枯草芽孢杆菌QM3对铅胁迫小麦根系的缓解效应

发布时间：2018-01-01 11:08

本文关键词：枯草芽孢杆菌QM3对铅胁迫小麦根系的缓解效应　出处：《山西师范大学》2016年硕士论文　论文类型：学位论文

【摘要】：重金属铅严重影响植物生长发育导致农业作物产量严重下降,这已成为迫切解决的问题,而生物修复法越来越引起人们的注意。在微生物方面能够筛选出一株既能够减轻重金属铅污染又能够促进作物生长状况的菌株具有很重要的意义。枯草芽孢杆菌(Bacillus subtilis)是一类生防细菌,既能够促进植物生长又能够缓解重金属对植物的胁迫伤害,菌株不同其缓解效应也不同。本文以小麦为实验材料,研究不同浓度的B.subtilis QM3菌液对Pb2+胁迫环境中小麦根系的理化特性以及根尖细胞形态的影响,为研究缓解植物重金属胁迫以及开发微生物的农业新应用提供理论依据。下面是本文主要的研究结果:(1)重金属铅对小麦根系具有抑制其生长的作用。铅胁迫可明显降低根长、根表面积、根系总体积及根系投影面积,且铅浓度越高抑制效果越明显。铅胁迫环境下,B.subtilis QM3菌液对小麦根系形态各个指标均有显著的促进作用,当Pb2+浓度为500mg/L时,107 CFU/mL B.subtilis QM3菌液可使根长、根表面积、根系体积以及根系投影面积分别提高43.37%、42.28%、237.80%、286.06%(p0.05)。(2)铅胁迫使小麦根系生物量以及根系活力呈现先增大后减小的趋势,均在Pb2+为50mg/L时达到最大值,且铅浓度越高抑制效果越明显,B.subtilis QM3菌液处理小麦根系能够促进其生物量的积累、提高根系活力,当Pb2+浓度为250 mg/L时,107CFU/mL B.subtilis QM3菌液可使生物量以及根系活力分别提高6.87%、99.93%(p0.05)。(3)铅胁迫使小麦根系可溶性糖、可溶性蛋白、Pro、MDA以及细胞膜相对透性(电导率)均增加。低浓度Pb胁迫,不同浓度B.subtilis QM3菌液处理均能明显降低以上物质在根系中的含量以及降低细胞膜的相对透性,当Pb2+浓度为500 mg/L时,107 CFU/mL B.subtilis QM3菌液可使细胞膜相对透性降低13.82%(p0.05)。(4)Pb胁迫可诱导小麦根系SOD、CAT、APX和POD活性随着Pb浓度的增大呈现先增大后减小的趋势。B.subtilis QM3处理能够有效提高Pb胁迫环境中根系的抗性酶活性,当Pb2+浓度为500 mg/L时,107 CFU/mL B.subtilis QM3菌液可使SOD、CAT、APX和POD分别提高5.38%、83.46%、44.17%、10.11%(p0.05)。(5)铅胁迫使小麦根系还原型谷胱甘肽(GSH)含量和抗坏血酸(ASA)含量先升高后降低。当Pb2+为50、250、2000mg/L时,B.subtilis QM3菌液可显著提高根系GSH含量(p0.05);中低浓度铅胁迫,B.subtilis QM3菌液可显著提高根系ASA含量。(6)铅胁迫可导致小麦根系表皮细胞厚度、宽度随着Pb浓度的增大呈现先增大后减小的趋势。低铅胁迫时,菌液处理组较无菌水处理组细胞形态更为完整,而在中高铅浓度下时,无菌水处理组细胞形态较菌液处理组更为完整;无菌水处理,皮层厚度随Pb2+浓度升高呈先增厚后变薄的趋势,B.subtilis QM3菌液处理时,当铅浓度为0、50、500mg/L根系皮层厚度均小于无菌水处理组;铅浓度为2000mg/L时,107CFU/ml B.subtilis QM3处理组皮层厚度大于对照,而108、106CFU/mL B.subtilis QM3菌液处理组皮层厚度却小于无菌水处理。
[Abstract]:Pb seriously affects plant growth in agricultural crop yield declined seriously, which has become an urgent problem, and bioremediation has attracted more and more attention. To select a strain which has very important significance to reduce heavy metal pollution and can promote crop growth status. Microbial strains in Bacillus subtilis (Bacillus subtilis) is a kind of biocontrol bacteria, which can promote the growth of plants and can alleviate the stress of heavy metals to plants, different strains are different. The mitigation effect of using wheat as experimental materials, B.subtilis QM3 bacteria were studied on the physicochemical characteristics in wheat root stress and the influence on the morphology of Pb2+ the root tip cells, and provide a theoretical basis for the application of new agricultural plant heavy metal stress as the research and development of microbial ease. Here is the main research The results: (1) Pb has inhibiting effect on wheat root. Lead stress can significantly reduce the root length, root surface area, root volume and root area, and lead the higher concentration the more obvious inhibition of lead stress. Under the environment of B.subtilis QM3 bacteria on wheat root morphology indexes were significant effect, when the concentration of Pb2+ was 500mg/L, 107 CFU/mL B.subtilis QM3 bacteria can make