Effects On Micro-structures Of Leaves And The Photosynthetic Characteristics Of Rosa Hybrida With PP₃₃₃

Rosa hybrida is a rose of vine subfamily of shrubs.The plants are tall and have strong resistance.They grow quicky and have high ornamental value which can be used for vertical landscaping and greening. Plants growth retardants can effectively control the vegetative growth of plants and delay the elongation of the stem.so more photosynthetic products can be transported to the reproductive organs, promote the growth of flowering plants and reduce the need for plants cultivation or without cultivation[1] But reports on PP333 for chlorophyll fluorescence and anatomical structures of leaves are few.This article aims to study the external characteristics, chlorophyll content, chlorophyll fluorescence, photosynthetic characters and micro-structures of Rosa hybrida with different concentrations and times of PP333SO as to understand the growth mechanism of Rosa hybrida during the growth with PP333 and provide a theoretical basis for planting roses and improving the ornamental characteristics. The results of this study are as follows:1. Effect of PP333 on the length variation of branches; The shoot growth control will be more prominent with the same processing times and the higher concentrations.800mg/kg PP333 with 3times does the best,but high concentrations with processing times is not conducive to the healthy growth of plants, (a= 0.05)2. Effect of PP333 on the growth of leaves:To some extent, PP333 with different concentrations can increase theleaf thickness and water content.600mg/kg PP333 with 3times has the maximum water content of leaves and increases 33% compared with the control (α= 0.05)3. Effect of PP333 on chlorophyll content:PP333 with low concentrations and a small amount of processing times does not have obvious effect. PP333 with the same concentration and processing times can increase chlorophyll contents and deepen the colour of leaves gradually, but when 800mg/kg PP333 with six times, the chlorophyll content of plants will decrease and the leaves gradually turn yellow even damp off. (α = 0.05)4. Effect of PP333 on chlorophyll fluorescence parameters:Chlorophyll fluorescence parameters can reflect the performance of the photosynthetic apparatus and photosynthetic capacity of leaves. When 600mg/kg PP333 with processing 6 times, ETR is the highest, electron transfer rate is the fastest, levels of NPQ are low, less heat dissipation is low and the level of photosynthesis is high. Fv/Fm values are higher compared with the control treatment with a high level of energy capture, (a= 0.05)5. Effect of PP333 on the microstructure of the blade:The thickness of palisade tissue is longer than the tissue of spongy tissue after PP333 treatment, when 600 mg/ kg PP333 withsix times,the thickness of palisade tissue is longest, the tissue of spongy tissue is shortest without PP333.