地理气候因素对羊草性状分化的影响

Effects of geographical and climatic factors on traits differentiation of Leymus chinensis

羊草是我国重要优良牧草之一,在长期的自然演变过程中,发生了丰富的表型变异。文中以66份不同地理来源羊草为试验材料,采用同质园试验,观测其表型和繁殖相关性状,就羊草性状与原生境地理气候因子间关系进行了分析研究。发现:(1)不同地理来源羊草性状存在显著差异,叶片性状的变异小于其它性状,且叶长的变异最小;繁殖相关性状的变异较大,其中母株抽穗率的变异最大。(2)羊草性状的分化与原生境地理气候因子存在显著相关性,羊草种内变异是遗传分化的结果。(3)羊草表型相关性状受纬度、海拔和经度的共同影响,受温度、降水量和日照相关因子的共同影响;母株抽穗率主要受纬度和温度相关因子的影响;母株分蘖倍数主要受海拔、经度和降水量相关因子的影响。(4)平均气温、最低温和极端最低温的升高和降水量的增加有利于羊草生长和繁殖。

Leymus chinensis is one of the most important fine forages in China.L.chinensis populations had abundant phenotypic variation in its long-term natural evolution.A common garden experiment with 66 L.chinensis ramets from split geographical origins as experimental materials was performed and phenotypic and reproductive traits were studied.The relationship between the L.chinensis traits and the geographical and climatic factors of original habitat was analyzed.Main conclusions were as follows:(1)The phenotypic and reproductive traits of L.chinensis were significantly different.The variations of leaf related traits were smaller than others,and the CV of leaf length was the smallest;the variations of reproductive traits were larger,of which the variation of heading rate was the largest.(2)There were significant correlations between the differentiation of L.chinensis traits with geographical and climatic factors of original habitats,that is to say the differentiation of L.chinensis populations was genetically based.(3)The phenotypic traits were jointly affected by latitude altitude and longitude,and by climatic factors related to temperature,precipitation and sunshine.The heading rate was mainly affected by latitude and temperature-related factors,while the tillering multiple was mainly affected by altitude longitude and precipitation-related factors.(4)The increase of mean temperature,the lowest and extreme lowest temperature and precipitation were beneficial to the growth and reproduction of L.chinensis.