黄淮棉区棉花品种萌发期对低温的响应及耐性评价
发布时间：2018-11-13 10:19
【摘要】：棉花属于喜温作物,在种子萌发期对低温比较敏感。近年来,随着农业劳动力成本大幅上升,棉花生产为轻简化种植已势在必行。精量播种是棉花轻简化种植的重要内容之一,这对棉种质量提出了更高的要求。因此提高棉种萌发期低温耐受性,对实现精量播种条件下的一播全苗具有重要的意义和作用。目前,关于棉花低温胁迫的研究主要集中在幼苗期。本研究从多个胁迫温度综合评价了38个棉花品种萌发期对低温胁迫的耐受能力,并结合生理水平、分子水平进一步了解棉花萌发期低温耐受性机制,对萌发期低温耐受品种选育具有重要的意义。本试验以黄淮棉区38个代表性棉花品种为材料,研究了18℃、15℃、12℃不同低温胁迫下的萌发指标,以25℃为对照,综合评价这些棉花品种萌发期对低温胁迫的耐受能力。同时,在对38个棉花品种耐低温萌发评价的基础上,从筛选出的耐低温萌发品种中选鲁棉研37号、鲁棉研36号和不耐低温萌发品种中选斯字棉2B、斯字棉5A共4个品种,分别于25℃、18℃、15℃、12℃不同温度下于种子吸胀萌发0h、12h、24h、36h、48h取萌发种子为材料,进行生理指标的测定。耐冷性基因表达仅以12℃低温下种子吸胀萌发0h、12h、24h、36h、48h取萌发种子为材料,进行基因表达测定,从而明确低温萌发的生理及分子机制,为选育耐低温萌发的棉花新品种提供理论依据和种质资源。本研究主要结果如下:1.38个棉花品种萌发期低温耐受性差异随着温度降低,所有棉花品种的发芽率、发芽指数、活力指数均呈下降趋势,品种间存在显著差异。主成分分析表明3个综合主成分代表了所有参试品种86.664%的原始数据信息量。聚类分析将38个棉花品种依据种子低温萌发耐受能力分为强耐低温萌发品种、耐低温萌发品种和不耐低温萌发品种3类。表明了早期引进品种以及由早期引进品种系统选育的品种在应对低温胁迫时,明显弱于近期杂交选育品种,近期育成的转基因抗虫棉品种鲁棉研37号、鲁棉研36号在抵御低温胁迫方面表现出更强的优势。2.低温胁迫下棉花种子萌发期生理指标的变化生理指标研究结果表明,低温胁迫导致MDA(丙二醛)含量总体高于对照,并随着胁迫温度降低而随之升高,耐低温萌发品种MDA含量低于不耐低温萌发品种;抗氧化酶活性、渗透调节物质含量随着胁迫温度降低而上升,耐低温萌发品种上升幅度高于不耐低温萌发品种。表明耐低温萌发品种鲁棉研37号、鲁棉研36号在种子萌发期具备较高的抗氧化酶活性,细胞膜系统过氧化程度较小,能有效清除ROS(活性氧),从而表现出较强的低温耐受性。3.12℃低温胁迫下棉花种子萌发期耐冷性基因的表达差异CBF(C-repeat bingding transcription factor)基因在植物抗冷过程中通过调控大量下游因子的表达,以此提高植物的抗冷性。据报道,CBF基因家族包括CBF1、CBF2、CBF3、CBF4、CBF5、CBF6共6个成员。本研究结果表明CBF1、CBF2、CBF4、CBF64个基因家族成员均参与种子低温胁迫应答途径。鲁棉研37号、鲁棉研36号中4个基因表达上调,在胁迫12h时,达到表达高峰。斯字棉2B、斯字棉5A中4个基因表达上调不明显。
[Abstract]:The cotton belongs to a temperature-sensitive crop, and is sensitive to low-temperature in the seed germination period. In recent years, with the increase of the cost of agricultural labor, the production of cotton is imperative to light and simplify the planting. Precision sowing is one of the important contents of the light and simple planting of the cotton, which has made a higher requirement for the quality of the cotton seeds. therefore, the low-temperature tolerance of the cotton seed germination period is improved, and the seedling-sowing full-seedling under the condition of precise seeding is of great significance and effect. At present, the research on the low-temperature stress of cotton is mainly focused on the seedling stage. In this study, the tolerance ability of 38 cotton varieties to low-temperature stress was comprehensively evaluated from a plurality of stress temperatures, and the low-temperature tolerance mechanism of the cotton germination period was further studied with the combination of the physiological level and the molecular level, which was of great significance to the selection and selection of the low-temperature tolerant species during the germination period. The germination index at 18 鈩，
本文编号：2328804
[Abstract]:The cotton belongs to a temperature-sensitive crop, and is sensitive to low-temperature in the seed germination period. In recent years, with the increase of the cost of agricultural labor, the production of cotton is imperative to light and simplify the planting. Precision sowing is one of the important contents of the light and simple planting of the cotton, which has made a higher requirement for the quality of the cotton seeds. therefore, the low-temperature tolerance of the cotton seed germination period is improved, and the seedling-sowing full-seedling under the condition of precise seeding is of great significance and effect. At present, the research on the low-temperature stress of cotton is mainly focused on the seedling stage. In this study, the tolerance ability of 38 cotton varieties to low-temperature stress was comprehensively evaluated from a plurality of stress temperatures, and the low-temperature tolerance mechanism of the cotton germination period was further studied with the combination of the physiological level and the molecular level, which was of great significance to the selection and selection of the low-temperature tolerant species during the germination period. The germination index at 18 鈩，
本文编号：2328804
本文链接：https://www.wllwen.com/shoufeilunwen/zaizhiyanjiusheng/2328804.html
