A pot experiment with the same nitrogen level was carried out to analyze the root morphological and physiological properties which affecting the nitrogen uptake efficiency of 20 arabica coffee genotypes to understand the characteristic of nitrogen uptake and to provide a material basis for the selective breeding. There were no significant difference in chlorophyll content, nitrate reductase activity (NRA), nitrogen content in root (NCR), nitrogen content in stem (NCS), nitrogen content in leaf (NCL) among most genotypes. There existed rather weak correlation among chlorophyll content, NRA, N accumulation in leaf (NAL), N accumulation in total (NAT) and N uptake rate (NUR). Root length, root volume and root surface area were positively correlated with root nitrogen accumulation, NAT and NUR. The nitrogen distribution order was NCR>NCL>NCS. Cluster analysis demonstrated that the highest NUR was ‘M13’ (84.43%), the lowest was ‘CATUAI’ (32.12%), and the rest was 58.36%-43.08%.
In order to realize the intelligent assessment of fruit yield, this paper carried out an research on the fruit recognition of Shengxin mango image in natural environment, and proposed an online method of recognition and counting with deep learning of mango images. Firstly, the recognition algorithm for mango image was realized using the Faster R-CNN Model, a deep learning framework. Secondly, an upload module for mango images based on Wechat applet and Web platform was developed, which can upload images to a server at all times and places. Thirdly, a server-client communication mode based on the TCP protocol and the Faster R-CNN assembly in MATLAB were adopted to construct an online analysis module, which realized the real-time and online recognition and counting for mango images. Finally, the recognition and counting results for a single picture, or all pictures in an orchard, were feedback to users through the Wechat applet program and Web page program, including the classification statistics of green mango and red mango. A total of 125 mango images in natural environment had been collected and analyzed using the method proposed in the paper. The results showed that the correct recognition and counting rate of mango fruit was 82.3%, among which the rate of missed detection and error detection was 11.7% and 8.6%, respectively, the average counting error was 4.2 and the average counting error rate was 7.9%. The experimental results demonstrated that, the method proposed in the paper was able to provide a scientific decision-making basis for the wisdom management of orchards through results quantity analysis obtained by images recognition and counting.
Four treatments (without residues (CK), adding Sesbania residues (S), adding Trifolium repens residues (W) and adding banana residues (B)) by the thermostatic indoor incubator method were conducted to identify the effects of leguminous green manure residues on the soil fertility of continuous cropping banana plantation. The change of soil physical and chemical properties, cultivable microorganisms after adding plant residues were investigated. Adding plant residues of Sesbania (S), T. repens residues (W) and banana (B) could improve the amount of cultivated Fusarium oxysporum, fungi and bacteria on the fifth day of incubation, compared with K. However, the number of F. oxysporum declined after adding S, W 45 days after. Compared with B, S and W could reduce the amount of F. oxysporum by 33.09% and 79.92%, respectively. Compared with CK and B, S pH significantly decreased, while pH and available potassium content significantly increased in W. The principal component analysis (PCoA) and multiple regression tree analysis (MRT) showed significant difference in S and W with CK, indicting that the soil fertility could be improved by applying legume green manure residues. Therefore, we can improve the soil physical and chemical properties, and the soil microbial cultivability to alleviate the continuous cropping obstacle of banana by intercropping T. repens in banana fields.
A field trial was conducted to select the milk vetch varieties suitable for Fujian and breed new varities by comparing the economic characteristics, phenological period and resistance of ten local Chinese milk vetch cultivars.The results indicated that Xinyang, Dawu, Xiangxiang and Glossy species were early manuring milk vetch cultivars grown in Fujian, and the fresh grass yield of the varieties was 44 225.59 kg/hm 2, which was lower than that of medium and late maturing varieties. The fresh grass yield and seed yield of Dawu were higher, reaching 48 015.75 and 342.04 kg/hm 2, respectively, and it was cold-resistant and disease-resistant, so it could be used as an excellent early-maturing variety. In addition, the average yield of the medium and late maturing varieties was 52 600.43 kg/hm 2. In terms of the grass yield, different varieties followed the orders of Yujiang Daye>Nanqiao species>Shengzhong species>Jinsha species>Changde species>Yijiang Species.Moreover, higher plant height, stem diameter, leaf area, leaf circumference, and the fresh grass yield were generally observed. Additionally, leaf area and leaf circumference were significantly (P<0.05) positive correlation, but no significant correlation existed between leaf area, leaf circumference and chlorophyll SPAD value. The medium and late-maturing varieties including Zhongshengzhong, Yujiang big leaf and Jinsha species had stronger cold resistance and disease resistance, higher nitrogen (2.85%-3.00%), phosphorus (0.31%- 0.34%) and potassium (3.11%-3.85%) contents than those of the other varieties. At the maturity stage, the medium and late-maturing varieties had higher seed number (7.34-7.85) per pods, 1000-grain weight (3.35-3.42 g), and seed yield (333.01-346.52 kg/hm 2) were also observed. In general, the three medium- and late-maturing varieties of Shengzhong, Yujiang and Yesha species exhibit excellent characters as green manure in Fujian, and thus can be used as the propagation of improved varieties and breeding materials.
