Ontogenetic Changes in Calcium Concentration and Content in Pickling Cucumber Fruit as Influenced by Genotype and Environment

Abstract

A field experiment was conducted to quantify the ontogenetic changes in Ca concentration and content of pickling cucumber fruits as influenced by environmental conditions and genotype. Pericarp tissue Ca concentrations (1.1% to 0.7% of dry weight) were higher but declined less rapidly during fruit development than endocarp concentrations (0.8% to 0.2% of dry weight). About 90% of net fruit Ca content accumulated within the pericarp of ≈150 g fresh weight fruit, the rest in the endocarp. The rate of Ca accumulation was highly variable during fruit ontogeny but was closely correlated with growth rate (grams fresh weight/day). Environmental conditions had the largest effect on Ca accumulation rate. Fruit tissue Ca concentrations were affected both by genotype and the cultural environment, especially at the later stages of fruit development. Calcium concentrations (1.5 to ≈3.0% of dry weight) in fully expanded leaf tissue were higher than in rapidly growing fruit tissues on the same plants.