【摘要】：棉花屬于喜溫作物,在種子萌發(fā)期對(duì)低溫比較敏感。近年來,隨著農(nóng)業(yè)勞動(dòng)力成本大幅上升,棉花生產(chǎn)為輕簡(jiǎn)化種植已勢(shì)在必行。精量播種是棉花輕簡(jiǎn)化種植的重要內(nèi)容之一,這對(duì)棉種質(zhì)量提出了更高的要求。因此提高棉種萌發(fā)期低溫耐受性,對(duì)實(shí)現(xiàn)精量播種條件下的一播全苗具有重要的意義和作用。目前,關(guān)于棉花低溫脅迫的研究主要集中在幼苗期。本研究從多個(gè)脅迫溫度綜合評(píng)價(jià)了38個(gè)棉花品種萌發(fā)期對(duì)低溫脅迫的耐受能力,并結(jié)合生理水平、分子水平進(jìn)一步了解棉花萌發(fā)期低溫耐受性機(jī)制,對(duì)萌發(fā)期低溫耐受品種選育具有重要的意義。本試驗(yàn)以黃淮棉區(qū)38個(gè)代表性棉花品種為材料,研究了18℃、15℃、12℃不同低溫脅迫下的萌發(fā)指標(biāo),以25℃為對(duì)照,綜合評(píng)價(jià)這些棉花品種萌發(fā)期對(duì)低溫脅迫的耐受能力。同時(shí),在對(duì)38個(gè)棉花品種耐低溫萌發(fā)評(píng)價(jià)的基礎(chǔ)上,從篩選出的耐低溫萌發(fā)品種中選魯棉研37號(hào)、魯棉研36號(hào)和不耐低溫萌發(fā)品種中選斯字棉2B、斯字棉5A共4個(gè)品種,分別于25℃、18℃、15℃、12℃不同溫度下于種子吸脹萌發(fā)0h、12h、24h、36h、48h取萌發(fā)種子為材料,進(jìn)行生理指標(biāo)的測(cè)定。耐冷性基因表達(dá)僅以12℃低溫下種子吸脹萌發(fā)0h、12h、24h、36h、48h取萌發(fā)種子為材料,進(jìn)行基因表達(dá)測(cè)定,從而明確低溫萌發(fā)的生理及分子機(jī)制,為選育耐低溫萌發(fā)的棉花新品種提供理論依據(jù)和種質(zhì)資源。本研究主要結(jié)果如下:1.38個(gè)棉花品種萌發(fā)期低溫耐受性差異隨著溫度降低,所有棉花品種的發(fā)芽率、發(fā)芽指數(shù)、活力指數(shù)均呈下降趨勢(shì),品種間存在顯著差異。主成分分析表明3個(gè)綜合主成分代表了所有參試品種86.664%的原始數(shù)據(jù)信息量。聚類分析將38個(gè)棉花品種依據(jù)種子低溫萌發(fā)耐受能力分為強(qiáng)耐低溫萌發(fā)品種、耐低溫萌發(fā)品種和不耐低溫萌發(fā)品種3類。表明了早期引進(jìn)品種以及由早期引進(jìn)品種系統(tǒng)選育的品種在應(yīng)對(duì)低溫脅迫時(shí),明顯弱于近期雜交選育品種,近期育成的轉(zhuǎn)基因抗蟲棉品種魯棉研37號(hào)、魯棉研36號(hào)在抵御低溫脅迫方面表現(xiàn)出更強(qiáng)的優(yōu)勢(shì)。2.低溫脅迫下棉花種子萌發(fā)期生理指標(biāo)的變化生理指標(biāo)研究結(jié)果表明,低溫脅迫導(dǎo)致MDA(丙二醛)含量總體高于對(duì)照,并隨著脅迫溫度降低而隨之升高,耐低溫萌發(fā)品種MDA含量低于不耐低溫萌發(fā)品種;抗氧化酶活性、滲透調(diào)節(jié)物質(zhì)含量隨著脅迫溫度降低而上升,耐低溫萌發(fā)品種上升幅度高于不耐低溫萌發(fā)品種。表明耐低溫萌發(fā)品種魯棉研37號(hào)、魯棉研36號(hào)在種子萌發(fā)期具備較高的抗氧化酶活性,細(xì)胞膜系統(tǒng)過氧化程度較小,能有效清除ROS(活性氧),從而表現(xiàn)出較強(qiáng)的低溫耐受性。3.12℃低溫脅迫下棉花種子萌發(fā)期耐冷性基因的表達(dá)差異CBF(C-repeat bingding transcription factor)基因在植物抗冷過程中通過調(diào)控大量下游因子的表達(dá),以此提高植物的抗冷性。據(jù)報(bào)道,CBF基因家族包括CBF1、CBF2、CBF3、CBF4、CBF5、CBF6共6個(gè)成員。本研究結(jié)果表明CBF1、CBF2、CBF4、CBF64個(gè)基因家族成員均參與種子低溫脅迫應(yīng)答途徑。魯棉研37號(hào)、魯棉研36號(hào)中4個(gè)基因表達(dá)上調(diào),在脅迫12h時(shí),達(dá)到表達(dá)高峰。斯字棉2B、斯字棉5A中4個(gè)基因表達(dá)上調(diào)不明顯。
[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，

本文編號(hào)：2328804