硅提高高羊茅耐盐性的生理机制研究

发布时间：2018-05-21 21:24

本文选题：硅 + 盐浓度　；参考：《西北民族大学》2017年硕士论文

【摘要】：高羊茅须根发达、生长迅速、再生能力强,并具有耐热,耐盐碱,耐寒,耐干旱,抗病能力强等特点,是我国北方干旱半干旱地区人工草地和草坪绿地的主要草种之一,灌溉是维护北方高羊茅人工草地高产和草坪绿地健康的主要手段,但长期灌溉容易导致土壤次生盐渍化而又影响其健康生长,因此提高高羊茅的耐盐性是其人工草地和草坪绿地管理中亟待解决的科学问题。已有研究表明添加外源性营养物质硅能够快速有效提高植物耐盐性,但是硅提高其耐盐性的生理机制尚不清楚,因此本研究通过盆栽和水培试验相结合的方法,研究了不同盐浓度胁迫条件下硅对高羊茅出苗、地上地下部分生长、光合作用、抗氧化系统、渗透调节以及质膜过氧化作用的影响,以期揭示硅提高高羊茅耐盐性的生理机制,其研究结果如下:1、硅促进了不同盐浓度下高羊茅出苗及地上部分生长随盐浓度增加,高羊茅出苗率、生物量、株高、叶片数和分蘖均呈降低趋势,添加外源性硅显著增加高羊茅出苗率、生物量、叶片数,盐浓度低于200mmol/L时,添加硅显著增加了高羊茅株高(P0.01),盐浓度为50mmol/L时,株高增幅最大,为15.89%,但添加硅对高羊茅分蘖影响不显著,这可能是硅提高了细胞伸长率或者增强了高羊茅细胞分裂能力,从而促进细胞生长,增强高羊茅盐生环境下生长发育。2、硅促进了不同盐浓度下高羊茅地下部分生长高羊茅根系生物量、根系表面积、根系体积、根系平均直径、根系总长随着盐浓度增加呈降低趋势。添加外源性硅对高羊茅根系生物量、根系表面积、根系体积、根系平均直径和根系总长有增加趋势;当盐浓度小于等于150mmol/L时,硅极显著提高了高羊茅根系生物量、根系表面积、根系总长(P0.01),其中盐浓度为150mmol/L时,根系生物量增幅最大,为34.4%,增幅呈现先降低后增加的趋势;盐浓度为100mmol/L时,根系总表面积增幅最大为31.3%,增幅呈现先增加后降低的趋势;盐浓度为150mmol/L时,高羊茅根系总长增幅最大,为36%。说明硅通过增加高羊茅根系生物量,改变根系形态特征,提高高羊茅在盐生境的生长能力。3、添加硅提高不同盐浓度下高羊茅光合作用,增强了渗透调节能力以及抗氧化酶活性添加硅能显著增加0～300mmol/L盐浓度下高羊茅叶片净光合速率、气孔导度和胞间C02浓度,降低了叶片蒸腾速率,同时硅通过增加盐胁迫下高羊茅幼苗体内SOD、CAT、POD活性,降低盐胁迫条件下高羊茅幼苗体内的丙二醛、脯氨酸、可溶性糖含量和相对电导率,其中盐浓度为100mmol/L时,丙二醛含量降幅最大,为18.05%,当盐浓度介于50mmol/L到200mmol/L时,硅使高羊茅幼苗体内脯氨酸含量分别降低23.63%,16.77%,12.25%,2.78%,降幅呈降低趋势。这说明硅可以增强高羊茅在盐生境下的光合作用,提高高羊茅幼苗抗氧化系统的防御能力,降低脂膜过氧化程度,促进叶片渗透调节,而且硅直接参与了盐胁迫条件下高羊茅的生理生化过程,增强了高羊茅幼苗适应盐生境的能力。
[Abstract]:The tall fescue has developed fibrous roots, fast growth, strong regeneration ability, and has the characteristics of heat resistance, salt tolerance, cold tolerance, drought resistance and disease resistance. It is one of the main grass species of artificial grassland and lawn green space in arid and semi-arid areas of North China. Irrigation is the main means to maintain high yield of Tall Fescue and turf green space in northern China, but it has long been a long term. Irrigation can lead to the secondary salinization of soil and affect its healthy growth. Therefore, improving the salt tolerance of tall fescue is a scientific problem to be solved in the management of artificial grassland and lawn green space. The research has shown that adding exogenous nutrients can effectively improve the salt tolerance of plants, but silicon improves the physiological mechanism of its salt tolerance. In this study, the effects of silicon on the growth of tall fescue, photosynthesis, antioxidant system, osmotic regulation and plasmalemma peroxidation under different salt stress conditions were studied by pot culture and hydroponic test in order to reveal the physiological mechanism of silicon to improve the salt tolerance of tall fescue. The results are as follows: 1, silicon promotes the growth of Tall Fescue and aboveground growth with the increase of salt concentration, the emergence rate of tall fescue, biomass, plant height, leaf number and tillering of tall fescue, and adding exogenous silicon to increase the emergence rate of tall fescue, biomass, leaf number and salt concentration lower than 200mmol/L, the addition of silicon is significantly increased. When the height