Abstract:

To understand the differences of photosynthetic characteristics between interspecies and to clarify the features of adaption to ecological environment, the light response characteristics and seasonal changes of four Miscanthus species were tested using Li-6400 photosynthetic apparatus. The test results showed that the responses of photosynthetic parameters to photosynthetic active radiation were different among four species. The light saturation point (LSP) of M. lutarioriparius was about 800 μmol·m^-2·s^-1 and the others were about 1000 μmol·m^-2·s^-1. The P_nmax of tesates species were ordered as M. sacchariflorus (47.3 μmol·m^-2·s^-1) >M. lutarioriparius (38.6 tari·m^-2·s^-1) >M. floridulus (20.4 μmol·m^-2·s^-1) >M. sinensis (8.0 μmol·m^-2·s^-1). The order of AQY were M. sacchariflorus(0.123) >M. lutarioriparius (0.108)>M. floridulus (0.089)>M. sinensis (0.022). The light energy conversion rates of M. sacchariflorus and M. lutarioriparius were higher than that of M. floridulus and M. sinensis. The P_n values in main growing season showed that the growth rate was synchronous with seasonal change. There were extremely significant differences (P< 0.01) among different species, the P_n values of M. sacchariflorus and M. lutarioriparius were significantly higher than that of M. sinensis and M. floridulus. The water use efficiency (WUE) of plant in main growing season significantly differed among interspecies (P< 0.05). The minimum of WUE appeared from June to July and the maximum appeared from September to October. The tested species had the abilities of high temperature resistant and drought tolerance.

Key words: Miscanthus, Light-response, Net photosynthetic rate, Water use efficiency

摘要：

以芒(Miscanthus sinensis)、五节芒(M. floridulus)、荻(M. sacchariflorus)和南荻(M. lutarioriparius)等4种典型芒属植物为试验材料,用LI-6400便携式光合仪测量不同时期的光合特性,来研究芒属植物光响应及光合特性的季节性变化规律。结果表明:光合作用参数对不同光合有效辐射的响应在种间有差异,除南荻的光饱和点(LSP)在800 μmol·m^-2·s^-1左右外,其他3种约在1000 μmol·m^-2·s^-1;最大净光合速率(P_nmax)由大到小依次为荻(47.3 μmol·m^-2·s^-1)、南荻(38.6 μmol·m^-2·s^-1)、五节芒(20.4 μmol·m^-2·s^-1)、芒(8.0 μmol·m^-2·s^-1);表观量子效率(AQY)依次为荻(0.123)、南荻(0.108)、五节芒(0.089)、芒(0.022),荻和南荻的光能转化率强于五节芒和芒。主生长季的净光合速率(P_n)表现出明显的季节性变化,并与生长速率同步,种间差异极显著(P< 0.01),荻和南荻的P_n值高于芒和五节芒。 4种芒属植物在主生长季的水分利用率(WUE)最小值在6-7月,最大值在8-9月,表现出耐旱耐高温能力,且种间差异显著(P< 0.05)。

关键词: 芒属植物, 光响应, 净光合速率, 水分利用率