不同遮荫处理对芒萁冬季光合参数日变化的影响

Effects of shading condition on diurnal variation of photosynthetic parameters of Dicranopteris dichotoma in winter

采用不同遮荫处理(30%遮荫、50%遮荫、80%遮荫、全光照),比较分析盆栽芒萁冬季光合参数的日变化特征和资源利用效率.结果表明:(1)芒萁冬季净光合速率(Pn)日变化呈单峰型;(2)不同处理下,Pn、蒸腾速率(Tr)和气孔导度(Gs)三者之间均存在着显著相关性;(3)遮荫处理下Pn高于全光照(对照),峰值最高,为6.05μmolm-2·s-1,是对照的2.87倍,Tr和Gs明显高于对照,而胞间CO2浓度(Ci)低于对照;(4)不同处理下水分利用效率和光能利用率大小表现为30%遮荫>50%遮荫>80%遮荫>全光,表明遮荫处理提高了芒萁资源利用效率.

The diurnal variation of photosynthetic parameters and the resource use efficiency of Dicranopteris dichotoma were ana- lyzed under different shading conditions（30%, 50%, 80%, full light） in winter. The results were as follows： （ 1 ） the diurnal change of net photosynthetic rate （Pn） of D. dichotoma showed one peak shape in winter; （2） there was a significant correlation among Pn, transpiration rate （ Tr ） and stomatal conductance （Gs） in different treatments; （ 3 ） Pn under shading condition was higher than that under full light （control group）, the maximum value was 6.05 μmol. m-2 . s-1 , that was 2.87 times of control group, Tr and Gs was higher than control group, and intercellular CO2 concentration （Ci）was lower than control group; （4） the values of water use efficiency and light use efficiency were in the order of 30% shading 〉 50% shading 〉 80% shading 〉 full light. It suggested that shading treatment increased the resource use efficiency of D. dichotoma.