《植物生理学报》 2017, 53(8): 1419-1427

栾树对镉的耐性、富集及胁迫响应

杨岚鹏¹, 朱健^1,*, 王平^1,*, 曾璟², 谭蓉¹, 杨雨中¹, 朱烨林¹, 章才建¹

中南林业科技大学¹环境科学与工程学院, ²生命科学与技术学院, 长沙410004

通信作者：朱健；E-mail: zhujian198312@163.com; csfuwp@163.com

摘　要：

通过水培模拟试验, 研究了栾树(Koelreuteria paniculata)对镉(Cd)的耐性、富集及转运特征, 采用扫描透射电镜(STEM)、傅里叶红外光谱仪(FTIR)、能谱仪(EDXA)分析了栾树对Cd胁迫的响应。结果表明: 栾树幼苗对浓度小于25 mg•L^-1的Cd表现为高耐受性, 高于该浓度时Cd对栾树产生明显的毒害作用, 抑制栾树的生长。不同组织对Cd的富集能力为根>叶>茎, 富集系数与转运系数均随Cd浓度升高而减小。低浓度Cd促进叶绿素和可溶性蛋白的合成; 高浓度Cd明显抑制叶绿素和可溶性蛋白的合成, 并且导致严重的膜脂过氧化和膜损伤, 丙二醛(MDA)含量持续升高。超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)能对Cd胁迫做出积极有效的响应, 但在高浓度Cd胁迫时失去活性。STEM分析表明, 高浓度Cd胁迫使栾树根部细胞壁结构破坏, 茎部导管堵塞, 叶片褶皱, 气孔结构受损。FTIR分析表明, Cd胁迫增加羟基自由基, 加剧膜脂过氧化, 连生羟基、巯基、羧基、氨基随之增加。EDXA分析表明, Cd胁迫会抑制栾树对矿质元素Ca、K、Mg的吸收, 同时影响S元素的吸收与利用。

关键词：栾树; Cd胁迫; 耐性; 富集; 转运; 胁迫响应

收稿：2017-05-22   修定：2017-07-24

资助：国家重点研发计划子课题(2016YFD0800805-4)、湖南省研究生科研创新项目(CX2017B404)和中南林业科技大学引进高层次人才科研启动基金项目(2015YJ041)。

Tolerance, accumulation and stress response of Koelreuteria paniculata to cadmium

YANG Lan-Peng¹, ZHU Jian^1,*, WANG Ping^1,*, ZENG Jing², TAN Rong¹, YANG Yu-Zhong¹, ZHU Ye-Lin¹, ZHANG Cai-Jian¹

¹College of Environmental Science and Engineering, ²College of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China

Corresponding author: ZHU Jian; E-mail: zhujian198312@163.com; csfuwp@163.com

Abstract:

Tolerance, accumulation and translocation characteristics of Koelreuteria paniculata to cadmium (Cd) were investigated by hydroponic experiments, and the stress response mechanisms of K. paniculata to Cd were analyzed using scanning transmission electron microscope (STEM), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analysis (EDXA). The results showed that K. paniculata had high tolerance when the Cd concentrations were lower than 25 mg•L^-1. The high concentrations of Cd (> 25 mg•L^-1) had a toxic effect on K. paniculata and significantly restricted the plant growth. The accumulation ability of Cd by different plant tissues followed the sequence of roots > leaves > stems. The bioconcentration factors and translocation factors decreased with the Cd concentration increase. Low concentrations of Cd promoted the synthesis of chlorophyll and soluble proteins, while high concentrations of Cd clearly inhibited the synthesis of chlorophyll and soluble proteins, caused membrane lipid peroxidation and severe membrane damages, and increased malondialdehyde (MDA) concentration. Peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) exhibited positive and effective responses to low-concentration Cd stress, but could not remove the toxicity caused by high-concentration Cd stress. The STEM analysis indicated that the high-concentration Cd stress caused the root cytoderm destruction, stomatal damage, stem blockage, and leaf folding. The FTIR analysis showed that Cd stress increased free hydroxyl groups, which led to membrane lipid peroxidation, membrane damage and also increased fixed hydroxyl, sulfydryl, carboxyl and azyl groups. The EDXA analysis indicated that Cd stress restricted adsorption of calcium (Ca), potassium (K) and magnesium (Mg) and interfered with adsorption and utility of sulfur (S) element.

Key words: Koelreuteria paniculata; Cd stress; tolerance; accumulation; translocation; stress response