安徽特有植物安徽羽叶报春的繁殖生物学研究

Reproductive biology of Primula merrilliana, an endangered plant endemic to Anhui Province

本文分别从物候、繁育结构和传粉等方面研究了国家三级保护植物、安徽特有种——安徽羽叶报春(Primula merrilliana)的繁殖生物学特征。研究结果表明:(1)安徽羽叶报春是典型的形态和功能意义上的花柱二型的二年生植物,其始苗期为9月,一直持续到第二年6月底或7月初死亡,各居群长柱花植株比短柱花植株开花略早3-5d;(2)安徽羽叶报春的散孔型花粉显示其在报春花属中有重要的系统意义和进化意义。同时,短柱花花粉量比长柱花少,但其花粉直径是后者的1.78倍左右;(3)长花柱的雌蕊长度是短花柱的1.64倍,而且其柱头上的乳头状突起比短花柱上的长而稀;(4)3个研究居群的P/O比都不相同,我们发现花粉量比胚珠数量有更大的变异,这可能与生境有关;(5)安徽羽叶报春为异花授粉植物,蓟马属(Thrips)昆虫为其重要的传粉者,其同型花授粉可育性远比异型花授粉的高;(6)其长、短柱型种子没有明显的形态差异,多属不等边七面体,少为其他多面体。据研究,在小居群中两种花柱类型植株的比例失衡,生境的破坏和伴生种的消失可能是导致安徽羽叶报春濒危的重要原因。

Primula merrilliana, a rare and endangered National Grade Ⅲ protected plant, is endemic to Anhui Province, China. We studied its reproductive characteristics from the aspects of phenology, breeding system structure and pollination. Our observations showed that： （1） P. merrilliana is typically distylous in both morphology and function, and it is a biennial plant that grows from September in the first year and lasts until late June or early July of the next year. In addition, the long-styled plants tend to flower 3 to 5 days earlier than the short-styled morphs in each population; （2） The pantoporate pollen ofP. merrilliana shows that the species has vital taxonomical and evolutionary significance in Primula. The short-styled pollen diameter is 1.78 times as wide as the long-styled, but the pollen production of a short-styled flower is less than that of a long-styled flower; （3） The long-styled pistil is about 1.64 times as long as that of the short-styled morph with shorter and more frequent papillae; （4） The pollen-ovule ratio （P/O） is different in the three studied populations, and we noted larger variation in pollen than ovule production, which may be related to habitats; （5） P merrilliana is an outcrossing plant pollinated by thrips, and the seed-set of legitimate pollination is higher than that of illegitimate; and （6） The seed morphology of P merrilliana usually appears like a nonequilateral heptahedron, a few seeds resembles an irregular polyhedron, but there is no obvious difference between the two morphs, the long-styled and the short-styled. Based on this study, biased morph frequencies in small populations ofP merrilliana, destruction of habitats and disappearance of accompanying species are possibly the main reasons for the endangerment of this species.