本文選題：木本植物 + 重金屬　； 參考：《中南林業(yè)科技大學(xué)》2017年碩士論文

【摘要】：土壤重金屬污染是一個(gè)日益嚴(yán)峻的環(huán)境問(wèn)題,植物修復(fù)是一種環(huán)境友好的土壤重金屬治理的方法,廣義上植物修復(fù)還具有重建植被、修復(fù)景觀、改良土壤性質(zhì)等功能。在此意義上,木本植物以生物量大、生長(zhǎng)周期長(zhǎng)成為首選對(duì)象。重金屬對(duì)植物的毒害作用表現(xiàn)在各個(gè)方面,其中植物光合作用受到抑制是重金屬毒害的顯著癥狀。為此,本文以闊葉樹(shù)種欒樹(shù)和櫸樹(shù)1年生幼樹(shù)為對(duì)象,采用室內(nèi)盆栽試驗(yàn),通過(guò)連續(xù)4次分別將PbCl2、ZnCl2摻入盆栽土壤,研究連續(xù)Pb、Zn單一脅迫處理對(duì)欒樹(shù)和櫸樹(shù)葉片的氣體交換參數(shù)、葉綠素?zé)晒鈪?shù)和富集等方面的影響,對(duì)比分析2種植物對(duì)Pb、Zn耐性能力,試圖找出2種植物光合生理參數(shù)與Pb、Zn濃度之間的定量響應(yīng)關(guān)系。研究結(jié)果將為耐性木本植物的篩選提供數(shù)據(jù)支撐。主要研究結(jié)論如下:1、連續(xù)Pb、Zn處理下,欒樹(shù)和櫸樹(shù)的最大凈光合速率(Pn)、蒸騰速率(Tr)、氣孔導(dǎo)度(Gs)和氣孔閥值(Ls)均表現(xiàn)為處理組對(duì)照,且差異性顯著(P＜0.05),胞間C02(Ci)則表現(xiàn)為處理組對(duì)照,出現(xiàn)了由非氣孔限制引起的Pn下降。并且,隨著Pb、Zn處理次數(shù)的增多,在處理組中,欒樹(shù)和櫸樹(shù)的Pn、Tr、Gs、Ls呈下降趨勢(shì),Ci呈上升趨勢(shì)。在Pb、Zn單一脅迫下,隨著Pb、Zn處理濃度的升高,櫸樹(shù)表現(xiàn)出的光合能力高于欒樹(shù)。重金屬Zn對(duì)二者光合作用的抑制比Pb強(qiáng)。2、Pb、Zn處理下欒樹(shù)和櫸樹(shù)PSII最大光化學(xué)效率(Fv/Fm)、實(shí)際光化學(xué)效率(ETR)低于對(duì)照,且ETR和對(duì)照相比差異顯著(P＜0.05);二者的光化學(xué)猝滅(qP)均顯著降低,非光化學(xué)猝滅(NPQ)顯著升高,說(shuō)明欒樹(shù)和櫸樹(shù)在Pb、Zn脅迫下發(fā)生了明顯光抑制現(xiàn)象,但可以通過(guò)熱的形式將PSII的過(guò)剩光能耗散掉。隨著Pb、Zn處理次數(shù)的增多,在處理組中,欒樹(shù)和櫸樹(shù)的Fv/Fm、ETR、qP總體呈下降趨勢(shì),NPQ呈上升趨勢(shì)。對(duì)比二者在Pb、Zn脅迫下的光保護(hù)能力,我們得出,在低濃度Pb處理下,欒樹(shù)的qP和NPQ高于櫸樹(shù),造成欒樹(shù)的光合能力高于櫸樹(shù),但隨著處理次數(shù)的增多,欒樹(shù)qP和NPQ低于櫸樹(shù),使得櫸樹(shù)表現(xiàn)出更強(qiáng)的光合能力。在Zn處理下,欒樹(shù)和櫸樹(shù)的Fv/Fm、ETR、qP、NPQ較對(duì)照而言,其變化幅度高于Pb處理,說(shuō)明了 Zn對(duì)于這兩種植物的傷害大于Pb;櫸樹(shù)在第1次Zn處理后,很快顯示出了比欒樹(shù)更好的光保護(hù)能力,在第2和第3次處理后,同對(duì)照相比,欒樹(shù)qP的下降幅度高于櫸樹(shù),這說(shuō)明了櫸樹(shù)比欒樹(shù)更耐Zn脅迫。3、在連續(xù)Pb、Zn處理下,欒樹(shù)和櫸樹(shù)各部位Pb2+、Zn2+含量明顯地高于對(duì)照相應(yīng)部位。根是欒樹(shù)和櫸樹(shù)吸收積累Pb2+的主要部位,Pb處理組的根吸收量比對(duì)照組高出6.42-32.89倍,莖的Pb含量小于根,Pb處理組比對(duì)照組高出2.95-11.67倍,Pb在葉的積累量比莖稍高,但從增加倍數(shù)來(lái)看,Pb處理組比對(duì)照組僅高出2.63-8.85倍,在整株中表現(xiàn)出來(lái)的富集能力均為:欒樹(shù)櫸樹(shù);而在吸收積累Zn2+的方面,根和莖的積累量相當(dāng),而葉對(duì)Zn2+的吸收量較少。在吸收富集Zn的能力方面欒樹(shù)要優(yōu)于櫸樹(shù),但在Zn處理下,櫸樹(shù)對(duì)Zn的吸收富集更具持續(xù)性。不同的重金屬在植物體內(nèi)的分配率存在差異,欒樹(shù)和櫸樹(shù)從土壤中吸收的Pb2+主要積累在根部,占了總吸收量的57.09%-76.68%;遷移至莖部的數(shù)量占總量的6.95%-15.98%;遷移至葉部的數(shù)量占了總量的10.36%-30.32%;Zn2+在櫸樹(shù)根莖葉部的分配率為表現(xiàn)為:42.99%、29.85%、27.16%,欒樹(shù)為:37.17%、33.81%、29.02%,說(shuō)明了 Zn2+在欒樹(shù)和櫸樹(shù)中的分配率高于Pb2+。在富集系數(shù)方面,欒樹(shù)和櫸樹(shù)對(duì)Pb、Zn的富集系數(shù)均隨著處理次數(shù)的增多而減少,其中,欒樹(shù)富集Pb、Zn的能力要高于櫸樹(shù)。4、基于Lake模型分析單一 Pb、Zn脅迫下欒樹(shù)和櫸樹(shù)的耐性能力得出,隨著Pb處理次數(shù)的增多,櫸樹(shù)耐Pb的能力逐漸表現(xiàn)為高于欒樹(shù);兩種植物對(duì)Zn的耐性不強(qiáng),相比之下,櫸樹(shù)對(duì)Zn的耐性高于欒樹(shù)。5、由光合、熒光參數(shù)對(duì)Pb、Zn污染劑量的響應(yīng),可以得出欒樹(shù)對(duì)土壤Pb污染的耐受范圍在1.80-2.15g/kg之間,櫸樹(shù)為1.85-2.25g/kg;而連續(xù)Zn處理對(duì)欒樹(shù)和櫸樹(shù)所造成的破壞使得二者在土壤中Zn含量(≤0.5g/Kg)時(shí),光系統(tǒng)中的各參數(shù)下降明顯,最終表現(xiàn)為對(duì)Zn的耐性均不高,但從試驗(yàn)周期來(lái)說(shuō),櫸樹(shù)比欒樹(shù)更能存活在Zn污染更嚴(yán)重的土壤中。
