Welcome to Chinese Journal of Tropical Crops,

Chinese Journal of Tropical Crops ›› 2019, Vol. 40 ›› Issue (8): 1522-1528.DOI: 10.3969/j.issn.1000-2561.2019.08.010

• Phytophysiology and Biochemistry • Previous Articles     Next Articles

Effects of Trunk Injection Sucrose on Sugar Metabolism and Abscission of Fruitlet in ‘Shatangju’ under Summer Shoot Growth Condition

HUANG Yongjing1,2,WU Wen1,ZENG Jiwu1,CHEN Jiezhong2,**(),ZHANG Ruimin1,ZHU Congyi1   

  1. 1. Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences / Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization, Ministry of Agriculture and Rural Affaira, Guangzhou, Guangdong 510640, China
    2. College of Horticulture, South China Agricultural University, Guangzhou, Guangdong 510642, China
  • Received:2018-07-03 Revised:2019-05-09 Online:2019-08-25 Published:2019-08-20
  • Contact: CHEN Jiezhong

Abstract:

In order to reveal the roles of carbon nutrition on the fruitlet set under summer shoot growth condition of citrus, the experiment of trunk injection sucrose was carried out in 7-year old ‘Shatangju’ mandarin (Citrus reticulata Blanco) trees, and the effects of sugar accumulation, sucrose-related enzyme activities and abscission of the fruitlet were studied during the new shoot period. The results showed that, summer shoot obviously increased abscission of fruitlet, and the injecting of sucrose promoted the growth of fruitlet and decreased abscission. At the 85 th day after full blossom(15 th day of summer shoot growth), the accumulative abscission rate (AAR) in trunk injection sucrose was 73.35%, which was 10.05% lower than that in the control. Trunk-injected sucrose obviously increased the contents of sucrose and starch in the fruitlet, accompanied with the inhibition of the activities of acid invertase (AI) and neutral invertase (NI), but no significant difference was observed for the activities of sucrose phosphate synthase (SPS) and sucrose synthase (SS). It suggested that the increased accumulation of sucrose by the inhibited activities of sucrose degradation enzymes (AI and NI) during injecting sucrose contributed to the fruitlet set in ‘Shatangju’ mandarin. The injection of sucrose inhibited the fruitlet abscission during shoot growth, but the exogenous sugar couldn’t fully offset the impact of summer shoot on the fruitlet abscission. Sugar metabolism was not the only factor involved in the fruitlet abscission process caused by summer shoot growth.

Key words: citrus (Citrus reticulata Blanco), summer shoot, injection sugar, sugar metabolism, abscission

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