Hydraulic architecture with high root‐resistance fraction contributes to efficient carbon gain of plants in temperate habitats.
Hydraulic architecture with high root‐resistance fraction contributes to efficient carbon gain of plants in temperate habitats.
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具有高根系阻力分数的水力建筑有助于温带栖息地植物的有效碳增益。
DOI：
10.1002/ajb2.1753
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发表时间：
2021
影响因子：
3
通讯作者：
Takefumi Ikeda
中科院分区：
文献类型：
--
作者：
Haruhiko Taneda;Takefumi Ikeda
植物叶、茎和根中的水力结构通过气孔限制二氧化碳的吸收来限制水分运输和碳的获得。由于根是一系列植物水分运输的主要瓶颈，我们评估了木本植物和草本植物中高比例根水力阻力的生态生理机制和重要性。方法测定了日本结缕草(多年生草本植物)和泽尔科娃(Zelkova Serrata)叶、茎和根的生物量分配和水力传导性。通过理论分析验证了测量的水力结构和生物量分配是否最大化了植物的光合作用速率(叶面积和单位叶面积的光合作用速率的乘积)。结果根部水力阻力分别占日本虎杖和泽尔科娃植物总阻力的83%和68%。水力分配和生物量分配的比较表明，较高的抗根分配率是由于较低的生物量分配到根器官，而不是高质量比根电导。测量的水力阻力分配与预测的最优分配密切相关，使两个物种的植物光合作用速率达到最大。随着空气湿度和土壤水势的变化，根阻力的高比例被预测为最佳。结论这些结果表明，在中等肥沃的生境中生长的植物的水力结构不仅由于较少的生物量分配到根器官而导致高根阻力，而且有助于有效地获得碳。
PremiseThe hydraulic architecture in the leaves, stems and roots of plants constrains water transport and carbon gain through stomatal limitation to CO2absorption. Because roots are the main bottleneck in water transport for a range of plant species, we assessed the ecophysiological mechanism and importance of a high fraction of root hydraulic resistance in woody and herbaceous species.MethodsBiomass partitioning and hydraulic conductance of leaves, stems, and roots of Japanese knotweed (Fallopia japonica, a perennial herb) and Japanese zelkova (Zelkova serrata, a deciduous tall tree) were measured. Theoretical analyses were used to examine whether the measured hydraulic architecture and biomass partitioning maximized the plant photosynthetic rate (the product of leaf area and photosynthetic rate per leaf area).ResultsRoot hydraulic resistance accounted for 83% and 68% of the total plant resistance for Japanese knotweed and Japanese zelkova, respectively. Comparisons of hydraulic and biomass partitioning revealed that high root‐resistance fractions were attributable to low biomass partitioning to root organs rather than high mass‐specific root conductance. The measured partitioning of hydraulic resistance closely corresponded to the predicted optimal partitioning, maximizing the plant photosynthetic rate for the two species. The high fraction of root resistance was predicted to be optimal with variations in air humidity and soil water potential.ConclusionsThese results suggest that the hydraulic architecture of plants growing in mesic and fertile habitats not only results in high root resistance due to small biomass partitioning to root organs, but contributes to efficient carbon gain.