不同生态环境条件沙生植物沙鞭的结实研究

为了阐明不同生态环境条件下沙生植物沙鞭的结实规律,该文对沙鞭137个种群结实情况进行了实地观察,发现沙鞭种子的结实情况可被划分为无种子、种子饱满和种子不饱满3种类型;在此基础上,该文采用聚类分析、Kruskal-Wallis检验和典范对应分析(CCA)等方法探究沙鞭种群结实情况与22个地理气候因子的相关性。结果表明:(1)沙鞭137个种群按照地理气候因子不同聚为3个组;(2) Kruskal-Wallis检验显示沙鞭3个组间种子结实情况差异不显著(P=0.269),即沙鞭种群间种子结实与其所处的地理气候因子无直接相关性;(3)典范对应分析(CCA)表明沙鞭种群间种子结实情况差异也不显著(P0.05),但地理气候因子与种子饱满度以及无种子特征具有显著相关性,其中海拔和降雨因子(bio12-bio19)与种子饱满度呈正相关,而经纬度和温度因子(bio4,bio7)与种子饱满度呈负相关,无种子特征仅与最湿季平均温度(bio8)呈正相关。地理气候因子对沙鞭天然种群有性繁殖(有种子)重要性高于无性繁殖(无种子),表明制约沙生植物沙鞭有性繁殖的环境因子复杂,其无性繁殖可能是种群数量稳定的适应性表现。

Fruiting of Psammochloa villosa, an endemic desert plant, under different ecological and environmental conditions

In order to clarify the fruiting regularities of Psammochloa villosa in different ecological environments, we observed the fruiting of 137 populations of P. villosa, and found that the fruiting could be divided into seedless, filled and unfilled seeds. Based on them, we analyzed the correlation between the populations of P. villosa and 22 geographical and climatic factors by applying cluster analysis, Kruskal-Wallis test and canonical correspondence analysis(CCA). The results were as follows:(1)A total of 137 populations of P. villosa were clustered into three groups according to different geographical and climatic factors.(2)Kruskal-Wallis test showed that there was no significant differences in fruiting among three groups of P. villosa (P=0.269). That is, the fruiting of populations was not direct related with geographical and climatic factors.(3)Meanwhile, the CCA analysis showed that there was no significant differences in fruiting among populations(P>0.05). However, there was a significant correlation between geographical and climatic factors and plumpness of seeds and seedless feature. Among them, altitude and bio12-bio19 were positively correlated with filled seed, while longitude, latitude, bio4 and bio7 were negatively correlated with filled seed, but the seedless feature was only positively related to the mean temperature of wettest quarter(bio8). In summary, geographical and climatic factors are more important to the sexual reproduction(with seeds)than the asexual reproduction(without seeds)in the natural population of P. villosa, which proves that the environmental factors that restrict the sexual reproduction of P. villosa are complex, and its asexual reproduction may be a stable adaptive performance of the population.