Water Relations of Sunflower (Helianthus annuus) Shoots during Exposure of the Root
Water Relations of Sunflower (Helianthus annuus) Shoots during Exposure of the Root
复制标题
向日葵（Helianthus annuus）根部暴露期间的水关系
DOI：
10.1093/jxb/40.11.1255
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
M. Drew
中科院分区：
文献类型：
--
作者：
J. Everard;M. Drew
在环境控制室内研究了根系缺氧对水培向日葵水分平衡的影响。叶水势下降1小时内开始的厌氧处理的根。在最初的8小时的治疗过程中的水分胁迫的严重程度取决于空气环境的环境湿度。在处理的第二个全天开始时发生了芽水平衡的恢复，没有气孔关闭。连续厌氧处理3d后，同一实验中的植物反应遵循两种模式之一。在第一个阶段，叶片含水量、叶水势、叶片膨胀度、蒸腾速率和气孔导度均下降。发生渗透调节，但不足以防止膨压的损失，并且植物在处理的第4天萎蔫。完全再水化发生后6天的治疗，如果茎被切断（水下）的子叶下面，表明芽脱水是木质部闭塞在根/芽界面的结果。该区域的茎切片显示木质部导管变色，板状结构阻塞管腔。在其他模式的响应，植物没有开发一个更负的叶水势（除了初始阶段后立即开始治疗）在整个6天的厌氧处理期间。有没有水分亏缺的迹象，虽然其他症状，如早熟叶片衰老和上位性发生伴随着那些在第一组的植物，开发长期的水分胁迫。在拍摄水的关系的变化进行了讨论，在我们早期的观察缺氧引起的变化的水力传导性和选择性的根。对根系缺氧引起的植株间变异提供了可能的解释。
The influence of root anoxia on the water balance of hydroponically grown sunflower plants was investigated in a controlled environment room. Leaf water potentials declined within 1 h of the onset of anaerobic treatment of the roots. The severity of the water stress during the initial 8 h of treatment was dependent on the ambient humidity of the aerial environment. Recovery of shoot water balance occurred by the beginning of the second full day of treatment, without stomatal closure. After 3 d of continuous anaerobic treatment, plant response in the same experiment followed one of two patterns. In the first, there were declines in leaf water content, leaf water potentials, lamina expansion, transpiration rates and stomatal conductance. Osmotic adjustment occurred but it was not sufficient to prevent loss of turgor and the plants wilted at day 4 of treatment. Complete rehydration took place after 6 d of treatment if the stem was severed (under water) just below the cotyledons, indicating that shoot dehydration was a result of xylem occlusion at the root/shoot interface. Sections of the stem in this region showed xylem vessels to be discoloured and plate-like structures obstructing the lumen. In the other pattern of response, plants did not develop a more negative leaf water potential (except for an initial period immediately following treatment initiation) throughout the 6-d anaerobic treatment period. There were no signs of water deficit although other symptoms such as precocious leaf senescence and epinasty occurred concomitantly with those in the first group of plants that developed long-term water stress. Changes in shoot water relations are discussed in terms of our earlier observations on anoxia-induced changes in the hydraulic conductivity and selectivity of the roots. Possible explanations are offered for inter-plant variations in response to root anoxia.