Effects Of Phosphorus Stress On Physiology Characteristics Of Phyllostachys Praecox

As one of essential macronutrients for plant growth and development，phosphorus（P）is involved inalmost all of plant life activities. Phyllostachys praecox is the favorable bamboo specie which has beenchosen for decades.From1990, the intensive management models （massive fertilization and wintermulching） in Phyllostachys praecox stands have started and extensional widely, which inducingbamboo shoots earlier,yield higher,a better price and income for farmers. While with the prolongingplanting years of Phyllostachys praecox stands,the soil total phosphorus and available phosphoruscontent increased steadily.To understand the effect of different phosphorus concentration on nutritional and physiologicalcharacteristics of Phyllostachys praecox, the effects of phosphorus （P） addition, i.e.,0,0.5,2.5,5.0,25,50,250,500mg·L^-1, asexual reproduction of one-year old Phyllostachys praecox were investigatedthrough a sand-pot experiment. The main findings are as follows:1. The effect of different phosphorus concentration on root morphology of Phyllostachys praecoxhas significant influence. Correlation analysis indicated that, root length, root surface area, rootvolume per plant of Phyllostachys praecox and phosphorus concentrations showed a significantnegative correlation（r（root length）=-0.655**，r（root surface area）=-0.751**，r（root volume）=-0.750**）.2. The same for phosphorus level, Phyllostachys praecox leaf acid phosphatase （Apase）activity thanroot apical. In the range of0to5.0mg·L^-1of P concentration, acid phosphotase activities in theleaf and root decreased gradually. They were maximum as14.44μmol·g^-1·min^-1and11.46μmol·g^-1·min^-1respectively,when incubated under0mg·L^-1of P concentration. If phosphorusconcentration was higher than25mg·L^-1, the both leaf and root apical of acid phosphataseactivity were rebound, which causes the need for further research.3. With phosphorus concentration increasing, the indicators of chlorophyll fluorescence parametersshowed significant chang in different trends. The values of basal rate of chlorophyll fluorescence（Fo）, maximum chlorophyll fluorescence （Fm）, timely minimum fluorescence （Ft） and variablefluorescence （Fv） were the highest in5mg·L^-1of P concentration. In addition, ETR and actualphotochemical rate of PSⅡ （Yield） were higher, but non-photochemistry dissipation （qNandNPQ） coefficients were relatively lower in this P concentration. Therefore, P concentration of5mg·L^-1is appropriate for the normal photosynthesis of Phyllostachys praecox in the sand-potincubation.4. The concentrations of other nutrient elements in Phyllostachys praecox perform differently as theincreasing of phosphorus levels.Positively significant relationships are found between P and N,Mn and Zn in the leaves, while P is negatively significant related to Ca. P is negativelysignificant correlated to Ca,Mg,Cu and Zn, however, which is positively significant related tomany elements as N,Fe,Mn and B in stems. The correlations with other elements which Pand K, Zn have are negatively significant relationships,while P is positively significant related toCa,Fe,Mn,Cu and B.