【作者】 杜康； 赵文青； 周治国； 邵晶晶； 刘墨瑶； 王友华；

【Author】 Kang Du;Wenqing Zhao;Zhiguo Zhou;Jingjing Shao;Moyao Liu;Youhua Wang;College of Agriculture, Nanjing Agricultural University;

【机构】 南京农业大学；

【摘要】 【研究背景】相邻节位的玉米腋芽最终有两种截然不同的命运,即形成可育穗(上位穗)和败育穗(下位穗)。揭示幼穗强势/弱势分化的机制可为进一步增强强势穗提供思路,从而提高产量和效率;【材料与方法】为了阐明玉米幼穗强、弱势差异分化的关键时期及内源激素在此阶段的作用,在2017-2018年在江苏省大丰区选用两种不同穗型的品种苏玉41号(单穗型)和AN101(双穗型),进行大田试验;【结果与分析】结果表明,上位穗的生长速率在吐丝前8天(8 DBS)(上位穗从小花分化期进入性器官成熟期)显著超过下位穗,且这种差异在性器官成熟期不断拉大。在小花分化期和性器官成熟期(吐丝前12天到吐丝当日),IAA、ZR+ZT和GA3含量首先大幅增加,随后迅速降低,而ABA含量则先增加随后维持在较高的水平。上、下穗差(ULED)的IAA、ZR+ZT和GA3含量在吐丝前8天达到峰值。上、下穗位间IAA、ZR+ZT各自激素比值(HU/HL)在单穗品种中要显著高于其在双穗品种中的比值,而GA3和ABA各自激素比值在两品种间非常接近。(hormoneU-hormoneL)/(elongation rateU-elongation rateL)的时间进程表明激素在幼穗强势/弱势形成方面有不同的贡献;【结论】从小花分化期到性器官形成的阶段(大约在吐丝前8天左右)是幼更多还原

【Abstract】 Maize axillary buds at adjacent positions lastly have two distinct destinies as fertile ear(the superior ear) and infertile ears(the inferior ear). Unravel the superiority/inferiority differentiation mechanism may provide ideas to further strengthen the superiority of the fertile ear and then increase yield and efficiency. In order to figure out the key period for earshoots superiority/inferiority differentiation and how hormones mediate it, two-year experiments were carried by comparing earshoots development, hormones changes in single-ear hybrid Suyu 41 and double-ear hybrid AN 101. The results showed that the growth rate of the upper ear significantly exceeded that of the lower ear at around 8 days before silking(DBS), when it almost entered the sexual organ formation stage. And moreover, the upper ear’s superiority mainly and gradually accumulated in the sexual organ formation stage. During the floret differentiation stage and sex organ formation stage(from 12 DBS to silking), the concentration of IAA, ZR+ZT and GA3 increased dramatically first and then decreased quickly while ABA tepid increased and then kept in a high level. The difference of the upper to lower ear difference(ULED) of IAA, ZR+ZT and GA3 between the two hybrids peaked at around 8 DBS. The upper-to-lower hormone ratios(HU/HL) of IAA and ZR+ZT in the single-ear hybrid were much higher than those in double-ear hybrid, while the HU/HL of GA3 and ABA between the two hybrids were very close. The time course of(hormoneU-hormoneL)/(elongation rateU-elongation rateL) suggested that hormones contributed differently in the superiority/inferiority formation. From the results, we concluded that the joint stage of floret differentiation and sex organ differentiation(approximately 8 days before silking) was the key stage for superiority/inferiority differentiation of earshoots. IAA, ZR+ZT and GA3 can strength superiority/inferiority differentiation while ABA seems little related to the process.更多还原