不同生长时期多伞阿魏土壤养分及光合特性比较研究

以多伞阿魏(Ferula ferulaeoides)为研究对象，分别对其展叶期、成熟期、果期土壤含水量、pH、有机质、养分和叶片的净光合速率、蒸腾速率、水分利用率等光合指标的日变化进行比较研究。结果表明:土壤含水量、有机质、养分随着多伞阿魏生长呈下降趋势，而pH却有所上升，但变化幅度不大。在不同土壤深度上，土壤含水量、pH随着土层深度的加深逐渐升高，而土壤有机质、养分含量却随土层的加深逐渐减少。多伞阿魏3个时期的净光合速率日变化均为双峰曲线，在14:00出现明显的“光合午休”现象，日平均大小为展叶期>成熟期>果期；蒸腾速率日变化趋势表现为单峰曲线，在中午14:00达到最高值，日平均大小为展叶期>果期>成熟期；水分利用率日变化总体呈上升趋势，在14:00出现最低值，日平均大小为成熟期>果期>展叶期。通过对多伞阿魏净光合速率和蒸腾速率与影响因子的相关分析显示:在整个生长期气孔导度，光合有效辐射与净光合速率呈显著正相关性；光照强度与蒸腾速率有明显正相关性。

Comparison Study on Soil Nutrient and Photosynthetic Characteristics of Ferula ferulaeoides at Different Growth Periods

In this paper,the dynamic changes of soil water content,pH,organic substance and soil nutrient,as well as the diurnal variations of net photosynthetic rate,transpiration rate and water use efficiency of Ferula ferulaeoides at different growth periods were studied.We found that the soil water content,organic substance and soil nutrient showed downward tendency with the growth of F.ferulaeoides while the pH was reverse,but changed slightly.In different soil depths,the soil water content and pH gradually increased with the soil depth,while organic substance and soil nutrient gradually reduced.The net photosynthetic rates at three growth periods varied in a double-peak curve and presented obvious phenomenon of "midday rest" at 14:00,with the daily mean values of leaf expansion period>maturation period>fruit period;The transpiration rates appeared to vary in a single-peak curve and had the highest value at 14:00,with the daily mean values of leaf expansion period>fruit period>maturation period;The water use efficiency showed a increased tendency at growth period and had the lowest value at 14:00,with the diurnal mean values of maturation period>fruit period>leaf expansion period.The correlation analysis revealed that stomatal conductance,photosynthetic active radiation had positive correlation with photosynthetic rate;Light intensity had evident positive correlation with transpiration rate.