Effect Of Phosphorous Levels On Photosynthetic Characteristics And Accumulation Of Carbohydrate Of Phaseolus Coccineus L. Seedlings

Effect of phosphorus levels(10,100,1000μmol·L^-1) and treatment time(10d,15d,20d and 25d) on on physiological characteristics(height,root length,fresh weight,dry weight,root top ratio and total leaf area) and some morphological indicators(Chl content,photosynthetic indicators,sugar content,acid phosphatase activity,root activity,soluble protein content and nutritional status of nitrogen, phosphorus and potassium) of phaseolus coccineus L. seedlings were studied by hydroponic culture method. The main results are as follows:1.Height and root lengthen of phaseolus coccineus L. seedlings are remarkablely impacted in low phosphorus stress, height is decreased,root lengthen increased with the decreasing of phosphorus level; biomass is remarkablely impacted in low phosphorus stress, shoot fresh (dry)weight is decreased,sroot fresh (dry)weight is increased with the decreasing of phosphorus level, so root top ratio is increased with the decreasing of phosphorus level ; leaf area is decreased with the decreasing of phosphorus level.2.Chla and Chlb content of phaseolus coccineus L. seedlings are both decreased with the decreasing of phosphorus level, Chla content is impacted less than Chlb content, so Chla/ Chlb is raised; photosynthesis of phaseolus coccineus L. seedlings is remarkablely impacted in low phosphorus stress, photosynthetic rate,Stomatal conductance and Transpiration rate are decreased while Intercellular CO2 is increased with the decreasing of phosphorus level.3.Reducing sugar and soluble sugar content are both decreased in low phosphorus stress;external and internal acid phosphatase activity are increased with the decreasing of phosphorus level; soluble protein content of phaseolus coccineus L. seedlings is increased ,root activity is increased with the decreasing of phosphorus level.4.Nitrogen,phosphorus and potassium content in leaf,stem and root of phaseolus coccineus L. seedlings are decreased with the decreasing of phosphorus level,accumulative nitrogen,phosphorus and potassium amounts are shown the same trend as nitrogen,phosphorus and potassium content, but nitrogen,phosphorus and potassium utilization are increased with the decreasing of phosphorus level. Nitrogen,phosphorus and potassium content are reached maximum value on the tenth day between growthing period; potassium content in leaf and stem is reached maximum value on the 20th day between growthing period, potassium content in root is reached maximum value on the 25th day between growthing period.