亚高寒草甸不同坡向植物光合生理和叶片形态差异

Studies on physiological and leaf morphological traits for photosynthesis on different slopes in a subalpine meadow

绿色植物叶片的功能性状能用来解释不同层次复杂的生态学过程,被认为对植物的生存、生长和繁殖具有重要的影响。该研究对甘南亚高寒草甸坡向梯度代表物种的叶片形态和光合特性进行测定,分析了各坡向的土壤因子,比较不同物种(矮嵩草、米口袋、蒲公英和金露梅)之间的性状差异,研究叶片光合及形态特征与土壤因子之间的相关性。结果表明:1)不同坡向的土壤因子有着显著差异,土壤含水量、土壤全磷、土壤全氮及有机碳含量总体表现为北坡>南坡,而土壤温度及光照度则是南坡>北坡。2)坡向上不同物种在比叶面积、净光合速率和叶δ^(13)C值等方面有着显著的差异,比如物种在北坡具有较高的比叶面积和叶片含水量,而物种在南坡具有较高的净光合速率、相对叶绿素、叶干物质量及δ^(13)C值。3)冗余分析结果显示,物种的叶片形态及光合特性与土壤因子之间都具有显著的相关关系,其中土壤含水量变化的响应最为敏感。该研究揭示了亚高寒草甸坡向梯度上植物物种在叶片功能性状上的显著分化,使得这些物种能在同一个草地群落中共存。

The functional traits of plant leaves are considered to have significant effects on the survival, growth, and reproduction of plants. These traits are thus widely used to explain complex ecological processes at different levels. In this study, measurements of leaf morphological traits and photosynthesis taken from plants growing along typical slope aspect gradients in a subalpine meadow of Gannan were utilized to characterize the soil factors of each aspect, differences in plant species（Kobresia humilis, ueldenstaedtia verna, Taraxacum lugubre, and Potentilla fruticosa）, and correlations between the photosynthetic and morphological characteristics and soil factors. The following results were obtained （1） Soil factors were distinctly different on different slopes. Soil water content （SWC）, soil total phosphorus （STP）, soil total nitrogen （STN）, and soil organic carbon （SOC） were generally higher on the northern slope （N） than on the southern slope （S）, whereas soil temperature （ST） and light intensity （LI）were apparently greater on S than on N. （2） The specific leaf area （SLA）, net photosynthetic rate （Pn）, and leaf δ13C value were significantly different among the different plant species. SLA and leaf water content （LWC） were higher on N, where as Pn, SPAD, leaf dry matter content （LDMC）,and δ13C were higher on S. （3） Redundancy analysis showed a high correlation between leaf traits and soil factors. In particular, SWC showed the most sensitive response to change. This study revealed that the significant differences in plant leaf functional traits at different slope gradients in a subalpine meadow enables species to coexist in the same grassland community.