不同多效唑残留浓度对生菜苗期生长的影响

Effects of Different Concentrations of Paclobutrazol Residue on Seedling Growth of Lettuce

以5种生菜为试材,使用穴盘基质拌施多效唑育苗来模拟土壤多效唑残留的方法,其中多效唑浓度(以有效成分计)设置A1(0 mg·L^(-1))、A2(2.5 mg·L^(-1))、A3(5.0 mg·L^(-1))、A4(10.0 mg·L^(-1))、A5(20.0 mg·L^(-1))、A6(40.0 mg·L^(-1))和A7(80.0 mg·L^(-1))共7种残留水平,研究了多效唑残留对生菜幼苗质量、叶型及地上部可溶性固形物含量的影响,以期探明生菜育苗生长对多效唑残留浓度的响应机制。结果表明:随多效唑浓度增加,各生菜株高、地上部鲜质量、地上部干质量、总叶面积、总叶长、总叶宽、最大功能叶叶长、最大功能叶叶宽及可溶性固形物均降低,SPAD值及根冠比均增加,而根鲜质量及根干质量先增后降。其中A5、A6和A7处理株高、地上部鲜质量、地上部干质量、总叶面积及可溶性固形物等指标均显著低于A1处理,SPAD值和根冠比等指标却均显著高于A1处理。随菜地多效唑残留浓度增加,各生菜苗期生长发育受抑制程度增加,其中多效唑残留浓度为A5(20 mg·L^(-1))及其以上时其抑制效果均达显著水平,对生菜育苗质量极为不利。

Taking five lettuce cultivars as experiment materials,the method of simulating the residue of paclobutrazol in soil by mixing the paclobutrazol in plug substrate for seedling was used,and the concentrations of paclobutrazol(measured by active ingredients)were set with 7 residue levels of A1(0 mg·L^(-1)),A2(2.5 mg·L^(-1)),A3(5.0 mg·L^(-1)),A4(10.0 mg·L^(-1)),A5(20.0 mg·L^(-1)),A6(40.0 mg·L^(-1))and A7(80.0 mg·L^(-1)).The effects of paclobutrazol residue on seedling quality,leaf types and the content of aboveground soluble solids of lettuce were studied,in order to explore the response mechanism of lettuce seedling growth to the paclobutrazol residual concentration.The results showed that with the increasing of the concentration of paclobutrazol,the plant height,fresh weight of the aerial parts,dry weight of the aerial parts,total leaf area,total leaf length,total leaf width,maximum functional leaf length,maximum functional leaf width and soluble solid of all cultivars were decreased,the SPAD value and root-shoot ratio were increased,while fresh root weight and dry root weight first were increased and then decreased.Among them,the plant height,fresh weight of the aerial parts,dry weight of the aerial parts,total leaf area and soluble solids of A5,A6 and A7 treatments were significantly lower than A1 treatment,and the SPAD value and root-shoot ratio were significantly higher than A1 treatment.With the increasing of paclobutrazol residue concentration in vegetable fields,the inhibition degree of growth and development in lettuce seedling stage was higher,and the inhibition effect reached significant level when paclobutrazol residue concentration was A5(20.0 mg·L^(-1))and above.