Photoperiod during stem elongation in wheat:: is its impact on fertile floret and grain number determination similar to that of radiation?
Photoperiod during stem elongation in wheat:: is its impact on fertile floret and grain number determination similar to that of radiation?
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DOI：
10.1071/fp04103
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发表时间：
2005-01-01
影响因子：
3
通讯作者：
Miralles, DJ
中科院分区：
文献类型：
--
作者：
González, FG;Slafer, GA;Miralles, DJ
通过暴露于短日照来延长茎伸长的持续时间会导致开花期穗干重增加，这与小麦可育小花和籽粒的数量呈正相关。然而，当仅通过光周期处理实现穗重变化时，很难确定光周期对可育小花和籽粒的影响是否仅仅由向生长中的穗供应同化物所介导。本研究的目的是通过比较光周期效应和冠层遮荫效应的大小，来确定光周期对可育小花和籽粒数量的影响是否可能是直接的，即不通过同化物供应所介导。在茎伸长期间，通过对以在此阶段对光周期敏感而闻名的品种巴克·马南蒂亚尔（Buck Manantial）进行不同光周期（自然光照和延长6小时光照）和遮荫（无遮荫和67±3%遮荫）处理的因子组合，改变了开花期穗干重。这两种处理分别独立地改变了开花期穗干重以及可育小花和籽粒的数量。当通过暴露于自然光照延长茎伸长持续时间且入射辐射较高时，开花期穗干重分别增加了33%（自然光照+0小时与自然光照+6小时）和27%（无遮荫与遮荫）。可育小花数量的增加与穗干重相似（自然光照+0小时与自然光照+6小时为34%，无遮荫与遮荫为28%），从而导致籽粒数量增加。光周期对可育小花数量以及因此对籽粒数量的大多数影响是由向生长中的穗供应同化物所介导的，因为在光周期和遮荫处理中都观察到可育小花数量与开花期穗干重之间存在相同的关系（R² = 0.99，P < 0.05）
Increasing duration of stem elongation by exposure to short photoperiod would result in higher spike dry weight at anthesis, which is positively associated with the number of fertile. florets and grains in wheat. However, it is not easy to determine whether photoperiod effects on fertile florets and grains are only mediated by assimilate supply to the growing spike when spikeweight variation is attained only with photoperiod treatments. The aim of this study was to determine whether photoperiod effects on number of fertile florets and grains may be direct, that is, not mediated by assimilate supply, by comparing the magnitude of photoperiod effects with those of shading the canopy. Spike dry weight at anthesis was changed through the factorial combination of different photoperiod ( natural and 6 h extended photoperiod) and shading (un-shaded and 67 +/- 3% shaded) treatments during stem elongation of Buck Manantial, a cultivar known for its photoperiod sensitivity in this phase. Both treatments modified spike dry weight at anthesis and the number of fertile florets and grains, independently. When duration of stem elongation was lengthened by exposure to natural photoperiod and when incident radiation was high, spike dry weight at anthesis increased by 33% (NP+0 v. NP+6) and 27% ( un-shaded v. shaded), respectively. The number of fertile florets increased similarly to spike dry weight (34% NP+0 v. NP+6 and 28% un-shaded v. shaded) resulting in higher number of grains. Most photoperiod effects on the number of fertile florets and, consequently, on the number of grains, were mediated by assimilate supply to the growing spike as the same relationship between the number of fertile florets and spike dry weight at anthesis was observed for photoperiod and shading treatments (R-2 = 0.99, P< 0.05).