本文選題：欒樹 + 鎘脅迫��； 參考：《中南林業(yè)科技大學》2017年碩士論文

【摘要】：土壤重金屬污染影響食品安全,危及人類健康。欒樹具有富集重金屬的特性,且生長迅速、生物量大、適應性強,是礦山廢棄地修復的首選樹種。然而,不同欒樹品種間富鎘生理機制和富鎘差異至今仍未見報道。本研究采用盆栽試驗,研究了鎘脅迫對復羽葉欒樹、黃山欒樹和北京欒樹植株株高、葉綠素含量、超氧化物歧化酶(SOD)活性、過氧化物酶(POD)活性、過氧化氫酶(CAT)活性、可溶性蛋白含量和游離脯氨酸含量的影響,以及3個欒樹品種植株葉和根富鎘差異,其目的是篩選出富鎘性較強的欒樹品種并闡明其富鎘生理機制,為欒樹應用于鎘污染土壤修復提供理論依據(jù)。主要研究結果如下:(1)隨著土壤中外源添加鎘濃度的增加,3種欒樹植株株高的增量呈逐漸降低的趨勢。除鎘濃度為50mg.kg-1處理外,其余各處理植株株高與CK相比影響顯著。(2)隨著土壤外源添加鎘濃度的增加,3個品種欒樹植株葉綠素含量呈現(xiàn)上升后下降的趨勢,三個品種葉綠素含量的大小為:復羽葉欒樹黃山欒樹北京欒樹。各處理葉綠素含量與CK相比差異顯著,各但品種之間葉綠素含量差異不顯著。在鎘濃度為400mg.kg-1時,3個品種欒樹幼苗葉綠素含量低于對照組。(3)不同鎘濃度脅迫下,三個品種欒樹植株葉和根中SOD、POD、CAT活性隨著鎘濃度的增加呈現(xiàn)先升高后降低的趨勢,葉中酶活性高于根,且葉和根SOD、POD、CAT活性達峰值時所受的鎘脅迫濃度不同。各項酶活與CK相比差異顯著或極顯著。(4)不同鎘濃度脅迫下,三個品種欒樹植株葉和根中可溶性蛋白的含量隨著鎘濃度的增加呈現(xiàn)先上升后下降的趨勢,且葉中可溶性蛋白含量高于根;葉中游離脯氨酸的含量隨著鎘濃度的增加呈現(xiàn)逐漸上升,而根中脯氨酸含量在鎘濃度為400mg.kg-1時,呈現(xiàn)下降的趨勢。(5)不同鎘濃度脅迫下,欒樹植株根系對鎘的富集大于葉片,各處理和各品種間鎘含量差異極顯著,可以認為根系是欒樹富集鎘的主要部位。結果表明欒樹富鎘的生理機制為根吸收土壤中的鎘并轉運到葉中,抗氧化酶活性的升高及可溶性蛋白含量及游離脯氨酸含量的增加,提升了對鎘脅迫逆境的抵抗能力。綜合比較得出復羽葉欒樹耐鎘性較強,可以作為鎘污染土壤修復樹種。
[Abstract]:Heavy metal pollution in soil affects food safety and endangers human health. Luan tree has the characteristics of enrichment of heavy metals, rapid growth, large biomass, strong adaptability, and is the first choice of tree species for the restoration of mine wasteland. However, the physiological mechanism of cadmium enrichment and the difference of cadmium enrichment among different Luan tree varieties have not been reported. Pot experiment was conducted to study the effects of cadmium stress on plant height, chlorophyll content, superoxide dismutase (SOD) activity, peroxidase (POD) activity and catalase (CAT) activity in the leaves of Luan, Huangshan Luan and Beijing Luan. The effects of soluble protein content and free proline content, and the difference of cadmium enrichment in leaves and roots of three Luan tree varieties, were studied in order to screen the varieties with strong cadmium enrichment and elucidate the physiological mechanism of cadmium enrichment. It provides a theoretical basis for the application of Luan tree to the remediation of cadmium contaminated soil. The main results were as follows: (1) the increment of plant height of three kinds of Luan tree showed a decreasing trend with the increase of exogenous cadmium concentration in soil. Except for the 50mg.kg-1 treatment, the plant height of the other treatments had a significant effect on the plant height compared with CK.) with the increase of exogenous cadmium concentration in soil, the chlorophyll content of the three varieties Luan Shu plants increased and then decreased. The chlorophyll content of the three varieties is: Luanchuan Luan, Huangshan Luan, Luan, Beijing Luan. There was significant difference in chlorophyll content between treatments and CK, but there was no significant difference among varieties. When cadmium concentration was 400mg.kg-1, the chlorophyll content of three varieties Luan tree seedlings was lower than that of the control group. (3) under different cadmium concentration stress, the activities of POD cat in leaves and roots of three varieties Luan tree increased first and then decreased with the increase of cadmium concentration. The activity of enzyme in leaves was higher than that in roots, and the concentration of cadmium stress was different when the activity of POD cat in leaves and roots reached the peak. The content of soluble protein in leaves and roots of three varieties of Luan tree increased firstly and then decreased with the increase of CD concentration. The soluble protein content in leaves was higher than that in roots, and the content of free proline in leaves gradually increased with the increase of cadmium concentration, while the content of proline in roots showed a decreasing trend when cadmium concentration was 400mg.kg-1. The concentration of cadmium in roots of Luan tree was higher than that in leaves, and there were significant differences among different treatments and varieties. It can be concluded that root system is the main part of cadmium enrichment in Luan tree. The results showed that the physiological mechanism of cadmium rich in Luan Shu was that the root absorbed cadmium from soil and transported it to the leaves. The increase of antioxidant enzyme activity and the increase of soluble protein content and free proline content increased the resistance to cadmium stress. The comprehensive comparison showed that the compound leaf Luan tree had stronger tolerance to cadmium and could be used as a remediation tree for cadmium contaminated soil.
【學位授予單位】：中南林業(yè)科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：X53;X173;S792.99
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本文編號：1877824