Abstract: To investigate the effect of trehalose pretreatment with different concentrations of 0， 2， 20 and 40 mmol·L-1 on seed germination， Yangmai19， a highyielding winter wheat cultivar， was selected as the experimental material. Furthermore， the optimal concentration of trehalose （2 mmol·L-1） was screened out to study its effect on growth and physiological characteristics of Yangmai19 under salt stress （3 g·L-1 NaCl）. The results showed that the seed germination and plant height were not significantly affected in the pretreatment with 2 mmol·L-1 trehalose， but the dry weight per plant was significantly increased. Under salt stress， compared with the nontreated seeds， the relative growth rate， biomass per plant， relative chlorophyll content and N content in the pretreatment of 2 mmol·L-1 trehalose were significantly improved by 200%， 650%， 1507% and 925%， respectively. Proline accumulation rate was found to be significantly increased in the seedlings pretreated with 2 mmol·L-1 trehalose than the nontreated seeds， as well as the total K+ content and K+/Na+ ratio， while Na+ content was significantly decreased （P<005）. Twofactor variance analysis showed that the factor orders of impacting K+ content was trehalose>NaCl>trehalose×NaCl. Trehalose pretreatment could improve the seedlings adaption to salt stress earlier， by increasing their proline accumulation and also increasing their K+ absorption.

Key words: wheat Yangmai19, trehalose, salt stress, soaking seed, physiological characteristics