小麦兰考矮早八茎蘖幼穗激素差异及其密度调控效应

 【目的】探讨大穗型小麦品种兰考矮早八主茎和两分蘖间幼穗部激素差异与分蘖成穗的关系及其密度调控效应。【方法】在大田条件下,设置150(D1)、262.5(D2)和375万株/hm2(D3)3个种植密度,在拔节期取标记株区分主茎、分蘖Ⅰ和分蘖Ⅱ,显微镜下剥取幼穗液氮保存,用酶联免疫法测定幼穗中赤霉素(GAs)、吲哚乙酸(IAA)、分裂素(ZR)和脱落酸(ABA)含量。【结果】小花分化期主茎与分蘖幼穗分化进程差异很小,之后差距增大,表现为主茎幼穗分化进程要快于两分蘖。在分蘖两极分化过程中,幼穗中GAs、IAA和ZR含量及其IAA/ABA和ZR/ABA比值表现为主茎＞分蘖Ⅰ＞分蘖Ⅱ,在拔节后期幼穗ABA含量表现为分蘖Ⅱ＞分蘖Ⅰ＞主茎,IAA/ZR较高或呈升高趋势时对分蘖生长产生抑制作用。【结论】分蘖幼穗中较高的GAs、IAA、ZR含量以及IAA/ABA和ZR/ABA比值有利于幼穗生长发育,而较高的ABA含量及IAA/ZR比值不利于分蘖成活。分蘖与主茎差距越大,分蘖衰亡时间越早,且密度对其具有显著的调控效应。

Difference of Endogenous Hormones in Young Spike Between Main Stem and Tillers and Its Effects Under Different Densities in Lankao Aizao 8

【Objective】The objectives of this study were to analyze the relationship between the endogeneous hormones of young spike and the senescence of the tillers, and to investigate the regulating effects of planting densities on the endogeneous hormones of young spike in Lankao Aizao 8 with large spike. 【Method】 The experiment was conducted with three density treatments respectively as 150(D1), 262.5(D2) and 375(D3) million basic seeding per hectare in 2007-2008. At the wheat jointing stage, labeled plants were selected to distinguish main stem, tiller Ⅰ and tiller Ⅱ during the young pinicle differentiation process. Young spikes were stored in liquid nitrogen. The contents of indoleacetic acid (IAA), gibberellins (GAs), abscisic acid (ABA), zeatin riboside (ZR) were determined using enzyme-linked immunosorbent assay (ELISA) method. 【Result】The difference of spike differentiation process between main culm and two tillers was small at florets initiation, and increased after then, which indicated that the young pinicle differentiation process in main culm was faster than that of two tillers. The content of GAs, IAA and ZR, the ratio of IAA/ABA and ZR/ABA in young spike appeared as main culm ＞ tillersⅠ＞ tillers Ⅱ during tiller polarizing stage, but the content of ABA was contrary at late jointing stage, higher IAA/ZR had inhibition on tillers growth.【Conclusion】The higher content of GAs, IAA, ZR and ratio of IAA/ABA and ZR/ABA in young spike were beneficial to young spike growth, but higher content of ABA and ratio of IAA/ZR had opposing effect on tillers growth and young pinicle differentiation. The senescence stage of tillers was earilier, the difference of endogeneous hormones content was larger between main culm and tillers, and plant densities had significant regulating effects on endogeneous hormones and tillers decease.