不同施氮水平对碱地植物种子萌发及幼苗生长的影响.pdfVIP

摘 要 种子发芽和幼苗生长是盐生植物生活史的重要阶段，其过程受植物种子自身遗传 特征和各种环境因子制约。本文应用人工气候箱和盆栽的方法，系统研究了分布于我 国西北干旱区盐碱荒漠中的草本植物盐角草在不同浓度盐胁迫和氮素添加条件下种 子的萌发过程及氮素添加对盐角草和梭梭幼苗生长的影响。种子萌发的结果表明，盐 角草种子的发芽率、发芽势和发芽指数均随着盐分浓度的增加而线性降低，而平均 发芽速度则是增加，且以Na SO 混合盐的影响为最。氮素添加对盐角草种子萌发 同 2 4 盐分胁迫影响趋势基本相似，但低浓度氮素添加 （氮浓度≤89mmol/L ）使发芽率和发 芽指数出现增加迹象。盐胁迫和氮素解除后的种子复萌实验结果显示，复萌率同盐胁 迫强度和氮素添量呈显著负相关关系。盐胁迫和氮素添加的交互作用对种子萌发的结 果表明，生长于不同的盐渍化土壤中的种子对氮沉降的响应是不同的。氮素添加对幼 苗生长的结果表明，氮素处理后的两种盐生植物的平均生长速率和根长增加，梭梭和 盐角草的平均生长速率分别增加了 0.53 和 1.371，而根长则分别增加了 34.556mm 和 2.342mm ；梭梭的地径增大了0.145mm，而盐角草的则是减少了0.041mm 。研究植物 种子萌发对盐胁迫和氮沉降的响应和不同植物幼苗生长对氮沉降的响应，能够增进我 们对全球变化条件下植物生活史对策的理论认识，同时在实践上可以为筛选改良盐碱 地的植物种类提供科学依据。 关键词：氮素添加；盐分胁迫；盐碱地植物；种子萌发；幼苗生长 Effect of Nitrogen Addition Rate on Seedling Germination and Seedling Growth of Saline-alkali Land Plants Abstract Seed germination and seedling growth are an important stage of halophytes life, this process is usually constrained by the genetic characteristic of plant seeding as well as various environmental conditions. In the present study, seed germination of Salicornia europaea, which distributed in arid saline-alkali of northwest China, was investigated under a gradient of salt stress and nitrogen deposition by applying a climatic cabinate method, and the seeding growth of the Salicornia europaea and Haloxylon ammodendron under a gradient of nitrogen deposition by applying a pot method. The results of seeding germination showed that Salicornia europaea seed germination percentage, germination energy and germination index were linearly declined with increased nitrogen addition rate,but average germination velocity are increased, with g reater influence caused by Na SO than other sal