One of the main factors affecting the growth of D. huoshanense is the physical and chemical properties of substrates. The objective of this study was to investigate the effects on the growth performance of D. huoshanense when using the spent mushroom substrate (SMS) of P. geesteranus to replace part of the pine bark. D. huoshanense were grown in nine matrix containing SMS and mushroom substrate compost (SMC) or not during different period. The proportion of SMS in the mixtures elaborated with pine bark was 25%, 50% and 75% V/V residue, while the proportion of SMC was 25%, 50%, 75% and 100%. A substrate of 100% pine bark was used as the control in each experiment. Prior to cultivating, some physicochemical properties of the growing media were determined and the growth index of P. geesteranus were also measured after the cultivation. The gas permeability of both the SMS and SMC was good for the growth of P. geesteranus. Compared to SMS, the pH and conductivity of SMC extremely increased, which seriously affected the survival rate of P. geesteranus. The total porosity and water holding porosity of SMS mainly affected the survival rate and root length. There was no negative effect on the growth of P. geesteranus when the substrate of bark was substituted with 50% SMC or 25% SMS, and the growth indexes such as leaf number, plant height, root development and survival rate were even better than that grown in bark. However, when the substitution rate of SMS or SMC exceeded 50%, the matrix would be linked to higher pH, conductivity, water holding porosity, and total porosity which was not suitable for the growth of P. geesteranus. Therefore, SMS and SMC could be used to replace bark partially in P. geesteranus cultivation, but the amount should not exceed 50%.
Ploidy of rubber tree germplasm in the Rubber Tree Germplasm Repository and the ratio of tetraploid cells in chimeras were analyzed by flow cytometry, and the stomatal traits of different ploidy were analyzed. Eleven triploids and one tetraploid were found from 5177 1981’IRRDB germplasms, nine triploids and two tetraploid and fourteen chimeras were found from 552 Wickham germplasms. The ratio of tetraploid cells in fourteen chimeras ranged from 49.06% to 78.26%. The difference of stomatal length, stomatal width, and stomatal density between different ploidy was significant (P<0.01), the rank of stomatal length and stomatal width was tetraploid>triploid>chimeras, while the stomatal density was reversed. This study was valuable for the use of tetraploid germplasm resources for cross breeding between the ploidy of rubber trees.
The effect of regeneration population on the genetic integrity of sesame germplasm was studied to determine the appropriate population size and provide theoretical references for germplasm renewal and reproduction.The genetic parameters of two different types of sesame germplasm including released cultivar and local germplasm were analyzed using SRAP markers. (1) Released cultivar: Seven gradients of population size including 10, 15, 20, 25, 30, 35 and 40 were selected randomly. 24 pairs of primers were co-amplified to 525 loci, with an average of 21.88 loci per primer pairs, including 24 polymorphic loci, accounting for 4.57% of the total locus. With the increase of population size, the total amplification loci and genetic similarity coefficient increased, and the ratio of polymorphic loci and genetic distance increased and then decreased. When the population size reached 35-40 plants, the genetic similarity coefficient reached a certain high value (0.998 73 and 1.000 00), and the genetic distance decreased to a certain degree (0.000 64 and 0.000 00). The clustering results showed that the populations with 35 and 40 were closely clustered. So the genetic integrity could be maintained when the population size of released cultivar reached 35-40. (2) Local germplasm: Eleven gradients of population size including 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 were selected randomly. 24 pairs of primers were co-amplified to 552 DNA locus, with an average of 23.00 locus per primer pairs, and including 44 polymorphic loci, accounting for 7.97% of the total loci. With the increase of population size, the total amplification loci fluctuation increased, and the ratio of polymorphic loci and genetic distance first increased, then decreased and then slightly changed. With the increase of population size, the genetic similarity coefficient first decreased, then increased, then slightly decreased and then rose again, and reached the maximum value of 0.99758 when the population size was 40 and 60 plants. The clustering results showed that the populations of 50, 55 and 60 plants were closely clustered. So it could be considered that the genetic integrity of local germplasm could be maintained when the reproductive population reached 50-55 plants. (3) In the regenerating of sesame germplasm, different germplasm types should have different population size to maintain the genetic integrity because of the different genetic purity.
