 7 germplasms, which are mainly characterized by high grain yield and high fresh straw yield. The second group includes 12 germplasms, which are mainly characterized by general grain yield, high plant height, high yield of fresh straw and thick stem. There are 27 germplasms in the third group, and the agronomic characters and nutritional quality are general. The fourth group includes five germplasms, which are mainly characterized by low grain yield and small grains. According to the comprehensive evaluation model of membership function analysis, it is found that there are7 Coix lacryma-jobi comprehensive value>0.5: HNYY-34 can be used for seed combine with feeding, HNYY-39 and Hnyy-40 are suitable for feeding, HNYY-22 and HNYY-38 are used for seed utilization, CQYY-01 and HNYY-43 are used for comprehensive utilization. This study provides materials for the screening and efficient utilization of excellent characters of Coix lacryma-jobi in Hunan and the subsequent breeding of new varieties of Coix lacryma-jobi in food, medicine and forage.

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    Resources Investigation of Nymphaea nouchali in Hainan Island
    LI Yaru, YUN Yingying, FAN Qiuyun, WANG Jian, SHI Youhai
    2022, 43 (7):  1375-1381.  doi: 10.3969/j.issn.1000-2561.2022.07.008
    Abstract ( 79 )   HTML ( 6 )   PDF (1450KB) ( 74 )  

    Nymphaea nouchali Burm. f. is a native species of water lily and a rare aquatic flower in Hainan. It has important garden ornamental, ecological protection and certain medicinal and edible value, and is also an excellent material for breeding new tropical water lily varieties. In order to fully understand the resource distribution and conservation status of N. nouchali Burm. f. in Hainan Island, and to provide reference for scientific conservation and orderly utilization of the plant, this paper carried out several field investigations on N. nouchali Burm. f. resources in Hainan Island, recorded and observed the distribution, habitat conditions and living conditions of N. nouchali Burm. f. resources. N. nouchali Burm. f. was naturally distributed in Haikou, Wanning, Changjiang, Sanya, Ledong and other cities and counties, but the number and growth potential of wild plants in each distribution point were different. The growth condition of N. nouchali Burm. f. was better in Ganzaling distribution point of Sanya, and the number of plants in Qiugang village of Ledong was the largest. N. nouchali Burm. f. mainly grows in static water with a water depth of 0.2?1.6 m, and has high requirements on living environment such as water quality and water level. It is easy to reduce or even disappear due to the interference of environmental factors. Most of the natural distribution sites are not protected, and the wild plants are seriously disturbed by exotic biology invasion and human factors. The wild number is rare, and they are endangered and in urgent need of protection.

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    Current Situation and Suggestions on Protection of New Tropical Crop Variety Rights in China
    LIU Dong, LIU Ruijin
    2022, 43 (7):  1382-1392.  doi: 10.3969/j.issn.1000-2561.2022.07.009
    Abstract ( 82 )   HTML ( 4 )   PDF (2118KB) ( 81 )  

    Strengthening the protection of intellectual property rights of new tropical crop varieties and promoting independent innovation of seed industry are of great significance for maintaining national strategic security and meeting the needs of people’ s better life. In the past 20 years, 20 genera (species) of tropical crops in China have been included in the catalogue of new variety rights protection, and the protection of new varieties of tropical crops has made great progress. Based on the public data of the Science and Technology Development Center of the Ministry of Agriculture and Rural Areas, this paper analyzes the current situations of the protection of tropical crop variety rights in China from different perspectives, such as the gennus or species, types, application or authorization years and breeding subjects of tropical crops, and summarizes and analyzes the problems existing in the protection of tropical crop variety rights in China, which includes weak awareness of protection, difficulty for protection, little number of breeding entities, insufficient innovation ability, and delay in the granting of variety rights. Finally, suggestions were put forward to improve the awareness of variety rights protection, strengthen the infringement attack and technical protection, enhance policy support and funding, reinforce the collection and utilization of tropical crop germplasm resources, and accelerate the construction of new varieties of tropical crops test capacity.

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    Plant Cultivation, Physiology & Biochemistry
    Ammonia Volatilization and Nitrogen Leaching under Specific Cave-applied Nitrogen Fertilization of Rubber Plantation
    WANG Dapeng, MA Zhaona, WU Min, WEI Jiashao, ZHANG Xian, WANG Guihua, ZHAN Shan, CHA Zhengzao
    2022, 43 (7):  1393-1400.  doi: 10.3969/j.issn.1000-2561.2022.07.010
    Abstract ( 93 )   HTML ( 5 )   PDF (1266KB) ( 85 )  

