旱稻吸收、积累砷的基因型差异及其生理响应研究

发布时间：2018-11-09 16:39

【摘要】：农田砷污染是水稻种植区面临的重要环境问题之一,其危害人体健康和生态环境安全。本研究通过土壤盆栽试验,运用HPLC-ICP-MS、紫外分光光度计、光合仪等技术,研究93个不同基因型旱稻在不同砷浓度土壤(58.9 mg·kg-1和82.6 mg·kg-1)条件下,其对砷的吸收、累积差异,并根据不同基因型旱稻对砷的耐性及其地上部对砷吸收、累积和转运特点,筛选出高吸收基因旱稻和低吸收基因旱稻;进而通过对比研究砷高吸收基因型旱稻(3个品种)和低吸收基因型旱稻(4个品种)在不同砷浓度土壤(20.9 mg·kg-1、58.9 mg·kg-1和82.6 mg·kg-1)条件下,从生长状况(株高、根长、分蘖数、籽粒重、地上部重)、不同器官(根、秸秆、叶鞘、叶片、稻壳和糙米)中砷的含量及其分布、根表铁膜、抗氧化酶系统(POD、CAT、APX、GR)这几个角度来探讨其对砷吸收、累积和分布差异及其在砷胁迫下的生理响应。研究结果如下:1、93份不同基因型旱稻在不同砷浓度土壤条件下,旱稻V2、V3、V4、V7、V10、V15、V16、V22、V32、V35、V36、V37、V40、V43、V45、V50、V51、V59、V62、V66、V67、V71、V72、V76、V78、V83、V84、V87、V88均生长发育正常,表观上未见明显的砷毒害症状,但在株高、生物量和穗重上差异显著。其他不同基因型旱稻表观不同程度的砷毒害症状。并在此基础上,筛选得到了高吸收基因型旱稻V2、V16和V78,低吸收基因型旱稻V22、V40、V50和V62;2、本研究条件下,高吸收基因旱稻(V2、V16和V78)和低吸收基因旱稻(V22、V40、V50和V62)在根、秸秆、叶鞘、叶片、稻壳和糙米中砷含量均具有显著差异;随着土壤中砷浓度的增加,不同器官中砷含量也增加,且砷主要在根中积累,约占60%-80%,糙米中砷累积最少,约占0.10%-0.25%,各器官中砷含量的大小为:糙米稻壳叶叶鞘秸秆根。3、在土壤中砷浓度为20.9 mg·kg-1时,高吸收基因型旱稻根、秸秆、叶鞘中砷含量和低吸收基因型旱稻相应的含量具有明显的差异,而其叶、稻壳和糙米中砷含量无显著差异,但随着土壤砷浓度为58.9 mg·kg-1和82.6 mg·kg-1时,高吸收基因型旱稻和低吸收基因型旱稻在各不同器官中砷含量差异显著。4、随着土壤中砷浓度的增加,旱稻根表形成的铁膜(锰膜)数量减少,且高吸收基因型旱稻的根表铁膜数量明显比低吸收旱稻少;砷主要积累在旱稻根部(约65%-85%),少量吸附在根表铁膜中(约15%-35%),低吸收基因旱稻根表铁膜中砷含量高于高吸收基因型旱稻。5、本研究条件下,不同基因旱稻的株高、根长、分蘖数、地上物和单株产量均减少;但低吸收基因型旱稻的株高、根长、分蘖数、地上部干重和单株籽粒高于高吸收基因型,且品种间具有显著的差异。6、本研究条件下,不同基因型旱稻叶片中POD、CAT、APX和GR组成的抗氧化酶系统活性增加,且砷高吸基因型旱稻的酶活性增加的多,使其对砷的耐性增强了,以缓解因砷胁迫而造成的毒害作用。
[Abstract]:Arsenic pollution in farmland is one of the important environmental problems in rice growing area, which endangers human health and ecological environment safety. In this study, 93 upland rice genotypes under different arsenic concentrations (58.9 mg kg-1 and 82.6 mg kg-1) were studied by means of HPLC-ICP-MS, ultraviolet spectrophotometer and photosynthetic apparatus. According to the arsenic tolerance of different genotypes and the characteristics of arsenic uptake, accumulation and transport in the shoot, the high and low uptake genes of upland rice with high absorption gene and low uptake gene were selected. The arsenic uptake genotypes (3 varieties) and the low uptake genotypes (4 varieties) were compared under different arsenic concentrations (20.9 mg kg-1,58.9 mg kg-1 and 82.6 mg kg-1). The content and distribution of arsenic in different organs (root height, root length, tiller number, grain weight, aboveground weight), different organs (root, straw, leaf sheath, leaf, rice husk and brown rice), iron membrane of root surface, antioxidant enzyme system (POD,CAT,APX,) GR) to explore the differences in arsenic uptake, accumulation and distribution and their physiological responses to arsenic stress. The results were as follows: 1 under different arsenic concentration soil conditions, 93 upland rice varieties with different genotypes, V2V3N V4V4V7, V10V15, V16V16, V32V35V32V35CnV40V40V43V45V50V51V59V62V66N and V671V72were collected from Upland rice with different concentrations of arsenic, and the results were as follows: 1. The growth and development of V76V783V83V83V84V87V88 were normal, and there were no obvious symptoms of arsenic toxicity on the surface, but there were significant differences in plant height, biomass and ear weight. The symptoms of arsenic toxicity in other upland rice genotypes were different. On the basis of the above results, high absorption genotype V2V16 and V78were obtained, and low uptake genotypes V22V40V40 V50 and V62were obtained. 2. In this study, the arsenic contents in root, straw, leaf sheath, leaf, husk and brown rice of high absorption gene upland rice (V2N V16 and V78) and low absorption gene upland rice (V22 V40V40 V50 and V62) were significantly different. With the increase of arsenic concentration in the soil, the arsenic content in different organs also increased, and arsenic mainly accumulated in the root, accounting for about 60-80, and the arsenic accumulation in brown rice was the least, about 0.10-0.25. The content of arsenic in each organ was as follows: straw root of leaf sheath of brown rice husk. When arsenic concentration in soil was 20.9 mg kg-1, root and straw of upland rice with high absorption genotype were obtained. The arsenic content in leaf sheath was significantly different from that in upland rice with low uptake genotypes, but there was no significant difference in arsenic content in leaves, rice husks and brown rice, but with the arsenic concentration of 58.9 mg kg-1 and 82.6 mg kg-1 in soil. There were significant differences in arsenic content in different organs between upland rice with high uptake genotype and those with low uptake genotype. 4. With the increase of arsenic concentration in soil, the amount of Fe (mn) film formed on root surface of Upland rice decreased. The amount of iron film in root surface of Upland rice with high uptake genotype was significantly less than that with low uptake rice. Arsenic was mainly accumulated in the root of Upland rice (about 65-85%), and a little adsorbed in the iron film of root surface (about 15-35%). The content of arsenic in the surface iron film of low absorption gene upland rice was higher than that of high absorption type Upland rice. The plant height, root length, tiller number, aboveground matter and yield per plant of Upland rice with different genes decreased. However, the plant height, root length, tiller number, dry weight of shoot and grain per plant of Upland rice with low uptake genotype were higher than those with high uptake genotype, and there were significant differences among varieties. 6. Under the conditions of this study, POD,CAT, in leaves of different genotypes of Upland rice was studied. The antioxidant enzyme system activity of APX and GR increased, and the enzyme activity of arsenic high uptake genotype upland rice increased, which made it more tolerant to arsenic, in order to alleviate the toxic effect caused by arsenic stress.
【学位授予单位】：天津农学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S511.6

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