滴灌甜菜叶丛生长期对干旱胁迫的生理响应

Physiological responses of sugar beet(Beta vulgaris) to drought stress during vegetative development period under drip irrigation

在人工控水条件下,于叶丛生长期设置0-40 cm土层含水量为70%田间持水量、50%田间持水量和30%田间持水量3个处理,研究干旱胁迫下甜菜叶片相关生理性状的变化.结果表明：甜菜叶丛生长期中度缺水处理（50%田间持水量）的补偿指数最大,甜菜叶片丙二醛（MDA）含量、相对电导率、过氧化氢酶（CAT）活性及可溶性糖含量均在复水后24 h产生补偿效应,脯氨酸产生的补偿效应在复水后48 h,过氧化物酶（POD）未发生补偿效应.酶促活性氧清除系统以CAT反应最为灵敏.因此,在甜菜叶丛快速生长期,当土壤含水量下降至田间持水量的50%时应及时进行补充灌溉,促使叶片产生补偿效应,从而降低干旱胁迫对甜菜产量和含糖量的影响.

Sugar beet（ Beta vulgaris cv. Beta 356） was subjected to drought stress during vegetative development by maintaining the soil water content in the 0-40 cm soil depth at 70%,50% or 30% of field capacity to study the physiological traits of the leaves. Results showed that the compensation index was the highest in the 50% field capacity treatment. Malonaldehyde（ MDA） content,relative conductivity,catalase（ CAT） activity,and soluble sugar content began to increase 24 h after rehydration. Proline content began to increase 48 h after rehydration. In contrast,no compensation effect was observed in peroxidase（ POD） activity after rehydration. Among the active oxygen scavenging enzymes,CAT was most sensitive to drought stress. Supplemental irrigation should be carried out promptly when the soil water content dropped to 50% of field capacity during vegetative development. Rehydration could promote self-repair functions in leaves,thus reducing the effects of drought on sugar beet yield and sugar content.