香蜂草秋季光合特性研究

采用Li-6400便携式光合测定仪对香蜂草的光合特性进行了研究,并测定了叶绿素含量.结果表明:香蜂草的净光合速率日变化为双峰型,有明显的“午休”现象.净光合速率与蒸腾速率、气孔导度呈正相关,与胞间CO2浓度呈负相关.日净光合速率最大值为4.02μ·mol·m-2·s-1.在400 μmol·mol -1 CO2浓度下,香蜂草光补偿点为49.68 μmol·m-2·s-1,光饱和点为1103μmol·m-2·s-1.叶绿素a/b为0.6798.香蜂草光合特性表现为的阳性耐荫植物.

Studies on Photosynthetic Characteristics of Melissa officinalis in Autumn

The Li-6400 portable photosynthesis system was used to study the photosynthetic characteristics of three-year-old herbaceons plant of Melissa officinalis,and its chlorophyll content was detected by spectrophotometer.The results showed that the net photosynthetic rate(Pn) of Melissa officinalis was a double-peak curve,and had the drastic characteristics of ’midday depression’ under field.Correlation analysis showed that Pn had positive relationship with transpiration rate(Tr) and stomatal conductance(Gs),and negative relationship with internal CO2 concentration(Ci).The maximum of net photosynthetic rate(Pn) was 4.02 μmol·m-2·s-1.Under the concentration of 400 μmol·mol-1CO2,the light compensation point(LCP) of Melissa officinalis was 49.68 μmol·m-2·s-1,and light saturation point(LSP) was 1103 μmol·m-2·s-1,chlorophyll-a/b reached 0.6798.Melissa officinalis was a masculine and shade-resistant plant.