phosphorus and zinc distribution in different parts and various growth stages of wheat under field conditions

abstract in order to determine the time of maximum demand of winter wheat (triticum aestivum l.) to phosphorous fertilizers and p and zinc (zn) distribution in different parts of wheat at various growth stages and study their relation to the contents of these elements in soil p and zn under field conditions, samples were collected from different parts of the plants at seven growth stages (i.e., the end of tillering to the complete seed ripening) and analyzed for p and zn. soil under the plants were also sampled, simultaneously, and analyzed for the same nutrients. the experimental plots consisted of three 5-ha fields located at bajgah experiment station, college of agriculture, shiraz university, shiraz, iran (52 32 e, 29 36 n, 1810 m above mean sea level). samples were taken during 2007-2008. shoot p and zn concentrations decreased as the growth proceeded from the end of tillering to the complete seed ripening stage. phosphorus and zn concentrations of flag leaf and stem increased from milk development toward complete seed ripening (stages 7 to 9), whereas those of spickle increased. certain relation between soil and plant p or zn was not found in the present study. the similarity of the p and zn changes in flag leaf and stem suggests that flag leaf concentration of p and zn (i.e., an almost non destructive analysis) can be used for evaluation of nutritional status of winter wheat plants under the field conditions.