Pb在水花生愈伤组织中的超微定位及对矿质元素的影响  

ULTRASTRUCTURAL LOCALIZATION AND EFFECT OF LEAD ON MINERAL ELEMENTS IN CALLUS OF ALTERNANTHERA PHILOXEROIDES

作　　者：王娟[1] 张乐乐[1] 康宜宁[1] 施国新[1] 

机构地区：[1]南京师范大学生命科学学院,江苏省生物多样性与生物技术重点实验室,南京210046

出　　处：《水生生物学报》2012年第2期307-315,共9页Acta Hydrobiologica Sinica

基　　金：国家自然科学基金资助项目(30870139)资助

摘　　要：水体重金属污染已经成为一个日益严重的环境问题,了解水体重金属污染原理、处理水体重金属,已经成为一个必需解决的课题。由于重金属元素具有难降解、易积累、毒性大等特点,另外还能被水生植物富集吸收进入食物链危害人畜健康。因此,植物对重金属毒害的抗性机理以及提高植物抗重金属胁迫能力的探索研究越来越引起人们的关注。虽然在铅(Pb2+)胁迫下植物的抗氧化反应已经有了一些报道,但有关于植物愈伤组织受到重金属胁迫后变化的研究报道较少。鉴于此,研究将分布广泛的挺水植物水花生进行愈伤组织培养,克服了光照、温度、水分及植物生长发育在自然状态下的不可控制性,使实验数据更具重复性和科学性。经过70%酒精30s、5%次氯酸钠10min和0.1%升汞10min消毒后,在激素为6-BA(3.0 mg/L)和NAA(0.2mg/L)的1/2MS培养基中培养出水花生茎段的愈伤组织并以此作为研究对象,以常见的污染环境的重金属离子—Pb2+为胁迫因子。研究了在不同Pb处理浓度(0、0.2、0.4、0.8和1.6 mmol/L)下愈伤组织对Pb的积累、亚细胞分布、亚显微定位及矿质元素的影响。结果表明,随着培养液中Pb浓度的增加,(1)愈伤组织体内的Pb含量极显著上升,富集系数为2341—2681;(2)各亚细胞组分中的Pb含量都呈逐渐上升的趋势,但分配比例明显不均,分布规律为细胞壁>细胞器>可溶性部分,Pb胁迫与处理浓度间存在显著的剂量—效应关系,Pb在亚细胞分布与对细胞超微结构的损伤关系密切;(3)超微定位观察发现在细胞壁上分布有大量的Pb颗粒,细胞内膜结构及基质中也都存在Pb;⑷Pb对各亚细胞组分中矿质元素的影响不同,其中抑制了大量元素P、K、Mg和微量元素Na、Zn、Mn的吸收;Ca在细胞壁中先升后降,细胞器中逐渐减少,可溶性部分中则是逐渐增加;Fe和B在各亚细胞组分中均表现出先升后降;Cu在前两个�Heavy metal pollution of water bodies has become an increasingly serious environmental problem.Understand the principles of heavy metal contamination and heavy metals in water treatment have become a topic that must be addressed.Heavy metals can cause serious health hazards to animals and humans through the food chain due to the refractory,easy accumulation,toxicity and other characteristics.Therefore,much attention has been devoted to the studies on the mechanisms of heavy metal tolerance in plants and how to improve heavy metal tolerance of plants.Although antioxidative reactions of plants subjected to Pb2＋ have been studied by several authors,there are few reports on the research of callus response to heavy metals.In view of this,callus of Alternanthera philoxeroides was cultured to overcome the uncontrollability of light,temperature,moisture and plant growth and development in the natural state,so that the experimental data is more repeated and scientific.Callus of Alternanthera philoxeroides stems was cultured in 1/2 MS medium including 6-BA（3.0 mg/L） and NAA（0.2 mg/L） after the disinfection of 70% ethanol 30s,5% sodium hypochlorite 10min and 0.1% mercuric chloride 10min,was used as experimental material,and Pb2＋ was selected as the stress factor.The toxic effects of Pb gradient concentrations（0,0.2,0.4,0.8 and 1.6 mmol/L） on the accumulation,subcellular distribution,ultrastructural localization and mineral elements were studied.The results indicated that,with the increasing of Pb concentration,（1） Alternanthera philoxeroides callus was able to accumulate lead,the bioconcentration factor was 2341-2681;（2） Subcellular fraction analysis revealed that the contents of Pb increased gradually in cell wall,organelles and soluble fraction,but the distribution ratio was obviously unequal,and the Pb levels occurred in different parts of callus cell with the following sequence cell wallorganellessoluble fraction.The toxic symptoms of callus showed an evident correlation between dose and effect a

关 键 词：愈伤组织 水花生 PB 亚细胞分布 超微定位 矿质元素 

分 类 号：Q945[生物学—植物学]