    Both ammonia (NH3) volatilization and nitrogen (N) leaching are important pathways for N loss and a lot of relevant studies have been carried out in agro-ecosystems. At the other hand, the application of N fertilizer has gradually become an important measure to improve the productivity of plantations. It is helpful to understand the process of N cycling in ecosystem by defining the direction and flux of N loss in different plantations under specific climate-soil conditions, which is also an important basis for optimal management of N fertilizer and formulation of emission reduction measures for plantation. Rubber tree (Hevea brasiliensis) is a typical tropical tree cash crop. In order to prevent the runoff loss of nutrients in rubber plantation, management measures of fertilizer cave application were gradually formed in production. However, this locally concentrated fertilization may also cause serious NH3 volatilization and N leaching losses. Due to the high spatial variability of nutrients caused by cave-applied fertilization and lack of quantitative studies on these loss processes, little is known about NH3 volatilization and N leaching loss after N fertilizer application in cave-applied method in rubber plantation. We used vented chamber method and pan lysimeter to study NH3 volatilization and N leaching loss after urea cave application in rubber plantation at levels of 0 kg/hm2 (CK), 100 kg/hm2 (LN), 230 kg/hm2 (MN) and 400 kg/hm2 (HN). The results showed that the loss of NH3 volatilization was completed within 14?20 days in dry season and 7?10 days in rainy season. NH3 fluxes peaked later in dry season, 6-13 days after fertilization, as compared to 1?3 days in rainy season. Compared with the CK, the NH3 volatilization losses were increased to 9.32?21.54 kg/hm2 in the N treatments (LN, MN and HN). N leaching concentrated in the rainy season (May to November), and nitrate leaching was the main process of nitrogen leaching loss. Under specific cave-applied nitrogen fertilization in rubber plantation, N leaching losses was 2.36?9.00 kg/hm2. N fertilization rate increased the NH3 volatilization and N leaching losses. In conclusion, NH3 volatilization potential was low in rainy season due to frequent occurrence of rainfall events. In the dry season, the arid soil conditions prolonged the hydrolysis process of urea and aggravate the loss of NH3 volatilization. The NH3 volatilization has the characteristic of high loss in dry season and low loss in rainy season. The loss of N leaching in rubber plantation varied greatly from year to year, and concentrated in rainy season. The main loss of N leaching was nitrate leaching, and nitrate leaching accounted for 77%?90% of the total N leaching amount. The loss of NH3 volatilization and N leaching in rubber plantation was not high under the unique ecological conditions and special fertilization methods.

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    Integrated Analysis of Soil Fertility Status in the Banana Orchards in China
    ZHANG Jiangzhou, LIU Yanan, GAO Wei, WANG Beibei, RUAN Yunze
    2022, 43 (7):  1401-1410.  doi: 10.3969/j.issn.1000-2561.2022.07.011
    Abstract ( 85 )   HTML ( 6 )   PDF (3245KB) ( 80 )  

    The objective of this study was to investigate the soil fertility status and identify the limiting factors in the banana orchard of China. It can provide important references for putting forward effective management practices to eliminate soil constraint factors and reasonable nutrient management programs. The soil database was established from published studies and soil survey including soil pH, organic matter, available nitrogen (N), phosphorus (P) and potassium (K), exchangeable calcium (Ca) and magnesium (Mg), available iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and boron (B). Referring to the second national soil survey and the classification index of soil nutrient, soil nutrients status of China and characteristics of different banana planting provinces (Hainan, Guangdong, Guangxi, Fujian and Yunnan) were analyzed. The average soil pH, organic matter, available N, P, K, exchangeable Ca, Mg, available Fe, Mn, Cu, Zn and B were 5.3, 14.9 g/kg, 77.3 mg/kg, 96.0 mg/kg, 227 mg/kg, 1039 mg/kg, 102 mg/kg, 169 mg/kg, 41.8 mg/kg, 2.84 mg/kg, 4.82 mg/kg and 1.16 mg/kg. The soil organic matter and exchangeable Mg belonging to the potential deficiency level or below was 86.3% and 60.8%, respectively. 97.1% of soil available N was at the middle level or below. More than 50% soil available P, K and micro-nutrients belonged to very high class. Soil nutrient concentrations and the soil organic matter, macro-medium nutrients, available Mn and B belonging to medium or below class were different in different banana planting provinces. The average soil integrated fertility index (IFI) index of the banana orchard was 0.71 in China. IFI in Fujian was 0.78, which was significantly higher than that of other provinces. IFI of Guangdong (0.71) and Yunnan (0.69) was significantly higher than that of Hainan (0.62) and Guangxi (0.61). IFI below medium class in different provinces was 13.3%?37.1%. The soil available P, K, exchangeable Ca and micro-nutrients (expect available B) was at medium class or above. Soil pH was low, and soil organic matter, exchangeable Mg and available B were at the medium or deficient level, which were the potential limiting factors of soil fertility in the banana orchards of China. Therefore, we should pay more attention to the application of organic fertilizer, magnesium fertilizer and boron fertilizer in banana production. Different banana planting provinces should take corresponding measures to eliminate obstacle factors. It would be helpful to improveing soil fertility of banana orchards, promoting banana yield and quality and the green development of banana industry.

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    Effects of Meteorological Factors on the Emergence Rate and Seedling Growth of Sugarcane
    WU Xuanke, MA Dongchen, HUANG Wei, LIU Yongyu, WEI Jianfeng, YAO Yuqun
    2022, 43 (7):  1411-1416.  doi: 10.3969/j.issn.1000-2561.2022.07.012
    Abstract ( 89 )   HTML ( 8 )   PDF (835KB) ( 78 )  

