摘要
多倍体化是植物进化的重要趋势之一.与二倍体植物相比,多倍体植物往往具有更强的抗耐性.海稻 86 是具有强耐盐碱能力的水稻种质资源,在盐碱地开发应用和粮食增产研究中具有重要利用价值.为充分利用多倍体植物抗逆性增强的优势,选育耐盐碱能力更强的四倍体水稻新品种,本研究以海稻 86 为基础,对其进行离体染色体加倍获得海稻 86 同源四倍体;以海稻 86-4x和海稻 86-2x发芽期和幼苗期NaCl、Na2CO3 和PEG-6000 胁迫处理的表型指标及生理生化指标鉴定,检测两者的耐盐碱特性及差异.结果表明:(1)通过离体染色体加倍可高效诱导获得四倍体植株,加倍率达 27.63%.(2)与海稻 86-2x相比,海稻 86-4x 的细胞核 DNA 含量及根尖染色体数目增加一倍;形态及农艺性状发生明显变化,如植株变矮、茎秆变粗、单株有效穗数减少、籽粒及千粒重增大、每穗总粒数及每穗实粒数减少、结实率降低等.(3)在发芽期,海稻 86-4x的发芽势、发芽率、芽长、根长、根数、含水量最高,海稻86-2x次之,对照黄华占最低;海稻 86-4x的盐碱害率最小、盐碱害等级最低,海稻 86-2x次之,对照黄华占的盐碱害率最大、盐碱害等级最高.(4)在幼苗期,海稻 86-4x的脯氨酸和叶绿素含量最高、丙二醛含量和相对电导率最低,超氧化物歧化酶和过氧化物酶活性最高,海稻 86-2x次之,而对照黄华占的脯氨酸和叶绿素含量最低、丙二醛含量和相对电导率最高、超氧化物歧化酶和过氧化物酶活性最低.综上可知,与海稻 86-2x相比,海稻 86-4x在表型指标和生理生化指标上均表现出明显的耐盐碱性优势,具有更强的耐盐碱能力.该研究结果为深入解析海稻 86 的耐盐碱机制奠定基础,也为耐盐碱四倍体水稻新品种的选育提供了材料基础和理论依据.
Abstract
Polyploidization is an important trend in plant evolution.Polyploid plants often have stronger resistance to stress than diploid ones.Haidao 86 is a rice germplasm resource with strong salt-alkali tolerance,which has important utilization value for the application of saline-alkaline land and the increase of grain yield.To make full use of the advantages of enhanced stress resistance in polyploid plants and breed new tetraploid rice varieties with stronger salt-alkali tolerance,diploid Hai-dao 86 was submitted for in vitro chromosome doubling to create autotetraploid Haidao 86 in this study.After stress treatment with NaCl,Na2CO3,and PEG-6000,the phenotypic indexes,physiological and biochemical indexes of tetraploid and diploid Haidao86 at germination and seedling stages were detected to understand the salt-alkali tolerance characteristics and differ-ences between them.The results showed as follows:(1)By in vitro chromosome doubling,tetraploid plants can be efficiently induced,with a doubling rate of 27.63%.(2)Compared with diploid Haidao 86,the nuclear DNA content and root tip chro-mosome number of tetraploid Haidao 86 was doubled.There were significant changes in morphology and agronomic traits,such as plants becoming shorter,stems becoming thicker,effective panicles per plant decreasing,grain and thousand grain weight increasing,total grains per panicle,and filled grains per panicle decreasing,and seed setting rate decreasing.(3)At germination stage,the germination energy,germination rate,shoot length,root length,root number,and water content of tetraploid Haidao 86 were the highest,followed by diploid Haidao 86,and the control Huanghuazhan was the lowest.Tetraploid Haidao 86 had the lowest salt alkali damage rate and grade,followed by diploid Haidao 86,and the control Huanghuazhan had the highest salt alkali damage rate and grade.(4)At seedling stage,tetraploid Haidao 86 had the highest proline and chlorophyll content,the lowest malondialdehyde content and relative electrical conductivity,the highest superox-ide dismutase and peroxidase activity,followed by diploid Haidao 86,and the control Huanghuazhan had the lowest proline and chlorophyll content,the highest malondialdehyde content and relative electrical conductivity,and the lowest superoxide dismutase and peroxidase activity.So tetraploid Haidao 86 had significant advantages in salt-alkali tolerance in both pheno-typic indexes,and physiological and biochemical indexes,and had stronger salt-alkali tolerance than diploid Haidao 86.The results lay the foundation for in-depth research on the salt-alkali tolerance mechanism of Haidao 86,and provide the material and theoretical basis for the breeding of new salt-alkali resistant tetraploid rice varieties.
维普
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