重金属胁迫下青藏高原芥菜型油菜种子发芽特征研究

Study on Seed Germination Characteristics of Qinghai-tibet Plateau Brassica juncea Under Heavy Metal Stress

为探明青藏高原乡土植物芥菜型油菜(Brassica juncea)在5种重金属离子Cu^(2+)、Fe^(3+)、Mn^(2+)、Zn^(2+)、Pb^(2+)胁迫下种子的发芽特征,采用组织培养的方法,分别设置5个不同浓度梯度处理油菜种子,探讨不同重金属离子胁迫对油菜种子萌发及幼苗生长的影响。结果表明:随着Cu^(2+)、Fe^(3+)、Pb^(2+)浓度的增大,油菜的发芽率、发芽势均呈现不同程度的降低趋势;其中,油菜种子对Cu^(2+)、Pb^(2+)的耐受能力相对较高,Cu^(2+)、Pb^(2+)浓度在2 000mg/L时平均发芽率分别达到57%和91%。在Mn^(2+)、Zn^(2+)处理下油菜种子的发芽率并没下降,反而表现出促进作用,Mn^(2+)浓度在200~1 000mg/L时,油菜种子发芽率均高于对照组,Zn^(2+)浓度在200~1 000mg/L时,平均发芽率达97%以上。5种重金属离子对油菜种子根长和芽长的生长具有强烈的抑制作用,对油菜种子根长的抑制效果较芽长更大,浓度过高使种子生长受毒害严重,超过植物的耐受限度就会直接导致死亡。研究结果表明,青藏高原芥菜型油菜对5种重金属有一定的耐性,能够在特定浓度的重金属尾矿区废弃地环境中生存,作为一种重金属富集植物对污染土壤进行修复。

In order to verify the germination characteristic of qinghai-tibet plateau native plant Brassica juncea under five kinds of heavy metal ions Cu2＋, Fe3＋, Mn2＋, Zn2＋, Pb2＋ seed stress. This study adopts the method of tissue culture, setting up five different concentration gradient respectively deal with seed and explore different heavy metal ion stress effects on seed germination and seedling growth of Brassica juncea.The results showed that with the increase of Cu2＋ , Fe3＋ , Pb2＋ concentration,the germination rate and germination potential of rapeseed were decreased with different degrees.Among them,the tolerance of Brassica juncea seeds to Cu2＋ and Pb2＋ was relatively high.The average germi- nation rate of Cu2＋ and Pbz＋ concentration in 2 000 mg/L was 57% and 91% respectively.The germi- nation rate of Brassica juncea seeds was not decreased in Mn2＋ and Zn2＋ processing,but showed the promoting effect. The germination rate of Mnz＋ concentration in 200--1 000 mg/L processing was higher than that in the control group,the average germination rate of Zn2＋ in 200--1 000 mg/L was over 97%.The five heavy metal ions have a strong inhibitory effect on the growth of seed root length and bud growth of Brassica juncea seeds.The inhibition effect on seed root length of Brassica juncea seeds was larger than that of bud, and the high concentration caused the seed growth to be poisoned seriously,and the tolerance limit of plant could lead to death directly.The study shows that the qing- hal-tibet plateau Brassica juncea seeds on 5 kinds of heavy metals have patience, can be in a certain concentration of heavy metal abandoned mining area environment survive,optional,as a kind of heavy metal enrichment plant to repair contaminated soil.