    In order to investigate the effects of meteorological factors on the emergence rate and growth of sugarcane seedling, two Guangxi master sugarcane varieties, T22 and G42 were selected to carry out sugarcane stage sowing experiment with one stage every half a month from February to May. The emergence rate and the growth status of sugarcane seedling in each stage were determined, and the meteorological factors, i.e., rainfall, average temperature, etc. in the same period were observed, and consequently relevant statistical analysis was performed based on the above data. The emergence rate of sugarcane varieties, T22 and G42, had a significant positive correlation with 20-day accumulated rainfall after sowing, but a non-significant correlation with 10-day accumulated rainfall after sowing. The logarithmic function equation of 20-day accumulated rainfall after sowing and the sugarcane emergence rate further showed that more than 80% of sugarcane seed stem emergence rates, needed more than 75 mm 20-day accumulated rainfall after sowing. The correlations between the plant height and stem diameter of sugarcane seedling at stem elongation stage, and meteorological factors, i.e., average temperature, rainfall and sunshine hours, etc. reached at least 5% significance level, however, stepwise regression analysis indicated that rainfall was the significant independent variable affecting the plant height and stem diameter of sugarcane seedlings. The results inferred that the accumulated rainfall of 10-20 days after sowing was the key meteorological factor determining the key period of sugarcane emergence, and the rainfall was crucial to the seedling growth of sugarcane, and the plant height and stem diameter of sugarcane seedling could be predicted by rainfall. In view of the above research results, in the process of sugarcane production in Guangxi, in order to improve the emergence rate of sugarcane, it is necessary to strengthen the water management within 20 days after sowing. During this period, the accumulated rainfall should be more than 75 mm to achieve the purpose of making sugarcane emergence well. After sugarcane emergence, it is also necessary to strengthen the water management, which is conducive to the rapid growth of sugarcane seedlings, and consequently improve the quality of sugarcane seedlings.

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    Effects of Large Scale Mechanized Sugarcane Harvesting Mode on Soil Physical Properties of Sugarcane Fields and Ratoon Sugarcane Yield
    LIN Zhaoli, ZHANG Hua, QUE Youxiong, WU Yanjing, LI Shiyan, LUO Jun
    2022, 43 (7):  1417-1430.  doi: 10.3969/j.issn.1000-2561.2022.07.013
    Abstract ( 81 )   HTML ( 7 )   PDF (1844KB) ( 92 )  

    The present study aims to clarify the effects of the mechanical harvesting on the soil physical properties of sugarcane fields and ratoon sugarcane yield and to eliminate sugarcane farmers’ concerns about whether the large-scale mechanized harvesting system wouldl cause serious compaction of the sugarcane plough layer. Regarding the red soil slope farmland in Guangxi, two treatments of mechanical harvesting and manual harvesting were set up to determine the effects of mechanical harvesting on the physical properties of plough layer and ratoon sugarcane yield. The results showed that there was no significant difference between mechanical harvesting and manual harvesting in soil bulk density, penetration resistance, shear strength, field moisture capacity and total porosity in the ridge of 0-40 cm layer. In the furrow of 0-20 cm layer, soil compaction, penetration resistance and shear strength significantly increased after mechanical harvesting, while the total porosity and aeration porosity decreased. Compared with manual harvesting, in the process of mechanical harvesting, the walking of the machine compacted the furrow soil, but had no significant impact on the plough layer of the ridge where the sugarcane grows. The soil compaction of the ridge surface had two obviously alternating layers along the vertical gradient, 0-20 cm layer was more compacted by manual harvesting, and 20-40 cm layer was more compacted by mechanical harvesting. The ratoon sugarcane yield after manual harvesting was higher than that after mechanical harvesting in the first year ratoon and the second year ratoon, but the difference was not significant. It also showed that under the permanent raised bed technology, the sugarcane mechanical harvesting has no significant effect on the soil physical properties of the ridge soil and the yield of ratoon sugarcane. The research would provide a scientific basis for standardizing sugarcane harvesting operations and reducing soil compaction of sugarcane field by large-scale machinery.

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    Characteristics of Nutrient Accumulation Distribution and Correlation with Yield Components in Southern Double-season Early Rice Areas under Triple Maturity Pattern
    LI Yufei, FANG Xilin, LIU Yuxi, LIU Peng, YANG Wenju, WANG Yue, CHEN Guanghui
    2022, 43 (7):  1431-1439.  doi: 10.3969/j.issn.1000-2561.2022.07.014
    Abstract ( 45 )   HTML ( 6 )   PDF (1085KB) ( 64 )  

    The tight season of southern double-crop rice stubble convergence under the triple-maturity model is the main problem in coordinating the double-crop rice annual yield increase. Although many previous studies have been done on rice variety pairing and fertilizer utilization under the triple maturity model, few studies have been reported on the correlation between the yield of southern double-season early rice and its nutrient accumulation distribution under the triple maturity model. In order to compare the nutrient accumulation and distribution characteristics of southern double-season early rice, 15 early rice varieties were studied in this paper, and the seedling quality, basic seedling and tiller dynamics, economic traits, nutrient accumulation and distribution, yield and yield components of different rice varieties were compared and analyzed. The results showed that there were significant differences in seedling quality among different varieties, and the leaf age, seedling height and fresh weight of 100 plants of Zhuliangyou 819 were better than those of other varieties, and the seedling quality performed well. The tiller dynamics survey showed that different varieties reached the peak of tillering at different times, among which the peak seedling of ‘Zhuliangyou 929’ was the largest, reaching 6 166 500 stems/hm2, and the difference between the peak seedling of ‘Zhuliangyou 929’ and ‘Zhongzao 39’ was the most significant, with ‘Zhuliangyou 929’ significantly increasing 33.62% compared with ‘Zhongzao 39’. Regarding the accumulation of total nutrients of nitrogen, phosphorus and potassium, the accumulation of nutrients of ‘Zhuliangyou 929’ and ‘Linliangyou 942’ was significantly higher than that of other varieties, 311.88 kg/hm2 and 376.35 kg/hm2respectively. The above-ground dry matter accumulation of ‘Lingliangyou 942’ was the highest, at 12 028.09 kg/hm2. The highest actual yield of 7873.01 kg/hm2 was recorded for ‘Zhuliangyou 929’. The correlation analysis between nutrient accumulation and grain yield of rice varieties at maturity showed that there was a significant positive correlation between nitrogen and phosphorus accumulation and effective spike (r = 0.62*, r = 0.50*), a highly significant positive correlation between plant height and thousand grain weight (r = 0.80**), a highly significant negative correlation between effective spike number and grain number per spike (r = ?0.76**), and a highly significant negative correlation between fruit set and thousand grain weight (r = ?0.76**). (r = ?0.68**). The correlation analysis showed that the overall performance of ‘Lingliangyou 942’ and ‘Zhuliangyou 929’ was significantly better than that of the other varieties. This study has important implications for the screening and efficient cultivation of early rice varieties in southern multi-maturity rice areas.

