化控剂对东北春玉米茎秆理化特性及抗倒伏的影响

Effect of Chemical Regulators on Physical and Chemical Properties and Lodging Resistance of Spring Maize Stem in Northeast China

通过探讨春玉米茎秆纤维素、半纤维素和木质素含量及木质素合成相关酶活性对不同化控剂的响应,明确化控剂调控茎秆抗倒伏能力的力学机制,可为生产上化控剂的合理运用提供理论依据。2015年和2016年在东北农业大学向阳实验实习基地进行大田定位试验,以玉米品种东农253为材料,分别于六叶期喷施吨田宝(代号DTB)及DCPTA[2-(3,4-二氯苯氧基)三乙胺]和ETH(2-氯乙基膦酸)复配剂(代号KP),对照为清水,完全随机区组排列。分析玉米不同生育时期茎秆抗折力、抗倒伏指数、木质素、纤维素和半纤维素含量及木质素合成关键酶的活性变化对不同化控剂处理的响应。喷施化控剂可显著提高茎秆4-香豆酸:Co A连接酶(4CL)和肉桂醇脱氢酶(CAD)活性,以及纤维素含量、半纤维素含量、木质素含量、茎秆抗折力和抗倒伏指数,显著降低实际倒伏率。相关分析表明,茎秆抗倒伏指数与木质素含量、半纤维素含量呈极显著正相关(相关系数分别是0.67和0.64);茎秆抗折力与纤维素含量呈极显著正相关(相关系数为0.89);木质素含量与CAD活性呈极显著正相关(相关系数为0.89),与4CL活性呈显著正相关(相关系数为0.51),而与苯丙氨酸转氨酶(PAL)和酪氨酸解氨酶(TAL)活性均没有显著相关性。六叶期喷施化控剂通过提高茎秆木质素合成相关酶的活性(特别是CAD和4CL的活性),改善茎秆纤维品质性状,显著增强了春玉米茎秆的抗倒伏能力。

In order to investigate the mechanical mechanism of controlling lodging resistance of corn stalk, effects of chemical regulators on contents of cellulose, hemicellulose and lignin and lignin related enzyme activity of spring maize stalk were studied. Field experiments were conducted at the Xiangyang experimental practice base of Northeast Agricultural University in 2015 and 2016 using spring maize cultivar Dongnong 253 with two chemical regulators, DTB and KP（a chemical regulator made of DCPTA and ETH）. Two chemical regulators were sprayed at the 6-leaf stage, with water spraying as the control. The randomized block group was designed with three replicates, and a plot area was 56 m2. The responses of bending resistance, lodging resistance index, lignin, cellulose and hemi-cellulose contents, and the activities of key enzymes of lignin synthesis at different growth stages of maize to different treatments were analyzed. The two chemical regulators application could significantly improve activities of 4-coumarate： Co A ligase（4 CL） and cinnamyl alcohol dehydrogenase（CAD） in maize stem. The contents of cellulose, hemi-cellulose and lignin, bending resistance, and lodging resistance index were also improved significantly, where actual lodging rate decreased significantly. The lodging resistance index was extremely positively correlated with contents of lignin and hemi-cellulose（correlation coefficients were 0.67 and 0.64, respectively）. The bending resistance was extremely positively correlated with the content of cellulose（correlation coefficient was 0.89）. The content of lignin was extremely positively correlated with the activity of CAD（correlation coefficient was 0.89） and positively correlated with the activity of 4 CL（correlation coefficient was 0.51）. However, there＇s no significant correlation of lignin content with phenylalanine transaminase（PAL） and tyrosine ammonia lyase（TAL） activityies. Our results suggest that spraying chemical regulators at the 6-leaf stage can improve activities of key enzymes in stem（especially activities of CAD and 4 CL）, and stem fiber quality significantly enhancing stem lodging resistance of spring maize.