| Phosphorous fertilizer is an important factor for the yield and quality production in apple trees.Biomass,phosphor concentration and accumulation in the cortex and xylem in different parts of apple tree were studied in field-grown "Fuji" apple trees(M micromalus Makino) in 2004 and 2005 growing seasons in Shaanxi Province,China.The objective of this study was to find the dynamic variety of phosphor uptake,transportation and distribution in different parts of the apple tree.The results showed that biomass of plant and the parts above ground vegetated quickly from March 26 to September 21,and developed slowly after fruit harvested in September 21.Phosphor accumulation in the parts above ground,root system and plant rapidly increased after July 30.Phosphor content and accumulation in cortex of branch,trunk and roots reached lowest in July 30,they were highest in the dormant period,and phosphor content order in cortex was Branch > Trunk > Roots.But phosphor content and accumulation in xylem were lowest in April 30,phosphor content order in xylem was Root >Branch > Trunk.Total 28.72 kg/hm2 phosphor was absorbed in a year and 7.94 kg/hm2 phosphor was move away by fruits and leaves.From July 30 to September 21,18.32 kg/hm2 phosphor was absorbed;it occupied 63.8% of total uptake.10.40 kg/hm2 phosphor was still absorbed from harvested to January 15,accounted for 36.2% of total uptake.Total phosphor in orchard was 47.86 kg/hm2 in one year,17.33 kg/hm2 of phosphor was as base fertilizer in autumn,and the rest of 30.53 kg/hm2 was used to topdressing before the fruit expanding time. |