Leaf expansion of four sunflower (Helianthus annuus L) cultivars in relation to water deficits. I. Patterns during plant development
Leaf expansion of four sunflower (Helianthus annuus L) cultivars in relation to water deficits. I. Patterns during plant development
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四种向日葵（Helianthus annuus L）品种的叶片扩张与水分亏缺的关系。
DOI：
10.1111/j.1365-3040.1981.tb02118.x
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
H. Rawson
中科院分区：
文献类型：
--
作者：
S. Takami;N. Turner;H. Rawson
在温室中研究了缓慢胁迫和恢复周期对四种不同向日葵品种（Helianthus annuusL. cvs. Hysun 31、Havasupai、Hopi 和 Seneca）叶片扩张模式的影响。胁迫对花芽出现和开花时间以及最终叶片数没有显着影响，但除海生31外，所有品种的高插入叶片的出现均延迟。当黎明前叶片水势从-0.35 MPa下降到-0.60 MPa，黎明前膨压从0.3 MPa下降到0.2 MPa时，叶片展开明显减少，在黎明前叶片水势为关于 -1.0 MPa，即当黎明前的膨胀压力达到零时。当停止浇水时，最终尺寸减小最多的叶子是在未受胁迫的植物中生长最快的插入处的叶子。所有品种的最终叶片尺寸最大减少 25-35% 是相似的，这是由于叶片扩展速率的延迟所致：叶片扩展的持续时间实际上因胁迫而增加。然而，在胁迫期间萌生但在重新浇水后出现的叶子的最终叶面积至少等于未胁迫植物中的叶子面积：在品种Seneca中，高插入的叶子的最终尺寸在胁迫下显着大于未胁迫植物，而在其他三个品种中，两种处理中的最终叶子尺寸相似。所检查的所有四个品种的渗透压调整程度相同，但其中一个品种（塞内卡）的叶水势在复水后比其他三个品种增加得更快，这可能导致该品种高插入的叶子的相对叶尺寸更大。
The influence of a slow stress and recovery cycle on the pattern of leaf expansion in four diverse sunflower cultivars (Helianthus annuusL. cvs. Hysun 31, Havasupai, Hopi and Seneca) was studied in a glasshouse. Stress had no significant effect on the time of flower bud emergence and anthesis, or on final leaf number, but delayed the appearance of leaves at high insertions in all cultivars except Hysun 31.Leaf expansion was markedly reduced as the predawn leaf water potential decreased from −0.35 to −0.60 MPa, and the predawn turgor pressure decreased from 0.3 to 0.2 MPa, and expansion ceased at a predawn leaf water potential of about −1.0 MPa, i.e. when the predawn turgor pressure reached zero.The leaves most reduced in final size when water was withheld were those at the insertions which grew the most rapidly in unstressed plants. The maximum reduction in final leaf size of 25–35% was similar in all cultivars and was due to retardation of the rate of leaf expansion: the duration of leaf expansion was actually increased by stress. However, leaves that were initiated during stress, but emerged after rewatering, had final leaf areas at least equal to those in the unstressed plants: in the cultivar Seneca, the final size of leaves of high insertion was significantly greater in stressed than unstressed plants, whereas in the three other cultivars the final leaf sizes were similar in both treatments. All four cultivars examined adjusted osmotically to the same degree, but leaf water potentials in one, Seneca, increased more rapidly after rewatering than in the other three, and this may have contributed to the greater relative leaf size in the leaves of high insertion in this cultivar.