Abstract:To study the alleviated effect of grafting with different rootstocks on watermelon allelochemicals, watermelon variety ‘Zaojia 84-24’ was used as scion,two kinds of gourd (‘Jingxin Zhen’ and ‘Zhenqiu’) and two kinds of pumpkin (‘Ribenxuesong’ and ‘Jiuzhen No.1’) as rootstock,the effects of diisobutyl phthalate (DIBP) and dioctyl phthalate (DOP) at 4 mmol·L-1 concentration,and effects of grafting with different rootstocks on root physiological characteristics and mineral elements content of watermelon seedlings were investigated.The results showed that:(1) the root length of grafted seedlings of pumpkin and calabash was longer than that of self-rooted seedlings under 4 mmol·L-1 DIBP and DOP treatment,and calabash rootstock had stronger root activity.(2) The malondialdehyde content of the four grafted seedlings under allelochemicals treatment significantly decreased,and the activities of superoxide dismutase (SOD),peroxidase (POD) and peroxidase (CAT) of the four grafted seedlings under 4 mmol·L-1 DIBP treatment were improved.Only gourd rootstock promoted the activities of three antioxidant enzymes.(3) Nitrate reductase activity of grafted seedlings of four rootstocks treated with allelochemicals was higher than that of self-rooted watermelon.(4) Under allelochemicals treatment,the absorption of mineral elements in roots of different grafted watermelon seedlings showed different rules.In general,grafted watermelon seedlings could promote the absorption of elements (phosphorus,potassium,calcium,magnesium),but inhibit the accumulation of trace elements (iron,copper,zinc) in roots.It is suggested that grafting can alleviate allelopathic effect of fatty acid ester on watermelon,improve root activity,reduce root growth inhibition,promote antioxidant enzyme activity,reduce malondialdehyde content accumulation,affect root absorption and accumulation of mineral elements,and maintain normal physiological activities of watermelon.The tolerance of calabash grafted seedlings to allelochemicals was stronger than that of pumpkin grafted seedlings,and ‘Jingxin stock’ was the best rootstock. |