摘要：

为探究盐胁迫对棉花生理机制的影响,以耐盐碱棉花中J0710为对照,对山西农业大学棉花育种课题组培育的2个棉花远缘杂交新种质 HL2、A₂H 幼苗进行为期15 d的盐溶液处理(浓度为200 mmol/L),分析参试材料的相对株高、相对根长及相对成活率,计算盐害指数;并结合不同处理时间(0,5,12,24,48 h)的幼苗原初光能转化效率(Fv/Fm)、抗氧化酶活性、脯氨酸含量、可溶性糖含量等生理指标的测定结果,对参试材料的耐盐性进行综合评价。结果表明,盐胁迫15 d后,对3个材料幼苗生长的伤害程度由弱到强依次为中J0710<HL2<A₂H,盐胁迫极显著抑制了A₂H 的相对株高、相对根长及相对成活率,说明该盐浓度处理下,对HL2及中J0710的生长发育影响较小,而对A₂H的影响较大。在不同的处理时间下,盐胁迫对3个材料的最大光能转化效率均具有不同程度的影响,相较于胁迫前,抑制程度由弱到强依次为HL2<A₂H<中J0710。相较于未胁迫之前,盐胁迫提高了过氧化物酶(POD)活性;其中,整个胁迫过程中HL2的POD活性显著高于A₂H和耐盐对照中J0710,并且在胁迫12~48 h达到显著水平;超氧化物歧化酶(SOD)活性变化规律不明显,且在盐胁迫过程中发挥作用较低;HL2及耐盐对照中J0710的脯氨酸含量积累量均随着盐胁迫时间的延长而增多,种质HL2的可溶性糖及可溶性蛋白含量在整个盐胁迫期间均显著高于耐盐对照中J0710和A₂H。综上,在盐逆境中,耐盐材料具有较发达的根系;而较高的光能转化效率、细胞内较高的活性氧清除能力以及较高的渗透调节物质的积累是其耐盐性较强的生理基础。

关键词: 棉花, 苗期, 耐盐性鉴定, 形态指标, 生理指标

Abstract:

In order to explore the effect of salt stress on the physiological mechanism of cotton,saline-tolerant cotton Zhong J0710 was used as a control,two new cotton distantly hybrid germplasms HL2 and A₂H cultivated in cotton breeding research group were treated with salt solution for 15 d(concentration of 200 mmol/L)at seedling stage,and the relative plant height,relative root length and relative survival rate of the test materials were analyzed,and the salt damage index was calculated.The salt tolerance of the test materials was comprehensively evaluated by combining the measurement results of physiological indicators such as primary light energy conversion efficiency (Fv/Fm),antioxidant enzyme activity,proline content,and soluble sugar of seedlings at different treatment times (0,5,12,24,48 h).The results showed that after 15 d of salt stress,the damage degree of the growth of seedlings of the three test materials was as follows:Zhong J0710<HL2<A₂H,and salt stress significantly inhibited the relative plant height,relative root length and relative survival rate of A₂H,indicating that the salt concentration treatment had less effect on the growth and development of HL2 and Zhong J0710,but had a greater effect on A₂H.Under different treatment times,salt stress had different degrees of influence on the maximum light energy conversion efficiency of the three test materials,and the inhibition degrees from weak to strong compared with before stress were HL2<A₂H<Zhong J0710.Compared with the non-stress period, the peroxidase (POD) activity of the tested materials was increased by salt stress, and the POD activity of HL2 during the stress process was significantly higher than that of A2H and Zhong J0710 in the salt-tolerant control, and reached a very significant level at 12—48 h of stress,and the change law of superoxide dismutase (SOD) activity was not obvious,and the role in salt stress was low.The contents of proline in HL2 and the salt-tolerant control increased with the increase of salt stress time,and the soluble sugars and soluble proteins of germplasm HL2 were significantly higher than those in the salt-tolerant control and A₂H during the entire salt stress period.In summary,in salt adversity,salt-tolerant materials have a more developed root system;higher light energy conversion efficiency,higher reactive oxygen species clearance capacity in cells and higher accumulation of osmoregulatory substances are the physiological basis for strong salt tolerance.

Key words: Cotton, Seedling stage, Salt tolerance identification, Pattern indicators, Physiological indicators