Physiological and Growth Response of Sweet Corn Hybrids to Aluminum-Induced Stress

Aluminum (Al) stress has strong negative effects on growth, development and yield formation in crops. However, few studies focused on aluminum stress in sweet corn seedlings. In the present study, 18 sweet corn varieties were used to analyze the morphological and physiological changes of sweet corn seedlings in response to Al-induced stress. Results have shown that treatment by AlCl3, significantly affected root elongation, chlorophyll content, plant height, fresh weight, superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity and Al content in root tips in sweet corn, according to the significant interaction by variety × AlCl3 treatment except for CAT. Al-induced stress inhibited root length in all sweet corn varieties, and it resulted in a decrease in chlorophyll content, plant height, fresh weight, and SOD activity in most of the sweet corn varieties. The treatment by AlCl3 increased in POD activity except for GLT31; however, the intensity of these effects varied among varieties. In addition, the correlation between morphological and physiological characteristics showed that Al content in root tips was negatively correlated with relative root growth (RRG) and chlorophyll content at a significant level of 0.01, and it was negatively correlated with CAT activity at the significant level of 0.05. There were significant positive correlations between plant height and fresh weight at a significant level of 0.01, and chlorophyll content was positively correlated with RRG and CAT at the significant level of 0.05. The principal component analysis showed that plant height, RRG, SOD activity, fresh weight, Al content of root tips and fresh weight were the main morphological and physiological characteristics in sweet corn seedlings affected by AlCl3 treatment. In addition, we found that HWT2, HWT1 and HZ388 were the high-tolerant varieties to Al treatment.