乙烯利对夏玉米果穗生长发育影响及生理机制探究

Influence of Ethephon on Maize Cluster Growth and Development and the Physiological Mechanism

采用大田种植方法,以郑单958为试验材料,于玉米7展叶期(E7)、9展叶期(E9)喷施乙烯利,比较研究玉米产量、果穗维管束特征、子粒干物质积累及相关生理指标,探讨乙烯利对玉米果穗发育的影响及生理机制。结果表明,乙烯利处理使玉米子粒千粒重下降;子粒灌浆起始生长势降低、灌浆天数缩短,可溶性淀粉积累量下降;子粒中IAA(生长素)含量降低、ABA(脱落酸)含量升高,果穗穗轴的维管束长度及筛管半径显著降低,穗柄维管束个数下降、维管束长度也下降。IAA含量下降抑制木质素前体苯丙烷及木质素的形成,进而抑制木质部的形成,使得维管束个数、长度下降,进而子粒库容降低,子粒库活性降低,导致最终产量下降。

The field cultivation was used as the main research method by taking hybrids Zhengdan 958 of mate- rials. In order to investigate effects of Ethephon on the dry matter accumulation of summer maize seeds and inquire related physiological mechanism, the changes of yield, vascular bundle characteristics, accumulation of dry matter of grain, changes of soluble sugar and starch grain hormone in root bleeding volume and changes of inorganic ion content and hormone content were compared by spraying ethephon in the seventh and ninth expansion leaf period maize.The results showed that under ethephon treatment, seed grain thousand weight and volume, grain storage and soluble starch accumulation in grain declined, grain-filling starting growth potential of Zhengdan958 reduced, g/out- ing days were shorten. Grain was with lower IAA content but higher ABA content. Spraying ethephon significantly reduced the length of the ear cob of vascular bundle and the radius of screen in the process of the maize grain devel- opment. The number of ear handle vascular bundle and the length of the bundle also decreased in the grain filling stage by spraying ethephon. The decline of IAA content inhibited the formation of the xylem through decreasing the accumulation of lignin and its＇ precursors benzene propane, and this may be a cause of reduction in both number and length of vascular bundle, so led to the decrease of the final production.