不同光强和土壤水分条件对芒萁光合作用和叶緑素荧光参数的影响

EFFECTS OF LIGHT INTENSITY AND SOIL WATER ON PHOTOS-YNTHESISAND CHLOROPHYLL FLUORESCENCE PARAMETERS OF Dicranopteris dichotoma

采取不同光强与水分处理,比较分析盆栽芒萁的光合和荧光参数以及叶绿素含量的响应特征。结果表明:随着遮荫程度的增加,芒萁的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、最大荧光(Fm)、可变荧光(Fv)、PSⅡ潜在活性(Fv/Fo)、PSⅡ光化学效率(Fv/Fm)、叶绿素a(Chl a)、叶绿素b(Chl b)、类胡萝卜素(Car)和总的叶绿素(Ct)呈现增加趋势,而胞间CO2浓度(Ci)则呈现下降趋势。相同的遮荫条件下,浇水处理的参数值均高于不浇水的,且80%遮荫下Fv和Fm在浇水和不浇水处理间差异显著(p<0.05)。因此,遮荫和浇水条件下,芒萁通过增加净光合速率、色素含量、PSⅡ原初光能转化效率及潜在活性,形成适应遮荫和土壤水分条件的生存策略。

Response characteristics of photosynthesis, fluorescence parameters and chlorophyll content of potted Dicranopteris dichoto- ma were analyzed under different light intensity and water treatments. The results showed that ： the net photosynthetic rate （ Pn ）, leaf stomatal conductance（Gs） ,transpiration rate（Tr）, maximal fluorescence （Fm） , variable fluorescence （Fv） , potential activity of PS I1 （Fv/Fo） , photochemistry efficiency of PS 11 （Fv/Fm） , chlorophyll a （ Chl a ）, chlorophyll b （ Chl b） , carotenoid （ Car ） and total chlorophyll （Ct） of Dicranopteris dichotoma presented ascending trend with the increased shadings, while intercellular space CO2 con- centration （Ci） presented a descending trend. Meanwhile, parameters in the watering samples were higher than those not be watered under the same shading, variable fluorescence （Fv） and maximal fluorescence （Fro） in the watering samples were significantly higher than those not be watered under 80% shading （p 〈 O. 05）. Hence, we can reach the conclusion that shading and soil watering treat- ments help to promote the growth of Dicranopteris diehotoma by increasing the net photosynthetic rate, pigment content, photochemistry efficiency of PS I1 and potential activity.