of tall fescue (P0.01) was high (P0.01) and the concentration of salt was 50mmol/L, the height of plant height was the largest, which was 15.89%, but the addition of silicon had no significant effect on the tillering of tall fescue. It may be that silicon increased the elongation of the cells or enhanced the cell division of tall fescue, thus promoted the growth of the cells and increased the growth and development of the Tall Fescue under the salt environment, and the silicon promoted the different salt. Under the concentration of tall fescue, the root biomass, root surface area, root volume, root mean diameter and total root length decreased with the increase of salt concentration. Adding exogenous silicon to the root biomass, root surface area, root volume, root mean diameter and root total length of tall fescue increased; when salt concentration was small, the concentration of salt was small. When it was equal to 150mmol/L, silicon pole significantly increased root biomass, root surface area and root length (P0.01) of tall fescue. When salt concentration was 150mmol/L, the increase of root biomass was 34.4%, and the growth rate was first decreased and then increased. When salt concentration was 100mmol/L, the maximum growth rate of root surface area was 31.3%, and the growth rate increased first. When the salt concentration is 150mmol/L, the root length of tall fescue has the greatest growth, which is 36%. shows that silicon can increase the root biomass of tall fescue, change the root morphology, improve the growth ability of fescue in salt habitat,.3, adding silicon to increase the photosynthesis of Tall Fescue under different salt concentration, and enhance the osmotic regulation and antioxidant capacity. Adding silicon can significantly increase the net photosynthetic rate of tall fescue leaves under 0 ~ 300mmol/L salt concentration, stomatal conductance and intercellular C02 concentration, reduce leaf transpiration rate, and silicon by increasing salt stress, SOD, CAT, POD activity in the seedlings of tall fescue seedlings under salt stress, reducing proline, proline and soluble content in the seedlings of Tall Fescue under salt stress. When the concentration of salt was 100mmol/L, the content of malondialdehyde was the largest, which was 18.05%. When the concentration of salt was from 50mmol/L to 200mmol/L, the content of proline in the seedlings of tall fescue decreased by 23.63%, 16.77%, 12.25%, 2.78%, indicating that silicon could enhance the photosynthesis of Tall Fescue under salt habitats. It can improve the defense ability of the antioxidant system of tall fescue, reduce the degree of lipid peroxidation and promote the osmotic regulation of leaves, and silicon directly participates in the physiological and biochemical process of Tall Fescue under salt stress, and enhances the ability of tall fescue seedlings to adapt to salt habitats.
【学位授予单位】：西北民族大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S688.4

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