The seedling growth of Pinus yunnanensis in response to the seeds soaked by exogenous phytohormone
The economic and ecological benefit of Pinus yunnanensis were restricted by slowly growing in the period of young forests,especially within three years after planting.In order to accelerate the seedling growth,the experiment of growth and biomass increment in response to exogenous phytohormone, IAA (indole - 3 - acetic acid) in combination with IBA(4 - indole -3 - ylbutyric acid) ,was carried out with 3×3 regression design.The phytohormone effect rules, the optimum amount and ratio were discussed and confirmed.The results showed that: ①The relationship between growth interment (or biomass accumulation) and the amount of IAA and IB A can be described by the convex surface models.Each growth index had a maximum value.The growth increment and biomass accumulation were increased with the increasing of IAA and IB A levels when they don't excced the maximum values, and the growth indexes were decreased as the increasing of IAA and IBA levels when they exceed maximum values.②The application of phytohormone obviously promoted the growth of seedling, but the regularities of different growth indexes in response to the amount and ratio of IAA and IBA had some differences.The application of IAA in combination with IBA had the promotion for the biomass accumulation of stem, leave, androot.High IB A level was suitable for stem height growth and root system development, while higher IB A level was advantageous to stem diameter growth, stem and leaf biomass accumulation.③ The optimum amounts and ratios of IAA and IBA, the reasonable phytohormones ranges and op - curve lines were gained based on phytohormone effect equations of different growth indexes.The optimum IAA for tree height,ground diameter,root system,stem and leaves growth were 50,57,53,49,45 mg/kg respectively,and IBA were 86,143,88,99,107 mg/kg respectively.And the corresponding proportion of IAA to IBA were 1∶ 1.72,1∶ 2.51,1∶ 1.67,1∶ 2.03,1∶ 2.37 respectively.The maximum increments of height,ground diameter were 8.00 cm and 0.51 cm,and biomass of root system,stem,and leaf were 0.380 g,0.387 g and 1.230 g, respectively,which increased by 22.64％ ,66.12％ , 62.40％ ,198.00％ ,83.30％ respectively,compared with those without phytohormone treatment.
seed soaked by IAA combined with IBAseedling growth incrementPinus yunnanensis phytohormone effect ruleoptimum amountsoptimum ratio
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维普
