混合盐胁迫下藜麦生理特性的研究

发布时间：2019-02-27 10:21

【摘要】：全球各地区盐碱化土地面积逐步增加,盐碱胁迫已经成为影响植物生长和作物产量的主要非生物胁迫。在自然状态下,土壤中并非仅含有一种盐分,往往是中性盐和碱性盐共存,称为混合盐胁迫。由于碱性盐导致土壤pH升高,其危害程度要远大于中性盐胁迫,因此混合盐对植物的影响及其抗性机制越来越受到人们关注。藜麦(Chenopodium quinoa Willd.)是一种天然的安第斯山脉作物,因其具有多种用途并且含有丰富的营养而被广泛研究。目前,关于藜麦的研究主要集中在中性盐胁迫和干旱胁迫,有关混合盐对藜麦生长的影响以及藜麦抵抗混合盐的机制未得到广泛关注。本研究试图通过探究混合盐胁迫下藜麦的光合特性、抗氧化机制和渗透调节,分析出混合盐对藜麦生长的影响,并且揭示藜麦抗混合盐胁迫的生理机制。本研究以藜麦(品种Titicaca)为实验材料,用不同浓度NaCl和NaHCO_3混合盐(100、200、300、400和500 mmol·L-1)进行胁迫处理。测定相关生理指标:生长参数(RWC、RGR、R:S和FW:DW)、光合参数(光合色素、气孔密度、gs、Pn、E和Ci)、抗氧化酶活性(SOD、POD、CAT和MDA)以及渗透调节物质含量(阴阳离子、有机酸、脯氨酸和可溶性糖)。实验结果表明:在适宜的混合盐浓度下,藜麦具有较好的保水能力和适应盐碱胁迫的能力;通过维持Mg2+含量来提高光合色素含量,气孔导度的提高有效调节水分平衡和气体交换,从而促进叶片光合作用,增加水分利用效率;较高的POD和CAT活性又能够维持ROS的平衡,减少MDA的产生,保证细胞正常生理功能;离子的吸收以及有效区域化、有机酸所占百分比的调整、有机渗透物(脯氨酸和可溶性糖)积累都为低浓度混合盐胁迫处理下藜麦的渗透调节作出重要贡献。即使是在高浓度胁迫条件下,藜麦也能通过维持特定的生理代谢途径维持植株存活。综上所述,在适宜盐碱条件下,藜麦通过提高抗氧化物酶活性,合成、积累无机离子、有机物质来维持内环境的水分平衡、pH的稳定,提高光合速率,保证植株的正常生长、发育。本论文结果表明,藜麦具有一定耐盐碱能力。
[Abstract]:Saline-alkali stress has become the main abiotic stress affecting plant growth and crop yield. In natural state, soil contains not only one kind of salt, but also neutral salt and alkaline salt, which is called mixed salt stress. The effect of mixed salt on plants and its resistance mechanism have been paid more and more attention due to the increase of pH in soil caused by alkaline salt, which is much greater than that of neutral salt stress. Quinoa (Chenopodium quinoa Willd.) Is a natural Andean crop, it is widely studied for its many uses and rich nutrition. At present, researches on quinoa mainly focus on neutral salt stress and drought stress, and the effect of mixed salt on the growth of quinoa and the mechanism of quinoa resistance to mixed salt have not been paid much attention. In this study, the photosynthetic characteristics, antioxidant mechanism and osmotic regulation of quinoa under mixed salt stress were investigated, and the effects of mixed salt on the growth of quinoa were analyzed, and the physiological mechanism of quinoa resistance to mixed salt stress was revealed. In this study, quinoa (Titicaca) was treated with different concentrations of NaCl and NaHCO_3 mixed salt (100200300400 and 500mmol 路L-1). The physiological parameters were measured: growth parameters (RWC,RGR,R:S and FW:DW), photosynthetic parameters (photosynthetic pigments, stomatal density, gs,Pn,E and Ci), antioxidant enzyme activities (SOD,POD,). CAT and MDA) and osmotic regulators (anion and cation, organic acids, proline and soluble sugar). The results showed that quinoa had better water retention ability and ability to adapt to salt-alkali stress under the suitable mixed salt concentration. By maintaining Mg2 content, photosynthetic pigment content was increased and stomatal conductance was increased to effectively regulate water balance and gas exchange, thus promoting leaf photosynthesis and increasing water use efficiency. The higher activity of POD and CAT could maintain the balance of ROS, reduce the production of MDA and ensure the normal physiological function of cells. The absorption of ions and effective regionalization, the adjustment of the percentage of organic acids and the accumulation of organic osmotic substances (proline and soluble sugar) all contribute to the osmotic regulation of quinoa under low concentration mixed salt stress. Even under high concentrations of stress, quinoa can maintain a specific physiological and metabolic pathway to maintain plant survival. In conclusion, under the suitable saline-alkali conditions, quinoa maintains water balance in the internal environment by increasing antioxidant enzyme activity, synthesizing, accumulating inorganic ions and organic substances, stabilizing pH, increasing photosynthetic rate and ensuring the normal growth of plants. Develop. The results of this paper show that quinoa has the ability of salt-alkali tolerance to a certain extent.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S519

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