3种龙胆科植物的资源分配对策

选择青藏高原东缘同一生境类型下具有不同交配系统特点和不同传粉者丰度的3种龙胆科植物湿生扁蕾(Gentianopsis paludosa)(自花授粉)、祁连獐牙菜(Swertia przewalskii)(高昆虫访问异花授粉)和线叶龙胆(Gentiana farreri)(低昆虫访问异花授粉)为对象,研究其资源分配特征。结果表明,1)3种植物的花粉胚珠比例(P/O)存在显著差异(P0.05),湿生扁蕾的P/O显著低于另外两种异花授粉植物的(P0.05),祁连獐牙菜的P/O显著低于线叶龙胆的(P0.05);2)3种植物的繁殖分配比例存在差异,湿生扁蕾的繁殖分配比例显著高于另外两种异花授粉植物的(P0.05),线叶龙胆的繁殖分配比例显著高于祁连獐牙菜的(P0.05);3)在繁殖分配比例与个体大小关系上,湿生扁蕾与其个体大小不存在显著相关关系(P0.05),而另外两种异花授粉植物则与其各自个体大小之间存在显著负相关关系(P0.05)。研究表明,交配系统类型和传粉者丰度与植物的资源分配模式有关,尽管3种植物的繁殖绝对投入量都与其个体大小显著正相关(P0.05),但自花授粉植物相对于异花授粉植物具有较高的繁殖分配比例,并且这种较高的繁殖分配比例不受个体大小影响,这种高繁殖投入的资源分配模式可能与自花授粉植物具有繁殖保障,从而降低其繁殖代价有关。

Reproductive allocation of three Gentianaceae species

To test the tactics of resource allocation,pollinator abundance,and mating system,the reproductive allocation characters of three species of the family Gentianaceae Gentianopsis paludosa (selfing),Gentiana farreri (outcrossing with high insect visit frequencies),and Swertia przewalskii (outcrossing with low insect visit frequencies)],were tested at the same habitat in the eastern Qinghai Tibetan Plateau.The results showed that the P/O ratios differ significantly among these three species.The P/O ratio of G.paludosa was significantly lower than that of the other two cross-fertilized species,and the P/O ratio of S.przewalskii was significantly lower than that of G.farreri.Reproductive allocation differed significantly among the three species.G.paludosa had a higher reproductive allocation than that in the two cross-fertilized species,and the reproductive allocation of G.farreri was higher than that in S.przewalskii.The reproductive allocations of the two cross-fertilized species G.farreri and S.przewalskii were negatively correlated with their respective individual sizes,whereas G.paludosa did not reveal any relationship between these two parameters.The results indicated that mating system and pollinator abundance might influence resource allocation characteristics.Although the reproductive biomass of the three species was positively correlated with their individual size,the reproductive allocation of the self-fertilized species was significantly higher than that in the two cross-fertilized species.In addition,its high reproductive allocation was not affected by individual size.It appeared that the high reproductive allocation might be caused by reproductive assurance,which in turn might reduce the reproductive cost in the self fertilized species.