欢迎访问《生态学杂志》官方网站,今天是 分享到:

生态学杂志 ›› 2023, Vol. 42 ›› Issue (8): 1793-1801.doi: DOI:10.13292/j.1000-4890.202308.016

• 研究报告 • 上一篇    下一篇

锦绣杜鹃对不同光环境的光合特性响应及适应机制

冷寒冰1,2,苏鸣1,2,张春英1,2*


  

  1. 1上海植物园, 上海 200231; 2上海城市植物资源开发应用工程技术研究中心, 上海 200231)

  • 出版日期:2023-08-10 发布日期:2023-07-27

Responses of photosynthetic traits and adaptive mechanisms of Rhododendron pulchrum Sweet to different light environments.

LENG Hanbing1,2, SU Ming1,2, ZHANG Chunying1,2*   

  1. (1Shanghai Botanical Garden, Shanghai 200231, China; 2Shanghai Engineering Research Center of Sustainable Plant Innovation, Shanghai 200231, China).

  • Online:2023-08-10 Published:2023-07-27

摘要: 以锦绣杜鹃(Rhododendron pulchrum Sweet)为试验材料,选取全光照(100% FL)、轻度遮阴(82.01% FL)、中度遮阴(50.13% FL)、重度遮阴(15.80% FL)4种光环境处理,研究不同光环境对锦绣杜鹃叶片光合生理生化特性的影响,探讨锦绣杜鹃对光环境变化的适应机制。结果表明:(1)随着遮阴程度的增加,锦绣杜鹃叶片面积、光合色素和氮含量显著增加,比叶重、碳含量、碳氮比显著降低,叶绿素a/b先降低后升高。(2)锦绣杜鹃叶片在中度遮阴和全光环境下分别具有显著较高的最大光化学量子效率和非光化学猝灭系数,而实际光化学量子产率、光化学猝灭系数、可调节性能量耗散量子效率、非可调节性能量耗散量子效率仅在重度遮阴环境有显著变化。(3)遮阴导致锦绣杜鹃叶片暗呼吸速率、光补偿点逐渐下降,表观量子效率、最大净光合速率、光饱和点在中度遮阴达到最高值,其光合性能最强。(4)全光照环境生长的锦绣杜鹃叶片净光合速率下调,同时气孔导度下降,气孔限制值上升,气孔限制因素是导致净光合速率下降的主要原因;重度遮阴下叶片光合受限,主要受光系统Ⅱ光化学效率降低以及吸收光能分配比例失衡影响。综上,锦绣杜鹃耐强光,也适应弱光环境,但中度遮阴的光环境,即全光照的50%左右最有利于其生长。在栽培和园林应用中,可将其适当遮阴或者配置于有一定透光性的落叶林下。


关键词: 锦绣杜鹃, 光环境, 叶绿素荧光, 气体交换, 光合适应性

Abstract: The aim of this study was to explore leaf photosynthetic and biochemical characteristics and adaptive mechanisms of Rhododendron pulchrum Sweet under different light environments, including full light (FL, 100% natural sunlight), slight shading (LS, 82.01% full light), moderate shading (MS, 50.13% full light), and severe shading (SS, 15.80% full light). The results showed that leaf area and the contents of photosynthetic pigments and total nitrogen increased with decreasing light intensity, while specific leaf mass, total carbon content and carbon/nitrogen ratio decreased, and chlorophyll a/b decreased firstly and then increased. Maximum quantum photochemical efficiency and non-photochemical quenching coefficient were significantly higher under MS and FL treatments than that under the other treatments, respectively. The actual quantum photochemical efficiency, photochemical quenching coefficient, and quantum yield of quenching under SS treatment were significantly lower than that under the other three treatments. Dark respiration rate and light compensation point decreased with decreasing light intensity, while the maximum values in apparent quantum efficiency, maximum net photosynthetic rate and light saturation point) were detected under MS treatment, suggesting the strongest photosynthetic capacity. R. pulchrum under FL treatment had lower net photosynthetic rate (Pn) accompanied with lower stomatal conductance and higher stomatal limitation value. Such decrease in Pn under FL treatment was mainly due to stomatal limitation. In comparison, Pn under SS treatment was inhibited mainly due to the reduction in photochemical efficiency and imbalance in fraction of incident light in photosystem Ⅱ. Our results suggested that R. pulchrum had good performance in tolerance range of light intensities, and that moderate shading (i.e., 50% full light) was optimal for its growth. Consequently, proper shading or community configuration under deciduous forest with sparse canopy should be employed regarding its cultivation or application in gardens.


Key words: Rhododendron pulchrum Sweet, light environment, chlorophyll fluorescence, gas exchange, photosynthetic adaptability.