干旱胁迫对沙芥幼苗根系形态及抗氧化酶活性的影响

以一年生沙芥幼苗根系为材料,采用盆栽试验,测定不同干旱处理下幼苗根系形态特性、渗透调节物质含量、抗氧化系统等生理指标。结果表明,干旱胁迫下沙芥幼苗根系主根长、主根体积和根冠比随着胁迫天数的延长不断增加,重度胁迫时分别上升154.39%、90.69%和189.59%。幼苗根系活力在重度胁迫时下降51.22%,根系可溶性蛋白、脯氨酸和可溶性糖含量在轻度和中度胁迫时上升,而重度胁迫时分别下降了1.65%、4.13%和11.84%。根系中的过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸活性随着胁迫程度加剧不断上升,过氧化物歧化酶(SOD)先上升后下降。丙二醛(MDA)含量和根系质膜透性随着胁迫程度增加逐渐上升到255.74%和122.78%,复水3 d后轻度和中度胁迫下根系中的抗氧化保护系统和渗透调节物质均可恢复到对照水平,重度胁迫复水3 d后只能恢复到轻度胁迫水平,说明沙芥幼苗根系受到了一定程度的伤害。

Root morphology and antioxidant enzyme activity of Pugionium cornutum (L.) Gaertn under drought stress

Root tissues of annual Pugionium cornutum seedlings under drought stress were used in a pot experiment to investigate the effect of soil water on root morphological characteristics, osmotic regulation substances content, antioxidant enzymes activity and other physiological indexes of seedling root by different drought treatments. The results showed that drought stress increased roots taproot length, root volume and root cap ratio of Pugionium cornutum seedlings with the extension of stress days, which under serve stress were elevated by 154.39%, 90.69% and 189.59%, respectively. Root soluble proteins, proline and soluble sugar content were increased under mild and moderate stresses, whereas went down by 1.65%, 4.13% and 11.84% under severe stress, respectively. Additionally, seedling root activity was dropped by 51.22% under severe stress. While the stress levels went up, malondialdehyde (MDA) content and root plasma membrane permeability gradually rose to 255.74% and 122.78%, respectively. Peroxidase (POD), superoxide dismutase (SOD) and ascorbic acid contents in root became increased under mild and moderate stresses, but were reduced under severe one. Three days after rewatering, the antioxidative defense system and the osmotic regulation substances in Pugionium cornutum seedlings root under the m ild and moderate water stress could quickly return to control levels, but these indexes under severe stress could only be recovered to the mild stress level, indicating that Pugionium cornutum seedlings roots were seriously damaged.