Translocation and accumulation of phosphorus applied to healthy and brown bast affected rubber (hevea brasiliensis) trees

A study to assess the movement and incorporation of phosphorus from applied source in rubber (hevea brasiliensis muellarg.) trees was conducted. radioactive phosphorus (32p) was applied to mature rubber either through root feeding or by soil injection. the radioactive phosphorus could be traced in the leaves,bark and latex indicating that the applied phosphorus was absorbed immediately by the tree. 32p activity in the different plant parts of three categories of trees viz.,normal,partially dry and completely dry were compared. no significant difference between the three groups was recorded in the 32p activity in the leaves on the 75th day of application. however,accumulation to a phenomenal extent was noted in the partially dry and completely dry trees with advancement of time,indicating non translocation to the site of latex biosynthesis and that the phosphorus movement to the sink is demand driven. in the bark on the 30th and 45 th day of sampling,no radioactive phosphorus could be traced in the normal and partially dry trees while in the completely dry trees,32p activity was recorded indicating lack of metabolic utilisation for the synthesis of latex. in the latex,32p activity was recorded on the 20th day in all the three categories of trees. however,on the 30th and 45th day,no 32p activity was recorded in the completely dry trees indicating non utilisation of phosphorus from applied source for latex biosynthesis and regeneration. the study indicated that in the tpd affected trees,the xylem and phloem transport mechanism is active up to the laticiferous system but the latex biosynthesis and regeneration is affected or impaired.