盐胁迫对菘蓝幼苗生长和抗性生理的影响

以“定蓝1号”为试验材料,采用不同浓度NaCl溶液(0,30,60,90,120和150 mmol·L^-1)对菘蓝幼苗进行处理,胁迫14 d后测定了其生长指标、生物量积累、叶片相对含水量、根系活力、根质膜透性、渗透调节物质含量以及抗氧化酶活性等指标,分析不同程度盐胁迫对菘蓝幼苗生长和抗性生理的影响。结果表明:NaCl胁迫对菘蓝幼苗株高和根长都有抑制作用,对根和叶的物质积累也有显著影响,并随浓度的递增呈降低的趋势;菘蓝幼苗叶片相对含水量和根系活力均随NaCl浓度的增加呈现下降趋势,而根质膜透性、叶片脯氨酸含量则呈升高趋势;丙二醛(MDA)含量、组织自动氧化速率(RAD)、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性都随NaCl浓度的增加呈先升高后降低的趋势。但当NaCl浓度低于90 mmol·L^-1时,菘蓝幼苗的生长没有受到盐胁迫的明显抑制,根系活力降低不明显,脯氨酸、丙二醛含量和保护酶活性也未显著升高,说明菘蓝幼苗对低浓度盐环境具有一定的耐受性。

Effects of salt stress on growth and physiology of Isatis indigotica seedlings

The effects of different concentrations of NaCl solution (0, 30, 60, 90, 120 and 150 mmol·L^-1) on the growth, biomass, leaf relative water content, root activity, root membrane permeability, osmotic adjustment and protective enzyme activity of Isatis indigotica seedlings (cv. Dinglan No.1) were assessed to determine the response of growth and physiological traits associated with resistance to salt stress after 14 days of exposure. Plant height, root length, root dry weight and leaf dry weight of I. indigotica seedlings under NaCl treatment were significantly reduced compared with the control (no salt). Reductions were greater under higher salt concentrations. As NaCl concentration increased leaf relative water content and root activity declined while root membrane permeability and leaf proline content increased. Superoxide dismutase (SOD) and peroxidase (POD) activity, malondialdehyde (MDA) content and rates of tissue autoxidation (RAD) all initially increased at lower salt levels and then declined. However seedling growth was not significantly inhibited under salt stress and root activity showed no obviously decrease. Malondialdehyde and proline content, SOD and POD activity were not affected by NaCl concentration <90 mmol·L^-1. This study showed that I. indigotica seedlings had some tolerance to low salt stress.