Hydraulic conductance and vulnerability to cavitation in corn (Zea mays L.) hybrids of differing drought resistance
Hydraulic conductance and vulnerability to cavitation in corn (Zea mays L.) hybrids of differing drought resistance
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DOI：
10.1016/j.envexpbot.2009.02.001
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发表时间：
2009-05-01
影响因子：
5.7
通讯作者：
Shao, Mingan
中科院分区：
文献类型：
--
作者：
Li, Yangyang;Sperry, John S.;Shao, Mingan
通过木质部的水分运输对于补充蒸腾过程中的水分损失是必不可少的。从而防止干燥并允许光合作用。干旱引起的空化和栓塞会损害向蒸腾叶的运输。这一学科的大部分研究都是在木本植物上进行的。对作物空化及其对理解作物水分关系的生理意义的研究较少。本文研究了不同抗旱性玉米杂交种的导水率和木质部对空化的敏感性。结果表明，抗旱品种‘先锋3902’不仅在叶面积和叶面积上具有较高的电导率，而且具有较强的抗气蚀能力。‘先锋3902’在63.2%电导率损失时的木质部压力(威布尔拟合参数b)和50%电导率损失时的木质部压力(P-50)比‘骄傲5’的木质部压力低约0.2兆帕。‘先锋3902’的较高电导率主要归因于单位茎面积维管束较多，而不是导管直径较大。中央维管束和外围维管束的空化程度相同，但中央维管束的血管一般比外围维管束大。皇冠版权所有(C)2009由Elsevier B.V.出版。保留所有权利。
Water transport through the xylem is essential for replacing water loss during transpiration. thus preventing desiccation and permitting photosynthesis. The occurrence of cavitation and embolism due to drought impairs transport to the transpiring leaves. Most research in this discipline has been conducted on woody plants. Less attention has been given to cavitation of crops and its physiological significance for understanding crop water relations. In this paper, hydraulic conductance and vulnerability of xylem to cavitation were studied in corn hybrids with different drought resistances. The results indicated that steins of drought-resistant 'Pioneer 3902' not only had a higher conductivity on both a stein area and leaf area basis but also had a greater resistance to cavitation. The estimated xylem pressure at 63.2% loss of conductivity (Weibull fitting parameter b) and at 50% loss of conductivity (P-50) in 'Pioneer 3902' were about 0.2 MPa lower than in 'Pride 5'. Higher conductivity in 'Pioneer 3902' was mainly attributed to more vascular bundles per stem area rather than greater vessel diameter. The central bundles and peripheral vascular bundles showed the same degree of cavitation although the vessels of central bundles were generally larger than in peripheral bundles. Crown Copyright (c) 2009 Published by Elsevier B.V. All rights reserved.