Positive contribution of stem growth to grain number per spike in wheat
Positive contribution of stem growth to grain number per spike in wheat
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DOI：
10.1016/j.fcr.2007.06.008
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发表时间：
2008-01-02
影响因子：
5.8
通讯作者：
Bancal, Pierre
中科院分区：
文献类型：
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作者：
Bancal, Pierre
本文对穗茎竞争决定小麦粒数的普遍看法提出了质疑。田间试验采用高密度、遮光和延长光周期3种不同处理和6个不同早熟性和穗茎比的基因型。在整个茎伸长过程中，在主穗的培养基和顶部小穗中计数小花原基。小花死亡在两个小穗中同时发生，并且相应的临界时间用于与生长分析进行比较。整个枝条的生长速率在小花死亡时最高，但在此后的一段时间内，茎和穗的生长都继续加速。尖峰呼吸测量在关键时间没有表明特殊要求。穗碳水化合物浓度开始下降或多或少小花死亡前，取决于基因型，但正是在穗伸长，从而表明一个发展过程，而不是营养限制的发育时间。复相关分析表明，穗粒数不仅与小花死亡时的穗生长速率呈正相关，而且与穗部和非穗部（茎+叶）的生长速率均呈正相关。粒数预测分区穗无论是地上部干物质或地上部生长速度在关键时刻。小花存活率与分配高度相关，复相关对小花存活率和非穗生长率无显著影响。可以得出结论，即使穗：stetn竞争降低小花存活，它只是松散的相关粒数。(c)2007年由Elsevier B.V.出版。
This paper challenges the common belief that spike:stem competition determines grain number in wheat. A field experiment was conducted using three contrasting treatments (high shoot density, shading, and extended photoperiod) and six genotypes of varying earliness and spike:stem ratio. Floret primordia were counted in medium and top spikelets of main spikes throughout stem elongation. Floret death occurred simultaneously in both spikelets, and the corresponding critical time was used for comparison with growth analysis. Whole shoot growth rate was highest at the time of floret death, but both stein and spike growth continued to accelerate for a period of time thereafter. Spike respiration measurements did not indicate special requirements at the critical time. Spike carbohydrate concentration started to decline more or less before floret death, depending on genotype, but exactly at the inflexion time for spike elongation, thus suggesting a developmental process rather than a trophic limitation. Multiple correlation indicated that grain number positively correlated not only with spike growth rate at the time of floret death, but with both growth rates of spike and non-spike (stem + leaves) shoot parts. Grain number was poorly predicted by partitioning to spike of either shoot dry mass or shoot growth rate at critical time. In contrast, floret surviving proportion was highly correlated to partitioning and multiple correlation did not indicate a significant effect on survival of non-spike growth rate. It is concluded that even though spike:stetn competition decreased floret survival, it was only loosely correlated to grain number. (c) 2007 Published by Elsevier B.V.