摘要
以野生马蔺种子培育的实生苗为试验材料,采用水培法研究不同质量浓度镉(0、10、25、50、100、150mg·L^-1)对马蔺幼苗生长、根系形态及部分生理指标的影响,分析镉胁迫下马蔺根系形态和生理指标的变化特征,以探讨马蔺的耐镉能力及耐镉机制。结果表明:(1)与对照相比,低浓度镉(10~25mg·L^-1)促进了马蔺株高、地上部干重、根干重、总根长、根表面积、根体积和根系活力的增加,中高浓度镉(50~150mg·L^-1)抑制根系生长,其株高、根干重、总根长等低于对照,根表面积、根体积和根系活力显著低于对照。(2)随镉浓度增加,马蔺叶片和根系中相对电导率、丙二醛(MDA)含量、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性和脯氨酸(Pro)含量增加,但可溶性蛋白含量(SP)则先升高后降低;根系的超氧化物歧化酶(SOD)活性随镉浓度增加先升高后降低,而叶片SOD活性则持续增加。(3)马蔺地上部和地下部镉含量随镉离子浓度升高而增加,根系和地上部镉含量分别达到829.39~8944.54和200.60~519.76mg·kg^-1,转移系数为0.06~0.32(<1.0),大多数镉离子被保留在根中,只有少量被转移到地上部。研究发现,在镉胁迫条件下,马蔺幼苗可能是通过根系对镉离子的积累,减少镉离子从根部到地上部的转移,并通过提高抗氧化酶活性、保持渗透平衡和清除过量自由基,从而提高其对镉的耐受性。
In order to evaluate the responses of physiological indexes of Iris lactea var.chinensis to cadmium stress and provide theoretical instructions to the further research of cadmium tolerance and tolerance mechanism for I.lactea var.chinensis,we carried out a water culture experiment to study the effects of different concentration of cadmium(0,10,25,50,100 and 150 mg·L^-1)on the growth,root morphology and partial physiological indexes of I.lacteal seedlings.The results showed that:(1)at lower Cd^2+treatments(10~25 mg·L^-1),the plant height,the shoot dry weight,root dry weight,total root length,root surface area,root volume and root activity of I.lactea var.chinensis were higher than those of the control and all of them decreased at higher Cd^2+levels(50~150 mg·L^-1),which mainly manifested as the plant height,root dry weight and total root length were lower than that of control,and root surface area,root volume and root activity of I.lactea var.chinensis were significantly lower than that of control.(2)With increasing concentrations of Cd^2+,the relative conductivity,malondialdehyde content(MDA),peroxidase activity(POD),catalase activity(CAT)and proline content(Pro)of I.lactea var.chinensis in both roots and leaves increased,but soluble protein content(SP)increased firstly and decreased afterwards.The superoxide dismutase activity(SOD)increased firstly and decreased in roots with increasing concentrations of Cd^2+,while the activity of SOD in leaves increased continuously.(3)When the Cd^2+concentration rises,the Cd^2+content in both roots and leaves increased,and the Cd^2+content in roots was 829.39~8 944.54 mg·kg^-1,while the Cd 2+content in shoots was 200.60~519.76 mg·kg^-1,and the Cd^2+translocation factors were always less than 1(0.06~0.32),suggesting that cadmium is mainly accumulated in the root of I.lactea var.chinensis seedlings,and only a few Cd^2+of roots were transferred to shoots.Overall,the findings suggest that I.lactea var.chinensis could increase the antioxidant enzyme activities,maintain osmotic equilibrium and scavenge excess free radicals by limiting translocation of Cd^2+from roots to shoots,thereby improving its Cd^2+tolerance.
作者
田小霞
毛培春
郭强
郑明利
张维成
孟林
TIAN Xiaoxia;MAO Peichun;GUO Qiang;ZHENG Mingli;ZHANG Weicheng;MENG Lin(Beijing Research and Development Center for Grass and Environment,Beijing Academy of Agriculture and Forestry Sciences,Beijing 100097,China;China Railway Fifth Survey and Design Institute Group Company Limited,Beijing 102600,China)
出处
《西北植物学报》
CAS
CSCD
北大核心
2019年第6期1105-1113,共9页
Acta Botanica Boreali-Occidentalia Sinica
基金
北京市农林科学院青年科研基金(QNJJ201704)
北京市农林科学院科技创新能力建设专项(KJCX20170110)
关键词
镉
马蔺
根系活力
抗氧化酶
渗透调节物质
转移系数
cadmium
Iris lactea var.chinensis
root activity
antioxidant enzyme
osmotic adjustment substances
translocation factors