A METHOD OF ESTABLISHING OPTIMAL ENDOGENOUS N, FE AND MN LEVELS IN TOMATO AND CUCUMBER
Leaves of tomato and cucumber plants grown under greenhouse conditions were sampled at 15 day intervals throughout their biological cycle, whased whit distilled water and deionized soap, and analyzed to determine several chemical and biochemical parameters. Foliar analysis "per se" was unable to detect excess levels of N, and was likewas unable to assess precisely the Fe-Mn interaction in cucumber. Biochemical and chemical analyses effectively measured odiphenols and the enzymes peroxidase and catalase. Variations in ionic acidity were not indicative of the plant's nutritional status, but did suggest the presence of excessive or deficient levels of nutrients.
Valenzuela, J.L., del Río, A., López-Cantarero, I., Sánchez, A. and Romero, L. (1993). A METHOD OF ESTABLISHING OPTIMAL ENDOGENOUS N, FE AND MN LEVELS IN TOMATO AND CUCUMBER. Acta Hortic. 335, 443-448