The relationships between photosynthate distribution in young ear at floret development stage and grain number per ear of large-ear-type wheat variety Zhoumai 16 and multiple-ear-type wheat variety Yumai 49-198 were studied.It was found that Zhoumai 16 transferred more photosynthate to ear than Yumai 49-198 in middle and later period of floret development.The number of perfect florets in flowering period was significantly positively correlated with the ear-stem weight ratio and ear-stem nitrogen accumulation ratio, and was very significantly positively correlated with the ratio of ear weight to ear nitrogen accumulation.The ear-stem dry weight ratio, and ear-stem nitrogen accumulation ratio of Zhoumai 16 were significantly higher than those of Yumai 49-198, and the ear weight / ear nitrogen accumulation of the former was very significantly higher than that of the latter.The number of perfect florets per unit area of Zhoumai 16 in flowering period was 3.85% higher than that of Yumai 49-198, and the difference reached a very significant level.The formation of perfect florets in flowering period was closely related to the distribution proportion of photosynthates in ear and vegetation organ (especially in ear).As for Zhoumai 16, higher grain number per ear was closely related to more perfect florets in flowering period, and the acquirement of large ears and more grains per ear depended on high distribution proportion of photosynthates in ear (especially ear weight / ear nitrogen accumulation).%分别以大穗型、多穗型小麦品种周麦16、豫麦49-198为试验材料,重点研究了大穗型和多穗型小麦品种在小花发育过程中,小花发育成粒与同化物分配之间的关系.在小麦幼穗发育过程中,通过比较分析2个穗型品种的同化物分配差异发现,在小花发育中后期,大穗型品种周麦16转移到穗部的同化物比多穗型品种豫麦49-198多.花期完善小花数与穗干重、穗氮积累量、茎干重、茎氮积累量呈正相关关系,但相关性不显著,与穗/茎干重、穗/茎氮积累量呈显著正相关,与穗重/穗氮积累量呈极显著正相关.大穗型周麦16在穗/茎干重、穗/茎氮积累量、穗重/穗氮积累量上显著高于豫麦49-198,且在穗重/穗氮积累量上达到极显著水平.前者在花期单位面积完善小花数较后者增加3.85%,且差异达到极显著水平.花期完善小花的形成与穗器官同化物供给总量的关系不大,而与同化物在穗部和营养器官的分配比例密切相关,与同化物在穗部的分配比例关系更加密切.大穗型周麦16较高的穗粒数与花期较高的完善小花数密切相关,且以穗部和营养器官间及穗部自身较高的同化物分配比例(尤其是穗重/穗氮积累量)取得大穗多粒.
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