Effect of polyamine on some physiological and biochemical indexes of maize seedling under waterloging stress
Hongyang Du ¹, Guting Liu ², Huaipan Liu ¹, Qinghua Yang ^{1, *}

¹College of Agronomy, Henan Agricultural University, Zhengzhou 450002, Henan, China;
²College of Life Sciences, Henan Normal University, Xinxiang 453002, Henan, China。
^*Corresponding author. Tel: (+86394)8178138; E-mail：duhongyang2005@yahoo.com.cn

Abstract
The contents of spermidine (Spd), lactate, alcohol, acetaldehyde and the activities of pyruvate decarboxylase (PDC), lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH) were investigated in seedling roots of two maize (Zea mays L.) cultivars, Nongda 108 and Yedan 13, under waterloging stress, with exogenous Spd seed soaking. On the 5^th day, after waterloging treatment, dry matter accumulation rate of Nongda 108 decreased more significantly than that of Yedan 13, while Yedan 13 showed a more significant increase in Spd level. Pre-treatment of seed-soaking with Spd resulted in increases of Spd level and dry matter accumulation rate of Nongda 108. Both activities of PDC and LDH increased in seedling roots and there was no difference between two cultivars. The ADH activity and alcohol content in seedling roots of Yedan 13 increased more greatly than that of Nongda 108 under stress, while acetaldehyde content of Yedan 13 increased more inferiorly than that of Nongda 108. Pre-treatment of seed-soaking with Spd resulted in facilitating the increase in ADH activity and inhibiting the increase in acetaldehyde content of Nongda 108. The results suggest that Yedan 13 is more tolerant to waterloging stress than Nongda 108 and exogenous Spd could alleviate the waterloging stress injury to seedling via increasing in Spd level and ADH activity and decreasing in acetaldehyde content in seedling roots.

Key Words: polyamine; maize seedling; waterloging stress