苜蓿对盐胁迫的生理响应及抗盐调控措施研究

发布时间：2018-09-03 09:45

【摘要】：我国苜蓿主要种植在盐渍化地区,盐渍化土壤是造成苜蓿产量较低且不稳定的重要因素。因此,研究盐胁迫对苜蓿耐盐生理指标的影响及探索有效的抗盐调控措施,为提高苜蓿鲜草、干草产量提供实践支持与理论依据。本研究采用培养皿发芽、盆栽和大田试验相结合的方法,研究盐胁迫对苜蓿各生育时期的耐盐特性、光合特性及刈割产量的影响,以及不同种植模式、品种选择等措施对苜蓿耐盐性、器官物质分配、鲜干草产量的调控作用。主要的研究结果如下：1.25个苜蓿品种中,中草3号、苜蓿王、新牧2号、康赛的种子发芽率、相对发芽指数、相对简易活力指数值较高,质膜透性、丙二醛含量较低,脯氨酸、SOD活性较高,耐盐性较强；中苜1号、Salt Buster、勇士表现相反,耐盐性较差。0.80%盐浓度为各项指标变化的“拐点”,综合分析苜蓿种子发芽指标及耐盐生理特性的聚类图谱,将苜蓿种子划分为三类,第一类包括中草3号、新牧2号、Nordica、黄花苜蓿、康赛,属耐盐性品种,第二类包括赤草1号、中苜1号、挑战者、Salt Buster、勇士,属敏感性品种,第三类包括2010,为中间型品种。2.净光合速率与蒸腾速率日变化呈现单峰曲线变化,11：00时达峰值,17：00时值最低；质膜透性、丙二醛含量、SOD活性、CAT活性和脯氨酸含量随苜蓿生育时期的推进逐渐增大,除CAT活性外其他生理指标随盐浓度的递增基本呈逐渐增加的趋势,以降低盐胁迫程度。但0.20%盐浓度促进了苜蓿的生长发育,较其他处理增加了中草3号和中苜1号的株高、净光合速率、蒸腾速率、气孔导度,提高了苜蓿的SOD活性、CAT活性和脯氨酸含量,降低了中草3号和中苜1号的的质膜透性和丙二醛含量,促进了苜蓿的产量提高。0.80%盐浓度处理对苜蓿造成了严重减产,使中草3号和中苜1号分别减产42.29%和47.82%。中草3号比中苜1号表现出较强的耐盐性。3.苜蓿生长的初期以茎部物质器官积累为主,之后叶部器官物质的积累幅度变大,开花期后逐渐向花部转移。混作处理增加了叶片叶绿素含量、鲜草重、干草重,提高了光合速率、蒸腾速率和气孔导度。中草3号与老芒麦混作效果最好,表现出明显的增产优势。2014年第一次刈割时,与老芒麦混作的中草3号较单作中草3号和与无芒雀麦混作的中草3号的鲜草产量分别增加了9.05%和2.02%,干草产量分别增加了14.99%和1.99%；第二次刈割时鲜草产量分别增加了15.00%和21.95%;干草产量分别增加了1.99%和和2.09%。中草3号与无芒雀麦混作也获得了相对较高的草产量。苜蓿与禾本科牧草混作有效提高了光合特性,增加了刈割产量。4.合理的间混作处理促进了苜蓿干物质积累、光合速率、蒸腾速率、气孔导度的提高,增加了干草产量。1：1间作处理较1：2、1：3间作处理提高了苜蓿的光合速率、蒸腾速率、气孔导度和干草产量。1：1间作处理中苜蓿边行处理的光合速率较1：2、1：3和单作处理分别提高了25.60%、77.76%和132.00%,干草产量分别提高了28.57%、80.00%和200.00%,蒸腾速率和气孔导度表现出相似的变化趋势。5.苜蓿形态指标、光合生理指标、耐盐生理指标及鲜干草产量的相关性分析表明,苜蓿的干重、净光合速率、蒸腾速率、胞间CO2浓度、SOD活性与产量呈极显著正相关(P0.01),对刈割产量影响较大。苜蓿鲜干物质向茎、花器官分配运移,促进苜蓿增产。
[Abstract]:Alfalfa is mainly planted in saline areas in China, and saline soil is an important factor causing low and unstable alfalfa yield. Therefore, the effects of salt stress on Physiological Indexes of salt tolerance of alfalfa and the effective control measures of salt tolerance were studied to provide practical support and theoretical basis for improving alfalfa fresh grass and hay yield. The effects of salt stress on salt tolerance, photosynthetic characteristics and cutting yield of Alfalfa at different growth stages, and the effects of different cultivation modes and varieties selection on salt tolerance, organ matter distribution and fresh hay yield of alfalfa were studied by dish germination, pot culture and field experiment. Among the varieties, Zhongcao No. 3, Alfalfa King, Xinmu No. 2, Kangsai had higher germination rate, relative germination index, relatively simple vigor index, lower plasma membrane permeability, lower malondialdehyde content, higher proline, SOD activity, stronger salt tolerance; Zhongcao No. 1, Salt Buster, Warrior showed the opposite, poor salt tolerance. "Inflection point" was used to analyze the clustering map of germination index and salt-tolerant physiological characteristics of Alfalfa seeds. The seeds of alfalfa were divided into three groups. The first group included Zhongcao No. 3, Xinmu No. 2, Nordica, Alfalfa, Kansai, which belonged to salt-tolerant varieties. The second group included Chicao No. 1, Zhongcao No. 1, Challenger, Salt Buster, Warrior, which belonged to sensitive