摘要
以盐碱荒漠草甸药用植物胀果甘草(Glycyrrhiza inflata)为材料,采用水培法研究了盐处理(50、100、200、300mmol·L–1NaCl)28天后幼苗株高、生物量、含水量、根粗、甘草酸含量和不同器官的离子含量及离子的选择吸收、运输能力,并对丙二醛、脯氨酸含量进行测定,以确定其耐盐范围及耐盐方式。结果表明,低盐浓度对胀果甘草幼苗生长无显著影响,只有较高盐浓度(≥200 mmol·L–1NaCl)使幼苗总生物量、株高、甘草酸含量显著降低;根据耐盐系数与盐浓度的拟合方程,确定适宜幼苗生长的盐浓度范围为0–278.17 mmol·L–1。随盐浓度上升,植株选择性吸收K+、Ca2+、Mg2+,而抑制Na+进入体内,幼苗对进入植株体内的Na+在不同盐浓度下采取了不同的分配策略,低盐浓度下(0–100 mmol·L–1),植株体内Na+主要积累在根中,避免了叶中Na+的过多积累,其盐适应机制以耐盐方式为主;高盐浓度下(≥200 mmol·L–1NaCl),Na+主要积累在下部叶,并通过叶片脱落的方式带走体内的盐分,其盐适应机制以避盐方式为主。盐胁迫下,幼苗能促进K+而抑制Na+向上部叶的运输,使上部叶拒Na喜K,维持了较高的K+/Na+比值,有利于幼苗生长;同时,地下根系能通过积累Ca2+、Mg2+和合成脯氨酸、甘草酸,以提高渗透调节能力,缓解Na+毒害,使根的生长不受影响,有利于保证幼苗在盐环境中吸收维持生长的必要养分,这是胀果甘草幼苗具有较强耐盐性的原因。以上结果说明,胀果甘草幼苗通过对盐离子的吸收和运输调控、离子区域化和渗透调节,以耐盐和避盐两种方式适应盐碱荒漠环境。
Aims The objectives were to examine the response of Glycyrrhiza inflata to NaCl stress and understand its salinity tolerance and salt tolerance mechanisms.Methods By the method of hydroponics,seedlings were cultured in plastic pots filled with a complete Hoagland nutrient solution containing 0,50,100,200 and 300 mmol·L–1NaCl.After four weeks,we measured the fresh weight,dry weight,water content,shoot height,root diameter,membrane permeability,glycyrrhizic acid,proline,malonaldehyde content and ion content of different parts of the plants.Important findings Low NaCl concentration had no significant effect on the fresh weight,dry weight and glycyrrhizic acid content of G.inflata seedlings,but ≥200 mmol·L–1NaCl inhibited growth.The optimal salt range for seedling growth was 0–278.17 mmol·L–1,which was calculated by the fitting equation for the relationship between salt tolerance index and salt concentration.With increasing NaCl concentration,the uptake of K＋,Ca2＋and Mg2＋by plants from outside a salt environment significantly increased,whereas the Na＋uptake was inhibited.For the 0–100 mmol·L–1concentration of NaCl,the preferential accumulation of Na＋in roots over leaves can be interpreted as a mechanism of tolerance.For concentrations of 200 mmol·L–1and above,most Na＋was transported to the lower leaves and then disposed through leaf fall,exhibiting salt efflux behavior of the seedling.Under salt stress,the transport systems selective for K＋were functioning.Thus the upper leaves maintained a high K＋/Na＋ ratio that was beneficial to the growth of seedlings.In addition,the salt-tolerant root accumulated Ca2＋and Mg2＋ as well as synthesized glycyrrhizic acid and proline to increase osmoregulation ability,maintain cell membrane stability and reduce Na＋toxicity.These are the ways that G.inflata seedlings are adaptive to a saline environment.
出处
《植物生态学报》
CAS
CSCD
北大核心
2013年第9期839-850,共12页
Chinese Journal of Plant Ecology
基金
国家自然科学基金项目(30760028)
关键词
胀果甘草
离子平衡
矿质离子
耐盐性
选择性吸收
Glycyrrhiza inflata
ion balance
mineral ion
salt tolerance
selective uptake
作者简介
通讯作者 （E-mail：lxshz@126．com）
