异苞滨藜两种异型种子对幼苗生长状况的影响

The Effects of Heterocarpic Seeds on Posterity Seedlings in Early Stage in Atriplex micrantha

【目的】研究异型种子对后代生态适应机制的影响。【方法】采用室外仿自然条件培育方法,观察异苞滨藜异型种子萌发物候,以及幼苗早期形态生长特征。【结果】异型种子的萌发物候不同步,异型种子萌生植株子叶存留时间长,且黑色种子萌生幼苗的子叶和褐色种子萌生幼苗的子叶留存时间有差异,褐色种子3月27日萌发,萌生幼苗的子叶持续时间长达39 d;黑色种子4月3日萌发,萌生幼苗的子叶持续30 d;褐色种子萌生幼苗的子叶大小、根长、地上生物量、地下生物量均显著大于黑色种子萌生幼苗(P<0.05);异型种子萌生幼苗在地上、地下生物量分配方面有差异(P<0.05),褐色种子萌生幼苗在子叶期的四次测量中其地上、地下生物量均显著大于黑色种子萌生幼苗,至5月1日最后一次测量,褐色种子萌生幼苗的地上生物量为(2.312±0.183)g,地下生物量为(0.098±0.008)g,黑色种子萌生幼苗的地上生物量为(0.402±0.05)g,地下生物量为(0.043±0.006)g;褐色种子萌生幼苗的根冠比逐渐降低,黑色种子萌生幼苗的根冠比逐渐升高。【结论】源于不同类型种子的幼苗在萌发物候、子叶存留时间、生长特性和根冠比指标参数方面表现出显著差异,这些差异是异苞滨藜长期适应荒漠异质环境而进化产生的生态适应机制,这种生态适应机制是异苞滨藜能够在荒漠异质环境中生存和繁衍的重要保障。

[ Objective] This study aims to explore the ecological adaptation mechanism of plants wi^h seed heteromorphism. [ Method ] Using molecular markers Pina - D1 b, Pinb - D1 b, and non - Pinb - D1 b of complemental gene to identify distribution. [ Result] （ 1 ） The germination phenology of heterocarpic seeds was not synchronous. The heterocarpic seed germination had a long retention time, and there were differences in the cotyledon retention time of the seed germination and brown seed germination and black seed germination. The brown seeds of A. micrantha germinated on March 27 th, cotyledon lasted 39 days, while black seeds ger- minated on April 3 rd, the cotyledon lastinged 30 days; （2） Compared with black seeds, seedlings grown from brown seeds had bigger size in cotyledon, seedling, root length and biomass of above and below ground. （ 3 ） The biomass distribution of above and below s＇round on the sprouting seedling of both seeds was different. The experiment dates showed that the root - top ratio of early seedlings grown from brown seeds decreased gradually, while the root -top ratio of seedlings grown from black seeds increased gradually. [ Conclusion ] Seedlings from the different types of seeds showed significant differences in germination phenology, cotyledon retention time, growth characteristics and parameters of root - top ratio indicators. These differences are Atriplex micrantha long - term adaptation to heterogeneous environment and ecological evolution of desert adapta- tion mechanism. This is an important indemnification for the ecological adaptation mechanism of Atriplex mi- crantha that can survive and thrive in the desert in a heterogeneous environment.