不同镉积累型叶用芥菜品种镉吸收与转运生理机制研究

发布时间：2018-04-01 12:09

本文选题：镉　切入点：叶用芥菜　出处：《华中农业大学》2017年硕士论文

【摘要】：随着人们生活质量的提高以及对膳食营养的重视,蔬菜每年的消费量也在逐年增加。但是由于近些年来土壤重金属污染问题的日渐突出,及一些食品安全事件的相继报道,蔬菜安全生产问题也开始引起人们的高度重视。本研究从生产实践出发以筛选低镉(Cadmium,Cd)积累型叶用芥菜品种为目的,通过研究高、低镉积累型叶用芥菜品种对镉的吸收和转运生理机制,以揭示高、低积累型叶用芥菜品种对镉吸收和转运差异机理,从而为确保蔬菜安全生产提供重要的理论依据,为培育低镉积累型的叶用芥菜品种提供明确的研究方向。研究结果表明,筛选出的高、低镉积累型叶用芥菜品种地上部镉积累差异的主要原因来源于其根部对镉的吸收和积累差异,具体研究结果如下:1、不同镉积累型叶用芥菜品种的筛选通过统计分析并结合生产实践的要求筛选出了高、低镉积累型的叶用芥菜品种:低镉积累型品种2(扁哈大肉芥菜)和高镉积累型品种4(水东灯笼甜脆芥菜)。2、不同镉积累型叶用芥菜品种对镉的转运特征相关性分析发现这两种镉积累型叶用芥菜品种木质部镉积累速率与培养介质中镉浓度有显著相关性(p0.05),但地上部镉积累量与木质部镉积累速率并不成线性关系,这表明了镉从根部向地上部运输及装载时会遇到一定的阻控作用。方差分析发现这两种镉积累型叶用芥菜品种木质部镉积累速率存在显著差异(p0.05),但是对镉的转运系数并无显著差异(p0.05),这很可能是由于二者地上部分对镉的装载速率差异弥补了木质部镉积累速率的差异从而造成了整个镉胁迫时间段内二者对镉的转运系数无显著差异,这也从侧面反映了镉从地下部向地上部转运的这个过程并不是造成这两种镉积累型叶用芥菜品种地上部镉积累差异的主要决定因素。3、不同镉积累型叶用芥菜品种根部镉的亚细胞积累特征通过研究镉在根部的亚细胞积累规律发现,在镉胁迫情况下低镉积累型叶用芥菜品种镉在根部亚细胞组分中的分配情况与高镉积累型叶用芥菜品种相比具有显著差异(p0.05),且低镉积累型叶用芥菜品种在镉胁迫下,镉在其根部细胞壁组分的百分含量有所增加,镉在其根部可溶性组分的百分含量有所减少,推测低镉积累型叶用芥菜品种有可能通过根部细胞壁对镉的固定作用来减少镉向地上部的转运;通过比较低镉积累型叶用芥菜品种与高镉积累型叶用芥菜品种根部镉的各化学形态百分含量发现,低镉积累型叶用芥菜品种根部乙醇提取态、氯化钠提取态、醋酸提取态、盐酸提取态镉含量与高镉积累型叶用芥菜品种相比存在显著差异(p0.05)。且在镉胁迫情况下低镉积累型叶用芥菜品种醋酸提取态、盐酸提取态镉的百分含量有所增加,推测低镉积累型叶用芥菜品种有可能通过在根部把镉转化成移动活性比较低的化学形态来减少镉向地上部的转运。4、镉胁迫下不同镉积累型叶用芥菜品种根系分泌物分泌特性通过研究不同镉积累型叶用芥菜品种根部对镉的富集情况及根系分泌物分泌特性发现,高镉积累型叶用芥菜品种根部对镉的富集能力要显著高于低镉积累型叶用芥菜品种(p0.05),高镉积累型叶用芥菜品种根系分泌物中3-甲基-2-氧丁酸的百分含量要明显高于其它被检出的根系分泌物百分含量,而低镉积累型叶用芥菜品种只有在高浓度镉处理情况下才检测出3-甲基-2-氧丁酸,推测3-甲基-2-氧丁酸可能会对高积累型叶用芥菜从介质中吸收镉具有很大的促进作用。
[Abstract]:With the improvement of people's living quality and nutritional value, consumption of vegetables each year is increasing year by year. But due to the heavy metal pollution problems have become increasingly prominent, and some have reported incidents of food safety, safety vegetable production also began to attract people's attention. This study from the production practice to screening of low cadmium (Cadmium, Cd) accumulation in leaf mustard varieties for the purpose, through the research of high, low Cd accumulation in leaf uptake and translocation of cadmium and physiological mechanism of mustard varieties, in order to reveal the high and low accumulation of leaf mustard varieties on cadmium absorption and transport mechanism of different, so as to provide an important theoretical basis the safe production of vegetables, for the cultivation of low cadmium accumulation in the leaf mustard varieties provide clear direction. The results show that the selected high and low Cd accumulation in leaf mustard varieties shoot CD The main reason of the difference of accumulation from the roots and accumulation of Cd uptake, the results are as follows: 1. Different Cd accumulation type leaf mustard cultivars screened by statistical analysis and combining with production practice, the requirements of selected high and low cadmium accumulation in the leaf mustard dishes: low Cd accumulation type 2 (Kazakhstan flat meat mustard) and high cadmium accumulation of 4 varieties (East.2, lantern sweet mustard) with different Cd accumulation in leaf mustard varieties on cadmium transport characteristics correlation analysis found that the two types of Cd accumulation in leaf mustard varieties xylem cadmium accumulation rate and there was a significant correlation between Cd concentration in the culture medium (P0.05), but the cadmium accumulation and xylem Cd accumulation rate is not a linear relationship, suggesting that cadmium from