Forms of sulfur in mature leaves of capsicum (Capsicum annuum L.) as affected by supplies of ammonium nitrate and potassium sulfate

Capsicum annuum plants were grown under controlled greenhouse conditions. I ncreasing doses of NK fertilizers were applied and sulphure (S) and its for ms were determined in leaves for all the treated plants. Our results showed that leaf S concentrations were related to the influence of NK applied. Th e highest concentrations of total S were obtained with the treatment in whi ch the rhizospheric concentration of N was low, while K was intermediate, t hus N has a more direct effect than K on leaf levels of total and organic S . In the case of sulphate (SO4-) concentration, the behaviour was often clo sely related to total S. The ratios or S index were used also as an possibl e indicator of the overall degree or level of S in plants.