Taking middle-aged PR107 and Reyan 7-33-97 as the research objects, treatment with five stimulation time (1, 2, 3, 4, 5 d before tapping) was set up, and the effects on the latex yield under the d6 tapping system were compared. The d4 tapping system was used as the control, and six treatment of the d6 tapping system with different stimulation intensity (including four concentrations of ethephon and three simulation frequencies under the highest concentration) was set up on the middle-aged PR107 and Reyan 7-33-97. The yield, latex physiology and the occurrence of TPD were analyzed. The optimal latex yield was obtained when ethephon was applied on the 2nd day after the last tapping or the 2nd to 3rd day of the first tapping in one stimulation cycle. The rubber-producing potential of the d6 tapping for middle-aged PR107 was difficult to be exploited through moderate stimulation. The stimulation strategy of 4% ethephon combined with 2 or 3 tapping intervals of stimulation frequency was able to obtain relatively good yield and physiological effects. While the d6 tapping system was practical in Reyan 7-33-97, the low stimulation intensity of 2.0%-2.5% ethephon combined with 2 or 3 tapping intervals of stimulation frequency could achieve a high yield, and maintain a good physiological response of laticifer. Annual variation of dry rubber yield (kilogram per tree per tapping, kg/t/t) showed that the d6 tapping system had an obvious high-yielding period (after Oct.) and the mean dry rubber yield (kg/t/t) in high-yielding months accounted for 3.0% to 4.8% of the annual production. Therefore, to ensure the tapping number in high yield period is key for a stable yield of the d6 tapping system.
Two wild alfalfa resources (Medicago lupulina, Medicago sativa) in Yunnan were used to study the effects of acid-aluminum stress on alfalfa seedling growth under water culture. The tolerance of the two alfalfa to acid and aluminum was compared by analyzing the changes of peroxidase and superoxide dismutase activities, root length, plant height, biomass, root vigor, chlorophyll content, malondialdehyde content under single and compound treatment of acid and aluminum. The seedling growth of the two alfalfas was inhibited significantly under acidity treatment. Comparation with pH 7.0 and pH 3.0, the root length, plant height, biomass and root activity of M. lupulina increased less than that of M. sativa. There were significant differences in the indexes for root length, plant height, biomass, root vigor between the two alfalfa resources under aluminum treatment. Seedling growth was seriously reduced with the increase of aluminum concentration. The influences of acidity and aluminum compound treatment on the seedling growth of the two alfalfa were greater than those of either stress in isolation. The growth of the two alfalfa was most severely inhibited under the pH 4.5, Al 3+ 300 mg/L treatment. Under the conditions of acid, aluminum or acid-aluminum stress treatments, the tolerance of M. lupulina to acid, aluminum and acid-aluminum was better than that of M. sativa from the point of view of the indexes of growth or decline of seedling growth, physiological indicators, inhibition rate.
The progeny of three species of Paspalum vaginatum (Sea Isle 2000, Platinum, Salam) treated with 60Co-γ ray irradiation were used as the materials, and the changes of physiological indexes such as relative water content, relative electrical conductivity, proline content, chlorophyll content and root activity were measured under NaCl stress to evaluate and select varieties with strong salt tolerance. The sensitivity of PL-40-8 to salt stress was lower than that of the parental control Platinum (PL-CK). The relative water content, chlorophyll content and root activity of the mutants were significantly higher than PL-CK (P<0.05). The degree of cell membrane damage was less than PL-CK, and the increase in proline produced by salt damage was significantly lower than PL-CK (P<0.05). Therefore, the mutant material could be further selected and promoted as a salt-resistance grass species.
The morphological characteristics of mangrove leaves, the relationship between color characteristic parameters of leaves and chlorophyll content were acquired by the computer vision image processing technology. The leaf morphological characteristics and regression models of leaf color parameters and chlorophyll content were established to provide a theoretical basis for seedling cultivation and nutritional diagnosis. It was reliable to obtain morphological characteristic values of mangrove leaves based on the image processing technology. There were significant differences in leaf morphological characteristics (leaf area, leaf length, leaf width, leaf circumference and leaf morphological factors) among the five mangrove species studied. Rhizophora stylosa and Bruguiera gymnorrhiza had the largest single leaf, followed by Kandeliaobvolata and Aegiceras corniculatum, and Avicennia marina had the smallest leaf. The leaf morphology of A. marina was nearly elliptic. R. stylosa and K. obvolata belonged to long strip type. The leaf morphology of B. gymnorrhiza and A. corniculatum was similar, and the correlation between leaf length and leaf width of R. stylosa was the biggest. The SPAD value and Dualex value of the five different mangrove species were significantly different. Five kinds of color images of mangrove leaves were acquired by a digital camera. RGB was extracted by an image processing software and 28 kinds of color eigenvalues were combined by difference, ratio, standardization and normalization, and the relative content chlorophyll (SPAD value, Dualex 4 value) was analyzed by regression. Statistical test showed that there was extremely significant correlation between B value and SPAD data, (R+B+G)/3, R/B and G/B were significantly correlated with SPAD data, and 18 color characteristic parameters were significantly correlated with Dualex data, among which G-B and G values had the largest correlation coefficient. Therefore, statistical model could be established to estimate the chlorophyll content of mangrove leaves based on the color characteristic parameters, which could provide a theoretical basis and technical support for the detection of mangrove growth, diagnosis of nutritional status and precise management of water and fertilizer.
