不同生境下细叶鸢尾表型可塑性及生物量分配差异性

Phenotypic plasticity and biomass allocation of Iris tenuifolia Pall. in different habitats

细叶鸢尾(Iris tenuifolia Pall.)为鸢尾科鸢尾属多年生草本,是干旱半干旱地区的野生观赏花卉之一。该植物在自然条件下萌发率极低,主要靠多年生根系进行繁殖。为了研究细叶鸢尾在异质性生境中的可塑性及其生态适应性,对3种不同生境(种群1:干旱严重;种群2:较干旱;种群3:相对湿润)中的细叶鸢尾自然分布种群的生物学特性,地上、地下生物量分配等进行比较。研究发现:3个不同生境的种群植株在外部形态上差异明显。种群1的根长与根冠比显著大于种群2和种群3,种群3的株高值较大;种群3地上生物量的比重显著大于种群1和种群2,但地下生物量与地上生物量分配呈反比。结果表明:细叶鸢尾植株具有较强的可塑性,在不同的环境条件下,通过外部形态结构和生物量的配比关系,能够形成有利于自身生长发育的适应对策。

Iris tenuifolia Pall. is distributed in arid regions as an ornamental flower species. The germination rate of I. tenuifolia seeds in nature is extremely low and the perennating rhizomes play an important role in its propagation. The purpose of this study was to understand the charac- teristics of phenotypic plasticity and ecological adaptation of I. tenuifolia. Three populations （ populations 1,2 and 3 represented severely dry, dry, and relatively humid habitats, respective- ly） in Xinjiang, China were chose to investigate the biological characteristics, above- and under- ground biomass of I. tenuifolia. The results showed that the plant＇ s external morphology was sig- nificantly different among the three populations. The total root length and root/shoot ratio were significantly higher in population 1 than in the other two populations, but plant height was higher in population 3. Aboveground biomass of population 3 was significantly higher, but the under- ground biomass was lower. These findings indicated that, through adjusting the morphology and the allocation ratio of biomass, I. tenuifolia has better phenotypic plasticity to form adaptation strategies in favor of their growth and development at different soil moistures.