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Abstract
The change of several biological and physiological indicators was studied in mature leaves of muskmelon plants (Cucumis melo L. cv. Galia) during the biological cycle. Plants were grown under greenhouse conditions, using differential fertilization with N, P, and K, and irrigation with brackish water. We measured total and soluble Fe and Mn, total and soluble Fe index, endogenous and Fe‐ and Mn‐inflitrated catalase and peroxidase and aconitase activities in leaves in an attempt to trace possible Fe deficiencies. The Fe‐Index is defined as follows: Fe Index = [(10P + K) 50]/Fe, where: P and K as % d.w. and Fe as μg/g d.w.
The physiological indicators (Fe Index) was markedly raised at the beginning of the biological cycle, indicating that foliar samples contained high concentrations of P and K, which may have induced Fe deficiency. The Fe Index decreased steadily during the biological cycle, indicating that fertilizer was applied correctly.
Comparisons of endogenous and Fe‐ and Mn‐infiltrated enzymatic activities revealed Fe deficiency during senescence. Catalase and peroxidase activity increased at the end of the biological cycle.