摘要
耐脱水性是指生物体或组织在丧失所有或几乎所有细胞水分的状态下而不产生不可逆损伤的存活能力。种子的耐脱水性是植物在长期进化过程中保证物种生存和繁衍的适应性机制,在植物种子(质)资源保存中起关键作用。种子的耐脱水性是一个复杂的性状,其分子机理至今尚不清楚。为此,本文综述了种子耐脱水性的生理及分子机制的研究进展。研究发现,正常性种子的耐脱水性是在发育过程中逐渐形成的,在生理成熟期达到峰值;顽拗性种子在整个发育过程中对脱水敏感,不具有成熟脱水的发育阶段。成熟的正常性种子在吸胀初期保持对重新脱水的耐性,随着萌发进程,种子的耐脱水性逐渐下降,最后完全丧失;在萌发初期,种子的耐脱水性可以重建,不同组织具有不同的耐脱水性。种子和胚的耐脱水性程度与其线粒体的呼吸活性下降呈负相关性,顽拗性种子的呼吸活性高于正常性种子。脱水过程中,耐脱水性胚(轴)的H_(2)O_(2)含量、超氧阴离子自由基(·O_(2)^(-))的产生速率和硫代巴比妥酸活性产物的含量显著低于脱水敏感性胚(轴),而活性氧清除(包括酶促和非酶促)系统的活性明显高于脱水敏感性胚(轴)。种子成熟过程中,胚胎发育晚期丰富(LEA)蛋白、小分子量热休克蛋白和非还原性棉子糖家族寡聚糖的积累与耐脱水性的形成密切相关。B3转录因子的AFL亚家族(包括ABI3(ABA INSENSITIVE3)、FUS3(FUSCA3)和LEC2(LEAFY COTYLEDON 2))通过正向调控贮藏物和保护性蛋白的积累增加种子(胚)的耐脱水性。在整个种子发育过程中,DNA甲基化水平显著增加,随后在种子萌发过程中逐渐降低;与发育早期阶段的胚和幼苗相比,成熟胚具有较高水平的基因组甲基化。在种子中,平行的ABA和DOG1(DELAY OF GERMINATION 1)信号转导途径激活棉子糖家族寡聚糖的合成、LEA基因和HSP基因的表达,从而调控耐脱水性
Dehydration tolerance (DT) is defined as the ability of an organism or tissue to survive the removal of all,or almost all the cellular water without irreversible damage.DT of seeds is an adaptive mechanism to ensure the survival and reproduction of plant species in the long-term evolution process,and plays a key role in the conservation of plant seeds and germplasm resources.However,the DT of seeds is a complex trait,and its molecular mechanism is not now largely understood.Therefore,in the present paper,the research progresses on the physiological and molecular mechanisms of seed DT were reviewed.It was found that the DT of orthodox seeds was gradually formed during development,and reached the peak at physiological maturity.Recalcitrant seeds do not undergo the development stage of maturity dehydration,and are very sensitive to dehydration throughout development.Mature orthodox seeds maintained their resistance to re-dehydration at the initial stage of imbibition.With the time course of germination,the DT decreased gradually,and finally lost completely.The DT of seeds and embryos can be re-established during the early stage of germination,and of different tissues is different.The DT of seeds and embryos was inversely correlated with the decrease in mitochondrial respiratory activity.Respiratory activity of recalcitrant axis mitochondria was higher than that of orthodox embryo ones.During dehydration,the H_(2)O_(2)content,the production rate of superoxide anion radical (·O_(2)^(-)) and the content of thiobarbituric acid reactive substance in desiccation-tolerant embryos (axes) were significantly lower than those of desiccation-sensitive embryos(axes),while the reactive oxygen species scavenging system in desiccation-tolerant embryos (axes),including enzymatic and non-enzymatic activities,was significantly higher than that in desiccation-sensitive embryos (axes).During the maturation of seeds,the accumulation of late embryogenesis abundant (LEA) proteins,small heat shock proteins and non-reducing oligosaccharides
作者
宋松泉
刘军
唐翠芳
程红焱
王伟青
张琪
张文虎
高家东
SONG SongQuan;LIU Jun;TANG CuiFang;CHENG HongYan;WANG WeiQing;ZHANG Qi;ZHANG WenHu;GAO JiaDong(Agro-Biological Gene Research Center,Guangdong Academy of Agricultural Sciences/Guangdong Provincial Key Lab for Crop Germplasm Resources Preservation and Utilization,Guangzhou 510640;Institute of Botany,Chinese Academy of Sciences,Beijing 100093;Shenzhen Qianhai Guoken Earth Fund Management Co.,Ltd,Guangzhou 510630)
出处
《中国农业科学》
CAS
CSCD
北大核心
2022年第6期1047-1063,共17页
Scientia Agricultura Sinica
基金
国家科技支撑计划(2012BAC01B05)
广东省农作物种质资源保存与利用重点实验室项目(2020B121201008)
国家自然科学基金(31871716)。
关键词
抗氧化系统
耐脱水性
遗传调控
种质资源的长期保存
代谢活性
保护性物质
antioxidant system
desiccation tolerance
genetic regulation
long-term conservation of germplasm resource
metabolic activity
protective substance
