铅锌尾矿渣对蓖麻光合特性及抗氧化酶系统的影响

Effects of lead / zinc tailings on photosynthetic characteristics and antioxidant enzyme system of Ricinus communis L

采用盆栽试验,研究了不同铅锌尾矿渣掺比基质对蓖麻光合特性、活性氧清除系统、叶绿素含量以及叶绿体超微结构的影响。结果表明:随着尾矿渣比例的增加,植株叶片中叶绿素含量、光合参数、SOD、POD及CAT活性呈先升后降的趋势,尤其在A组(100%矿渣)基质中,植株的各项生理生化指标均下降明显;而D组(80%矿渣+20%黄土)植株叶绿素a、b及总量、POD、SOD活性显著升高(P<0.05),较对照组G(50%黄土+50%泥炭土)分别提高了27%、33%、29%、98%和580%;电镜观测叶绿体超微结构发现,A组(100%矿渣)叶片叶绿体超微结构的损伤程度最深,片层系统解体,淀粉颗粒数量少,嗜锇颗粒增大、增多;当尾矿渣比例为80%时,叶绿体的基粒片层出现膨松,但仍具备光合能力,维持其个体生长;当尾矿渣比例低于60%时,叶绿体被膜、内部基粒及类囊体结构与对照相比无明显变化,且对光合特性及抗氧化酶系统具有一定的促进作用;说明蓖麻对Pb、Zn污染有一定的耐受性,具备修复铅锌污染土壤的潜力。

Effects of medium mixed with different contents of lead / zinc tailings on the photosynthetic capacity,active oxygen eliminating system and chloroplast ultrastructure of a castor bean variety,Xiangbi No. 1 were studied based on a pot experiment. The results showed that the chlorophyll contents,photosynthetic parameters,SOD,POD and CAT activities increased firstly,then declined with the increase of the tailings content,in particular those physiological and biochemical indices of group A（ 100% slag） decreased significantly. The contents of chl-a,chl-b and total chlorophyll,the activities of POD and SOD of plants in group D（ 80% slag ＋ 20% soil without Pollution） increased by 27%,33%,29%,98% and 580% respectively,compared to control group G（ 50% loess ＋ 50% peat）. The observation of chloroplast ultrastructure indicated that there were degenerated lammella system,fewer starch grains and more swollen osmiophilic glo-bule in the chloroplast of plant in group A than those of the other groups,which meant the damage of the chloroplast ultrastructure in group A was the most serious. Even though the grana lamellae vacuolated to some extent,the leaves had enough photosynthetic capacity to support plant growth when the slag ratio was up to 80%. Compared with control group,there was little change of the double-layer capsule,internal grana and structure of thylakoid of plants potted in medium containing less than 60% slag. Moreover,the photosynthetic capacity and antioxidase activity were enhanced. All the results suggested that the castor bean was lead / zinc tolerant,and could be used for remediation of lead / zinc contaminated soils.