水杨酸和甜菜碱浸种对低温干旱胁迫下玉米苗期生长的影响

沙培条件下,研究不同浓度水杨酸和甜菜碱浸种后对胁迫下玉米萌发和解除胁迫后苗期生长性状的影响,比较不同胁迫类型间的药剂浸种效果差异。结果表明,与低温胁迫相比,低温干旱双胁迫使玉米发芽势、地上部干鲜重和鲜重根冠比极显著下降。水杨酸和甜菜碱均能显著提高不同胁迫下玉米子粒发芽势,显著减少可溶性糖含量。对于幼苗高度和幼苗干鲜重,药剂浸种表现为低温胁迫下抑制效果和低温干旱双胁迫下促进作用。根系总长对药剂浸种的响应强于其他根系性状,且对甜菜碱的响应更为显著;地上部生长对水杨酸的响应强于甜菜碱。随着药剂浓度升高,水杨酸效果减弱,甜菜碱效果增强。

Effects of Presoaking with Salicylic Acid and Betaine on Germination and Seedling Growth of Maize under Chilling and Drought Stresses

Chilling and drought are two main stresses for the germination of spring maize. Through sand-culture method, an experiment was conducted to investigate the effect of presoaking maize seed with salicylic acid and betaine on germination under chilling and chilling+drought stresses and on the following seedling growth without any stresses. Also, the presoaking effects with salicylic acid or betaine between two stress types were compared. The main results showed that germinability, fresh and dry weights of shoot, and root/shoot ratio of fresh weight of maize seed were significantly decreased under chilling+drought stress when compared with that under single chilling stress. Both salicylic acid and betaine significantly improved germinability and reduced soluble sugar content under two stress types. Contrary effects of presoaking on height and fresh and dry weights of seedlings occurred between single chilling stress and chilling+ drought stress, that is, inhibition effect under chilling and promotion effect under chilling+drought were manifested respectively. The response of total root length to presoaking was stronger than that of other root characteristics, and this response was more significant in betaine treatments than in salicylic acid treatments, to which that shoot growth showed better response. With the increase of chemicals concentration, the effect of salicylic acid decreased, and on the contrary, the effect of betaine enhanced.