秋华柳对镉的积累及其亚细胞分布特征  

Accumulation and Subcellular Distribution of Cadmium in Salix variegate

作　　者：刘媛[1] 魏虹[1] 马文超[1] 张雯[1] 曾成城 周翠[1] 王婷[1] Liu Yuan;Wei Hong;Ma Wenchao;Zhang Wen;Zeng Chengcheng;Zhou Cui;Wang Ting(Key Laboratory of Eco-environments in Three Gorges Reservoir Region of the Ministry of Education Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region School of Life Sciences,Southwest University Chongqing 400715)

机构地区：[1]三峡库区生态环境教育部重点实验室重庆市三峡库区植物生态与资源重点实验室西南大学生命科学学院,重庆400715

出　　处：《林业科学》2018年第8期48-55,共8页Scientia Silvae Sinicae

基　　金：国家国际科技合作专项(2015DFA90900);三峡后续工作库区生态与生物多样性保护专项(5000002013BB5200002);中央财政林业科技推广示范项目(渝林科研2016-8)

摘　　要：【目的】探讨Cd在秋华柳各器官及叶片亚细胞组分中的分布特征,为深入了解秋华柳的耐受解毒机制,进一步指导其在Cd污染地区的植物修复工作提供理论依据。【方法】采用水培试验方式,设置CK(0 mg·L^(-1)Cd^(2+))、T_1(2 mg·L^(-1)Cd^(2+))、T_2(10 mg·L^(-1)Cd^(2+))、T_3(20 mg·L^(-1)Cd^(2+))、T_4(50 mg·L^(-1)Cd^(2+))5种Cd处理浓度,测定秋华柳各营养器官和0、6、12、18天叶片中亚细胞组分的Cd含量。【结果】1)不同浓度Cd处理下,秋华柳根部积累的Cd含量远高于茎和叶,表明秋华柳通过根系对Cd的滞留效应,可降低Cd向地上部分的转运,从而减少Cd对地上部分的毒害。2)时间和浓度处理均显著增加秋华柳各亚细胞组分中的Cd含量,但细胞壁和细胞质中Cd含量的增幅远大于细胞器,且其亚细胞组分中Cd含量的分布为细胞壁>细胞质>细胞器,表明细胞壁的固定和液泡的区室化均为秋华柳的重要解毒作用,但细胞壁对Cd的结合和固定作用占主导。3)相同处理时间下,与CK相比,低Cd浓度处理时,细胞壁组分中的Cd含量显著增加,而随着处理浓度的增加,细胞壁组分中的Cd含量及百分比呈降低趋势,细胞质组分中的Cd含量及百分比显著增加。同时,随着处理时间的延长,秋华柳细胞质组分中的Cd含量百分比上升,而细胞壁组分中的Cd含量百分比下降。高Cd含量和长时间胁迫时,细胞壁对Cd的固定能力有所下降,而液泡的区室化作用显著提高,这可能是秋华柳耐受高Cd含量和长时间胁迫的一种策略。4)时间和浓度的交互作用对秋华柳亚细胞组分中Cd含量的增加效应大于单一时间处理或单一浓度处理效应,表明在Cd处理浓度和处理时间的双重影响下,秋华柳细胞壁的固定作用和液泡的区室化作用更加显著。【结论】1)器官水平上,秋华柳通过根系对Cd的滞留效应限制其向地上部分的转运,从而降低Cd对地上部分细胞器的毒�【Objective】Cadmium（ Cd） is one of the most toxic heavy metals. With highly water soluble,Cd can be readily absorbed by plants,and eventually threaten the health of plants. With large biomass and fast growth rate,It has been widely reported that Salix variegatehas strong bioaccumulation on Cd and is a promising phytoremediation candidate for Cd contaminated area. However,its detoxification mechanisms at cellular scaleare not clear. To understand its detoxification mechanisms at cellular scale,the Cd content indifferent organs and subcellular factions of S. variegate was studied in this research.【Method】A hydroponic experiment with different Cd concentrations were conducted,including 0 mg·L-1（ CK）,2 mg·L-1（ T1）,10 mg·L-1（ T2）,20 mg·L-1（ T3） and 50 mg·L-1（ T4）. We determined the Cd content in different organs of S. variegatein 18 d of treatment sand in subcellular factions of the leaves in 0 d,6 d,12 d and 18 d after the treatments began.【Result】1） Under different concentrations of Cd,the Cd contents in roots were much higherthan in stems and leaves,which indicated the retention of Cd by roots decreased the transport of Cd to the aerial parts and sodecreased the Cd toxicity to shoots. 2） Both the experimental duration and treatment concentration affected the Cd subcellular distribution in S. variegate significantly. The Cd content increased with the increase of Cd concentration and the treatment time. However,the increase of the Cd content in cell wall and cytoplasm supernatant were far more than thatin organelles. The Cd contents in different subcellular fractions were in the order of cell wall cytoplasm supernatant cell organelles,indicating that cell wall binding and vacuolar compartmentalization were important detoxification mechanisms in S. variegate leaves,especially for cell wall that played adominant role. 3） In the same treatment duration,compared to CK,the Cd content in the cell wall increased significantly under low Cd concentration treatment,while the cell w

关 键 词：镉 秋华柳 亚细胞 区室化 解毒 

分 类 号：Q494[生物学—生理学] S718.43[农业科学—林学]