Effects Of Shading On Petal Color Of Tianpeng Tree Peony

The anthocyanin contents of petal of Tianpeng tree peony’Hongdanlan NO1’were studied at different growing stages and under different light intensities. The relationship between the anthocyanin contents and other physiological indexes, such as soluble sugar content, soluble protein content, activity of phenylalanine ammo-nialyase(PAL), polyphenol oxidase(PPO) and endogenous hormones,was also discussed. The results were as follows:1. Dynamic changes of anthocyanin contents at different growing stages had different tendency under different light intensities, and anthocyanin content was decreased with the decreasing of light intensity at the same growing stage.2. The correlation coefficients between the anthocyanin contents and other physiological indexes:the anthocyanin content was positive correlation (r=0.992) to soluble sugar content in the preliminary blooming stage, and negative correlation to that at full blooming stage (r=-0.972). The anthocyanin content was also positive correlation to soluble protein content at preliminary blooming stage(r=0.854) and at the senescence stage(r=0.833). The activity of PAL showed strong positive correlation to the anthocyanin content at preliminary stage(r=0.974) and full blooming stage(r=0.907), while the activity of PPO showed strong negative correlation to the anthocyanin content at full blooming stage (r=-0.996) and at the senescence stage (r=-0.868). It was concluded that complementing illumination was necessary for Tianpeng tree peony in the period of culturing, and the effect of shading on petal color was due to the impact of shading on physiological activity in Tianpeng tree peony.3.The Correlation coefficients between concentrations of endogenous hormones and activities of metabolic enzymes under different light conditions:At the bud occurring color stage, PAL activity was significantly related to the concentrations of GA3(r=0.710), IAA (r=0.762) and ABA (r=0.722), but it was not significantly related to the concentrations of ZT (r=0.145) and Ethylene (r=-0.149). There existed a significant positive correlation between PPO activity and ZT concentration (r=0.869), and a significant negative correlation between PPO activity and Ethylene production (r=-0.868). At the full-blooming stage, PAL activity was positively related to the concentrations of IAA (r=0.590), ABA (r=0.508), and Ethylene production (r=0.740). However, PPO activity was negatively related to the concentrations of GA3(r=-0.676), IAA (r=-0.914) and ABA (r=-0.870). At senescence stage, PAL activity was significantly related to the concentration IAA (r=0.516), ZT (r=-0.995) and Ethylene production (r=0.950), and there existed a significant negative correlation between PPO activity and GA3(r=-0.773), IAA (r=-0.942), ABA (r=-0.744), Ethylene production (r=-0.537). But PPO activity was positively related to ZT concentration (r=0.740). The relationship between endogenous hormones and activities of metabolic enzymes perplexing, and the effect of endogenous hormones on petal color was due to the impact of endogenous hormones on activities of metabolic enzymes in Tianpeng tree peony.Different from the study of Central Plains peony, Tianpeng tree peony should ensure adequate light in Chengdu region, otherwise it will affect Tianpeng tree peony ornamental value.