root to shoot transport and loading will have certain control effect. Variance analysis showed that the two type of Cd accumulation in leaf mustard Varieties of xylem cadmium accumulation rate had significant difference (P0.05), but there is no transfer coefficient of CD was significant difference (P0.05), which is likely due to the differences in two on the part of the CD loading rate difference for xylem cadmium accumulation rate and caused no significant difference in the time of cadmium stress transfer coefficient in two on the CD, which is also reflected from the side of cadmium from root to shoot transport of this process is mainly caused by the two kinds of decision Cd accumulation type leaf mustard varieties shoot Cd accumulation factor of.3, different Cd accumulation type leaf mustard varieties root subcellular Cd accumulation characteristics through the research the root of the accumulation of cadmium in subcellular found that compared with mustard varieties in the distribution of cadmium stress under the condition of low Cd accumulation in leaf mustard varieties of Cd in roots in subcellular fractions with high Cd accumulation in leaf has Significant differences (P0.05), and low cadmium accumulation in leaf mustard varieties under cadmium stress, content of cadmium in the root cell wall components increased, content of cadmium in the root soluble fractions decreased, presumably low cadmium accumulation in leaf mustard varieties may be reduced to CD the transport through the root cell wall immobilization of cadmium; by relatively low Cd accumulation in leaf mustard varieties and found high Cd accumulation type leaf with the chemical speciation content of root mustard varieties of cadmium, cadmium accumulation type low extractable leaf mustard varieties root ethanol, sodium chloride extractable, acetic acid extraction state, HCl extractable cadmium content and high Cd accumulation in leaf mustard varieties showed a significant difference (P0.05). And in the case of low cadmium cadmium accumulation in leaf mustard varieties of acetic acid extraction, the extraction percentage of cadmium increased hydrochloric acid, that is low Cadmium accumulation in leaf mustard varieties may put into chemical forms of cadmium through mobile activity is relatively low to reduce CD translocation of.4 in roots under Cadmium Stress of different cadmium accumulation type leaf secretion characteristics of mustard varieties root exudates by different Cd accumulation type leaf mustard varieties root accumulation and root exudates the cadmium secretion characteristics found that high cadmium accumulation in leaf mustard varieties root accumulation capacity of CD was significantly higher than low Cd accumulation in leaf mustard varieties (P0.05), high cadmium accumulation in leaf with percent of mustard varieties in root exudates of 3- methyl -2- butyric acid was higher than that of other oxygen was detected in root secretions content percent and low Cd accumulation type leaf mustard varieties only in high concentrations of cadmium treatment conditions to detect 3- -2- oxygen methyl butyric acid, 3- methyl butyric acid -2- that might be of high oxygen accumulation in leaves The use of mustard to absorb cadmium from medium has a great effect.

【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X503.231;S637

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