Floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during stem elongation
Floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during stem elongation
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DOI：
10.1071/fp04104
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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
小麦育种通过在茎伸长阶段（从末端小穗萌生到开花期）将更多的干物质分配给穗，提高了产量潜力，提高了小花的存活率。我们研究了沿穗不同小穗位置的小花原基的存活与穗生长动力学的关系，当茎伸长阶段施加的光周期和遮光处理改变了穗的干物质分配动力学时。品种 Buck Manantial 暴露于 (1) NP+0 无遮蔽（自然光周期和生长季节的入射辐射）、(2) NP+0 遮蔽（自然光周期但只有 33% 的入射辐射）和 (3) NP+6 无遮蔽（自然光周期延长 6 小时和自然入射辐射）。根据小穗位置的不同，小花存活率增加，在无遮蔽处理与遮蔽处理（均在 NP+0 下）下增加 1.1 - 2.5 倍，在 NP+0 与 NP+6 处理（均无遮蔽）下增加 1.3 - 1.8 倍，而处理对起始小花原基总数没有任何影响。小花原基的命运及其花期的最后阶段与茎伸长阶段小花发育的持续时间相关（R-2 = 82%，P<0.0001）。小花可分为三组：(i) 在所有处理下在花期可育的小花（主要是两朵小花 F1 和 F2，靠近小穗内的轴），(ii) 根据处理的不同，在花期达到不同阶段的小花，并且对花期可育小花的数量有不同的贡献（主要是小花 F3、F4 和 F5，位于小穗的中间），以及 (iii) 没有贡献的小花任何处理下可育小花的数量（主要是> = F6的小花）。 (ii)组中小花的退化与最大速率的穗生长相关，解释了在开花时穗干重与可育小花数量之间观察到的密切关系。然而，组(iii)中的小花退化似乎发生在穗以最大速率生长之前。通过在茎伸长过程中控制光周期敏感性来增加穗的生长，可以提高位于小穗中间的小花的存活率。
Wheat breeding has improved yield potential increasing floret survival through higher dry matter partitioning to the spikes during the stem elongation phase ( from terminal spikelet initiation to anthesis). We studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments applied during the stem elongation phase. The cultivar Buck Manantial was exposed to ( 1) NP+0 un-shaded ( natural photoperiod and incoming radiation of the growing season), ( 2) NP+0 shaded ( natural photoperiod but only 33% of the incoming radiation), and ( 3) NP+6 un-shaded ( natural photoperiod extended 6 h and natural incoming radiation). Floret survival increased, depending on spikelet position, 1.1 - 2.5 fold under un-shaded v. shaded treatments ( both under NP+0), and 1.3 - 1.8 fold under NP+0 v. NP+6 treatments ( both un-shaded), without any impact of treatments on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were associated with duration of floret development within the stem elongation phase (R-2 = 82%, P< 0.0001). Florets may be classified into three groups: (i) those that were fertile at anthesis under all treatments ( mostly the two florets F1 and F2, proximal to the rachis within the spikelet), (ii) those that reached different stages at anthesis, depending on treatment, and that contributed differentially to the number of fertile florets at anthesis ( mostly the florets F3, F4 and F5, positioned in the middle of the spikelet), and (iii) those that did not contribute to the number of fertile florets under any treatment ( mostly the florets >= F6). Degeneration of florets in group ( ii) was associated with spike growth at maximum rate, explaining the strong relationship observed between spike dry weight at anthesis and number of fertile florets. However, degeneration of florets in group ( iii) seemed to occur before spike growth at maximum rate. Survival of florets positioned in the middle of the spikelets could be improved by increasing spike growth through manipulation of photoperiod sensitivity during stem elongation.