摘要
通过水培实验,以耐镉(Cd)性不同的甘蓝品种‘绿丰’(Cd敏感性)和‘牛心’(Cd耐性)为材料,研究外源硅(Si)对Cd胁迫下甘蓝生长、Cd含量、养分吸收、光合特性和抗氧化酶活性的影响,以揭示外源硅对甘蓝镉毒害的缓解作用机制。结果表明:(1)与对照相比,Cd胁迫显著抑制了甘蓝植株的生长,降低了植株体内营养元素(Mg、Fe、Mn、Cu)的含量以及抗氧化酶[超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)]的活性和叶片的光合效率;并且显著增加了甘蓝植株内丙二醛(MDA)的含量。(2)与单独Cd处理相比,外源Si显著提高了甘蓝植株的生物量、地上部营养元素的含量以及光合参数[净光合速率(P_n)、气孔导度(G_s)及蒸腾速率(Tr)]、荧光参数值[原初光能转化效率(F_v/F_m)、实际光化学效率(Φ_(PSⅡ))、光化学淬灭系数(qP)]、光合色素含量和抗氧化酶活性;同时显著降低了甘蓝植株内MDA含量及Cd由根系向地上部的转运。研究发现,在镉胁迫环境下,外源Si可以通过降低Cd在甘蓝地上部的含量,提高抗氧化酶活性来降低膜脂过氧化,促进养分的吸收和转运,增强光合作用效率,从而缓解Cd对甘蓝生长的毒害。
We carried out a hydroponic experiment to study the effects of silicon（Si）on the growth,Cd content,nutrient absorption,photosynthetic characteristics and antioxidant enzymes activities of two cabbage（Brassica oleracea L.）cultivars with different Cd-tolerancers（Cd-tolerant‘Niuxin＇and Cd-sensitive‘Lüfeng＇）under Cd stress in order to reveal the alleviation mechanism of exogenous Si in cabbage under Cd stress.The results showed that：（1）Under the stress of Cd,the growth,contents of nutrients（Mg,Fe,Mn,Cu）,the activities of antioxidant enzymes（SOD,CAT,APX）and photosynthesis efficiency of leaves in plants were decreased significantly,while the malondialdehyde（MDA）content in leaves and roots of cabbages were increased significantly compared with the control.（2）Supply of exogenous Si under Cd stress promoted the biomass of plants,raised the nutrition element contents in shoots and increasedthe photosynthetic parameters（Pn,Gs,Tr）,fluorescence parameters（Fv/Fm,ΦPSⅡ,qP）and photosynthetic pigment contents.At the same time,MDA contents in plants and the transportation of Cd from roots to shoots were reduced significantly.It is suggested that Si can alleviate toxic effects of Cd by reducing the accumulation of Cd in shoots,increasing the activities of antioxidant enzymes to reduce membrane lipid peroxidation,promoting nutrient absorption and transportation,and enhancing photosynthesis.
作者
杨文嘉
王庆亚
孙建云
YANG Wenjia;WANG Qingya;SUN Jianyun(College of Life Science,Nanjing Agricultural University,Nanjing 210095,China)
出处
《西北植物学报》
CAS
CSCD
北大核心
2018年第6期1088-1098,共11页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家科技基础性专项(2015FY110500)
关键词
甘蓝
镉污染
硅
抗氧化系统
光合作用
生长
cabbage（ Brassica oleracea L.）
cadmium（Cd） pollution
silicon（Si）
antioxidant system
photosynthesis
growth