The identification of differentially expressed genes associated with laticifer differentiation is crucial for understanding the molecular mechanism of laticifer differentiation. The selection of a suitable reference gene is a precondition for accurate gene expression analysis by quantitative real-time PCR (qRT-PCR). In the present study, the expression stability of 22 candidate reference genes were evaluated on the basis of TSA-induced secondary laticifer differentiation using geNorm and NormFinder algorithms. According to the analysis of geNorm and NormFinder, UBC3, UBC4, eIF1Aa were the top three stable genes and ROC3, PTP, CYP2 were the last three stable genes in the process of TSA-induced secondary laticifer differentiation. The expression patterns of HDA1 and HDA2 in TSA treated bark were analyzed based on UBC3, Actin and ROC3 as the reference gene respectively. The results showed that UBC3 could serve as a qRT-PCR reference gene to analyze the gene expression pattern in TSA-induced secondary laticifer differentiation. And ROC3 was not suitable as reference genes for qRT-PCR.
In this study, the effects of different manganese (Mn) levels on the growth, chlorophyll content, secondary metabolites and activities of polyphenol oxidase (PPO) and phenylalnine ammonialyase (PAL) as well as SgPALs expressions were investigated using Stylosanthes (stylo) genotype RY2. Results showed that the chlorophyll concentration, maximum photochemical rate (Fv/Fm), shoot and root dry weight of stylo significantly decreased by 400 μmol/L and 600 μmol/L Mn treatments. The contents of proanthocyanidin, total phenol and tannin increased but the flavonoid content decreased in the leaves ranged from 100 μmol/L to 600 μmol/L. Furthermore, the activities of PAL, except PPO, increased under 400 μmol/L and 600 μmol/L Mn treatments compared to that in the 5 μmol/L Mn treatment. qRT-PCR analysis showed that the expressions of SgPAL3 and SgPAL4 in the leaves were significantly enhanced by excess Mn treatments, in despite of the expressions of SgPAL1 and SgPAL2 were not regulated by Mn. The results suggested that the regulation of the secondary metabolites through SgPALs mediated phenylalanine pathway might be involved in the response to Mn toxicity in stylo. The study would provide an important basis for exploring the mechanisms of stylo in response to Mn toxicity.
In order to explore the floral fragrance genes and develop ideas for molecular breeding of floral fragrance of orchid plants, the petals of Sedirea japonica were used as the experimental materials, and primers were designed according to the HMGR gene sequence of orchid plants registered in NCBI. The 3-hydroxy-3-methyl-glutaric coenzyme A reductase gene (SjHMGR) was cloned successfully by RT-PCR and RACE. The bioinformatics of SjHMGR gene was analyzed. The spatiotemporal expression characteristics of SjHMGR gene were analyzed using the internal reference gene EF1a. The results showed that the length of SjHMGR gene was 1892 bp, the open reading frame was 1689 bp, encoding 367 amino acids, and the login number was MK448292. SjHMGR had three special loci of HMG-COA and belonged to the HMG-COA supergene family. The SjHMGR was a hydrophilic protein in mitochondria. Alpha helix elongated chain and irregular folding were found in the secondary structure. Functional prediction of SjHMGR-encoded proteins revealed that SjHMGR played an important role in intermediate metabolism. Homology analysis and phylogenetic tree analysis showed that the homology of SjHMGR protein was the closest to the evolution of Orchidaceae and on the same branch. The results of qRT-PCR showed that the expression of SjHMGR gene in roots and leaves were very low, and that in sepals and petals was high, which had spatial and temporal specificity.
In order to enrich the molecular marker library, the SSR markers of Lagenariasiceraria (Mol.) Stand. 87 518 unigene sequences from bottle gourd transcriptome database were developed by the MISA software. A total of 11 029 SSR loci with an occurrence frequency of 9.85% were obtained from the transcriptome of Lagenariasiceraria (Mol.), the distribution distance of the SSRs was about 1 SSR per 8.3 kb ESTs. Around 6759 unigene sequences contained a single SSR loci, and the occurrence frequency was 7.72%. Average of 1858 unigene contained 2 or more than 2 SSR loci, and the occurrence frequency was 2.123%. 920 unigene contained the mixed SSR loci, and the occurrence frequency was 1.051%. Among the SSR locis, mononucleotide, trinucleotide and dinucleotide were the major types, accounting for 55.51%, 25.41% and 17.07% of the total, respectively. A/T, AG/CT and AAG/CTT were the dominant elements among mononucleotide, dinucleotide and trinucleotide, accounting for 98.22%, 55.39% and 39.86% of the total SSRs. 8617 pairs of SSR primers were found by Primer 3.0, six primer pairs were selected and applied in PCR amplification of 36 varieties, based on the clear and repeatable polymorphism, the fingerprint of the cultivars was constructed, however, there were no differences in some loci probably due to narrow genes. The cluster analysis showed that 36 bottle gourd varieties were divided into six categories when the genetic similarity coefficient was 0.68. The results aslo showed that the genetic diversity basis of bottle gourd germplasm resources in China was very low, limiting the potential of variety development using the existing bottle gourd germplasm resources. The introduction and exploration of specific wild bottle gourd germplasm should be highly emphasized. The results indicated that SSR markers could be acquired in bottle gourd by transcriptome sequencing analysis and abundant SSR markers would provide more reliable markers for genetic diversity analysis and genetic mapping construction in bottle gourd.
