红砂种群繁殖特性的研究

以 2个不同生境条件及发育阶段的红砂种群为对象 ,开展了红砂种群繁殖特性的研究。结果表明 ,红砂除以种子和根基劈裂方式繁殖外 ,特定条件下还存在不定根繁殖方式。3种繁殖方式在种群繁殖中所占比例因种群所处生境及发育阶段的不同而有较大差异。位于干旱、沙化生境的成熟阶段红砂种群以无性繁殖为主 ,占种群繁殖比例的 72 .4 % ,样地内未见当年实生苗和幼龄有性繁殖个体。位于相对湿润、以侵入种出现在山地草原的幼龄阶段种群以有性繁殖为主 ,占种群繁殖比例的 5 3.5 % ,其中当年实生苗占 3.9%。两个红砂种群中 ,红砂灌丛的劈裂繁殖体数与冠径均呈显著的正相关关系 (n=30 ,P<0 .0 1)。不定根繁殖与灌丛大小不相关 (n=30 ,P>0 .0 5 ) ,其发生主要依赖于枝条被流沙掩埋后 ,再遇降水使沙土含有足够萌根的水分。封育条件下 ,红砂种群当年仅有 4 8%的灌丛开花结实 ,平均种子产量为 0 .89g/丛 ,变化在 0 .0 4～ 3.6 3g/丛之间。此外 ,讨论了繁殖特性与环境条件的关系

Reproductive characteristics of Reaumuria soongorica populations

Reproductive characteristics of two Reaumuria soongorica populations was investigated at Alashan Region, Inner Mongolia. For the population A R. soongorica is the predominant species in the grassland vegetation. While for the population B R.soongorica is a secondary invader of the vegetation. The results showed that R.soongorica expands its population mainly by seed germination and by root splitting. However, its individual number could also be increased by producing adventitious roots and then separated from the mother plant under certain conditions. The ways of reproduction varied with the population. In the population A, vegetative reproduction is the major type. About 72.4% of the examined individual within the population was propagated asexually. No seedling developed from seeds was found in the population A. In the population B only seed germination and root splitting were found. About 53.5% of individuals within the population was reproduced sexually. About 3.9% of plants was developed from seeds. No plant was propagated by producing adventitious roots. For both populations A and B a significantly positive correlation ( n =30, P <0.01) was found between the number of individuals produced by root splitting and the canopy diameter of the shrubs. But no significant correlation was found between the number of individuals produced by producing adventitious roots and the canopy diameter of the shrubs. The adventitious roots production depended on two factors.i.e. one is the depth of branches buried by sand, and another is sufficient rainfall to keep the soil moisten. The first year after closing about 48% of shrubs within the population A produced seed. The average seed yield was 0.89 g/shrub with the range of 0.04~3.63 g/shrub. The relationship between reproductive characteristics and ecological environments were discussed.