在秋季对粤西乡土香根草的光合等生理特性日动态变化进行了测定.结果表明,香根草的净光合速率(Pn)日变化呈双峰型,蒸腾速率(Tr)和气孔导度(Gs)变化趋势与Pn相似,胞间CO2浓度(Ci)变化方向则与其相反.Pn与光合有效辐射(PAR)、Tr与PAR、Tn和大气相对湿度(RH)的相关程度都达到了极显著水平(P〈0.01),Gs则与空气温度(Ta)相关程度达到了显著水平(P〈0.05).同一环境因子对Pn、和Gs的影响程度不同,其中PAR是影响香根草光合作用最为强烈的环境因子.Tr是受环境因子拧制最为显著的生理参数.
The determinations on the photosynthetic parameters of native Vetiveria zizanioides in Western Guangdong in autumn showed that the net photosynthetic rate ( Pn ) of V. zizanioides had a diurnal change with two peaks, transpiration rate ( Tr ) and stomatal conductance ( Gs ) were similar with Pn, while intercellular CO2 concentration ( Ci ) was in adverse. There was a significant positive correlation between P, and photosynthetic active radiation (PAR) ( P 〈 0.01 ), Tr and PAR ( P 〈 0. 01 ), air temperature ( Ta ) and relative humidity ( RH ) ( P 〈 0. 01 ), and G and Ts ( P 〈 0. 05 ). Same environmental factors had different effects on Pn, Tr and Gs, and PAR had most intensive effect on the photosynthesis of V: zlzanioides. Among the test photosynthetic parameters, Tr was most sensitive to the environmental factors.