Mango bacterial black spot (MBBS) caused by Xanthomonas campestris pv. manganiferaeindicae (Xcm) is a risk plant disease in mango orchards. In order to screen an effective fungicide for controlling MBBS, the bacteriostatic activity of 22 fungicides against MBBS were assessed by th turbidimeter test in the laboratory, and the toxicity of the fungicides with good antibacterial activity was tested by the method of plate culture count and the control efficacy were carried out in the field. Laboratory bioassay results showed that the inhibitory effect of tetramycin, octylamine acetate, bromothalonil and benziothiazolinone was strong, with an inhibitory rate 90% treated with 2 mg/L, followed by pothioconazole and zhongsengmycin with an inhibitory rates up to 75% at 10 mg/L. Except for oxine-copper, the bacteriostatic activity of copper fungicides was relatively low. The toxicity of bromothalonil, benziothiazolinone, pothioconazole, kasugamycin and saisentong to Xcm was calculated, with EC50 of 0.048, 0.103, 0.900, 21.970 and 189.347 mg/L, respectively. At 30 days after treatment, the result of the field trial indicated that 20% zinc-thiazole SC 750 times solution (TS) had the highest control efficacy on the disease and its control effect reached 75%, followed by 3% benziothiazolinone ME, 20% pothioconazole SC and 25% bromothalonil EC reached above 70% control efficacy at 1000 TS. Beyond that, 46% copper hydroxide WG showed a better protective effect than other fungicides with lowest diseased leaf rate after treatment. Accordingly, copper hydroxide, zinc-thiazole, benziothiazolinone, pothioconazole and bromothalonil could be used as the chemicals for controlling mango bacterial black spot.
To determine the factors affecting the lethal effect of Coccophagus japonicus Compere on Parasaissetia nigra Nietner, the lethality of C. japonicus Compere was studied under different conditions including different parasitoid introducing time, ratio of parasitoid number to host number, supplementary nutrition and host stage. The results showed that when host stage was between the 2 nd larva and early adult, the reproductive host-mortality increased with host stage, and when host stage was between early adult and black adult, the mortality decreased with host stage. The reproductive host-mortality of early adult was the highest (67.8%) and the mortality of brown adult was the lowest (2.2%). The non-reproductive host-mortality decreased with host stage. The highest mortality was the 2 nd larva (60.0%) and the lowest at black adult (0). The lethality of C. japonicus was significantly affected by parasitoid introducing time. The reproductive host-mortality decreased with parasitoid introducing time, but the non-reproductive host- mortality and the total mortality increased with parasitoid introducing time. After being supplemented with six sugar substances, the total lethality of C. japonicus to P. nigra was ranked as from high to low: sucrose (96.5%) > glucose (95.0%) > fructose (91.3%) > honey (82.1%) > melezitose (80.0%) > trehalose (70.8%). When the ratio of parasitoid number to host number was between 1∶5 and 1∶15, the reproductive host-mortality decreased with ratio of parasitoid number to host number, but the non-reproductive host-mortality and the total mortality increased with ratio of parasitoid number to host number. In total, the lethality of C. japonicus to P. nigra increased with parasitoid introducing time and ratio of parasitoid number to host number, but decreased with host stage. Supplementary nutritions as sucrose would strengthen the lethal effect of C. japonicus.
A water-soluble fertilizer containing amino acids is a new type of green fertilizer, which has many advantages including high efficacy, no residue, potential to improve crop quality and resistance to stress. It can be used as a carrier to make microbial fertilizers. However, whether it influences the growth and reproduction of Bacillus strains has not been reported. We analyzed the impact of the solution of the water-soluble fertilizer containing amino acids (WFA) ‘Lvnonglin’ on the growth and reproduction of the Bacillus strains X05 and QB61, production of antagonistic metabolites, and plant growth promotion of tomato and banana, control efficiency of wilt disease of banana. The cells of Bacillus strains X05 and QB61 increased to 86-2900 fold of the initial inoculation number after 24 h cultivation in 1-50 g/L of the WFA solution, while that had no change in other concentration of the WFA solution and water (control). The supernatant that obtained from the culture of the Bacillus strains X05 and QB61 in 50 g/L of the WFA solution for 48 h showed significant inhibition on the growth of mycelial growth of the fungal pathogen Fusarium oxysporum f. sp. cubense, while the supernatant from the cultures of X05 and QB61 in other concentrations of the WFA solution and water (control) had no inhibition effect. Additionally, in contrast to th control plants (applied with the solution of the Bacillus strain X05 or QB61), the plant growth promotion of banana and tomato seedlings applied with the solution of WFA inoculated with X05 or QB61 showed to be significantly enhanced, and banana plantlets applied with WFA inoculated with QB61 and X05 showed 33.4% and 32.2% reduction in disease index of wilt disease of banana compared to those applied with the Bacillus strains QB61 and X05, respectively. These imply that WFA ‘Lvnonglin’ can promote the growth and reproduction of Bacillus strains X05 and QB61, and enable them to produce antagonistic metabolites. Meanwhile, the application with the combination of WFA and Bacillus strains can promote the plant growth of banana and tomato, and suppress the wilt disease of banana more efficiently. Thus, the combination of WFA and Bacillus strains X05 and QB61 has a good application prospect.
