Studies On Physiology Of Paeonia Rockii Flower Period Control

Peaonia rockii endemic to china is the most endangered speice of wild peonies.The effects of B9 treatment on growth and flowering of tree peony are studied.The physioiogical and biochemical changes during the senescence of tree peony flowers were studied with different Ca²⁺ contents.Callus were induced with peony root phloem as explants and callus subculture were conducted on MS adding different plant growth regulators,growth results and paeonol content of subculture were determined at different light and temperature conditions for 30d.With potted Paeonia suffruticosa Andr.cv.Manaopan as material,the effect of soil water on the photosynthesis characters of paeoy leaves under five drought stress developing.The results showed that:1.The effects of B9(daminozide)treatment on growth and flowering of tree peony are studied.The results showed that B9 was effective in retarding the new shoot growth of Peaonia rockii;B9 had obvious effect on promoting flowering and prolonging time of flowering. The effect of B treatment was better than the other treatments,prolonging time of flowering by about 9 days;However,B9 had not significant effect on the flower diameter of Peaonia rockii.2. With the increase of Ca content.total blossom periodcould be prolonged by 1～2 days,nevertheless,high Ca²⁺ content declined the blossom rate.Application of Ca²⁺ ,some physiological and biochemical indexes such as MDA content,O₂ production rate and ethylene releaserate diminished and the soluble protein content,SOD activity and photosynthesis increased.Those changes obviously maintained the structure and integrity of membrane,and then alleviated the process of senescence of Peaonia rockii flowers.3.The induced rate of callus was over 70% on MS adding 2,4-D(1.0mg/L)or NAA(1.5 mg/L),and the increased times and paeonol content of callus increased remarkably on MS adding 2,4-D(1.0mg/L)+TDZ(5.0×10^-6 mg/L) or NAA(1.5 mg/L) +TDZ(5.0×10^-3 mg/L) under the condition of 29℃in dark.4.W ith the soil water stressincreasing,the photosynthetic rate(Pn),transpiration rate(Tr) , stomatal conductance(Gs)declined , the apparent quantumyield(AQY) ,carboxylation efficiency(CE)and the light saturation point(LSP)reduced ; The light compensation.5.Point(LCP)and CO₂ compensation point(CCP)enhanced.When the relative soil water content were 55%-40%,themain reasons of the photosynthetic rate declined were stomatic limitation .When the relative soil water content were20% ,the main reasons of the photosynthetic rate declined were nonstomatic limitation.The optimum SRWC of Pn was 70%.