不同生境水曲柳种子的形态结构及抗旱性分析

Analysis of Morphological Structure and Drought Resistance of Fraxinus mandshurica Seeds in Different Habitats

为选育水曲柳耐干旱品种提供理论依据,选取不同生境水曲柳(Fraxinus mandshurica)种子为试验材料,对比分析不同生境下水曲柳种子的形态结构特征和吸水特性,采用不同质量浓度的聚乙二醇(Polyethylene glycol,PEG)溶液对水曲柳种子进行干旱胁迫,比较分析不同生境水曲柳种子在干旱环境下的萌发表现。研究结果显示,1)半干旱生境水曲柳的种子和种翅大小、千粒质量及种皮厚度等形态结构均显著大于适生生境种子;2)半干旱生境种子萌发时的吸水率显著低于适生生境种子7.75%;3)当PEG溶液质量浓度为10%时,半干旱生境水曲柳种子的发芽率、发芽指数、活力指数以及胚根长度开始显著高于适生生境种子。对发芽率进行线性回归,半干旱生境水曲柳种子的耐旱极限质量浓度是适生生境种子的1.23倍,具有更强的耐旱能力;4)干旱胁迫下,两生境水曲柳种子的过氧化氢酶、过氧化物酶、超氧化物歧化酶活性均表现出先上升后下降的趋势,且半干旱生境种子的酶活性始终高于适生生境。此研究结果表明在干旱环境造林选种时,可优先选用半干旱生境水曲柳种子作为造林种源,以提高种子萌发率和苗木成活率,为水曲柳资源扩大提供保障。

To provide a theoretical basis for selecting drought resistant varieties of Fraxinus mandshurica,this article selected Fraxinus mandshurica seeds from different habitats as experimental materials,and compared and analyzed the morphological and structural characteristics and water absorption characteristics of Fraxinus mandshurica seeds in different habitats.Different mass concentrations of polyethylene glycol(PEG)solution was used to treat drought stress on the seed of Fraxinus mandshurica,and the germination performance of Fraxinus mandshurica seeds in different habitats under drought conditions was compared and analyzed.The research results showed that,1)the seed and wing size,thousand grain mass,and seed coat thickness of Fraxinus mandshurica in semi-arid habitats were significantly larger than those in suitable habitats.2)The water absorption rate of seeds during germination in semi-arid habitats was significantly lower than that of seeds in suitable habitats by 7.75%.3)When the mass concentration of PEG solution was 10%,the germination rate,germination index,vitality index,and radicle length of Fraxinus mandshurica seeds in semi-arid habitats began to be significantly higher than those in suitable habitats.Linear regression was performed on the germination rate,and the drought tolerance limit mass concentration of Fraxinus mandshurica seeds in semi-arid habitats was 1.23 times that of seeds in suitable habitats,indicating stronger drought resistance.4)Under drought stress,the activities of catalase,peroxidase,and superoxide dismutase of Fraxinus mandshurica seeds in both habitats showed a trend of first increasing and then decreasing,and the enzyme activities of seeds in semi-arid habitats were consistently higher than those in suitable habitats.The results of this study indicate that in the selection of afforestation species in arid environments,priority should be given to selecting the seeds of Fraxinus mandshurica from semi-arid habitats as the afforestation source,in order to improve seed germination rate and seedling survival rate,and provide guarantees for the expansion of Fraxinus mandshurica resources.