High-throughput sequencing and bioinformatics analysis were used to analyze the composition of fungal communities in the rhizosphere and non-rhizosphere soils from the plants for mushroom cultivation. A total of 525 292 fungal ITS sequences from the samples were obtained. 7267 OTU (operational taxonomic units) could be grouped based on 97% sequence similarity as the threshold. The ACE of the fungal community was the lowest in the non-rhizosphere soil, and the rhizosphere soil of Lvzhou No. 1 was slightly higher than that in the rhizosphere soil of the plants for mushroom cultivation. The Shannon-wiener and Simpson values obtained for rhizosphere soils were higher than the values recorded from non-rhizosphere soils. Also, the Shannon-wiener and Simpson values for Lvzhou No. 1 rhizosphere soil was slightly higher compared to the values obtained for the rhizosphere soil of the plants for mushroom cultivation. This study further revealed Ascomycota, Basidiomycota, Zygomycota, Chytridiomycota, and Glomeromycota as the pre-dominant phylum present in all the rhizosphere soil samples. From class level analysis, we identified eight pre-dominant classes in all soil samples, including Eurotiomycetes, Sordariomycetes, Agaricomycetes, Leotiomycetes, Orbiliomycetes, Tremellomycetes, Dothideomycetes, and Wallemiomycetes. Nine pre-dominant genuses, including Talaromyces, Umbelopsis, Cladosporium, Cordana, Fusarium, Cryptococcus, Purpureocillium, Gibberella, and Ganoderma in all the soil samples were revealed. The results would provide insights into the prevailing upsurge in diversity in the rhizosphere fungi community compared to the non-rhizosphere soil and would serve as a reference for the characterization of rhizosphere fungi.
The phenolic compounds from the pericarp of six lychee varieties extracted with 80% methanol were used to compare the content, types and antioxidant activity. The content of total phenol and total flavonoids was measured and the antioxidant activity was evaluated by the FRAP and ABTS methods. Different monomer phenols were identified by HPLC and the differences among lychee pericarps of different varieties were analyzed. There were significant differences (P<0.05) in phenolic content and antioxidant capacity among different lychee pericarp. The content of phenolic compounds, antioxidant activity of FRAP and ABTS of ‘Lizhiwang’ were the highest, which was, 68.48 mg/g, 546.31 μmol/g, and 511.25 μmol/g, respectively. Eight monomer phenolics were identified in ‘Nuomici’, and the monomer phenols of relatively high content were A-type procyanidin trimer and proanthocyanidins A2. The result could provide a foundation for the development and utilization of lychee pericarp.
Dendrobium candidum was used to produce beverage fermented by Lactobacillus. The changes of polysaccharide, dendrobium, total polyphenols, total flavonoids and antioxidant capacity were discussed before and after fermentation. The consumption of dendrobium polysaccharide was the highest after fermented with Lactobacillus plantarum, 41.63% lower than the original juice. The consumption of dendrobium was the highest when fermented with Lactoba-cillus plantarum and Lactobacillus bulgaricus in 1∶1, 4.92% lower than the original juice. The content of total phenol and total flavonoids increased after fermentation. The content of total phenol and total flavonoids increased by 24.17% and 31.87% after fermented with Lactobacillus plantarum and Lactobacillus bulgaricus in 1∶1. The scavenging ability of hydroxyl radicals, DPPH radicals and superoxide anions after fermentation increased also. The experiment showed that the active substance dissolution rate of D. candidum could be improved through Lactobacillus fermentation, and the antioxidant function of the fermented beverage from D. candidum be improved as well.
