铅锌胁迫对蓖麻根系形态结构及元素吸收的影响

发布时间：2018-05-17 21:22

  本文选题：铅锌胁迫 + 蓖麻　； 参考：《中南林业科技大学》2017年硕士论文

【摘要】：蓖麻(Ricimus communist L.)属大戟科(Euphorbiaceae)蓖麻属(Ricinus)一年生或多年生草本植物。其生物量大,根系发达且抗逆性强,对多种重金属具有较强的耐受性和富集作用,是一种具有重要开发应用前景的重金属污染土壤修复工业油料植物。本研究以蓖麻“秀蓖2号”品种为试验材料,栽种于细沙和珍珠岩体积比5:4混合、添加不同浓度单一和复合Pb2+、Zn2+的基质中,定期观测蓖麻种子胚根伸长与萌发变化、根组织结构与根系形态结构的变化、植株对Pb2+、Zn2+及主要营养元素的吸收分配、植株生长势变化,分析蓖麻根生长和形态结构与重金属吸收累积、主要营养元素含量以及植物生长势的相关性,探明不同铅锌胁迫浓度下,蓖麻根系对Pb2+、Zn2+重金属的反馈与适应性变化,以期为制定合理的修复栽培措施,提高蓖麻对Pb/Zn污染土壤的修复能力提供参考和指导。主要研究结果如下:(1)Pb2+、Zn2+胁迫对胚根的伸长与种子萌发产生不同影响。相同浓度下,Zn2+对蓖麻胚根伸长的抑制作用较Pb2+的抑制作用强,当Pb2+为200 mg/kg、400 mg/kg时,胚根的伸长量和种子萌发率均大于对照,其萌发势与对照无明显差异;Zn2+为200 mg/kg时即对胚根伸长、种子发芽势与发芽率均产生较显著的抑制作用;胁迫总浓度为400 mg/kg时,对胚根伸长的抑制作用由强到弱依次为Zn2+(Pb2++Zn2+复合胁迫)Pb2+。胚根伸长和种子萌发率与Pb2+胁迫浓度成不显著负相关性,与Zn2+处浓度呈极显著负相关(R21=-0.806**,R22=-0.487**)。(2)Pb2+、Zn2+胁迫对蓖麻总根长、主根长、根表面积、根体积、根尖数产生不同影响。影响力从小到大依次为:Pb2+Zn2+Pb2+、Zn2+复合。单一胁迫Pb2+为200 mg/kg时,根系表面积、侧根数相比对照分别上升了 7.8%和33.3%;单一胁迫Zn2+≥200 mg/kg胁迫时,根系的各项形态指标都受到抑制,抑制效应随着Zn2+浓度的增加而加强。Pb2+、Zn2+复合胁迫下,根系各形态指标均随着胁迫浓度升高而降低。(3)Pb2+、Zn2+胁迫引起根解剖结构发生改变。随着Pb2+、Zn2+胁迫处理浓度的增加,根冠细胞体积、根冠体积逐渐变小,细胞排列不规则;根尖分生组织细胞变小、细胞着色深,排列欠整齐;表皮细胞和外皮层细胞的细胞壁木栓化程度逐渐增强,皮层薄壁细胞变小,细胞内结晶颜色加深,颗粒变大,严重时结晶颗粒占居整个细胞;内皮层及中柱鞘细胞细胞壁木栓化逐渐加厚。(4)Pb2+、Zn2+复合胁迫对Pb2+、Zn2+在蓖麻不同部位的累积量产生不同影响,且与根系形态指标密切相关。Pb2+、Zn2+在植株地下与地上部分的累积量均与其栽培基质中的Pb2+、Zn2+浓度呈极显著正相关;总根长、表面积、根尖数与地下部分Pb积累量呈不显著负相关,与地上部分的累积量呈不显著正相关;根系各形态指标与Zn地上地下部分积累量均呈极显著负相关。(5)Pb2+、Zn2+胁迫影响植株对N、P、K的吸收与分配,进而影响植株的生长。单一 Pb2+、Zn2+胁迫浓度≤400mg/kg时,植株地上与地下部分全N含量显著高于对照植株,复合处理下和浓度为600 mg/kg的Pb2+、Zn2+单一处理下,全N含量均低于对照;植株全P含量在Pb2+、Zn2+单一处理时的均高于对照,在复合处理时均低于对照组;植株全K含量在Pb2+、Zn2+单一与复合胁迫下均高于对照,且根部的积累量大于地上部分。随着Pb2+、Zn2+胁迫浓度上升,对植株地径生长的影响不明显,但株高和节间长显著降低。同时叶片的总厚度变薄,栅栏层组织厚度变薄,细胞趋向于变小、排列疏松,海绵层组织厚度变厚,输导组织横切面积变小(薄壁细胞数量、导管数量减少)。
[Abstract]:Ricimus Communist L. is an annual or perennial herb of the family euphorbifamily (Euphorbiaceae) of the genus Castor (Ricinus). It has a large biomass, developed root system and strong resistance to stress. It has strong tolerance and enrichment to a variety of heavy metals. It is a heavy heavy metal contaminated soil remediation industrial oil plant with important development and application prospects. In this study, the varieties of Ricinus ricinus 2 were used as experimental materials, planted in the mixture of fine sand and perlite volume ratio 5:4, adding different concentrations of single and compound Pb2+, Zn2+, to observe the root elongation and germination of Castor seeds, the changes of root structure and root morphology, and the plant to Pb2+, Zn2+ and the main nutrient elements. The relationship between the growth and morphological structure of castor root and the accumulation of heavy metals, the content of main nutrients and the growth potential of plant, and the feedback and adaptability of castor root to Pb2+ and Zn2+ heavy metals under different concentrations of lead and zinc were analyzed. The main results are as follows: (1) Pb2+, Zn2+ stress has different effects on the elongation of radicle and seed germination. Under the same concentration, the inhibitory effect of Zn2+ on the elongation of castor bean radicle is stronger than that of Pb2+, when Pb2+ is 200 mg/kg, 400 mg/kg, the elongation and species of radicle. The Zi Mengfa rate was greater than that of the control, and the germination potential was not significantly different from that of the control. When Zn2+ was 200 mg/kg, the root elongation, seed germination potential and germination rate were significantly inhibited. When the total stress concentration was 400 mg/kg, the inhibitory effect of the root elongation was from strong to weak to Zn2+ (Pb2++Zn2+ compound stress) Pb2+. radicle elongation and seed. There was no significant negative correlation between the