[Abstract]:Heavy metal pollution in soil is an increasingly serious environmental problem. Phytoremediation is an environmentally friendly method of remediation of heavy metals in soil. In the broad sense, plant restoration also has the functions of reconstructing vegetation, restoring landscape and improving soil properties. In this sense, the woody plants are the first choice for the large amount of raw materials and long growth cycle. The toxic effects of plants are manifested in various aspects, among which plant photosynthesis is inhibited as a significant symptom of heavy metal poisoning. For this reason, the 1 year old trees of broad leaved tree and beech tree were used as the target, and PbCl2 and ZnCl2 were added into the potted soil by indoor pot experiments, and the single stress treatment of Pb and Zn was studied. The effects of the gas exchange parameters, chlorophyll fluorescence parameters and enrichment on the leaves of the trees and beech trees were analyzed. The tolerance ability of 2 plants to Pb and Zn was compared and analyzed. The quantitative response relationship between the photosynthetic physiological parameters of 2 plants and the concentration of Pb and Zn was tried to find out. The results will provide data support for the screening of resistant wood plants. 1, 1, under continuous Pb, Zn treatment, the maximum net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and stomatal threshold (Ls) of the tree and beech were all compared with the treatment group, and the difference was significant (P < 0.05), and the intercellular C02 (Ci) was shown as the control of the treatment group, and the Pn decreased by the non stomatal restriction. And, with Pb, the Zn treatment times In the treatment group, the Pn, Tr, Gs and Ls of the tree and the beech showed a downward trend, and the Ci showed an upward trend. Under the Pb, Zn stress, with the increase of Pb and the concentration of Zn, the photosynthetic capacity of the beech tree was higher than that of the tree. The inhibition of the photosynthesis of the heavy metal Zn to the two was stronger than the Pb.2. Fm), the actual photochemical efficiency (ETR) was lower than that of the control, and the difference between ETR and photographic ratio was significant (P < 0.05); the photochemical quenching (qP) of the two groups decreased significantly, and the non photochemical quenching (NPQ) increased significantly. It indicated that the light inhibition of the tree and beech trees under the stress of Pb and Zn was obvious, but the excess light energy consumption of PSII could be dissipated through the form of heat. With the increase of the number of Pb and Zn processing, in the treatment group, the Fv/Fm, ETR and qP of the trees and the beech trees showed a downward trend, and the NPQ showed an upward trend. Compared with the light protection ability under the stress of Pb and Zn, we concluded that the qP and NPQ of the trees were higher than the beech trees under the low concentration of Pb treatment. The photosynthetic capacity of the tree was higher than that of the beech tree, but with the increase of the treatment times. More, the qP and NPQ were lower than the beech trees, making the beech stronger photosynthetic capacity. Under the Zn treatment, the Fv/Fm, ETR, qP, NPQ of the trees and beech trees were higher than the control of Pb treatment, which indicated that the harm of Zn to these two plants was greater than Pb, and the beech tree showed better light protection than the tree after first Zn treatment. After second