The present study was aimed to compare the effects of the extracts of Ilex kudingcha C.J. Tseng with different organic solvents (ethanol, ethyl acetate, petroleum ether) assisted by ultrasound and supercritical CO2 extraction against oxidation activities (DPPH?) scavenging activity, hydroxyl radical (?OH) elimination activity, superoxide anion free radical (O2 -?) scavenging activity and ABTS +? radical elimination ability), and component analysis by gas chromatography-mass spectrometry (GC-MS). The DPPH? and O2 -? scavenging abilities were as follows: ultrasound-ethanol extract > supercritical CO2 extract > ultrasound-ethyl acetate > ultrasound-petroleum ether extract. The OH? and ABTS +? radical scavenging abilities were as follows: ultrasound-ethanol extract > ultrasound-ethyl acetate extract > supercritical CO2 extract > ultrasound-petroleum ether extract. GC-MS analysis showed that there were five main types of substances in the four different extraction methods, a total of 50 chemical components and seven common components.
The leaf Perilla is of specific aroma and of biological activitie. The similarities and differences of the volatile organic compounds in the fresh leaves of P. frutescens (NMZS), P. frutescens var. frutescens (BS) and P. frutescens var. frutescens (ZS) were studied. Solid phase microextraction (SPME) was used to enrich and extract the volatile compounds. The volatile components were isolated and identified by GC-MS. The volatile components were significantly different in three Perilla plants. The three plants could be clustered into a single group by principal component analysis. The high matching (≥90%) and relatively high content (≥2%) volatile componets of three plants were different. The high matching and high content compounds of NMZS were 3,7-dimethyl-2,6-octadienal, (Z)- 3,7- dimethyl-2,6-octadienal, 1-octen-3-ol etc., while those of ZS were α-caryophyllene, β-caryophyllene, apiol etc., and those of BS were β-caryophyllene, 1-octen-3-ol, 3,7-dimethyl-1,6-octadien-3-ol etc. A total of 19 specific volatile components were fould in NMZS (3,7-dimethyl-2,6-octadienal, (Z)-3,7-dimethyl-2,6-Octadienal etc.), eight in BS (Apiol etc.), and six in ZS (3,7-dimethyl-1,6-octadien-3-ol and so on). Common volatiles were also found, which were β-elemene, germacrene D, β-caryophyllene and 1-octen-3-ol. Cluster analysis result showed that BS and ZS could be clustered into one group, while NMZS was clustered into another group. The study would provide a basis for the further development and utilization of Perilla plants.
A supervised residue trial was carried out in Yunnan in 2016 to study the digestion process of difenoconazole and thifluzamide in banana fruit, banana flesh and soil to analyze the residual digestion behavior and dietary intake risk in banana. The risk of long-term dietary exposure in China was assessed. The results showed that the linear equation of the standard curve of difenoconazole was y=1.45×10 7x+4.14×10 4, R 2=0.9962, and that of thifluzamide was y=2.99× 10 6x+1.43×10 4, R 2=0.9954. At the level of 0.04-1 mg/kg, the average recovery of difenoconazole was 75%-110%, and the relative standard deviation (RSD) was 0.9%-6.2%, while the average recovery of thifluzamide was 76%-114%, and RSD was 3.0%-9.5%. The limit of quantification (LOQ) of difenoconazole and thifluzamide in soil, banana fruit and banana flesh was 0.04 mg/kg, and the limit of detection (LOD) was 5 pg. The digestion of difenoconazole and thifluzamide was basically in accordance with the first-order kinetic equation. The half-life of difenoconazole in banana fruit and soil was 16 and 20 days, and the half-life of thifluzamide in banana fruit and soil was 20 and 27 days. Risk assessments indicated that the long-term dietary intake risk of difenoconazole in banana was acceptable, while thifluzamide had a certain long-term dietary risk.
The anatomical characteristics of the wood of Pemphis acidula, Suriana maritima, Guettarda speciosa and Tournefortia argentea above in Xisha Islands were reported. The macrostructure and microstructure of the wood and bark of the plants were observed by the method of digital microscopy. The bark of P. acidula, S. maritima and G. speciosa was brown and the pore distribution type was diffuss-porous. The bark of T. argentea was silver white and the pore distribution type was diffuss-porous to semi-ring porous. The wood of P. acidula and S. maritima was the heaviest and hardest, and the pith was the smallest. while the wood of G. speciosa and T. argentea was the lightest and softest. The length of vessel of the four plants were short, less than 800 μm. Vessel grouping of P. acidula, S. maritima and G. speciosa was mainly composed of radial multiple pore, and that for T. argentea was pore cluster. The axial parenchyma was best developed and had some small vessels. The wood ray of P. acidula was mostly homogeneous uniseriate, that of S. maritima and G. speciosa was heterogeneous II type, mostly two to four series, frequent occurrence 2-3 times of multiseriate parts in the same ray; and that of T. argentea was mostly homogeneous multiseriate.
