在 48 个玉米（Zea mays）基因型中，影响土壤干燥过程中蒸腾作用下降的地上和地下特征。
Above and belowground traits impacting transpiration decline during soil drying in 48 maize (Zea mays) genotypes.
机构信息
Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland.
Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany.
出版信息
Ann Bot. 2023 Mar 8;131(2):373-386. doi: 10.1093/aob/mcac147.
BACKGROUND AND AIMS
Stomatal regulation allows plants to promptly respond to water stress. However, our understanding of the impact of above and belowground hydraulic traits on stomatal regulation remains incomplete. The objective of this study was to investigate how key plant hydraulic traits impact transpiration of maize during soil drying. We hypothesize that the stomatal response to soil drying is related to a loss in soil hydraulic conductivity at the root-soil interface, which in turn depends on plant hydraulic traits.
METHODS
We investigate the response of 48 contrasting maize (Zea mays) genotypes to soil drying, utilizing a novel phenotyping facility. In this context, we measure the relationship between leaf water potential, soil water potential, soil water content and transpiration, as well as root, rhizosphere and aboveground plant traits.
KEY RESULTS
Genotypes differed in their responsiveness to soil drying. The critical soil water potential at which plants started decreasing transpiration was related to a combination of above and belowground traits: genotypes with a higher maximum transpiration and plant hydraulic conductance as well as a smaller root and rhizosphere system closed stomata at less negative soil water potentials.
CONCLUSIONS
Our results demonstrate the importance of belowground hydraulics for stomatal regulation and hence drought responsiveness during soil drying. Furthermore, this finding supports the hypothesis that stomata start to close when soil hydraulic conductivity drops at the root-soil interface.
背景与目的
气孔调节使植物能够迅速应对水分胁迫。然而，我们对地上和地下水力特性对气孔调节的影响的理解仍不完整。本研究的目的是探讨关键植物水力特性如何影响玉米在土壤干燥过程中的蒸腾作用。我们假设气孔对土壤干燥的响应与根土界面处土壤水力传导率的丧失有关，而这又取决于植物水力特性。
方法
我们利用一种新的表型设施研究了 48 个不同玉米（Zea mays）基因型对土壤干燥的响应。在这种情况下，我们测量了叶片水势、土壤水势、土壤含水量和蒸腾之间的关系，以及根系、根际和地上植物特性。
主要结果
不同基因型对土壤干燥的响应存在差异。植物开始减少蒸腾作用的临界土壤水势与地上和地下特性的组合有关：具有较高最大蒸腾作用和植物水力传导率以及较小根系和根际系统的基因型，在土壤水势较负时关闭气孔。
结论
我们的结果表明，地下水力对气孔调节以及土壤干燥过程中的干旱响应很重要。此外，这一发现支持了这样一种假设，即当根土界面处的土壤水力传导率下降时，气孔开始关闭。
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