varieties, and the third group was packed with salt tolerance. The diurnal variation of net photosynthetic rate and transpiration rate reached the peak at 11:00 and the lowest at 17:00. Plasma membrane permeability, malondialdehyde content, SOD activity, CAT activity and proline content gradually increased with the development of alfalfa, except CAT activity. However, 0.20% salt promoted the growth and development of alfalfa, increased the plant height, net photosynthetic rate, transpiration rate and stomatal conductance of Zhongcao 3 and Zhongmu 1, increased the SOD activity, CAT activity and proline content of alfalfa, and decreased Zhongcao 3 and Zhongmu 1 compared with other treatments. Membrane permeability and malondialdehyde content promoted alfalfa yield increase. 0.80% salt treatment caused serious yield reduction of alfalfa, resulting in 42.29% and 47.82% yield reduction of Zhongcao No. 3 and Zhongcao No. 1, respectively. Zhongcao No. 3 showed stronger salt tolerance than Zhongcao No. 1. 3. The accumulation of stem and leaf organs was dominant in the early stage of Alfalfa growth, and then the accumulation of leaf organs. Mixed cropping increased leaf chlorophyll content, fresh grass weight, hay weight, photosynthetic rate, transpiration rate and stomatal conductance. Mixed cropping of Zhongcao No. 3 and Old Mango showed the best effect and obvious yield-increasing advantage. Compared with single cropping Zhongcao 3 and mixed cropping Zhongcao 3, the yield of fresh grass increased by 9.05% and 2.02%, the yield of hay increased by 14.99% and 1.99%, the yield of fresh grass increased by 15.00% and 21.95% respectively, and the yield of hay increased by 1.99% and 2.09% respectively. Higher grass yield. Mixed cropping of alfalfa and grasses effectively improved photosynthetic characteristics and increased cutting yield. 4. Reasonable intercropping promoted dry matter accumulation, photosynthetic rate, transpiration rate, stomatal conductance of alfalfa, and increased hay yield. 1:1 intercropping treatment increased photosynthetic rate of Alfalfa compared with 1:2,1:3 intercropping treatment. The photosynthetic rate, transpiration rate, stomatal conductance and hay yield were increased by 25.60%, 77.76% and 132.00%, respectively, compared with 1:2, 1:3 and single cropping. The hay yield was increased by 28.57%, 80.00% and 200.00%, respectively. The transpiration rate and stomatal conductance showed a similar change trend. 5. The morphological index, photosynthesis of alfalfa. The correlation analysis of physiological index, salt tolerance physiological index and fresh hay yield showed that the dry weight, net photosynthetic rate, transpiration rate, intercellular CO2 concentration, SOD activity and yield of alfalfa were significantly positively correlated (P 0.01), which had a great influence on cutting yield.
【学位授予单位】：内蒙古农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q945.78
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本文编号：2219615