不同生长期淡竹叶片解剖结构及其光响应研究

【目的】探讨淡竹开花期间不同形态叶片显微结构的差异,对比分析淡竹开花期间佛焰苞显微结构及其光响应的变化,阐明淡竹开花期间叶片衰老机制。【方法】取淡竹未开花竹株营养叶、开花竹株营养叶以及不同开花时期佛焰苞,70%FAA固定,石蜡切片后用于显微结构观察。戊二醛固定,常规电镜制片用于透射电镜观察。同时,对不同时期叶片进行光合速率测定。【结果】淡竹花期内,随着花的不断发育,佛焰苞厚度、相邻维管束间距离及维管束横截面积不断降低。佛焰苞叶绿体有明显的淀粉粒、类囊体、基质片层及嗜锇颗粒的存在,开花后期佛焰苞中叶绿体结构崩溃。淡竹开花后期3种不同功能叶片最大光合速率分别下降了87.03%、62.48%和55.00%。【结论】淡竹开花期间,随着花的不断发育,叶片维管束面积与数量减小,叶片合成及运输营养物质的能力减弱,叶片逐渐衰老脱落,进而造成竹株死亡。

Research on the structure and photosynthetic responses of Phyllostachys glauca spathes during flowering

Abstract: 【Objective】This study aimed to evaluate the morphological differences in Phyllostachys glauca leaves, analyze changes in the ultrastructure and photosynthetic responses of the spathes during flowering, explain the mechanisms of bamboo leaf senescence, and explore the reasons for bamboo plant death after flowering. 【Method】Normal leaves of non-flowering and flowering bamboo plants and spathes at different flowering periods were collected and fixed in volume fraction 70% FAA in order to observe their microstructure. Some leaves were fixed in glutaraldehyde in order to observe the ultrastructure. The leaves of bamboo plants that were growing well, without damage from pests or disease, were selected for determination of the photosynthetic rate. 【Result】During the flowering period, the distance between the adjacent vascular bundle and transverse area of the spathe vascular bundle decreased with continuous development of flowers. The spathe chloroplasts showed obvious starch grains, thylakoids, matrix lamellae and osmiophilic granules. The chloroplast structure collapsed in the later flowering period. The maximum photosynthetic rate of three different functional leaves decreased by 87.03%, 62.48% and 55.00%, respectively, in the late flowering period of Phyllostachys glauca. 【Conclusion】During the Phyllostachys glauca flowering period, the area and quantity of the leaf vascular bundles continuously decreased, therefore diminishing the ability of leaves to synthesize and transport nutrients. The leaves then gradually became senescent, which may be the major reason for death of bamboo plants.