二氢赤霉素对不同种植密度下小麦抗倒伏能力及产量的影响

Effects of 16,17-Dihydro Gibberellin A 5 on Lodging Resistance and Yield of Wheat under Different Planting Densities

为探究新型赤霉素抑制剂二氢赤霉素(2HGA 5)对不同种植密度下小麦植株抗倒伏能力和产量的影响,在2021-2022和2022-2023两个生长季,选用小麦品种蜀麦133在成都平原大邑县开展二因素裂区试验,主区设置250万株·hm^(-2)(B1)、300万株·hm^(-2)(B2)、350万株·hm^(-2)(B3)、400万株·hm^(-2)(B4)4个种植密度,副区于拔节期设置100 mg·L^(-1)二氢赤霉素(C2)、200 mg·L^(-1)二氢赤霉素(C3)2个喷施水平,以喷施清水(CK0)和多效唑-甲哌鎓混合药剂(CK1)为对照。结果表明,随种植密度的增大,小麦倒伏率、倒伏等级、第二节间长度、株高和重心高度均增加,而第二节间直径、壁厚、木质素含量和抗折力均降低。喷施2HGA 5显著提高小麦抗倒伏能力。与CK0相比,在B4条件下C3的第二节间长度、株高和重心高度分别降低31.1%、6.6%和10.7%,第二节间直径、壁厚、充实度分别增加11.3%、17.3%和52.6%,木质素含量、苯丙氨酸解氨酶活性、络氨酸解氨酶活性、4-香豆酸:CoA连接酶活性、肉桂醇脱氢酶活性和茎秆抗折力分别增加12.2、18.4%、42.6%、27.5%、51.7%和61.4%;与CK1相比,C3的株高和重心高度差异不显著,第二节间长度降低13.9%(P<0.05),直径、壁厚和茎秆充实度分别提高4.5%、4.3%和19.0%(P<0.05),木质素含量和抗折力分别提高9.4%和7.2%。同一种植密度下,有效穗数、产量及收获指数整体表现为C3>C2>CK1>CK0,C3的穗粒数显著高于其他处理;同一喷施浓度下,有效穗数随种植密度的增大整体呈增加趋势,穗粒数、千粒重呈下降趋势,产量呈先增后降趋势,且在B2下达最大。综上所述,在300万株·hm^(-2)种植密度下配施200 mg·L^(-1)二氢赤霉素可以实现小麦抗倒能力和产量的协同增长。

To investigate the effects of a novel gibberellin inhibitor,16,17-Dihydro Gibberellin A 5(2HGA 5),on the lodging resistance and yield of wheat under different planting densities,a two-factor split plot experiment was conducted in Dayi County,Chengdu Plain,using wheat variety Shumai 133 as material in the 2021-2022 and 2022-2023 growing seasons.The main plot was the four planting densities of 2.5×106 plants·hm^(-2)(B1),3.0×106 plants·hm^(-2)(B2),3.5×106 plants·hm^(-2)(B3)and 4×106 plants·hm^(-2)(B4),and the sub-plot was the chemical regulator treatments of water control(CK0),200 mg·L^(-1)polybulobuzole-methylpiperium mixture(CK1),100 mg·L^(-1)2HGA 5(C2)and 200 mg·L^(-1)2HGA 5(C3).The results showed that with the increase of planting density,the lodging rate,lodging grade,second internode length,plant height,and centroid height of wheat all increased,while the diameter,wall thickness,lignin content,and flexural strength of the second internode decreased.Spraying 2HGA 5 significantly improved the lodging resistance of wheat.Compared with CK0,under B4 conditions,the second internode length,plant height,and centroid height of C3 decreased by 31.1%,6.6%,and 10.7%,respectively.The second internode diameter,wall thickness,and plumpness increased by 11.3%,17.3%,and 52.6%,respectively.Lignin content,phenylalanine deaminase,tyrosine deaminase,4-coumaric acid:CoA ligase,cinnamyl alcohol dehydrogenase activity,and stem bending strength increased by 12.2%,18.4%,42.6%,27.5%,51.7%,and 61.4%,respectively.Compared with CK1,there was no significant difference in the plant height and centroid height of C3,and the length of the second internode decreased by 13.9%(P<0.05).Diameter,wall thickness,and stem plumpness increased by 4.5%,4.3%,and 19.0%,respectively(P<0.05),while lignin content and flexural strength increased by 9.4%and 7.2%,respectively.Under the same planting density,the overall performance of effective ear number,yield,and harvest index ranked as C3>C2>CK1>CK0,and the number of grains per ear in C3 is significantly higher than that in other treatments.At the same spraying concentration,the effective number of spikes showed an overall increasing trend with the increase of density,while the number of grains per spike and thousand-grain weight showed a decreasing trend.The yield showed a trend of first increasing and then decreasing,and reached its maximum at B2.In summary,co-application of 200 mg·L^(-1)2HGA 5 at a density of 3.0×106 plants·hm^(-2)can achieve a synergistic increase in lodging resistance and yield.