NaCl胁迫对唐古特白刺愈伤组织的生理效应

以唐古特白刺(Nitraria tangutorum Bobr.)愈伤组织为材料,研究低(75 mmol/L)、中(150 mmol/L)、高(300 mmol/L)浓度NaCl处理下其膜脂过氧化、抗氧化酶活性及渗透性调节物含量的变化,试图从细胞水平揭示唐古特白刺适应盐环境的生理机制。结果显示:(1)唐古特白刺愈伤组织中MDA含量在低浓度NaCl处理下与对照无显著性差异,而在中高浓度下显著升高。(2)白刺愈伤组织超氧化物歧化酶(SOD)活性在各浓度NaCl胁迫下均比对照显著升高,且此效应无浓度依赖性;其过氧化氢酶(CAT)活性随胁迫浓度的增加呈先升高后降低的变化趋势,在中低浓度下比对照显著增加,高浓度下显著降低为对照的64%;其过氧化物酶(POD)活性在低浓度下无显著性变化,在中高浓度显著下降为对照的55%和29%。(3)随NaCl胁迫浓度的增加,白刺愈伤组织中脯氨酸、可溶性糖和可溶性蛋白含量均呈先升高后降低的变化趋势,且除高浓度下可溶性蛋白含量约降为对照的87%外,其余NaCl胁迫处理的3种渗透调节物含量均高于对照。研究发现,白刺愈伤组织在低浓度的盐胁迫下具有较强的抗氧化酶活性和渗透性调节作用,因而表现出较强的抗氧化作用,但高浓度NaCl胁迫对白刺愈伤组织造成了显著的氧化损害。

Physiological Responses to NaCl Treatment in Nitraria tangutorum Bobr.Callus

The callus of Nitraria tangutorum Bobr.was employed to study the relation of NaCl stress with the changes about the peroxidations of membrane lipid,the activities of antioxidases and the osmotic regulations,which was tried to reveal the physiological mechanism of Nitraria tangutorum Bobr.under salty environment at the cellular level.The results showed that there was no change of malondialdehyde(MDA) content in Nitraria tangutorum Bobr.callus exposed to 75 mmol/L NaCl stress for 12 d,but 150 and 300 mmol/L NaCl brought significant increase in the amount of MDA.Compared to the control,NaCl stress induced increased activity of superoxide dismutase(SOD) in the callus.However,the activity of catalase(CAT) was firstly increasing,then decreasing with the enhance of NaCl concentration.In addition,no changes in peroxidase(POD) activity were observed in Nitraria tangutorum Bobr.callus exposed to 75 mmol/L NaCl stress for 12 d,but 150 and 300 mmol/L NaCl brought significant decrease in the POD activity.With the addition of NaCl concentration,the amount of proline,soluble sugars and soluble protein in Nitraria tangutorum Bobr.callus were fell into the tendency increased firstly and then decreased.300 mmol/L NaCl treatment resulted in enhancement of proline and soluble sugar content in Nitraria tangutorum Bobr.callus,but reducement of the CAT activity and the soluble protein content.The results suggested that the higher activity of antioxidase and the stronger effect of osmotic regulations were existed in the Nitraria tangutorum Bobr.callus under a lower concentration of salty stress,so the forter antioxidanted role appeared,but the higher NaCl concentration caused obviously oxidated damage in Nitraria tangutorum Bobr.callus.