蜂糖李果实内源激素含量与其生理落果的关系

【目的】明确蜂糖李幼果脱落规律及落果生理特性,为生产上保果调控提供依据。【方法】采用酶联免疫法对蜂糖李生理落果期间正常果和脱落果中的生长素(IAA)、赤霉素(GA₃)、玉米素(ZT)和脱落酸(ABA)的含量进行测定,同时记录幼果脱落动态以及幼果和新梢的生长量。【结果】蜂糖李盛花后各时期正常果的单果重和果实直径均显著高于脱落果(P<0.05),正常果生长快速,脱落果生长缓慢;脱落果单果重积累速度慢,正常果直径的增长速度比落果快。蜂糖李整个落果期持续时间为花后14~70 d,分为快速落果期(花后14~28 d)和缓慢落果期(花后28~70 d),其中快速落果期为主要的落果发生时期,花后28 d为落果高峰,约82.73%幼果脱落。幼果在前期生长缓慢,花后42 d开始进入快速生长期;新梢生长呈快—慢—快的趋势,新梢生长在花后21~28 d与落果率呈正相关。整个生理落果期,正常发育的幼果中积累的GA₃、IAA和ZT含量整体高于脱落果,ABA含量低于脱落果。正常发育果实中促进生长型与抑制生长型激素的比值IAA/ABA、GA₃/ABA、ZT/ABA和(IAA+GA₃+ZT)/ABA]大于脱落果,说明果实中高水平促进生长型激素和低浓度抑制生长型激素有利于坐果。【结论】蜂糖李幼果中ABA含量高而GA₃与IAA含量低可能是出现幼果大量脱落的根本原因,此外,新稍伸长也是致使果实脱落的重要因素。

Relationship between endogenous hormone content and physiological fruit drop of Fengtang plum

【Objective】To clarify the pattern of young fruit drop and physiological characteristics of fruit drop of Fengtang plum,and to provide a basis for fruit preservation and control in production.【Method】The contents of growth hormone(IAA),gibberellin(GA₃),zeatin(ZT) and abscisic acid(ABA) in normal and abscised fruits during physiological fruit drop were measured by enzyme-linked immunoassay,and the dynamics of young fruit drop and the growth of young fruits and shoots were also recorded.【Result】The fruit weight and fruit diameter of normal fruit were significantly higher than those of dropped fruit in all periods after flowering(P<0.05),and the growth of normal fruit was fast while that of dropped fruit was slow; the accumulation of fruit weight of dropped fruit was slow,and the growth of fruit diameter of normal fruit was faster than that of dropped fruit. The whole fruit drop period of Fengtang plum lasted from 14 to 70 d after flowering and was divided into rapid fruit drop period(14-28 d after flowering) and slow fruit drop period(28-70 d after flowering),with rapid fruit drop period being the main fruit drop period and the peak of fruit drop at 28 d after flowering,when about 82.73% of young fruits fell off. Young fruits grew slowly in the early stage and started to enter the rapid growth period at 42 d after flowering; new tip growth showed a fast-slow-fast trend,and new tip growth was positively correlated with fruit dropping rate from 21 to 28 d after flowering. Throughout the physiological fruit drop period,the contents of GA₃,IAA and ZT accumulated in the normally developing young fruits were higher than those in the dropped fruits,and ABA content lower than that in the dropped fruits. The ratios of growth-promoting and growth-inhibiting hormonesIAA/ABA,GA₃/ABA,ZT/ABA and(IAA + GA₃+ ZT) /ABA]in normally developing fruits were greater than those in dropped fruits,indicating that medium and high levels of growth-promoting hormones and low concentrations of growth-inhibiting hormones in fruits were beneficial to fruit setting.【Conclusion】The high content of ABA and low content of GA₃ and IAA in young Fengtang plum fruits may be the root cause of large number of young fruit drop,in addition,shoot elongation is also an important factor causing fruit abscission.