2,4-D在柑橘果实留树保鲜中的作用和可能机制研究

Effects of 2,4-D on Keeping Citrus Fruit Fresh on Tree and the Underlying Mechanisms

以‘锦橙’(Citrus sinensis Osbeck)为材料,比较2,4-D不同浓度、不同施用时期对锦橙果实落果率和品质的影响,同时研究2,4-D在柑橘果实留树保鲜中的可能机制。结果发现,在盛花后200d(柑橘果实转黄期)施用20 mg·L^-1的2,4-D,能显著降低柑橘果实留树越冬的落果率,且对果实品质无不良影响,果实能够留树保鲜50 d左右。研究还发现,2,4-D处理能延缓果蒂离层的形成,抑制细胞壁降解相关酶基因CX16、PG2、PME1、PME2的表达。综上所述,2,4-D能够用于锦橙果实留树保鲜,其主要机制可能是抑制细胞壁降解和离层形成。

In the present study,effects and underlying mechanisms of 2,4-D,applied at different concentrations and at various time points,on fruit dropping rate and fruit quality of Jincheng(Citrus sinensis Osbeck)were investigated.The results showed that exogenous application of 2,4-D at 20 mg·L^-1 and at 200 days after full blooming could prominently reduce the fruit shedding rate,without influencing the fruit quality.It suggests that 2,4-D treatment could keep fruit fresh on tree for approximately 50 days.Moreover,2,4-D treatment was found to delay formation of abscission zone and down-regulated expression of genes encoding enzymes involved in cell wall degradation,such as CX16,PG2,PME1 and PME2.Our finding revealed that the potential mechanism responsible for keeping fruit fresh on tree by 2,4-D is ascribed to inhibition of cell wall degradation and abscission zone formation.