植物生长调节剂对毛梾嫩枝扦插生根及内源激素含量的影响

为筛选适宜毛梾嫩枝扦插生根的植物生长调节剂处理方法，提高毛梾嫩枝扦插生根率，揭示其生根机理。以3 a实生毛梾当年生半木质化枝条为试验材料，采用3种不同植物生长调节剂:萘乙酸（NAA）、吲哚丁酸（IBA）、双吉尔6号生根粉（GGR），分别以3种不同浓度1 000、1 500、2 000 mg/L做处理，以清水为对照。对生根情况和生根过程中内源激素含量进行测定。结果表明，植物生长调节剂种类、浓度以及二者的交互作用对毛梾嫩枝扦插生根影响极显著。在植物生长调节剂种类和浓度的交互作用下，IBA 2 000 mg/L处理后，插穗的生根率为67.33%、平均根长达到88.52 mm、平均根数为8.33根、根表面积41.52 cm²、根体积0.53 cm³、平均根直径1.82 mm、根生物量282 mg，均显著高于其他处理。IBA 2 000 mg/L处理能明显加快不定根发生前ABA、GA₃、ZR含量的降低速度，使其提前到达谷值，同时抑制IAA含量的降低，使IAA和IAA/ZR处在相对较高的水平，以促进不定根的发生。在本试验条件下，IBA 2 000 mg/L促进毛梾嫩枝扦插生根效果最好。不定根的发生需要较高浓度的IAA和较低浓度的GA₃、ZR和ABA，较高水平的IAA/ZR有利于根的发生。

Effects of Plant Growth Regulators on Rooting and Endogenous Hormones Content of Cornus walteri Softwood Cuttings

The aims of this study were to select the plant growth regulators suitable for improving the rooting rate and to reveal the rooting mechanism for softwood cuttings of Cornus walteri.Semi-lignified branches (softwood cuttings) of the three-year-old seedlings were used as the materials,which were treated by three plant growth regulators,including naphthalene acetic acid (NAA),indole butyric acid (IBA),and “Shuangjier” No.6 rooting powder (GGR),each with three different concentrations of 1 000,1 500,2 000 mg/L,and pure water was used as the control.Rooting performance and the endogenous hormone content during the rooting process were measured.The type and concentration of plant growth regulators and their interactions presented significant effects on the rooting of C.walteri softwood cuttings.Under the interaction of plant growth regulator type and concentration,after treated with 2 000 mg/L IBA,the rooting rate of cuttings was 67.33%,the average root length reached 88.52 mm,the average root number was 8.33,the root surface area was 41.52 cm²,and the root volume was 0.53 cm³,average root diameter was 1.82 mm,root biomass was 282 mg,which were significantly higher than other treatments.IBA of 2 000 mg/L could significantly promoted the reduction of ABA,GA₃,ZR contents before adventitious roots formation,and made them earlier to reach the minimum contents,while inhibiting the reduction of IAA content and making IAA and IAA/ZR at a relatively high level to promote adventitious roots formation.Among the plant growth regulators used in this experiment,IBA of 2 000 mg/L had the optimum effect on promoting the rooting of C.walteri softwood cuttings.Adventitious root formation needed higher concentrations of IAA,lower concentrations of GA₃,ZR,and ABA,and higher levels of IAA/ZR were beneficial to adventitious roots formation.