5种悬钩子属植物的光合荧光特性

研究了高粱泡Rubus lambertianus，寒莓R. buergeri，山莓R. corchorifolius，茅莓R. parvifolius和蓬蘽R． hirsutus等5种悬钩子属植物叶片的光合色素含量、气体交换参数-光响应曲线和叶绿素荧光参数-光响应曲线。结果表明，在5种植物中，山莓的拟合最大净光合速率、光饱和点和光补偿点光强最小，且光饱和点小于500 μmol·m^－2·s^－1，而其余4种均高于800 μmol·m^－2·s^－1；蓬蘽和山莓的叶绿素 a/b和叶绿素/类胡萝卜均显著低于和高于其他3种；光强超过光饱和点时，净光合速率、气孔导度、胞间二氧化碳浓度、水分利用效率、光系统Ⅱ有效光化学量子产量、光化学猝灭和表观电子传递速率随光强增加而引起的变化以山莓为最大，蓬蘽、茅莓和高粱泡次之，寒莓最小；非光化学猝灭的变化却以寒莓为最大，山莓为最小；光饱和点以下的水分利用效率以山莓最大，蓬蘽和高粱泡最小。光系统Ⅱ最大光化学量子产量和量子需要额也以山莓最大，蓬蘽和高粱泡为最小。说明山莓耐阴但不耐光，容易发生光抑制；其余4种较耐光又耐阴，并忍耐光抑制，而又以寒莓最强，其次分别为高粱泡、茅莓和蓬蘽。图2表3参13

Photosynthetic and chlorophyll fluorescence characteristics with five Rubus species

Photosynthetic pigment content,gas exchange response,and chlorophyll fluorescence parameters for photosynthetic photon flux densities （PFD） in five Rubus species,i.e.Rubus lambertianus,R.buergeri,R.corchorifolius,R.parvifolius,and R.hirsutus,were determined.PED were 10 levels of 2 000,1 500,1 200,1 000,800,500,200,100,50,0 （the control） μmol·m-2·s-1.Results showed that in R.hirsutus the calculated maximum net photosynthetic rate （Pmax）,light saturation point （LSP）,and light compensation point （LCP） were lowest with LSP below 500 μmol·m-2·s-1,whereas in the other four species LSP exceeded 800 μmol·m-2·s-1.The ratio of chlorophyll a to b （Chl a/b） of R.hirsutus and R.corchorifolius was significantly lower,but their Chl/Car was higher than three other species.When PFD exceeded LSP,changes in net photosynthetic rate （Pn）,stomatal conductance （Gs）,intercellular CO2 concentration （Ci）,water use efficiency （EWU）,photosystem II （PSⅡ） effective photochemical quantum yield efficiency （F＇v/F＇m）,photochemical quenching （qP）,and apparent electron transport （RET） in response to PFD were in the order：R.corchorifolius R.hirsutus,R.parvifolius,and R.lambertianus R.buergeri;however,for changes in non-photochemical quenching （qN） the species order was reversed.With PFD below LSP,maximums for EWU,PSⅡ maximum photochemical quantum yield （Fv/Fm）,and quantum demand （QR） were found in R.corchorifolius with minimums in R.hirsutus and R.lambertianus.Thus,R.corchorifolius could only tolerate low irradiance and easily suffered photo-inhibition;whereas the other four species could tolerate both low and high irradiance as well as photo-inhibition with R.buergeri R.lambertianus,R.parvifolius,and R.hirsutus.