germination rate and the concentration of Pb2+ stress, which was significantly negatively correlated with the concentration of Zn2+ (R21=-0.806**, R22=-0.487**). (2) Pb2+, Zn2+ stress had different effects on the length of the total root, the length of the root, the root surface area, the root volume and the number of root tips. The influence was from small to large in order of Pb2+Zn2+Pb2+ and Zn2+. The single stress Pb2+ was 200 mg/kg. The root surface area and the number of lateral roots increased by 7.8% and 33.3%, respectively. When single stress Zn2+ > 200 mg/kg stress, the various morphological indexes of root system were inhibited, and the inhibitory effect was enhanced with the increase of Zn2+ concentration. Under Zn2+ compound stress, the index of root forms decreased with the increase of stress concentration. (3) Pb2+, Zn2+ stress. The root anatomic structure changed. With the increase of Pb2+, Zn2+ stress treatment concentration, the volume of root cap cells, the root cap volume gradually smaller, the cells arranged irregular, the apical meristem cells became smaller, the cells were coloured and arranged poorly, the cell wall of epidermal cells and outer layer cells increased gradually, and the cortex parenchyma cells changed. The crystallinity of the cells was deepened and the particles became larger, and the crystalline particles occupied the whole cell when the cells were serious. The endothelium and the cell wall of the middle column sheath cells were thickened gradually. (4) Pb2+, Zn2+ compound stress had different effects on the accumulation of Pb2+ and Zn2+ in different parts of castor, and it was closely related to the morphological indexes of the root system.Pb2+, Zn2+ in the underground and ground of the plant. The accumulation of the upper part was significantly positively correlated with the concentration of Pb2+ and Zn2+ in the cultivation matrix, and the total root length, surface area, and the number of root tips were not negatively correlated with the accumulation of Pb in the underground part, and had no significant positive correlation with the accumulation of the upper part of the ground, and the root morphology indexes were significantly negatively correlated with the accumulation of the underground part of the ground part of Zn. (5) Pb2+, Zn 2+ stress affects the absorption and distribution of N, P, and K, and then affects the growth of plants. When single Pb2+, Zn2+ stress concentration is less than 400mg/kg, the total N content on the ground and underground part of the plant is significantly higher than that of the control plant. The total N content is lower than the control under the compound treatment and the concentration of 600 mg/kg, under the Zn2+ single treatment. The single treatment was all higher than the control in the compound treatment. The total K content of the plant was higher than the control under Pb2+, Zn2+ single and compound stress, and the accumulation of root was greater than that in the upper part. With the increase of Pb2+, the growth of plant height was not obvious with the increase of Zn2+ stress, but the plant height and internode length decreased significantly. Leaves at the same time leaves and leaves. The thickness of the total thickness of the palisade layer thinner, the cells tend to be smaller, the arrangement of the tissue is loose, the thickness of the tissue in the sponge layer becomes thicker, the cross cutting area of the conduction tissue is smaller (the number of parenchyma cells and the decrease of the number of ducts).
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X173;S565.6
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本文编号：1902912