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2006年8月2—8日的连续晴天中,在天山中部的国家林业局天山森林生态系统定位站野生天山雪莲自然分布区3种生境(分布下限区2630m,中部区2740m,上限区2890m),利用便携式光合测定仪LI-6400测定天山雪莲野生植株的光合生理生态特性。分布下限区、中部区和上限区天山雪莲的光补偿点(LCP)分别为(15.69±0.31),(15.94±0.05)和(19.93±0.12)μmol·m-2s-1,光饱和点(LSP)在1550～1610μmol.m-2s-1之间,3者之间无差异性,而3者间的最大净光合速率(Pmax)差异显著。表观量子效率(AQY)在3个生境之间差异不显著,但在上限区处的羧化效率(CE)分别与下限区和中部区处的差异显著。相同生境下天山雪莲的光呼吸速率值(Rp)要高于暗呼吸速率值(Rd),且下限区处的光呼吸速率分别与中部区和上限区处的有显著的差异。下限区全天接受日光直接照射的天山雪莲的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)的日变化为单峰曲线,在中部区和上限区未接受到太阳直接辐射时段的Pn值随时间迅速下降,Tr下降缓慢,而Gs则有所上升。随着海拔的升高,天山雪莲Pn的日均值降低,但光能利用率(PE)却显著增加。不同生境下天山雪莲的水分利用效率(WUE)和气孔限制值(Ls)没有显著差异。天山雪莲的Pn与叶温(Tl)、大气温度(Ta)和光照强度(PAR)具有极显著的正相关,与海拔高度(E)呈显著的负相关,但与空气相对湿度(RH)和大气CO2浓度(Ca)之间的相关性均不显著。Tr与Ta,Tl和PAR具有极显著的正相关性,与RH之间存在显著的负相关。Gs只与Ca浓度之间呈极显著的负相关,与其他因子之间相关性不显著。Pn与Tr,Gs和叶温下蒸汽压亏缺(Vpdl)分别具有极显著的正相关性,与Ci呈极显著的负相关。通过对不同海拔高度内光合生理参数与光、温等生态因子关系的对比分析表明:天山雪莲具有一定的对高山自然环境变化的温度和光强有明显的生态适应性。
During the sunny days from August 2-8, 2006, three habitats (2630m in the distribution area, 2740m in the central area and 2890m in the upper area) were found in the natural distribution area of the wild Tianshan Saussurea in the Tianshan Forest Ecosystem Positioning Station of the State Forestry Administration in the central Tianshan Mountains. The Photosynthetic Physiological and Ecological Characteristics of Wild Plant in Tianshan Saussurea Using LI-6400 Portable Photosynthesis System. The light compensation points (LCP) in the lower, middle and upper Tianshan snow lotus were (15.69 ± 0.31), (15.94 ± 0.05) and (19.93 ± 0.12) μmol · m-2s-1, respectively. ) Between 1550 ~ 1610μmol.m-2s-1, there was no difference among the three, but the difference of maximum Pmax among the three was significant. There was no significant difference in apparent quantum yield (AQY) between the three habitats, but the carboxylation efficiency (CE) in the upper region was significantly different from that in the lower region and the middle region, respectively. Under the same habitat, the light respiration rate (Rp) was higher than that of dark respiration rate (Rd), and the light respiration rate at the lower region was significantly different from the middle region and the upper region respectively. The diurnal variations of net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of the lotus seedlings exposed to direct sunlight all day in the lower zone were single peak curve, and the direct sunlight was not received in the middle and upper zone The Pn value of radiation period decreased rapidly with time, Tr decreased slowly, and Gs increased. With the elevation increasing, the average daily value of Pn in Tianshan snowdrop decreased, but the light energy utilization rate (PE) increased significantly. There was no significant difference in water use efficiency (WUE) and stomatal limitation (Ls) between different habitats. There was a significant positive correlation between Pn and temperature (Tl), atmospheric temperature (Ta) and light intensity (PAR) and significant negative correlation with altitude (E) Atmospheric CO2 concentration (Ca) between the correlation was not significant. Tr has a significant positive correlation with Ta, Tl and PAR, and has a significant negative correlation with RH. There was a significant negative correlation between Gs concentration and Ca concentration, but no significant correlation with other factors. There was a significant positive correlation between Pn, Tr, Gs and vapor pressure deficit (Vpdl) at leaf temperature, and extremely significant negative correlation with Ci. The comparative analysis of the relationship between photosynthetic physiological parameters and light, temperature and other ecological factors in different altitudes shows that the Tianshan snow lotus has obvious ecological adaptability to temperature and light intensity of alpine natural environment.