Study On The Nutrient Absorption Characteristics And Response To Potassium Nutrition Of Young Apple Tree With Different Rootstocks Types

Dwarfing cultivation is the direction and trend of apple industry in the world.Dwarfing self-rooted rootstock and interstocks are the main ways to realize apple dwarfing and high density cultivation.The absorption and translocation of nitrogen,phosphorus and potassium of young apple trees were influenced significantly by the different types of dwarfing rootstocks.Nutrient requirements of different types of dwarfing rootstocks were vary in different growth period.Potassium was closely related with photosynthesis,hormones synthesis,and other nutrients absorption in the trees growing process.The potassium absorption and translocation mechanism of apple trees with different rootstock types in different periods is not yet clear.Therefore,the absorption and translocation of mineral nutrition of young apple trees with T337 self-rooted rootstock and interstocks were explored.The difference of growth index,mineral nutrition,endogenous hormones,photosynthetic function of young apple trees with T337 self-rooted rootstock,T337 interstock and vigorous rootstock under different K nutrient solution were studied.This study provided a theoretical basis for rational fertilization,high yield and high efficient cultivation techniques of apple industry.The main results were as follows:1.There was differences in the nutrients absorption and growth potential of young Fuji apple trees with two kinds of dwarfing rootstocks.The growth potential of Young Fuji apple trees with T337self-rooted rootstock was significantly weaker than that with T337 interstocks.Nitrogen,phosphorus and potassium absorption rate of young Fuji apple tree with T337 self-rooted rootstock were the highest at120-150 days after planting.Nitrogen and phosphorus absorption rate of trees with T337 interstock were highest at 60-90 days after planting,and potassium absorption rate was the highest at 30-60 days after planting.In the annual growth period,nitrogen,phosphorus and potassium absorption ratio of young Fuji apple tree with T337 self-rooted rootstock was 5.02:1:12.26,and that with T337 interstock one was5.01:1:12.62.2.There was differences in the growth potential and biomass of young Fuji apple trees with three types of rootstocks under different concentrations of potassium.The growth potential and biomass under low and high potassium treatment conditions were lower than that of medium potassium.And the rank of growth potential and biomass under different potassium concentration treatment was vigorous rootstock>T337 interstock>T337 self-rooted rootstock.3.There was differences in the mineral elements absorption of young Fuji apple trees with three types of rootstocks under different concentrations of potassium.With different concentration of potassium,the total nitrogen,phosphorus and potassium accumulation were medium potassium treatment higher than low and high potassium treatment.And the leaf potassium content were high potassium>medium potassium>low potassium.The leaf calcium content of young Fuji apple tree with T337 self-rooted rootstock and interstock were affected by the concentration of potassium.The higher potassium,the lower leaf calcium content.However,for Fuji apple tree with vigorous rootstock,high concentrations of potassium prevented the calcium accumulation in leaf,medium potassium promoted the calcium accumulation in leaf.The leaf nitrogen content of young Fuji apple trees with T337 self-rooted rootstock was lower than T337 interstock and vigorous rootstock.And in the whole annual growth cycle,the content of magnesium had small differences.4.There was differences in the leaf endogenous hormones content of young Fuji apple trees with three types of rootstocks under different concentrations of potassium.Under the low and high potassium concentrations treatment,the leaf IAA,GA,ZR content were lower than medium potassium treatment.However,the content of ABA was higher than that in medium potassium treatment.And that was to say?IAA+GA+ZR?·ABA^-1 was lower than medium potassium treatment.The IAA content of young Fuji apple trees with T337 interstock were lower than T337 self-rooted rootstock and vigorous rootstock.And the leaf ABA content of T337 self-rooted rootstock was higher than T337 interstock and vigorous rootstock expect for the September.5.There was differences in the leaf net photosynthetic rate?Pn?of young Fuji apple trees with three types of rootstocks under different concentrations of potassium.The leaf Pn under medium potassium treatment were higher than that under low and high potassium treatment.And the leaf Pn of young Fuji apple trees with T337 self-rooted rootstock and interstock were lower than vigorous rootstock expect for August.