Department of Forest Botany, Dendrology and Geobiocenology, Mendel University in Brno, Brno, Czech Republic.
Siberian Federal University, Krasnoyarsk, Russia.
J Exp Bot. 2017 Mar 1;68(7):1757-1767. doi: 10.1093/jxb/erx052.
The effect of temperature on stomatal conductance (gs) and corresponding gas exchange parameters was studied in two tree species with contrasting leaf anatomy and ecophysiology-a broadleaf angiosperm, Populus deltoides x nigra (poplar), and a needle-leaf gymnosperm, Pinus taeda (loblolly pine). Experiments were conducted in growth chambers across a leaf temperature range of 19-48°C. Manipulations of temperature were done in well-watered and drought soil conditions and under ambient (400 ppm) and elevated (800 ppm) air CO2 concentrations. Increases in leaf temperature caused stomatal opening at both ambient and elevated [CO2]. The gs increased by 42% in poplar and by 40% in loblolly pine when leaf temperature increased from 30°C to 40°C at a vapour pressure difference of 1 kPa. Stomatal limitation to photosynthesis decreased in elevated temperature in loblolly pine but not in poplar. The ratio of net photosynthesis to gs depended on leaf temperature, especially at high temperatures. Evaporative cooling of transpiring leaves resulted in reductions in leaf temperature up to 9°C in well-watered poplar but only 1°C in drought-stressed poplar and in loblolly pine. As global mean temperatures rise and temperature extremes become more frequent and severe, understanding the effect of temperature on gs, and modelling that relationship, will become increasingly important.
我们研究了两种具有不同叶解剖结构和生理特性的树种——一种是阔叶被子植物黑杨杂种（杨），另一种是针叶裸子植物火炬松（松）——在温度对气孔导度（gs）和相应气体交换参数的影响。实验在生长室中进行，叶片温度范围为 19-48°C。在充分浇水和干旱土壤条件下，并在环境（400 ppm）和升高（800 ppm）空气 CO2 浓度下，对温度进行了操纵。在环境和升高的[CO2]下，叶片温度的升高导致气孔张开。当叶温从 30°C升高到 40°C，水汽压差为 1 kPa 时，杨的 gs 增加了 42%，松增加了 40%。在升高的温度下，松的光合作用受到气孔限制的程度降低，但杨没有。净光合速率与 gs 的比值取决于叶片温度，尤其是在高温下。蒸腾叶片的蒸发冷却导致充分浇水的杨叶片温度降低多达 9°C，但在干旱胁迫的杨和松中仅降低 1°C。随着全球平均气温上升，极端温度变得更加频繁和剧烈，了解温度对 gs 的影响，并对这种关系进行建模，将变得越来越重要。
