Potential for selection on plants for water‐use efficiency as estimated by carbon isotope discrimination
Potential for selection on plants for water‐use efficiency as estimated by carbon isotope discrimination
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DOI：
10.1002/j.1537-2197.1994.tb15574.x
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发表时间：
1994-07
影响因子：
3
通讯作者：
L. Donovan;J. Ehleringer
中科院分区：
文献类型：
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作者：
L. Donovan;J. Ehleringer
基于水分利用效率提高与碳增益和生物量积累减少相关的普遍预期，水分利用效率被认为与植物性能和干旱生境中植物的自然选择有关。使用叶碳同位素辨别 (A) 来确定综合水分利用效率，我们估计了木本灌木 Chrysothamnus nauseosus 的全兄弟家族的遗传方差，并检查了 A、生物量和气体交换特征之间的关系，该灌木是从犹他州廷蒂克收集的种子生长的。在浇水良好的温室和普通花园实验以及限水普通花园实验中，A、生物量和形态特征都存在显着的家族差异，表明响应选择而发生遗传变化的潜力。然而，A 的广义遗传力估计较低，表明响应选择的变化率相对较慢。这与 A 观察到的大量表型可塑性一致，因为它随着水处理和花园实验年份的不同而不同。表型上，地上生物量和A在浇水良好的处理中呈负相关（即，水分利用效率更高的植物更大），在限水处理中不相关，而在浇水良好和限水花园处理中呈正相关，这表明光合能力和气孔限制的变化都会导致A的变化。与表型相关性相反，生物量和A的遗传相关性在每个处理中始终呈负相关，并且选择较高的该群体中的恶心棒状植物通过低 A 的水利用效率往往会导致群体转向更大的植物。对于恶心念珠菌来说，用水效率的提高并不一定与碳增益的减少相关。
Water-use efficiency is thought to be related to plant performance and natural selection for plants in arid habitats, based on a general expectation that increased water-use efficiency is associated with decreased carbon gain and biomass accumulation. Using leaf carbon isotope discrimination (A) to determine integrated water-use efficiency, we estimated genetic variance for, and examined the relationships among A, biomass, and gas exchange characters for full-sibling families of the woody shrub, Chrysothamnus nauseosus, grown from seed collected at Tintic, Utah. In both well-watered greenhouse and common garden experiments, and water-limited common garden experiments, there were significant family differences for A, biomass, and morphological characters, indicating a potential for genetic change in response to selection. However, estimates of broadsense heritabilities for A were low, indicating that the rate of change in response to selection would be relatively slow. This was consistent with the large amount of phenotypic plasticity observed for A as it differed with water treatment and year in the garden experiment. Phenotypically, aboveground biomass and A were negatively correlated within the well-watered treatments (i.e., more water-use efficient plants were larger), not correlated within the water-limited treatment, and positively correlated for combined well-watered and water-limited garden treatments, suggesting that variation in both photosynthetic capacity and stomatal limitation contribute to the variation in A. In contrast to the phenotypic correlations, genetic correlations for biomass and A were consistently negative within each treatment, and selection for higher water-use efficiency through low A for C. nauseosus plants in this population would tend to shift populations toward larger plants. For C. nauseosus, increased water-use efficiency is not necessarily associated with decreased carbon gain.