the root length, root surface area, root volume and root area were increased by 43.37%, 42.28%, 237.80%, 286.06% (P0.05). (2) the lead stress of root biomass and root activity of wheat increased first and then decreased the trend reached the maximum value at Pb2+ is 50mg/L, and the higher the concentration of lead inhibition effect is more obvious, B.subtilis QM3 bacteria liquid treatment can promote the root biomass accumulation, increase root activity, when the concentration of Pb2+ was 250 mg/L, 107 CFU/mL B.subtilis QM3 can make the bacteria biomass and root activity were increased by 6.87%, 99.93% (P0.05). (3) the lead stress of wheat root soluble sugar, soluble protein, Pro, MDA and cell membrane permeability (electrical conductivity) were increased. The low concentration of Pb stress, different concentrations of B.subtilis QM3 bacteria liquid treatments the above material content significantly decreased in roots and decreased the cell membrane permeability, when the concentration of Pb2+ was 500 mg/L, 107 CFU/mL B.subtilis QM3 bacteria liquid. The relative permeability of cell membrane decreased 13.82% (P0.05). (4) Pb induced wheat root system SOD, CAT, APX and POD activity with the increase of Pb concentration showed Pb can effectively improve the resistance enzyme activity in root stress environment can.B.subtilis QM3 trend first increased and then decreased, when the concentration of Pb2+ was 500 mg/L, 107 CFU/mL B.subtilis QM3 bacteria can make SOD, CAT, APX and POD were increased by 5.38%, 83.4 6%, 44.17%, 10.11% (P0.05). (5) the lead stress of wheat root glutathione (GSH) and the content of ascorbic acid (ASA) content increased first and then decreased. When the Pb2+ is 502502000mg/L, B.subtilis QM3 solution can significantly increase the GSH content of root (P0.05); low concentration of lead stress, B.subtilis QM3 broth can significantly increase the ASA content in root. (6) lead stress can lead to root epidermal thickness, width along with the increase of Pb concentration increased first and then decreased. Low lead stress, compared with sterile water treatment group cell morphology is more complete in bacteria, high concentration of lead, sterile water treatment group cells than bacteria group is more complete; aseptic water treatment, cortical thickness increased with the concentration of Pb2+ was thicker after thinning trend, B.subtilis QM3 broth processing, when the lead concentration is 0,50500mg/L root skin thickness were less than the sterile water treatment group When the lead concentration is 2000mg/L, the cortical thickness of 107CFU/ml B.subtilis QM3 treatment group is larger than that of the control group, while the thickness of cortex of 108106CFU/mL B.subtilis QM3 bacteria treatment group is smaller than that of aseptic water treatment.

【学位授予单位】：山西师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S512.1;S182

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