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    Exogenous Glycine Promotes Pitaya (Hylocereus polyrhizus) Root Growth and Nutrient Absorption
    YANG Yongzhi, GAO Wei, GAO Xiang, ZHONG Long, LI Ju, WANG Chaobi, WANG Tingzhong, ZHANG Ke, RUAN Yunze
    2022, 43 (7):  1440-1449.  doi: 10.3969/j.issn.1000-2561.2022.07.015
    Abstract ( 74 )   HTML ( 8 )   PDF (3690KB) ( 72 )  

    Root is important organ for plant nutrient absorption. Controlling the absorption of water and nutrients greatly affects the yield of crops. Therefore, the establishment of a large and healthy root network is of decisive significance for promoting crop production. Pitaya (Hylocereus polyrhizus) is a perennial climbing plant belonging to the cactus family and the genus Hylocereus, with high nutritional value and commercial value. Pitaya is a shallow-rooted crop, and the root system is one of the important factors that determine plant growth. The growth of the root system also determines the yield of the crop. With the rapid expansion of dragon fruit planting areas in tropical areas, research on the absorption of nitrogen by dragon fruit roots is still very scarce. Amino acid nitrogen is an important nitrogen source for plants and plays an important role in improving root growth and fruit quality. However, there is no relevant report on how exogenous amino acid nitrogen affecting pitaya root growth and nutrient absorption. In this study, pitaya Ruanzhi was used as the research object. Under hydroponic conditions, the effects of different exogenous amino acid nitrogen (glycine, glutamic, arginine) on the root system and nutrient absorption of pitaya seedlings were analyzed. Meanwhile, the most suitable type of exogenous amino acids for the growth of pitaya were explored. The results of the study showed that under the conditions of glycine treatment, the aboveground biomass and lateral branch length of dragon fruit seedlings was 18.12 g/plant and 59.0 cm, respectively, which were significantly higher than that of inorganic nitrogen (NH4++ NO3?), glutamic acid and arginine. The nutrient absorption of the above ground was also significantly affected by the types of amino acids. The absorption of nitrogen, phosphorus, potassium and trace elements in the treatment of glycine was significantly higher than that of other treatments. In the underground part, compared with glutamic acid and arginine, glycine treatment significantly promoted the growth of roots. The total root length and root surface area of seedlings reached 2578 cm/plant and 401 cm2/plant, respectively, but lower than that of the control inorganic nitrogen treatment. The transmittance of FTIR spectra of pitaya seedling roots treated with glycine was higher than that of other treatments at the wave numbers of 1604 cm?1 and 1380 cm?1. The content may be caused by the redistribution of nitrogen to the aboveground. In summary, compared with glutamate and arginine, glycine can significantly promote the root growth of pitaya at the seedling stage, resulting in increased above-ground biomass and nutrient absorption.

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    Effects of Different Forms and Ratios of Nitrogen on Yield and Quality of Leaf-vegetable Sweet Potato Stem Tips
    LI Chengyang, CHAI Shasha, LIU Yi, Soviguidi Deka Reine Judesse, WANG Lianjun, LEI Jian, CHENG Xianliang, YANG Yuanyuan, YANG Xinsun, ZHANG Wenying
    2022, 43 (7):  1450-1458.  doi: 10.3969/j.issn.1000-2561.2022.07.016
    Abstract ( 72 )   HTML ( 9 )   PDF (3414KB) ( 64 )  

