野榆钱菠菜三种异型种子幼苗的生长特性

Investigation of growth characteristics of seedlings from three types of heteromorphic seeds of Atriplex aucheri

野榆钱菠菜是新疆重要的荒漠野生牧草资源,具有褐色(非休眠类型)、黑色大、黑色小(休眠类型)3种异型种子。以种子异型性植物野榆钱菠菜为材料,对3种异型种子在自然条件下进行培育,对比观察研究3种异型种子的萌发物候及幼苗的生长特性。结果表明:1)异型种子萌发物候不同步,萌发策略不同,褐色种子集中萌发,出苗率为74.30%,萌发期为3 d;两种黑色种子萌发期长,分散萌发,出苗率分别为6.58%(黑色大种子)和1.55%(黑色小种子),萌发期分别为21和17 d。2)异型种子子叶存留时间长,但存留时间有差异,种子越小子叶存留时间越短。3)褐色种子幼苗在初期其子叶长宽、根长、地上地下生物量均显著大于黑色种子幼苗,但随着幼苗的生长,3种异型种子幼苗在这些指标方面的差异逐渐缩小。4)异型种子幼苗具有不同的生物量分配策略,褐色种子幼苗主要将养分输送到地上部分,两种黑色种子幼苗主要将养分输送到地下部分,这种不同的生物量分配策略能够使种子异型性植物在面对荒漠异质环境时具有不同的应对方式,是种子异型性植物能够长期适应荒漠异质环境的重要生态适应机制。研究结果为揭示种子异型性植物长期适应荒漠异质环境提供新的科学依据,也为"两头下注"对策理论提供新的理论基础。

Atriplex aucheri is an important wild forage germplasm resource in Xinjiang desert regions. It exhibits seed heteromorphism, with 3 types of seed produced： brown seeds （non-dormant）, large black and small black seeds （dormant）. Seeds from a single A. aucheri plant （grown from one particular seed type） were used as experimental material. The three types of seeds were cultivated under natural conditions, and comparative studies of germination phenology and growth characteristics of three types of seeds carried out. It was found that： 1） The germination phenology of heteromorphic seeds were unsynchronized, and different types of seeds had different germination strategies. The germination of brown seeds was rapid with an emergence rate of up to 74.30% within 3 days. The germination of the other two types was delayed with emergence rates of 6. 58% and 1. 550./00, after 21 and 17 days, respective seeds were retained for an extended time The smaller the seeds were, the shorter ly, for large and small black during germination, but the 2） The cotyledons of all three types of retention time varied with the seed size. cotyledon retention time. 3） The cotyledon size, root length, and above- and black ferent seeds seed belowin the types ground biomass of brown seeds were early growth stages, but as decreased gradually. 4） The tes. Seedlings grown from b allocation strategi seedlings seedlings all significantl developed, the from different y greater than those of the two types of size differences between plants from diftypes of seed displayed rown seeds showed comparatively greater devel different biomass opment of the above-g morph stress round organs, ism therefore while the two types of black seeds prioritized be provides different seedling survival strategies （rapi tolerance in less favourable conditions）. low-ground developm d establishment after This seed heteromorphism is an import mechanism for plants growing in the hash desert environment. This study provides nov logical significance of seed heteromorphism in this desert environment and also provides retical theory of ecological bet-hedging. ent. Seed hetero occasional rain or ant ecological adaptive el insight into the eeoa basis for a new theoretical theory of ecological bet-hedging.