阳生和阴生地木耳生理生化特性的比较

以生长于不同光环境下的地木耳为材料,对其Fv/Fm的日变化、光合作用特性、叶绿素和类胡萝卜素的含量进行了研究,以了解其光适应的生理生化基础。同阴生地木耳相比,阳生地木耳的光饱和点、类胡萝卜素含量、类胡萝卜素和叶绿素的比值均比较高,但其P-I曲线光限制部分的斜率、暗呼吸速率、Fv/Fm、叶绿素、MAAs含量和单位面积干重较低。二者最大光合速率和光补偿点无明显差异,二者均无明显的光呼吸。同等条件的光抑制后,阳生地木耳在暗处能更快、更大程度地恢复其Fv/Fm活性。原位研究表明,阴生和阳生地木耳在雨后强光下均有不同程度的光抑制发生,但在弱光下或夜晚时会及时恢复。阳生和阴生地木耳的光合特性及色素含量显著不同,以此来适应不同环境中的光因子。

Comparative Studies on Physiological and Biochemical Characteristics of Sun and Shade Acclimated Nostoc commune

In order to clarify the physiological and biochemical basis of Nostoc commune lived in different environmental light levels,their daily changes of Fv/Fm,photosynthetic characteristics and content of carotenoids and chlorophyll were studied.Compared with shade-acclimated N.commune,sun-acclimated N.commune had higher light saturation point,higher content of carotenoids and higher ratios of carotnenoids to chlorophyll as while as lower ascending slope of light-limited part of P-I curve,lower dark respiration,lower Fv/Fm and lower content of chl a and MAAs on the basis of dry weight or surface areas.And their maximum photosynthetic rate and light compensation point were insignificantly different.Both of them had no obvious photorespiration.Shade-acclimated N.commune was more sensitive to high light than sun-acclimated ones.If the sunlight was high enough after rain,they both were photoinhibited,but they could recover immediately at lower light levels or at night.Results showed that photosynthetic characteristics and pigmentation for sun-acclimated and shade-acclimated N.commune were significantly different and these might be responsible for their adaptations to different light levels.