and third treatments, the decrease of qP was higher than that of the beech tree, which showed that the beech tree was more resistant to Zn stress than that of the beech tree, and that the content of Zn2+ content was obviously higher than that of the photographing site. The content of Zn2+ was significantly higher than that of the photographic site. The root was the main part of the accumulation of Pb2+ in the root of the tree and the beech tree, and the root absorption of the Pb treatment group. The amount of Pb in the stem was less than that of the control group, the content of the stem was less than that of the root, the Pb treatment group was higher than the control group 2.95-11.67 times, and the accumulation of Pb in the leaves was slightly higher than that of the stem, but from the increase, the Pb treatment group was only 2.63-8.85 times higher than the control group, and the accumulation energy in the whole plant was all: the 6.42-32.89 beech tree; and the root of the accumulation of Zn2+. The accumulation of stems is equal, but the absorption of Zn2+ is less. In the capacity of absorbing and enriching Zn, the tree is better than the beech tree, but the absorption and enrichment of the beech tree to Zn is more persistent under the Zn treatment. The distribution rate of different heavy metals in the plant is different, and the Pb2+ of the tree and beech from the soil is mainly accumulated in the root. The total absorption of 57.09%-76.68%; the number of migrating to the stem accounted for 6.95%-15.98% of the total amount; the number of migrating to the leaves accounted for 10.36%-30.32% of the total amount; the distribution rate of Zn2+ in the root and leaf of the beech was 42.99%, 29.85%, 27.16%, and 37.17%, 33.81%, 29.02%, indicating that the allocation rate of Zn2+ in the tree and beech was higher than that of Pb2+. in the rich. In the aspect of set coefficient, the enrichment coefficient of Pb and Zn in Luan and beech decreased with the increase of the number of processing times. Among them, the ability to enrich Pb and Zn was higher than that of beech.4. Based on Lake model, the tolerance ability of Luan tree and beech under Zn stress was analyzed. With the increase of Pb treatment times, the ability of Pb to resist Pb was gradually higher than that of Luan. The tolerance of the two plants to the Zn was not strong. In contrast, the tolerance of the beech tree to the Zn was higher than that of the.5. In response to the photosynthesis, the fluorescence parameters to the Pb, Zn pollution dose, it could be found that the tolerance range of the Pb pollution in the soil was between 1.80-2.15g/kg and the beech was 1.85-2.25g/kg; and the damage caused by the continuous Zn treatment to the tree and beech tree caused two people. When the Zn content in the soil (less than 0.5g/Kg), the parameters of the optical system decreased obviously, and the endurance of Zn was not high, but from the test period, the beech tree was more able to survive in the more serious soil contaminated by the Zn.

【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X53;X173;S792.99
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本文編號(hào)：1829318