三种外源植物激素对黄花风铃木幼苗生物量、叶绿素荧光参数及光合特性的影响

以黄花风铃木(Tabebuia chrysantha (Jacq.) Nichols)幼苗为材料,采用L16(45)正交实验方法,测定生根粉(GGR)、3-吲哚乙酸(IAA)、多效唑(PP333) 3种外源植物激素不同组合处理下黄花风铃木幼苗的生物量、叶绿素含量、叶绿素荧光参数以及光合特性,研究3种外源植物激素不同组合对黄花风铃木幼苗生长和光合作用的影响,筛选出适宜黄花风铃木幼苗生长的最佳浓度组合。结果显示:11号处理(GGR 400 mg/L、IAA 400 mg/L、PP333400 mg/L)幼苗鲜重、干重均大于其他组合处理。3种外源植物激素中,GGR对幼苗鲜重、幼苗干重增长起主导作用,IAA和PP333的作用不明显。11号处理下的幼苗净光合速率、气孔导度、蒸腾速率、叶绿素含量、叶绿素荧光参数均大于其他处理,胞间二氧化碳浓度值最低。分析得出IAA对黄花风铃木幼苗的净光合速率、气孔导度、蒸腾速率、光合系统潜在活性、最大光能转换效率和叶绿素含量起主导作用,GGR和PP333的作用不明显。综合分析各指标得出,适宜黄花风铃木幼苗生长的最佳外源激素浓度组合为11号处理,此浓度下黄花风铃木幼苗综合质量最佳。

Effects of three plant exogenous hormones on the biomass,chlorophyll fluorescence parameters,and photosynthetic characteristics of Tabebuia chrysantha seedlings

We applied a L₁₆(4⁵) orthogonal experimental design to determine and compare the biomass, chlorophyll content, chlorophyll fluorescence parameters, and photosynthetic characteristics of Tabebuia chrysantha (Jacq.) Nichols seedlings under different combinations of rooting powder (GGR), indole acetic acid (IAA), and paclobutrazol (PP₃₃₃). The effects of the different combinations of plant exogenous hormones (GGR, IAA, and PP₃₃₃) on the growth and photosynthesis of T. chrysantha seedlings were used to derive the optimal concentration combination. Results showed that fresh weight and dry weight were highest under Treatment 11 (GGR 400 mg/L, IAA 400 mg/L, PP₃₃₃ 400 mg/L) compared with the other treatments. Among the three plant exogenous hormones, GGR played a leading role in the increase in fresh and dry weights, whereas IAA and PP₃₃₃ did not have a significant effect. The net photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll content, and chlorophyll fluorescence parameters of seedlings were also highest under Treatment 11, whereas intracellular carbon dioxide concentration was lowest. Results also showed that IAA played a leading role in the net photosynthetic rate, stomatal conductance, transpiration rate, potential activity of photosynthesis system, maximum light energy conversion efficiency, and chlorophyll content of T. chrysantha seedlings, whereas the effects of GGR and PP₃₃₃ were not obvious. Comprehensive analysis further showed that the appropriate concentration combination of different exogenous hormones was that of Treatment 11, under which the quality of T. chrysantha seedlings was optimal.