不同生境条件下蕨类和被子植物的气孔形态特征及其对光强变化的响应

气孔是植物与大气环境进行气体交换的重要通道, 在调控植物碳水平衡方面发挥着重要作用。为探讨生境和植物类型对气孔形态特征的影响以及气孔对光强变化的响应格局在不同植物间和不同生境条件下的变异, 选取开阔生境和林下生境的5种蕨类植物和4种被子植物, 测定了它们的气孔形态特征和气孔导度对光强变化的响应。此外, 还收集了8篇文献中开阔和林下生境的45种蕨类植物和70种被子植物的气孔密度和气孔长度数据, 以增大样本量从而更好地探讨不同生境条件下蕨类和被子植物气孔密度及长度的变异格局, 并通过分析生境和植物类型对气孔形态特征的影响来推测生境和植物类型对气孔响应行为的可能影响。实验结果表明, 与林下植物相比, 开阔环境下的植物气孔密度更大, 气孔长度更小, 气孔对光强降低的响应更敏感; 但植物类型对气孔形态特征的影响以及对气孔响应光强的敏感程度的影响均不显著。对文献数据的分析表明, 生境和植物类型对气孔形态特征均有显著影响。考虑到气孔响应快慢与气孔形态特征密切相关, 与蕨类植物相比, 被子植物小而密的气孔可能为其更快地响应环境变化提供了基础。研究表明生境和植物类型对气孔响应行为均有显著影响。

Stomatal characteristics of ferns and angiosperms and their responses to changing light intensity at different habitats

Aims Stomata are critical in controlling the exchange of water vapour and carbon dioxide and maintaining the balance between plant water and carbon relations. Here, we investigated the effects of habitat (open and understory) and plant type (ferns and angiosperms) on stomatal morphology and stomatal responses to changing light intensity. Methods We measured stomatal morphology and stomatal conductance in response to transitions in light intensity in five ferns and four angiosperms from different habitats. To increase the sample size, we also collected data on stomatal characteristics for 45 ferns and 70 angiosperms from published studies.Important findings For all the nine species, the plants in open-habitat had significantly greater stomatal density, shorter stomatal length and greater sensitivity to decreasing light intensity than those in the understory, but the effect of plant type was not significant. Combined analysis with published data indicated that the effects of both habitat and plant type on stomatal morphology were significant. As stomatal sensitivity was closely linked to stomatal morphology, more and smaller stomata might enable angiosperms to respond more quickly to environmental perturbations than ferns. We conclude that both habitat and plant type affect the stomatal response to light.