限氮培养对小球藻水分含量和叶绿素荧光参数的影响

摘要

限氮培养是提高小球藻油脂含量的一种方法,本研究探讨了小球藻限氮培养过程中藻细胞的生物量、水分含量和叶绿素荧光参数的变化.结果表明:在限氮培养条件下,小球藻藻细胞的生物量和水分含量分别下降了18％和7％；藻细胞的最大光能转化效率(Fv/Fm),表观量子效率(α)和最大光合电子传递速率( rETRmax)在整个限氮培养过程中均快速下降,到培养末期下降至接近于0,显著低于对照；半饱和光强(Ek)在对数期迅速下降,到稳定期后显著上升；最小荧光(Fo)在整个限氮培养过程中显著上升.可见,限氮培养显著影响了小球藻细胞光系统Ⅱ的结构和功能.%Nitrogen-limited culture is a kind of method improving the oil content of Chlorella sorokiniana. The biomass, water content and fluorescence parameters of chlorella cultivated under nitrogen-limited medium were investigated. The results showed that the biomass and water content of chlorella under nitrogen-limited culture declined 18% and 7% , respectively; the maximal photochemical efficiency of PS II (Fv/Fm), apparent quantum efficiency (a) and maximum photosynthetic electron transport rate (rETRmax) rapidly fell during the course of nitrogen-limited culture,and fell to close zero by the later period of culture;the minimum saturating irradiance (Ek, light-resistant index) firstly rapidly decreased from the early logarithmic period,and then remarkably increased during stable period; the minimum fluorescence(F0) obviously increased during the nitrogen-limited culture. These results showed that nitrogen-limited culture significantly influenced the structure and function of PS D in chlorella.