Leaf lamina conductance contributes to an equal distribution of water delivery in current-year shoots of kudzu vine shoot
Leaf lamina conductance contributes to an equal distribution of water delivery in current-year shoots of kudzu vine shoot
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叶片导度有助于当年葛藤枝条水分输送的均匀分布
DOI：
10.1093/treephys/tpr072
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Masaki Tateno
中科院分区：
文献类型：
--
作者：
Haruhiko Taneda; Masaki Tateno
叶面抗性（RL）在许多植物物种的分枝抗性中占很大比例。这项工作假设，较大的lis对于将水分均匀地分配给茎上的叶子至关重要，并通过理论分析和测量来验证这一假设，使用了超过10米长的葛根藤，葛根藤，野葛根。Ohwi。首先，通过对葛藤茎部和叶部的水流量进行模拟，从理论上获得了实现均匀输水的水力结构和动力分布。该模型预测，横向通道相对于轴向通道的阻力较大，与节点间从轴向通道底部到横向通道的水力导度变化较小密切相关，使得在水流动力变化较小的情况下，各横向通道的输水量相等。测得的葛藤茎部侧抗（叶柄）与轴抗（茎）之比为115。当rl加入外侧通路时，比例增加到1136。根据模型预测，这些值表明，由茎和叶柄组成的通道（KBP）在基节点上的水力传导能力更强，而由茎、叶柄和叶片组成的通道（KSL）在节点上的水力传导能力略有不同。对于有叶片层状的枝条，将枝条分成4部分的3节上叶片蒸腾速率的日变化没有差异。ksl与节点数无显著相关。相反，远端淋巴结的KBPat是基底淋巴结的0.06倍。此外，水流动力在节点间的变化应该是6.64倍，以补偿kbp的有利分布，这是一个不现实的值。这些结果表明，rl在很大程度上有助于均匀分布的水输送在一个射击，支持我们的假设。
Leaf-lamina resistance,RL, accounts for a large fraction of branch resistance across a wide range of plant species. This work hypothesized that largeRLis essential for distributing water equally to leaves on the shoot, and tested this hypothesis through theoretical analyses and measurements using over 10-m-long current-year shoots of kudzu vine,Pueraria lobata[Willd.] Ohwi. First, the hydraulic architecture and the distribution of the motive force achieving equal distribution of water delivery were theoretically obtained by simulating water flow through a hypothetical shoot comprising an axial pathway and several lateral pathways as a stem and leaves, respectively, in a kudzu-vine shoot. The model predicts that large resistance of the lateral pathway relative to that of the axial pathway is associated strongly with small variation in the hydraulic conductance of a pathway from the base of the axial pathways to the lateral pathway among the nodes, rendering water delivery to each lateral pathway equal under small variation in motive force for water flow. For the kudzu-vine shoot, the measured ratio of the lateral (a petiole) to the axial (a stem) resistance was 115. WhenRLwas added to the lateral pathway, the ratio increased to 1136. According to the model prediction, these values imply that the hydraulic conductance of a pathway comprising a stem and a petiole,KBP, is favored strongly at the basal nodes, while the hydraulic conductance of a pathway including a stem, a petiole and a lamina,KSL, is slightly different across the nodes. For the shoots with leaf lamina, the diurnal change in transpiration rate was not different between the leaves on the three nodes dividing the shoot into four parts.KSLwas not related significantly to node number. Conversely,KBPat the distal node was ∼0.06-fold that at the basal node. Furthermore, the motive force for water flow should vary by 6.64-fold among nodes to compensate for the favored distribution ofKBP, which is an unrealistic value. These results indicate thatRLcontributes largely to an equal distribution of water delivery in a shoot, supporting our hypothesis.