海岛棉不同基因型幼苗对盐胁迫的生理响应

Physiological Response to NaCl Stress of Different Sea Island Cotton Genotypes in Seedlings

以海岛棉品种新海21号(XH 21,盐敏感基因型)和新海28号(XH 28,耐盐基因型)为材料,采用水培法,从3叶期开始进行NaCl处理(NaCl浓度为0、50、100、150、200、250mmol/L),研究了盐胁迫下海岛棉不同基因型幼苗干物质分配、生长特征、游离脯氨酸含量、根系活力、膜透性及丙二醛含量的变化规律。结果表明:NaCl胁迫对海岛棉耐盐基因型和盐敏感基因型根长、根系活力、茎粗及干物质分配影响具有明显差异,低浓度的NaCl(≤50mmol/L)能够提高耐盐基因型根系活力,促进根长及茎的生长,增加生物量,而对盐敏感基因型无促进作用;随盐浓度的增加,二基因型功能叶丙二醛含量和细胞膜透性均显著上升,但XH 28与XH 21相比,则具有较低丙二醛含量和电解质外渗率。故盐胁迫下海岛棉叶中能保持较高的游离脯氨酸含量及较低丙二醛含量、膜透性是耐盐性品种的生理基础。

In this experiment,two Sea Island Cotton varieties,Xinhai 21（XH 21,NaCl sensitive genotype） and Xinhai 28（XH 28,NaCl tolerant genotype） were selected,and germinated in full nutritional solution.NaCl was added to solution at 3 full expand leaves stages at 6 NaCl levels（0,50,100,150,200 and 250 mmol/L）Dry matter partitioning,the growth of the plants characteristics,soluble protein content,root activity,relative conductance ratio and malonyldialdehyde（MDA） contents were investigated after 30 d.The results showed that root length,root activity,stem diam and dry matter partitioning in both cultivars had significant differences.Under low NaCl concentration stress（≤50 mmol/L）,root length,root activity,stem diam were enhanced in tolerant genotype XH 28.While XH 21 s′decreased.With the increasing of a salinity concentration the increase of MDA content and membrane permeability in tolerant genotype XH 28 was more significant under saline stress than in sensitive genotype XH 21.In conclusion,under saline stress,higher soluble protein content,lower membrane permeability and MDA content in Sea Island Cotton leaf were the physiological basis of tolerant genotype Sea Island Cotton.