Effects of chlormequat chloride treatment on the growth and physiological indices of wheat

Plant growth regulators, particularly chlormequat chloride, are crucial for enhancing plant yield, quality, and lodging resistance. This study investigated the impact of different concentrations of chlormequat chloride (0%, 1%, 1.5%, 2.0%, 2.5%) on wheat seed germination, growth indices, and physiological parameters in Shenfu Reform and Innovation Demonstration Zone, Shenyang. The results showed the seed germination rates of Liaochun 18 and Luyuan 502 sreached to the highest point when treated with 1.5% chlormequat chloride, which were 9.3% and 14.0% higher than the control experiment (CK). While treated with 2.0% and 2.5% of chlormequat chloride, Luyuan 502 and Liaochun 18 showed a significant reduction of plant height, which was 38.71% and 18.95% lower than CK, respectively. The root length of Luyuan 502 reached to the peak when treated with 2% chlormequat chloride and was 38% longer than that of CK, however, although Liaochun 18 showed the longest roots at the concentration of 1.5%, but insignificantly varied with CK. The fresh weight of Luyuan 502 and Liaochun 18 increased by 0.25 g and 0.71 g, when treated with 1.0% and 1.5% of chlormequat chloride. Both varieties exhibited the highest leaf area at 1.5%, with Luyuan 502 was 164% higher than CK, whereas Liaochun 18 was comparable to CK. 2% chlormequat chloride treatment has the best effect on improving the antioxidant enzymes activities (SOD, POD, CAT) and osmoprotectants contents (soluble sugar, proline and soluble protein) in wheat leaves and has a positive effect on the physiological indices (antioxidant enzymes activities and osmoprotectants contents) of the two varieties. In summary, 1.5% chlormequat chloride can promote the seed germination of two wheat varieties, while both varieties presented better physiological indicators 2% concentration. In future, field study is needed in future to verify the real effect of chlormequat chloride on wheat growth and production.