镉胁迫对马蔺根系形态及部分生理指标的影响
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引用本文:田小霞,毛培春,郭 强,郑明利,张维成,孟 林.镉胁迫对马蔺根系形态及部分生理指标的影响[J].西北植物学报,2019,39(6):1105~1113
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田小霞1,毛培春1,郭 强1,郑明利1,张维成2,孟 林1* (1 北京市农林科学院 北京草业与环境研究发展中心北京 1000972 中铁第五勘察设计院集团有限公司北京 102600) 
基金项目:北京市农林科学院青年科研基金(QNJJ201704);
中文摘要: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、150 mg·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(10~25 mg·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(50~150 mg·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829.39~8 944.54 和200.60~519.76 mg·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。
中文关键词:  马蔺  根系活力  抗氧化酶  渗透调节物质  转移系数
 
Effect of Cadmium on Root Morphology and Partial Physiological Indexes of Iris lactea var. chinensis
Abstract: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 Cd2+ 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 Cd2+ 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 Cd2+, 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 Cd2+, while the activity of SOD in leaves increased continuously. (3) When the Cd2+ concentration rises, the Cd2+ content in both roots and leaves increased, and the Cd2+ content in roots was 829.39~8 944.54 mg·kg-1, while the Cd2+ content in shoots was 200.60~519.76 mg·kg-1, and the Cd2+ 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 Cd2+ 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 Cd2+ from roots to shoots, thereby improving its Cd2+ tolerance.
keywords:cadmium  Iris lactea var. chinensis  root activity  antioxidant enzyme  osmotic adjustment substances  translocation factors
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