    This study was conducted to solve the problems of low yield, poor quality, and ecological environment deterioration caused by unreasonable fertilization in the planting process of leaf-vegetable sweet potato. As the main part of agricultural fertilizer input, nitrogen fertilizer is an important factor affecting the yield and quality of leaf-vegetable sweet potato. The response mechanism of yield and quality of leaf-vegetable sweet potato to nitrogen form ratio was revealed by setting different nitrogen form ratio treatments and according to the changes of related indexes of yield and quality of leaf-vegetable sweet potato stem tip. It provides a theoretical basis for reasonable fertilization to improve the yield and quality of leaf-vegetable sweet potato and reduce environmental pollution caused by unreasonable fertilization. This study was a field experiment. Two main leaf-vegetable sweet potato varieties, ‘Fushu 18’ and ‘Eshu 10’, were used. A field experiment with the two-factor split-plot experiment design with five treatments was conducted: (1) NH4+-N∶NO3--N∶CONH2-N = 1∶1∶1 (N1); (2) NH4+-N∶NO3--N∶CONH2-N = 1∶0 ∶2 (N2); (3) NH4+-N∶NO3--N∶CONH2-N = 2∶0 ∶1 (N3); (4) NH4+-N∶NO3--N∶CONH2-N = 1∶2 ∶0 (N4); (5) NH4+-N∶NO3--N∶CONH2-N = 2∶1∶0 (N5). The results showed that N4 and N5 treatments significantly increased shoot tip yield, total phenol content, total flavonoids content, soluble sugar content, PAL activity and IbPAL gene expression of leaf-vegetable sweet potato. There were significant differences between different treatments in the same period. With the continuous progress of the growth period, the changes of various indicators showed a trend of increasing first and then decreasing. Among them, the effect of N4 treatment was more significant. Except the soluble sugar content was the lowest under N3 treatment, the other indicators were the lowest under N2 treatment. The correlation analysis confirmed that total phenols, total flavonoids, soluble content and PAL enzyme activity were positively correlated with IbPAL gene expression, while the soluble sugar content was negatively correlated with gene expression, indicating that the change of soluble sugar content was not correlated with IbPAL gene expression. It can be seen from the treatment of nitrogen morphology ratio that N4 and N5 treatments provided more NO3--N for plants than N2 and N3 treatments, suggesting that NO3--N played a more important role in promoting the growth and development of leaf-vegetable sweet potato, but the effect of CONH2-N on yield and quality of sweet potato was not prominent in this experiment. N4 treatment (NH4+-N∶NO3--N∶CONH2-N = 1∶2∶0) was the best combination to promote the yield and quality of leaf-vegetable sweet potato. The results of this study could provide a theoretical basis for reasonable fertilization to obtain ideal crop yield and quality, and provide reference for related research on other crops.

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    Comparative Analysis of Pollen Viability and Stigma Receptivity of Five Bougainvillea Cultivars
    DU Xuelin, LIU Yueming, HUANG Zifeng, LIU Huiya, HU Zhiren, LI Zhimei, WANG Fenglan
    2022, 43 (7):  1459-1466.  doi: 10.3969/j.issn.1000-2561.2022.07.017
    Abstract ( 211 )   HTML ( 4 )   PDF (3404KB) ( 65 )  

    The purpose of this study was to investigate the pollen viability and stigma receptivity of different varieties of Bougainvillea so as to improve the hybridization efficiency. Using five Bougainvillea varieties including B. glabra ‘Mrs Eva’, B. glabra ‘Sao paulo’, B. glabra ‘Mrs Eva White’, B. × buttiana ‘California Gold’ and B. × buttiana ‘Afterglow’ as test materials, the pollen viability was tested by FDA and liquid culture medium methods, and effects of different preservation methods on pollen viability were explored. The stigma receptivity of five Bougainvillea cultivars was analyzed by benzidine- hydrogen peroxide method. The results showed that: (1) 0.01% FDA staining solution could stain all varieties. The pollen viability of B. glabra ‘Mrs Eva White’ was the highest (27.16%), followed by B. glabra ‘Mrs Eva’ and B. glabra ‘Sao paulo’, which were 13.98% and 11.86%, respectively. The lowest pollen viability of B. × buttiana ‘Afterglow’ and B. × buttiana ‘California Gold’ were 7.17% and 4.01%, respectively. (2) Pollen viability of five cultivars differed significantly under different storage conditions. Under the condition of drying and preservation at 28℃, the order of vigor of each variety was B. glabra ‘Sao paulo’ > B. glabra ‘Mrs Eva’ > B. glabra ‘Mrs Eva White’ > B. × buttiana ‘Afterglow’ > B. × buttiana ‘California Gold’. Under the condition of 4℃ refrigerator, the order of vitality of each variety was B. glabra ‘Mrs Eva’ > B. glabra ‘Mrs Eva White’ > B. glabra ‘Sao paulo’ > B. × buttiana ‘California Gold’ > B. × buttiana ‘Afterglow’. (3) The pollen germination rates of five varieties were all low after 12 hours of culture in liquid medium. The pollen germination rate of B. glabra ‘Sao paulo’ was relatively high (4.50%), B. glabra ‘Mrs Eva White’ and B. glabra ‘Mrs Eva’ followed with 2.78% and 2.51% respectively. B. × buttiana ‘California Gold’ and B. × buttiana ‘Afterglow’ had the lowest germination rates (0.98% and 0.08%, respectively). (4) There were significant differences in stigma acceptability among five cultivars. The stigma acceptability of B. glabra ‘Sao paulo’ and B. glabra ‘Mrs Eva’ was better, followed by B. glabra ‘Mrs Eva White’, but the stigma acceptability of B. × buttiana ‘California Gold’ and B. × buttiana ‘Afterglow’ was lower. In conclusion, three Bougainvillea varieties, such as B. glabra ‘Sao paulo’, B. glabra ‘Mrs Eva’ and B. glabra ‘Mrs Eva White’ are suitable as parent materials in cross breeding.

