【作者】 李鑫；

【导师】 戴飞；

【作者基本信息】 浙江大学 ， 作物栽培学与耕作学， 2018， 硕士

【摘要】 种子休眠是植物适应自然环境的重要手段,有助于植物体种群繁衍以应对不良自然环境的影响。西藏野生大麦起源于我国青藏高原地区,是我国特有的野生大麦种质资源,其遗传多样性丰富。西藏野生大麦因其起源地独特的地理自然环境产生了独特的休眠机制,在育种上具有特殊的意义。然而,种子休眠受到的复杂的内源信号网络调控尚未被完全解析。本研究以西藏野生大麦为材料,通过基于RNA-seq的转录组和代谢组的研究方法,探究西藏野生大麦种子在后熟作用和低温层积过程中休眠破除机制,取得的主要研究结果有:1.西藏野生大麦种子对低温层积和后熟作用的响应6个不同西藏野生大麦基因型种子在低温层积和后熟作用处理的过程中,种子发芽率都出现显著提高,休眠减弱的情况。显示无论低温层积或者是后熟作用都可以有效的打破西藏野生大麦种子的休眠。低温层积的过程中,6个西藏野生大麦基因型种子出现萌发的情况,表明一些西藏野生大麦基因型可以在4℃低温条件下萌发。2.后熟作用过程中西藏野生大麦种子代谢物变化分析对不同时间后熟作用处理的西藏野生大麦种子代谢物进行分析发现,甘油磷酸代谢途径;半乳糖代谢途径和淀粉、蔗糖代谢途径在休眠破除的过程中起到重要的作用。甘油磷酸代谢途径中变化最大的差异代谢物磷脂酸是公认的ABA信号途径的中间物质。3.低温层积过程中西藏野生大麦种子基因表达变化分析通过低温层积过程中基因表达情况的分析可知,低温层积快速破除种子休眠是由于种子内部系列改变引起的大麦种子对于ABA的信号响应变低。ABA信号途径中最为核心的PYL,PP2C,Sn RK2等基因的表达都出现变化,因此对于植物激素的信号感应变弱。植物激素特别是ABA也是低温层积过程中调控休眠的主要因素。更多还原

【Abstract】 Seed dormancy is important for plants to adapt to natural environment,making them successfully spread into a vast area with harsh circumstances.Tibetan wild barley,orginated from the Tibetan Pleteau,is one of the special genetic resources with great genetic diversity for barley improvement.Seed dormancy is regulated by complex internal signal interactions and has not been fully understood,including dormancy of Tibetan wild barley.Herein,transcriptome and metabolome are used to study the mechanism of dormancy breaking underlying the role of after-ripening or cold stratification.The major results were summaried as follows:1.Responses of the Tibetan wild barley seeds to after-ripening and cold strification6 different Tibetan wild barley genotypes showed significant increase in germination rate and decrease in dormancy under either cold strification or after-ripening.It indicated that no matter cold strification or after-ripening made effects on dormancy release.During the process of cold strification,6 Tibetan wild barley seeds germinated,showing that some wild barley genotypes were able to germinate in cold temperature.2.Metabolome of Tibetan wild barley under the process of after-ripeningMetabolome analysis was carried out with the Tibetan wild barley seeds under different after-ripening treatment time.It showed that Starch and sucrose metabolism,Glycerophospholipid metabolism and Galactose metabolism played the major roles in dormancy release.One of the most differential metabolites in Glycerophospholipid metabolism,PA,was widely thought to be an intermediate substance controlled by plant phytohormone ABA.3.Gene expression analysis of Tibetan wild barley under the process of cold strification.By analyzing the gene expression under cold strification,it could be found that reduced responses to ABA might be the important reasons why dormancy release happened.Related genes like PYL,PP2 C and Sn RK2 in ABA signaling pathway showed different expressions.So plant phytohormones,especially ABA were also major reason for dormancy release under cold strification.更多还原