THE EFFECTS OF SOIL AND ATMOSPHERIC DROUGHT ON PHOTOSYNTHESIS AND STOMATAL CONTROL OF GAS-EXCHANGE IN 3 CONIFEROUS SPECIES
THE EFFECTS OF SOIL AND ATMOSPHERIC DROUGHT ON PHOTOSYNTHESIS AND STOMATAL CONTROL OF GAS-EXCHANGE IN 3 CONIFEROUS SPECIES
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DOI：
10.1111/j.1399-3054.1988.tb09199.x
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发表时间：
1988-05-01
影响因子：
6.4
通讯作者：
AUSSENAC, G
中科院分区：
文献类型：
--
作者：
GRIEU, P;GUEHL, JM;AUSSENAC, G
在花旗松、大果黄杉和大西洋雪松的2年生幼苗中检查了稳态CO2同化速率（A）、蒸腾速率（E）和气孔导度（gs）一方面对叶-空气蒸气压差（Δ W）变化的响应，另一方面对土壤干旱增加的响应。通过A与细胞间CO2摩尔分数（ci）图分析数据，我们可以确定气孔和叶肉对A变化的贡献，因为Δ W或土壤干旱增加。土壤干旱程度的增加对气孔导度和叶肉光合作用的影响是独立的，因为在黎明前叶水势（ψ.p）区域中，气孔导度和叶肉光合作用的影响都占主导地位。这两种黄杉属物种表现出大的psi.p范围（在约-0.8和-1.5至-1.9MPa之间），其中只有气孔负责A.叶肉光合作用从高达-1.2MPa（C.大果杨（P. macrocarpa）为-1.5 MPa，门氏杨（P. menziesii）为-1.9 MPa。在高土壤含水量下增加Δ W导致A急剧下降，这主要是由于叶肉光合作用的改变。气孔导度对CO2扩散的影响较小，但与叶肉光合作用的变化密切相关，表明叶肉光合作用与气孔之间存在着功能联系。抗旱大果杨在两种干旱条件下表现出最低的水分利用效率。在本种干旱适应似乎主要是由于其高根生长和土壤勘探能力。
The responses of steady-state CO2 assimilation rate (A), transpiration rate (E), and stomatal conductance (gs) to changes in leaf-to-air vapour pressure difference (.DELTA.W) on one hand and to increasing soil drought on the other hand were examined in 2-year-old seedlings of Pseudotsuga menziesii, Pseudotsuga macrocarpa and Cedrus atlantica. Analysing the data through A vs intercellular CO2 molar fraction (ci) graphs, we could determine stomatal and mesophyll contributions to changes in A as .DELTA.W or soil drought were increased. Increasing soil drought affected gs and mesophyll photosynthesis independently, since clearly distinct predawn leaf water potential (.psi.p) regions appeared in which either stomatal or mesophyll effects prevailed for explaining the changes in A. The two Pseudotsuga species exhibited a large .psi.p range (between ca -0.8 and -1.5 to -1.9 MPa) in which only stomata were responsible for the decrease in A. A dramatic decline in mesophyll photosynthesis was noticed starting from values as high as -1.2 MPa (C. atlantica), -1.5 MPa (P. macrocarpa) and -1.9 MPa (P. menziesii). Increasing .DELTA.W at high soil water content led to a sharp decline in A primarily due to an alteration of mesophyll photosynthesis. Stomatal conductance for CO2 diffusion was affected in a lesser extent and in close correlation with the changes in mesophyll photosynthesis, which could suggest the existence of a functional linkage between mesophyll photosynthesis and stomata. Surprisingly, the drought resistant P. macrocarpa exhibited the least conservative water use efficiency in response to the two types of drought. In this species drought adaptation seems to be mainly due to its high root growth and soil prospection ability.