土壤含水量和光照对沙地柏光合生理指标的影响

Effects of soil water content and light on photosynthetic characteristics of Sabina vulgari Ant.

试验采用人工控制土壤水分的方法,测定不同土壤含水量条件及有效辐射强度下沙地柏苗木的蒸腾速率、净光合速率、水分利用效率等指标,分析沙地柏在不同土壤含水量和光照条件下影响的光合生理响应特征及其变化规律。土壤含水量(SWC)用称重法测定,将硬塑盆中的土壤水分含量设置为7.5%,10%,12.5%,15%,17.5%,20%等6个不同的处理,每天进行称重,瞬时土壤水分含量用TDR100土壤水分测速仪(上海赛弗生物公司)测定,用Li-6400光合测定仪(美国LI-COR公司)测定沙地柏在不同土壤水分条件下光合生理指标。研究表明沙地柏的蒸腾速率、净光合速率均随着土壤含水量的增加呈先上升后下降的趋势。光合有效辐射在400—2000μmol·m^(-2)·s^(-1)范围内,沙地柏的净光合速率、蒸腾速率和水分利用率均呈现最高值。土壤水分含量在18.71%,17.99%和12.44%时,沙地柏的净光合速率、蒸腾速率和水分利用率达到最高值。土壤含水量12.44%—18.71%是沙地柏生长最适宜的土壤水分区间。在实践中利用沙地柏最适宜的土壤水分区间对沙地柏的栽植和生长可以进行有效地指导。

The transpiration rate,net photosynthetic rate and water use efficiency of Sabina vulgari seedlings under different soil water content and effective radiation intensity were determined.Soil moisture content(SWC)was measured by weighing method,and the soil water content in the hard plastic basin was set to 6 different treatments,including 7.5%,10%,12.5%,15%,17.5%,20%,etc,and the instantaneous soil moisture content was weighed every day by TDR100 soil moisture velocimeter.Determination of photosynthetic physiological indexes of S.vulgari under different soil water conditions was done using Li-6400 photosynthetic apparatus(LI-COR).The results showed that the transpiration rate and net photosynthetic rate of S.vulgari increased with the increase of soil water content.Photosynthetically available radiation was in the range of 400-2000μmol·m^(-2)·s^(-1).The net photosynthetic rate,transpiration rate and water utilization rate showed the highest values.Net photosynthetic rate,transpiration rate and water content were at 18.71%,1.79%and 12.44%utilization to the highest value.The soil moisture content of 12.44%to 18.71%was suitable range of soil moisture in sandy cypress.In practice,the planting and growth of S.vulgari can be effectively guided by the optimum soil moisture range.