瑞丽山龙眼幼苗光合特性研究

使用Li-6400XT便携式光合仪测定高黎贡山南段2种环境(野外、大棚)下生长的我国特有种植物瑞丽山龙眼幼苗的光合特性,结果表明:(1)2种环境下生长的幼苗净光合速率(PN)日变化出现"双峰"曲线,有"午休"现象,但峰值出现的时刻与大小不同,野外幼苗在10:00、16:00出现高峰值,分别为4.608、2.118μmol/(m~2·s),大棚幼苗在11:00、15:00出现2个高峰值,分别为4.102、3.982μmol/(m~2·s);蒸腾速率(Tr)、气孔导度(Gs)变化趋势与净光合速率变化趋势一致,也有"午休"现象;水分利用率(WUE)无明显变化规律;胞间CO_2浓度(Ci)与净光合速率日变化相反。(2)净光合速率与环境因子偏相关性分析表明,环境因子:光合有效辐射(PAR)、大气CO_2浓度(Ca)、空气温度(Ta)、相对湿度(RH)对幼苗PN值影响均为:PARCaTaRH;(3)两地幼苗光饱和点(LSP)均较高,野外为2 674.995μmol/(m~2·s)、大棚幼苗为2 228.754μmol/(m~2·s),光补偿点(LCP)分别为38.250、8.322μmol/(m~2·s)。

Photosynthetic Characteristics of Helicia shweliensis W. W. Smith Seedlings

The photosynthetic characteristics of Helicia shweliensis W.W.Smith seedlings of two habitats (wild,nursery) in the southern section of Gaoligong Mountains were measured by Li-6400XT Portable Photosynthesis System.Research indicated that:① The diurnal courses of net photosynthetic rate (PN) of the two seedlings occurred " double peak" curve and " lunch break" phenomenon,but the peak time was different of the two seedlings,that for the wild appeared at 10:00 and 16:00 was 4.608 μmol/(m2·s) and 2.118 μmol/(m2·s),and that for the nursery appeared at 11:00 and 15:00 was 4.102 μmol/(m2·s) and 3.982 μmo]/(m2·s).Transpiration rate (Tr),stomatal conductance (Gs) trends were consistent with the net photosynthetic rate trends.Water use efficiency (WUE) had no significant variation.Intercellular CO2 concentration (Ci) was opposite to the net photosynthetic rate.②The net photosynthetic rate and environmental factors correlation analysis showed that:PN was influenced by environmental factors in the order from high to low:light intensity (PAR),the atmospheric CO2 concentration (Ca),air temperature (Ta),relative humidity (RH).③The light saturation point (LSP) of the two seedlings were high.That for the wild was 2 674.995 μmol/(m2 ·s),and that for the nursery was 2 228.754 μmol/(m2 ·s).The light compensation point (LCP) for the two was 38.250 μmol/(m2·s),8.322 μmo]/(m2·s),respectively.