To explore the effect of rubber-cassava intercropping on the soil fungal community structure in the rhizosphere of rubber trees, the soil physiochemical properties, fungal community structure in the rhizosphere of rubber trees were analyzed by traditional and high-throughput sequencing techniques. Compared to rubber monoculture, the contents of soil alkalide N, available P, available K, organic matter and Shannon index of fungal diversity in the rhizosphere of rubber trees of rubber-cassava intercropping were significantly decreased, but the Simpson index was significantly increased. In addition, there were no significant differences for soil pH and chao1 index. Ascomycota, Zygomycota and Basidiomycota were the three dominant fungi at phylum level for both intercropping and monoculture treatments, but compared to monoculture, the relative abundance of Zygomycota and Basidiomycota were decreased, and Ascomycota was increased to 91.54% in intercropping treatment. At the genus level, the top 10 fungal genera accounted for 61.30%-65.59% of the total genera. The relative abundance of Phyllosticta, Gibberella and Lecythophora were higher in the intercropping treatment. The α-diversity of fungi was not only interfered by the content of soil alkalide nitrogen, available phosphorus and potassium, but was also affected by the content of soil organic matter. It indicated that rubber-cassava intercropping significantly decreased soil nutrients content and fungal diversity in the rhizosphere of rubber trees. Meanwhile, the relative abundance of soil pathogenic fungi in the rhizosphere was also enriched by intercropping treatment.
Based on 12 samples collected from the sea waters near Meiji Reef in August 2018, the characteristics of the phytoplankton community and environment factors were analyzed. The results showed that a total number of 199 species belonging to 83 genera, in which diatoms and dinoflagellates were predominant in the species composition and the cell abundance. The dominant species were Rhizosolenia calcaravis, Oscillatoria erythraea, Guinardia flaccida, R.alata f. gracillima, Bacteriastram hyalinum, Navicula sp., Gymnodinium aeruginosum, Amphora sp. and Thalassiothrix frauenfeldii. The Meiji Reef waters were rich in phytoplankton species, the average Shannon-Wiener diversity index, Pielou evenness index and Margalef diversity index was 4.21, 1.18, 6.64, respectively. In addition, there were more phytoplankton species outside the reef than those in the reef. Conductivity and nitrate content were the main environment factors affecting the phytoplankton community structure. The phytoplankton diversity had positive relationship with conductivity, and negative relationship with nitrate content.
One of the most important manifestations of climate change affecting ecosystems is the change of net primary productivity (NPP) of vegetation. Under the background of global warming, how much the net primary productivity of vegetation in natural rubber tree planting areas in China is affected needs to be studied. Based on the national climate data from 1981 to 2010 and the climate prediction data of RCP 4.5 scenario, and the net primary productivity model of climate vegetation, the NPP changes in natural rubber planting areas in China were analyzed from 1981 to 2010, 2041 to 2060 and 2061 to 2080. With climate warming, NPP in the natural rubber planting areas increased first and then decreased slightly. The annual average NPP of vegetation in the study area was 12.89 tC/hm 2 from 1981 to 2010, 15.07 tC/hm 2from 2041 to 2060, and 15.01 tC/hm 2 from 2061 to 2080. In spatial distribution, the high value areas of NPP in different periods were mainly distributed in the eastern coast of Hainan, Xinyi, Dianbai, Dongxing of Guangxi, Jinghong and Mengla of Yunnan, and the areas of low value of NPP were mainly distributed in Lincang, north of Pingbian of Yunnan, west coast of Hainan and Xuwen of Guangdong. Relevant results could provide making decisions on the adaptation of rubber to future climate change.
Soil carbon pool affects soil fertility and global climate change. Soil organic carbon and its fractions are sensitive indicators of changes in soil carbon pool. Therefore,the study on soil organic carbon and its fractions under different land uses is of great significance to guide reasonable utilization and management of soil resource. Topsoil samples (0~20 cm) were collected under six land uses (woodland, tea garden, orchard land, abandoned land, paddy field and paddy-upland rotation) in northern Guangdong, soil organic carbon (SOC) and its fractions including easy oxidation of organic carbon (EOC), particulate organic carbon (POC), humic acid C (HAC), humic acid C (FAC) and humin C (HMC) were determined. The respond of SOC and its fractions to different land uses and the relationship among SOC fractions were evaluated. SOC in paddy field (16.70 g/kg) and woodland (16.42 g/kg) was the highest, which was 28.86% and 26.99%, 21.54% and 20.56%, 37.79% and 35.48% higher compared with tea plantations, orchards and abandoned farmland respectively, with significant difference (P<0.05). (2) Soil EOC (4.83 g/kg), POC (0.98 g/kg), HAC (2.81 g/kg). The ratio of HAC to FAC (0.83), the proportion of HAC to SOC (16.8%) in paddy field and FAC in wood land were significantly higher than the other five land uses. SOC was significantly positively correlated with EOC, fPOC, POC, HAC, FAC and HMC. Therefore, in mountainous areas of northern Guangdong, humin C was the dominant fraction of SOC, and the content of SOC fractions increased with the increase of SOC content. Rice planting and woodland utilization are beneficial to SOC accumulation, and can increase soil organic carbon pool and improve soil fertility.