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    Tissue Culture with Two Different Organs of Aquilaria sinensis
    ZHANG Yan, MENG Hui, LYU Feifei, WEI Jianhe, FAN Xiaohong, HE Xin, YUAN Baixue, CHEN Bo, YANG Yun
    2022, 43 (7):  1467-1476.  doi: 10.3969/j.issn.1000-2561.2022.07.018
    Abstract ( 69 )   HTML ( 7 )   PDF (1203KB) ( 93 )  

    Agarwood, Aquilaria sinensis (Lour.) Gilg, is one of the most famous medicinal and spice resources in the world. In many Asian countries, the agarwood industry is both a traditional and rapidly developing emerging industry. As we all know, the large-scale application of high-quality agarwood germplasm resources is of great significance for the sustainable development of the agarwood industry. Therefore, high quality agarwood germplasm resources have been the focus and hotspot of the agarwood industry in recent years. However, the characteristics of some high quality germplasm cannot be inherited through sexual reproduction, and the technical barriers for large-scale breeding exist in now. Tissue culture has outstanding advantages in aspects of maintaining excellent traits of varieties, preservation of seed resources, and rapid propagation, which is widely used in Chinese medicine resources conservation and traditional Chinese medicine industry development. In order to establish a broad-spectrum agarwood regeneration system for industrial production, aseptic seedlings and mature plant branches were used to plant regeneration techniques research from explant disinfection, cluster bud induction and rooting culture in this study. The results showed that the tender stems picked in the field were effectively sterilized by soaked in 0.1% carbendazim solution for 3 min and rinsed with flowing water for 3 h. The survival rate of explants could be maintained by disinfecting with 0.1% mercury liter solution for 6~8 min. In addition, appropriate addition of sterilizer into the culture medium could also control material contamination effectively. The stems of aseptic seedlings were easier to induce new buds, while the stems of branch were more difficult to induce secondary shoots as explants. The multiple shoots of aseptic seedlings could induced in WPM medium supplemented with 0.5 mg/L 6-BA, 0.2 mg/L NAA and 20 g/L sucrose (G4). The three advisable multiplication media for branches were 1/2 MS + 25 g/L sucrose + 2 mg/L 6-BA + 0.01 mg/L NAA (I3), 1/4 MS+20 g/L sucrose + 2 mg/L 6-BA + 0.5 mg/L NAA (J2) and WPM + 20 g/L sucrose + 1 mg/L 6-BA + 0.01 mg/L NAA (K2). Then the enlarged clump bud clusters were cut and transferred to WPM medium without plant growth additives which helped grow buds to become rootless shoots. New shoots could be induced to root in the WPM medium with adding 20-30 g/L sucrose 0.1-0.2 mg/L NAA. In this paper, two explants of agarwood were used for tissue culture and successfully obtained regenerated plants, which provided a technical reference for the asexual reproduction of high-quality agarwood germplasm.

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    Effect of Exogenous NO on the Germination of Eggplant (Solanum melongena cv. Yanzhiqie) Seeds and the Physiological Characteristics of Seedlings under Low Temperature Stress
    CHEN Yaoyao, YAN Liangwen, LIU Zhicheng, ZHENG Zuoyun, YU Jie, CHEN Pingping, JIANG Wei
    2022, 43 (7):  1477-1484.  doi: 10.3969/j.issn.1000-2561.2022.07.019
    Abstract ( 64 )   HTML ( 3 )   PDF (900KB) ( 88 )  

    Seeds and seedlings of Solanum melongena cv. Yanzhiqie, a local eggplant cultivar in western Fujian, were soaked with different concentrations of (0, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.5 mmol/L) for 6 hours, respectively cultured in dark at 28℃ and 4℃ for 3 days and then transferred to an incubator for conventional culture and germination, and the germination indicators of each treatment were statistically analyzed. The leaves of S. melongena cv. Yanzhiqie seedlings were pretreated with different concentrations of SNP (0, 0.1, 0.3, 0.5, 0.8, 1.0, 1.2, 1.5 mmol/L) for 3 days and subjected to low temperature stress at 10℃ / 5℃. The effects of exogenous nitric oxide (NO) pretreatment on the germination of seeds, and growth and related physiological and biochemical characteristics of seedlings were studied by determining plant height, stem diameter, fresh weight, and dry weight of seedlings, activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and contents of soluble protein, proline, and malondialdehyde (MDA) in leaves. The germination percentage, germination energy, germination index and vigor index of S. melongena cv. Yanzhiqie seeds increased firstly and then decreased with the increase of SNP (an exogenous NO donor) concentration, and all indicators of seed germination reached the maximum at 0.2 mmol/L, and decreased at > 0.5 mmol/L.Pretreatment with low concentration (0.1-1.0 mmol/L) of SNP could increase plant height, stem diameter, fresh weight and dry weight of S. melongena cv. Yanzhiqie seedlings, increase the contents of soluble protein and proline in leaves, improve the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and decrease MDA accumulation in leaves, The CAT activity was the highest at 0.5 mmol/L, and other indicators were optimal at 0.8 mmol/L. High concentration of SNP inhibited all indicators. The above suggests that pretreatment with low concentration of SNP could effectively promote the germination of S. melongena cv. Yanzhiqie seeds and growth of seedlings under low temperature stress, while high concentration cause damage. The results of this study would provide a theoretical basis for the proper use of exogenous NO to promote the germination of S. melongena cv. Yanzhiqie seeds and the growth of seedlings, and are of reference value for effectively protecting eggplants from low temperature damage in western Fujian.

