Abstract: In order to explore the adaptability of Commelinaceae plants under different light intensities,in this research,Commelina purpurea,Tradescantia flurnuensis ‘Variegata’,Tradescantia zebrina and Tradescantia flurnuensis ‘Vairidia’ were used as experimental material to study the physiological and biochemical indicators as well as mesophyll cell ultrastructure,when grown at different light levels. Shading net was used to creat a series of five light levels. The results indicated that:with the decrease of light intensity,the soluble protein content of the four plants decreased significantly,the soluble sugar content and proline content showed different trends. The O₂^·- content,H₂O₂ content,and MDA content of four plants were the highest under 100% natural light intensity;The activities of SOD,CAT and POD in four plants maintained high levels under 100% natural light intensity. As the light intensity decreases,they showed different trends. The study on the ultrastructure of mesophyll found that 100% natural light intensity damaged the four plants severely,for example,the plasma membrane structure was damaged,the number of chloroplasts and mitochondria reduced significantly,and the number of starch grains and osmophilic granules decreased. In summary,the damage caused by strong light to the four plants is much severe than that of the weak light. The order of the light-adaptability was that:Tradescantia zebrina > Commelina purpurea > Tradescantia flurnuensis ‘Variegata’ > Tradescantia flurnuensis ‘Vairidia’.

Key words: Light intensities, Commelinaceae plants, Physiological characteristics, Ultrastructure

摘要： 为探究鸭跖草科植物对不同光强的适应能力，本研究以紫鸭跖草（Commelina purpurea）、‘花叶’水竹草（Tradescantia flurnuensis ‘Variegata’）、吊竹梅（Tradescantia zebrina）和‘绿叶’水竹草（Tradescantia flurnuensis ‘Vairidia’）为试验材料，通过遮光网设置5种光强梯度进行试验，研究不同光强对4种植物生理生化指标以及叶肉细胞超微结构的影响。结果表明：随光强的降低，4种植物的可溶性蛋白含量显著降低，可溶性糖和脯氨酸含量呈不同的变化趋势；4种植物的O₂^·-，H₂O₂以及丙二醛含量在100%自然光强下最高；4种植物的超氧化物歧化酶、过氧化氢酶和过氧化物酶活性在100%自然光强下保持较高水平，随光强的降低，则呈不同的变化趋势。对叶肉超微结构的研究发现，100%自然光强对4种植物造成了强光伤害，导致质膜结构破损，叶绿体和线粒体数量显著减少，淀粉粒和嗜锇颗粒数量增加。综上可得，强光对4种植物造成的伤害远大于弱光伤害，4种植物光适能力的强弱的顺序为：吊竹梅 > 紫鸭跖草 > ‘花叶’水竹草 > ‘绿叶’水竹草。

关键词: 光强, 鸭跖草科植物, 生理特性, 超微结构