采用盆栽法,以海岛棉(Gossypium barbadense)品种新海21号、新海34号和陆地棉(G.hirsutum)品种新陆早50号、新陆早57号为材料,探讨了盐胁迫下海岛棉和陆地棉植株的生长、叶绿素含量、净光合速率、蒸腾速率、抗氧化酶活性、渗透调节物质及丙二醛含量变化的差异.结果显示,随着盐浓度的增加,4个供试品种幼苗的生长、叶绿素含量、净光合速率、蒸腾速率均呈不同程度的下降,而过氧化物酶、超氧化物歧化酶及可溶性糖含量随着盐浓度的增加呈先增后降的趋势,脯氨酸和丙二醛含量均上升.不同品种之间,新海21号和新海34号受胁迫的影响程度小于新陆早57号和新陆早50号.在0.6％ NaCl胁迫下,海岛棉和陆地棉品种均表现出较好的耐盐性.而0.8％和1.0％的NaCl胁迫对4个供试品种的生长抑制作用大,导致新陆早57号和新陆早50号幼苗生长缓慢、叶面积小、干物质积累少甚至死苗.在较高浓度的盐胁迫下,棉花品种幼苗第1片真叶展开受到显著抑制,可以作为棉花耐盐品种的筛选指标.%Adopting a potting method with two Sea Island cotton varieties,Xinhai 21 and Xinhai 34,and two Upland cotton varieties,Xinluzao 50 and Xinluzao 57,as materials,we examined changes in growth,chlorophyll content,net photosynthetic rate,transpiration rate,antioxidant enzyme activity,osmotic adjustment substances and malondialdehyde (MDA) content between Sea Island cotton and Upland cotton under NaCl stress.With increasing salt concentration in soil,the growth,chlorophyll content,net photosynthetic rate and transpiration rate indicators declined to different degrees in the four varieties,whereas peroxidase (POD),superoxide dismutase (SOD) and soluble sugar content showed a trend of increasing first in level and then decreasing with increasing salt concentration,proline and malondialdehyde content.Xinhai 21 and 34 showed less impact of stress than Xinluzao 57 and 50.Under 0.6％ NaCl,the Sea Island cotton and Upland cotton cultivars showed good salt tolerance.The difference in salt tolerance between the two cultivated species was not significant.However,the growth of the four varieties was inhibited under 0.8％ and 1.0％ NaCl stress.Xinluzao 57 and 50 seedlings grew slowly,with small leaf area and little dry matter accumulation and even death.Leaves of cotton seedlings were sensitive to salt stress;the growth of leaf width and leaf length was inhibited with increasing salt concentration,which could be used as an index to select salt-tolerant varieties.
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