CNR, Istituto di Biometeorologia (IBIMET), Florence, Italy.
Oecologia. 2013 Jan;171(1):71-82. doi: 10.1007/s00442-012-2406-9. Epub 2012 Jul 19.
Plant stomata display a wide range of short-term behavioural and long-term morphological responses to atmospheric carbon dioxide concentration ([CO(2)]). The diversity of responses suggests that plants may have different strategies for controlling gas exchange, yet it is not known whether these strategies are co-ordinated in some way. Here, we test the hypothesis that there is co-ordination of physiological (via aperture change) and morphological (via stomatal density change) control of gas exchange by plants. We examined the response of stomatal conductance (G(s)) to instantaneous changes in external [CO(2)] (C(a)) in an evolutionary cross-section of vascular plants grown in atmospheres of elevated [CO(2)] (1,500 ppm) and sub-ambient [O(2)] (13.0 %) compared to control conditions (380 ppm CO(2), 20.9 % O(2)). We found that active control of stomatal aperture to [CO(2)] above current ambient levels was not restricted to angiosperms, occurring in the gymnosperms Lepidozamia peroffskyana and Nageia nagi. The angiosperm species analysed appeared to possess a greater respiratory demand for stomatal movement than gymnosperm species displaying active stomatal control. Those species with little or no control of stomatal aperture (termed passive) to C(a) were more likely to exhibit a reduction in stomatal density than species with active stomatal control when grown in atmospheres of elevated [CO(2)]. The relationship between the degree of stomatal aperture control to C(a) above ambient and the extent of any reduction in stomatal density may suggest the co-ordination of physiological and morphological responses of stomata to [CO(2)] in the optimisation of water use efficiency. This trade-off between stomatal control strategies may have developed due to selective pressures exerted by the costs associated with passive and active stomatal control.
植物气孔表现出广泛的短期行为和长期形态响应，以适应大气二氧化碳浓度 ([CO2])。这些响应的多样性表明，植物可能有不同的控制气体交换的策略，但目前尚不清楚这些策略是否以某种方式协调。在这里，我们检验了一个假设，即在植物对气体交换的生理（通过孔径变化）和形态（通过气孔密度变化）控制方面存在协调性。我们研究了在大气中升高的 [CO2]（1500ppm）和亚大气 [O2]（13.0%）环境中生长的维管植物进化横切面上，气孔导度（G(s)）对外部 [CO2]（C(a)）瞬时变化的响应，与对照条件（380ppm CO2，20.9% O2）相比。我们发现，主动控制气孔对高于当前环境水平的 [CO2] 的孔径，不仅限于被子植物，在裸子植物 Lepidozamia peroffskyana 和 Nageia nagi 中也存在。分析的被子植物物种似乎比表现出主动气孔控制的裸子植物物种对气孔运动有更高的呼吸需求。那些对 C(a)几乎没有或没有气孔孔径控制（称为被动）的物种，当在大气中升高的 [CO2] 中生长时，比具有主动气孔控制的物种更有可能减少气孔密度。在优化水分利用效率方面，气孔对高于环境的 C(a)的孔径控制程度与气孔密度任何减少程度之间的关系，可能表明气孔对 [CO2] 的生理和形态响应之间存在协调性。这种气孔控制策略之间的权衡可能是由于与被动和主动气孔控制相关的成本施加的选择压力而发展起来的。