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    Plant Protection & Bio-safety
    Resistance Evaluation of Main Leaf Diseases and Smut Diseases in 274 Commonly-used Sugarcane Parents
    HUANG Hairong, XU Lin, LI Xiang, YAN Meixin, YANG Rongzhong, LEI Jingchao, DENG Yuchi
    2022, 43 (7):  1485-1496.  doi: 10.3969/j.issn.1000-2561.2022.07.020
    Abstract ( 66 )   HTML ( 5 )   PDF (1098KB) ( 89 )  

    Sugarcane parental screening and utilization is a key factor of sugarcane variety breeding. Many researches were focused on single character evaluating in sugarcane parental resources, while few were studied on comprehensive diseases evaluating. To understand the resistance of sugarcane parents, and select parent for hybrid combination, 274 commonly-used sugarcane parents, including 15 from the United States (US), 31 from other countries (GW), 25 from Taiwan, China (TWCHN), 92 from mainland China (GN) and 111 form Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences (GT) in Hainan Sugarcane Hybrid Base, Guangxi Academy of Agricultural Sciences, were investigated by the incidence of sugarcane smut disease and evaluated 1-9 grade levels for disease resistance (1-3 grade for Resistance, 4-6 grade for Medium and 7-9 grade for sensitive) by visual evaluation on leaf scald disease, leaf scorch disease, red rot disease, ring spot disease, mosaic disease, yellow leaf disease, pokkah boeng disease and yellow spot disease of 8 main leaf diseases in China. Grey correlation degreed analysis and Fuzzy clustering were used to analyze the correlation relationship of Brix between smut disease and 8 main leaf diseases, and to evaluate the resistance of comprehensive diseases for sugarcane parents. Ring spot disease was the most popular in Guangxi commonly-used sugarcane parents by incidence of 78.10% and 214 parents were infected, but only 9 parents were in 7-9 grade disease resistance which was belonging to less harmful disease. Leaf scald disease, pokkah boeng disease and yellow spot disease were least infecting the parents. The parents from US and TWCHN were the most important parents for breeding in mainland China and had been used to breed many excellent progenies. US parents got the highest frequency of leaf scald, leaf scorch and yellow leaf disease by 20.00%, 33.33% and 33.33%, respectively. TWCHN parents had higher frequency rate on ring spot disease, yellow leaf disease and leaf scorch disease. GT and GN parents were belonging to the medium level in disease incidence, but ring spot disease incidence rate of GT parents was 80.18%. Smut disease was the most harmful disease in mainland China. The incidence frequency rate of smut disease of 15 US parents was 13.33% and the highest was 2.17%, belonging to popular infection but slight harm. However, TW parents were the highest in maximum incidence by 10.00% and highest frequency of 24.00% in all the parent regions. Brix was the highest by 0.960 in grey correlation degreed with pokkah boeng diseas, but the lowest by 0.711 with smut disease. Weighted grey correlation degreed analysis, a mathematical assessment model containing many factors, is effective to evaluate the comprehensive properties of crops or things. F171, Tai98-2817, RB92-579, YuanL7, YueY R1, GF2, GT03-1462 and GT08-120 showed high weighted correlation degreed and good disease resistance, and YZ99-596, CP01-1178, YunY06-450, CP94-1100 and CP09-4256 showed poor disease resistance. The 274 sugarcane parent could be classified into six groups by Fuzzy clustering on the incidence of smut disease and 8 leaf diseases. The comprehensive evaluation for the commonly-used sugarcane parent could be used to select parents for sugarcane hybrid with high disease resistance.

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    Screening of Fungicides for Sugarcane Smut and Yield Evaluation
    YAN Meixin, ZHANG Xiaoqiu, WANG Zeping, LEI Jingchao, HUANG Hairong, HUANG Weihua, CHEN Xiaohang, QIN Xingyun, HUANG Hai, HUANG Dongmei, LI Qiufang, SONG Xiupeng
    2022, 43 (7):  1497-1507.  doi: 10.3969/j.issn.1000-2561.2022.07.021
    Abstract ( 68 )   HTML ( 6 )   PDF (1467KB) ( 84 )  

    Sugarcane smut caused by Sporisorium scitamineum is the most harmful disease during sugarcane growth period in China, which causes serious yield and economic losses to sugarcane industry. Chemical control is one of the important measures for the comprehensive control of the diseases. It is of great significance for the effective control of sugarcane smut and improving sugarcane yield by screening high-efficiency, low toxicity and low residue chemicals against sugarcane smut in the field. In order to recommend fungicides for the chemical control of sugarcane smut in the field, the inhibitory effect of 11 fungicides on S. scitamineum was tested by the bioactivities assay. The antifungal mechanism of effective fungicides was analyzed by scanning electron microscope. The control effect of fungicides to sugarcane smut and the effects on the main agronomic characters of sugarcane including yield per hecta, plant height, stalk diameter, brix, effective stalks per hecta and stalk weight were evaluated through chemical control tests of sugarcane smut for new plant cane and ratoon cane in the field. The results showed that four fungicides were obtained by bioactivities assay to inhibit the haploid growth, sexual mating and teliospores germination of S. scitamineum, which were 42.4% pyraclostrobin·fluxapyroxad SC, 75% tebuconazole·trifloxystrobin WG, 250 g/L pyraclostrobin EC and 325 g/L difenoconazole·azoxystrobin SC. Scanning electron microscopy assay showed that the four effective fungicides destroyed cell tissues of teliospores and haploid conidia of S. scitamineum and caused inactivated sugarcane smut fungus. In the chemical control experiment of sugarcane smut for plant cane in the field, the control effects of fungicide 42.4% pyraclostrobin·fluxapyroxad SC, 75% tebuconazole·trifloxystrobin WG, 250 g/L pyraclostrobin EC and 325 g/L difenoconazole·azoxystrobin SC was 91.81%, 82.84%, 81.76% and 70.92%, respectively. The yield in chemical treatment area increased by 20.84%, 17.13%, 15.92% and 13.35%, respectively, compared with the control. In the experiment of chemical control of sugarcane smut for ratoon crop, the control effects of the above fungicides was 89.35%, 82.21%, 81.51% and 70.18%, respectively, and the yield in chemical treatment area increased by 30.15%, 24.05%, 20.33% and 16.58%, respectively, compared with the control. Other agronomic characters of sugarcane for new plant and ratoon cane in sugarcane smut chemical treatment area were better than those in the control area. The four tested fungicides had good control effect on sugarcane smut and increasing sugarcane yield. They can be used as recommended fungicides for chemical controlling sugarcane smut in the field.

