外源亚精胺对水分亏缺下冬小麦小花发育及结实特性的调控效应

Effects of Exogenous Spermidine on Floret Development and Grain Setting Characteristics of Winter Wheat under Water Deficit

为了探究外源亚精胺(Spd)对水分亏缺下冬小麦小花发育动态、结实特性、内源激素含量及籽粒产量的影响,以冬小麦品种泰科麦33为试验材料,设置正常灌水WW(相对含水量为田间持水量的75%~80%)和水分亏缺WD(相对含水量为田间持水量的50%~60%)2个水分处理进行研究。结果表明,喷施外源Spd对水分亏缺下小麦强势小花的发育无显著影响,但是显著加快了弱势小花的发育进程。正常灌水条件下喷施Spd显著提高了小麦穗基部的可孕小花数(FF)、结实粒数(GN)和结实率(GS)。正常灌水和水分亏缺条件下喷施Spd提高1,2,3,4花位的结实粒数,分别提高4.6%,9.1%,21.8%,57.1%和0.7%,1.4%,4.1%,31.5%,同时提高弱势小花内源Z+ZR的含量,在开花前2~6 d,强势小花的Z+ZR高于弱势小花,水分亏缺处理强势小花和弱势小花的ABA含量均高于其他处理。从开花前14 d至开花期,小麦小花中Spd、Spm和Put含量呈明显下降趋势。正常灌水和水分亏缺条件下喷施Spd处理后提高小花中内源Spd和Spm,降低Put的含量,显著提高小麦籽粒产量,籽粒产量分别提高2.01%和20.83%。因此认为,水分亏缺条件下外源喷施Spd,增加了弱势小花内源Spd、Spm和Z+ZR含量,提高弱势小花(Z+ZR)/ABA的比值,同时加速弱势小花的发育,抑制小花退化,提高结实率,进而改善结实特性,从而提高小麦穗粒数,最终提高籽粒产量。

In order to explore the effects of exogenous Spermidine(Spd)on dynamics of floret development,grain setting characteristic,endogenous hormones content and grain yield under water deficit.Winter wheat(Taikemai 33)was sown in the filed under normal irrigation(the relative water content is 75%-80%of the field moisture capacity)and water deficit(the relative water content is 50%-60%of the field moisture capacity).The results showed that the application of exogenous Spd had no significant effect on the development of strong florets under water deficit,but significantly accelerated the development of weak florets.Spraying Spd under normal irrigation condition significantly increased the number of fertile florets(FF),grain number(GN)and grain setting(GS)at the base of wheat ears.Spraying Spd under normal irrigation and water deficit conditions increased grain number at 1,2,3,and 4 flower positions,which increased by 4.6%,9.1%,21.8%,57.1%,and 0.7%,1.4%,4.1%,31.5%,respectively.At the same time,the content of endogenous Z+ZR in weak florets was significantly increased.Z+ZR of strong florets was significantly higher than that of weak florets 2-6 d before flowering.The ABA content of strong florets and weak florets in water deficit treatment was higher than other treatments.From the 14th day before flowering to the flowering stage,the contents of Spd,Spm and Put in wheat florets showed a significant downward trend.Spraying Spd under normal irrigation and water deficit conditions increased endogenous Spd and Spm in florets,and decreased Put content.Grain yield increased significantly by 2.01%and 20.83%,respectively.In summary,exogenous Spd accelerates the development of inferior floret and inhibites the degradation of inferior florets due to increasing inferior floret Spd,Spm,Z+ZR content and ratio of(Z+ZR)/ABA under water deficit.Grain yield has significantly increased due to improving and number of grains.