高光和低光下木本植物形态和生理可塑性响应

光资源的时空异质性普遍存在.为了提高光利用效率或有效避免强光的伤害,植物通常采取多种调节措施.植物适应林下异质、多变的环境过程中,表型的可塑性是非常关键的.植物表型可塑性与其环境异质性密不可分.植物通过生长变化、生物量分配、光合器官结构调整、叶氮分配、抗氧化防御系统、热耗散机制,以及长期的表型可塑性来增大截取光资源的潜力和实际光资源利用效率,同时也为自身提供了一种有效的保护机制.大量实验证明,阳生植物比阴生植物表现出较大的表型可塑性,且其可塑性方式存在差异.本文主要阐述了植物对高光和低光条件的形态和生理可塑性适应,为了解植物在极端光照条件下生存与繁殖提供参考.大量的人工模拟与自然光照实验有待进行来阐明植物对自然光照条件的适应,为植被恢复和重建提供参考和依据.参96

MORPHOLOGICAL AND PHYSIOLOGICAL PLASTICITY OF WOODY PLANT IN RESPONSE TO HIGH LIGHT AND LOW LIGHT

Being sessile, plants have evolved numerous strategies to accommodate contrasting light environment, so as to efficiently capture and use limited light resource and to avoid the damaging effects of excessive irradiance. Plant performance is enhanced through morphological and physiological acclimation to light environment. The plasticity of morphological and physiological traits enables the woody plants to survive at the extremes of light gradients. Shade plants and sun plants have developed distinct morphological and physiological strategies for acclimation to contrasting light environment. These strategies involve changes in growth, alteration in biomass allocation, readjustment in structure of the photosynthetic apparatus, nitrogen allocation to different photosynthetic processes, up - regulation antioxidant defense systems and thermal dissipation, as well as a long -term adjustment that renders a differentiated phenotype. Frequent evidence indicates that sun plants display a larger phenotype plasticity than shade - tolerant ones, though the reverse is sometimes observed. A rational understanding of how plants survive and thrive in adverse light environment is provided in this review. Results from this review lead to useful conclusions for establishing better management practices. Extensive studies on natural light conditions in conjunction with artificial simulation experiments are needed to quantify the effects of natural light conditions on woody plants, so as to facilitate the development of silvicultural regeneration techniques for forest management. Ref 96