生长抑制剂对大叶黄杨形态及光合作用的影响

Effects of Plant Growth Inhibitors on the Morphology and Photosynthesis of Euonymus japonicus

目的]探究抑制剂对大叶黄杨生长的抑制作用以及对其叶片形态和光合作用的影响,为灌木绿篱的化学修剪提供技术指导。[方法]在北京林业大学林场苗圃采用3种生长抑制剂(多效唑(PP_(333))、三碘苯甲酸(TIBA)以及脱落酸(ABA))对密植成绿篱状的1年生大叶黄杨扦插苗进行叶面喷施,对其生长、叶片形态及光合作用等指标进行测定。[结果]3种抑制剂均有矮化植株、抑制新梢生长的作用,矮化效果最佳、抑制作用最强的为PP_(333),且高浓度PP_(333)对于高生长的抑制作用持效性较长。叶宽、叶厚以及叶面积在短期PP_(333)处理下高于对照。PP_(333)能提高大叶黄杨净光合速率,主要通过增加叶厚、气孔导度、叶肉导度及叶绿素含量来实现,并且PP_(333)使蒸腾速率提高的同时降低了水分利用效率。TIBA有显著减小叶长、叶宽的作用,但能使叶厚增加,且随浓度的增加作用效果增强,主要通过减小叶面积,降低叶肉导度、气孔导度、胞间CO_2浓度及叶绿素含量来降低净光合速率。ABA能增加叶面积(10 mg·L^(-1)处理除外)、叶长以及减小叶片厚度,通过抑制气孔导度、叶肉导度、叶绿素含量降低净光合速率。TI-BA及ABA均通过降低蒸腾速率,使水分利用效率提高。[结论]3种抑制剂均有矮化植株、抑制新梢生长的作用,并且影响叶片发育,进而影响叶片光合作用,且800 mg·L^(-1)的多效唑对大叶黄杨具有较好的正向作用。

[Objective]To study the effect of plant growth inhibitors on growth,leaf morphology and photosynthesis of Euonymus japonicus,and provide technical guidance for the chemical pruning shrubs.[Method]One-year-old E.japonicus cutting stocks planted into hedge were treated with 3 kinds of growth inhibitors,Paclobutrazol(PP 333),triiodobenzoic acid(TIBA)and abscisic acid(ABA)by foliar spraying in the nursery of Beijing Forestry University.Then the growth,leaf morphology and photosynthesis were measured.[Result]These 3 kinds of chemicals can inhibit both plant height growth and shoot growth,and PP 333 performed the best.The time of inhibitory effect of high concentration PP 333 lasted longer.The leaf area,leaf width and leaf thickness were higher than the control with PP 333 in the short term.PP 333 increased photosynthetic rate by increasing leaf thickness,stomatal conductance,mesophyll conductance and chlorophyll content and it reduced water use efficiency by increasing the transpiration rate.The leaf length and leaf thickness significantly reduced,but the leaf thickness increased with TIBA concentration increasing.Photosynthetic rate reduced in TIBA mainly due to reduced leaf area,mesophyll conductance,stomatal conductance,intercellular CO 2 concentration and chlorophyll content.The Leaf area(except 10 mg·L^-1 ABA)and leaf length increased,but the leaf thickness reduced with ABA.ABA can reduce photosynthetic rate mainly by reducing the mesophyll conductance,stomatal conductance and chlorophyll content.TIBA and ABA increased water use efficiency by reducing the transpiration rate.[Conclusion]All the 3 kinds of chemicals can inhibit both plant height growth and shoot growth,and affect leaf development,and then affect leaf photosynthesis.PP 333 with a concentration of 800 mg·L^-1 performs the best.