CARBON ISOTOPE DISCRIMINATION AND THE RATIO OF CARBON GAINED TO WATER LOST IN BARLEY CULTIVARS
CARBON ISOTOPE DISCRIMINATION AND THE RATIO OF CARBON GAINED TO WATER LOST IN BARLEY CULTIVARS
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DOI：
10.1111/j.1365-3040.1989.tb01641.x
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发表时间：
1989-11-01
影响因子：
7.3
通讯作者：
FARQUHAR, G
中科院分区：
文献类型：
--
作者：
HUBICK, K;FARQUHAR, G
在使用12个大麦品种进行的盆栽实验中，确立了水分利用效率（W，定义为植物中碳的摩尔数与蒸腾的水的摩尔数之比）和碳同位素判别（Δ）之间的负相关关系。在四个不同的受控环境中进行的两次独立实验中，这种相关性很强，在这些环境中，环境温度和水汽压亏缺有所变化，植物要么水分充足，要么给予有限的水量。在Δ和W方面，不同品种之间存在差异，并且根据品种，这两个参数的排序在不同环境中是相似的。限制水分通常会提高植物的水分利用效率。在计算水分利用效率时，可以用总干物质代替碳的摩尔数，但W和Δ之间的相关性是使用干物质的碳含量计算的。植物各部分之间的Δ存在差异，并且这些差异在不同品种之间有显著变化。尽管存在这些差异，整株植物的W和任何植物部分的Δ之间的相关性也很大。分配到生殖生长的干物质量存在遗传差异，胁迫对分配的影响也是如此。将大麦的生长、W和Δ与从气体交换特性推导出来的理论以及其他文献进行了比较。在这些实验中，通过将W乘以水汽压亏缺得到参数k（帕摩尔碳/摩尔水），消除了水汽压亏缺变化对W的影响。这使得能够在具有不同水汽压亏缺的实验之间进行比较。这些大麦品种的平均κ与其他人对草本植物计算出的结果相似。然而，发现了差异，并且与之前将κ视为物种常数的研究不同，我们得出结论，选择提高κ是有希望的。
A negative correlation between water-use efficiency (W), defined as the ratio of moles of carbon in the plant to moles of water transpired, and carbon isotope discrimination (.DELTA.) was established for barley in pot experiments using 12 cultivars. The correlation was strong in two independent experiments in four different controlled environments where ambient temperature and vapour pressure deficit were varied and plants were either well-watered or given limited amounts of water. Variation among cultivars was found in both .DELTA. and W and rankings of both parameters, according to cultivar, were similar in different environments. Limiting water usually increased water-use efficiency of plants. Total dry matter can be substituted for moles of carbon when calculating water-use efficiency but the correlation between W and .DELTA. were calculated using the carbon content of dry matter. There were differences in .DELTA. among plant parts, and these differences varied significantly among cultivars. Despite these differences, correlations were also large between whole plant W and .DELTA. of any of the plant parts. The amount of dry matter partitioned into reproductive growth varied genetically, as did the effect of stress on the partitioning. Growth, W and .DELTA. of barley were compared with theory derived from gas exchange properties and with other literature. The effect on W of variation in vapour pressure deficit in these experiments was removed by multiplying W by vapour pressure deficit to derive the parameter, k(Pa mol C/mol H2O). This allowed comparisons among experiments with different vapour pressure deficits. The mean .kappa. for these barley cultivars was similar to that calculated by others for grasses. However, variation was found, and, in contrast with previous work which treats .kappa. as a species constant, we conclude that there is promise in selecting for increased .kappa.