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    Control Effect of 2% Clothianidin Granule and Sex Pheromone on Chilo sacchariphagus Bojer in Fruit Sugarcane Field
    FU Jiantao, AN Yuxing, LU Yinglin, LI Jihu, LIU Jingye, CHEN Lijun, DAI Sixing, SUN Donglei
    2022, 43 (7):  1508-1515.  doi: 10.3969/j.issn.1000-2561.2022.07.022
    Abstract ( 49 )   HTML ( 4 )   PDF (1280KB) ( 63 )  

    Fruit sugarcane is a characteristic fruit in South China. Chilo sacchariphagus Bojer is one of the most important pests of fruit sugarcane, which seriously affects the yield and quality. Pesticide control is the most important technical means at present, but the application of a large number of chemical pesticides not only harms the environment, but also causes safety risks to human health. In order to promote the reduction and efficiency of chemical pesticides and the green development of fruit sugarcane, this study established a technical model of “2 % clothianidin granules + sex pheromone” based on the prediction and prediction technology of C. sacchariphagus Bojer in fruit sugarcane field. The field experiments were carried out in Dongchong Town and Lanhe Town, Nansha District, Guangzhou, in 2019. The results showed that the prediction results of sex pheromone were consistent with the artificial investigation, but the peak of mosaic rate was 7 to 10 days behind the peak of moth-trapping population. 30 days after treatment with 2% clothianidin granules at seedling stage, the dead heart rate was 0.47%±0.04% in Dongchong town, 0.66%±0.23% in Lanhe town, and 5.03%±3.09% in control group, respectively. The control effects of 2% clothianidin granules on dead heart rate at seedling stage was 90.60%±0.85% and 86.88%±2.69% in Dongchong Town and Lanhe Town, respectively. Plant in Dongchong Town and Lanhe Town after 15 days was 86.52%±2.56% and 89.64%±3.00%, respectively, and the control effect on stem borers was 77.48%±7.97% and 89.64%±2.38%; there was also no significant difference between Dongchong Town and Lanhe Town treatment groups. The final investigation before the harvest showed that the control effect of damage plant in Dongchong Town and Lanhe Town was 75.44%±3.56% and 82.63%±5.13%, respectively, and the control effect of the damage nodes was 74.08%±11.00% and 78.84%±6.44%, respectively. The results showed that the “2% clothianidin granule + sex attractant” technology model had a good control effect on C. sacchariphagus in Nansha, Guangzhou, which would provide technical reference for the prevention and control of cane borer and the reduction and efficiency of pesticide.

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    Distribution and Ecotoxicological Risk of Polycyclic Aromatic Hydrocarbons in Biochar Prepared from Tropical Agricultural Wastes
    TAN Huadong, ZHANG Xiaoying, WU Chunyuan, ZHAO Shuqiao
    2022, 43 (7):  1516-1526.  doi: 10.3969/j.issn.1000-2561.2022.07.023
    Abstract ( 63 )   HTML ( 4 )   PDF (1928KB) ( 61 )  

    In order to replenish the data on safe biochar utilization as originated from tropical agricultural wastes, biochar was prepared at 300, 500 and 700℃ from typical tropical agricultural wastes, including pineapple leaves (PL), litchi sticks (LS), coconut shells (COS), banana stems (BS), rice straws (RS), cassava stems (CAS) and mushroom residues (MR). The distribution characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in biochar were determined by QuEChERS, coupled with gas chromatography-mass spectrometry (GC-MS). Furthermore, the key influencing factors of the PAHs were analyzed by redundancy analysis, based on biochar’s physicochemical properties and preparation temperatures. Then, the ecotoxicological risks of the PAHs were evaluated based on risk quotient method (RQ). The results depicted that the concentration of PAHs was 1217.6 to 9547.1 μg/g, with naphthalene (NAP) and phenanthrene (PHE) having the highest detection frequency and level. The arranged concentration level of PAHs was BS>PL>LS>RS>COS>MR>CAS. The main species of the biochar PAHs were significantly different, which was relative to their source and temperature. Redundancy analysis determined that the conductivity (EC), carbon oxygen ratio (C/O), and carbon-hydrogen ratio and temperature had a significant influence on the concentration of PAHs (P<0.01). PAH content was positively correlated with electric conductivity (EC) and carbon oxygen ratio (C/O), and was negatively correlated with hydrocarbon ration (C/H) (P<0.05). Likewise, it was significantly affected by temperature (P<0.01). Risk assessment results depicted that low-ring PAHs contributed to the toxicity of PAHs; thus, the carcinogenic and toxic effects of individual PAHs could be ignored. Except for NAP, the RQ values of the other monomer PAHs were less than 0.1, indicating that no high and medium ecological risks had occurred. However, the total RQ of the PAHs was higher than 1, denoting that greater attention should be paid to the multi-residues of PAHs in biochar. The results of this study could provide a scientific basis for the safe use of biochar in tropical soils.

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