Screening Strengthening Seedling Mediums And Study On Effects Of Phosphorus Nutrition On Microtubers

Effect of plant growth regulators on tuber seedlings growth and action of phosphorus nutrition on microtuberization as well as mechanism were studied in the experiments.IBA, 6-BA,B9 with 3 levels respectively form completely random assortment test.Choose the best from 27 treatments by comparing seedling height and growth situation.MS without phosphorus as basic medium,and supplement K₂SO₄.adding to different KH₂PO₄ concentrations(0,0.312,0.625,0.937,1.25mmol/L,1.25 mmol/L as comparison) and compared to the impact of phosphorus nutrition on diameter and the number of microtubers in potato varieties(strains) 97-1-1,â…§-8,Chuan Yu 5 and Chuan Yu Zao. Water and phosphorus contents of microtuber as well as adult plants(root,stem,leaf) and phosphorus content in Culture medium were test to analysis phosphorus active mechanism.(1) Seedlings show the most vigorous in MS+0.25mg/L IBA+6mg/L B9+2%sucrose treatment.Extravagant concentration of IBA inhibits seedling growth but seedlings slight when IBA absence.The action of 6-BA on invigorating seedlings is small.Suitable concentration of growth retardant B9 could reduce internodes length,increase diameter of stem and make plaints stronger.(2) Two experiments display that the number of microtuber is the highest in 0.625 mmol/L treatment,then 0 mmol/L treatment,which is not mentioned by the predecessor studies.Microtuber production of 97-1-1,â…§-8 and Chuan Yu 5 in 0.625 mmol/L treatment are 2.1,1.5 and 1.1 per plant,respectively in the first experiment and Chuan Yu 5,Chuan Yu Zhao are 2.3,1.4 per plant in the second repeated experiment.The average diameter of tuber in those varieties(strains) are middle level under 0.625 mmol/L treatment while in CK are biggest.In the first experiment 97-1-1,â…§-8,Chuan YU 5 are5.43mm,5.03mm, 6.0mm,respectively and in the second experiment Chuan Yu Zhao,Chuan Yu 5 are 3.4mm, 5.0mm.(3) Water contents of tuber change with phosphorus treatment,the water contents of 97-1-1,â…§-8,Chuan Yu Zhao and Chuan Yu 5 in 0.625mmol/L treatment are 87.1%(highest),86.8%(the sec-highest),86.7%(highest),83.1%(the sec-highest)both reaching relative high level.Phosphorus contents of tuber with the phosphorus content treatments increased is proportional to phosphorus treatments.(4) Both plants and culture medium phosphorus contents of Chuan Yu Zao and Chuan Yu 5 are the lowest in 0 mmol/L treatment but in 1.25mmol/L are the highest.Phosphorus contents of plants increase with phosphorus contents in treatments.It indicates the positive correlation between initial adding to phosphorus and absorbing phosphorus by plants.