我国狗牙根种质资源根状茎特征的研究

Studies on rhizome characteristics of germplasm resource of Cynodon dactylon in China

对50份我国狗牙根种源的根状茎深度、密度和直径进行了田间观测分析。结果表明,1)我国狗牙根种源的根状茎特征变异很大,根状茎深度、密度和直径的变异系数分别为44%、41%和33.7%;2)狗牙根根状茎深度、直径和密度3项指标高度正相关,其相关系数分别达0.73(P<0.01)(直径与深度)、0.69(P<0.01)(直径与密度)和0.73(P<0.01)(深度与密度);3)我国狗牙根根状茎深度、密度和直径随纬度的增加而呈现出明显的地带性变异特征,而且三者相对于纬度呈现极显著的线性关系,即随纬度的增加而显著加深、加密、加粗;4)依据根状茎特征的3项指标,在欧氏距离1.8处,可将50份狗牙根种源分为4大类型:即浅(无)根茎型、疏浅根茎型、深密根茎型和特深密根茎型,4类狗牙根与其相应的地理分布有较好的吻合度。本研究还探讨了狗牙根根状茎特征与其抗寒性的关系及其体现的植物避寒的机理。

Measurement and analysis were carried out on the depth, density and diameter of rhizomes of 50 accessions of Cynodon dactylon in China. The results showed:1) The variation range of rhizome characteristics was very large and the coefficients of variation of depth, density and diameter were 44%, 41% and 33.7%, respectively; 2) The rhizome characteristics were also obviously positively correlated with each other. The correlated coefficients were 0.73 (P<0.01) (diameter and depth) 0.69 (P<0.01) (diameter and density) and 0.73 (P<0.01) (depth and density); 3) The rhizome characteristics were remarkably linearly correlated with the latitude, too. That is to say, with the increasing of latitude, the rhizomes were deeper, denser and thicker. 4) Four types were determined according to the results of cluster analysis on rhizome characteristics, which were named as follows:shallow (no) rhizome type, thin and shallow rhizome type, deep and dense rhizome type and special deep and dense rhizome type, respectively. This paper also inquired into the relationship between the rhizome characteristics and the low temperature avoidance and the mechanism of the low temperature avoidance of Cynodon dactylon in China.