Abstract

ABSTRACT: Calcium (Ca) is often supplied to crop species for avoiding the occurrence of Ca-related disorders. The mechanisms of Ca absorption and transport are not fully understood and the effectiveness of root and/or foliar Ca fertilization may be variable. For characterising the rate of Ca absorption and transport, trials were developed with chili pepper and sweet cherry plants, using 45CaCl2 as tracer. The Ca treatments supplied were: (1) No 45Ca (control); (2) 45Ca soil application; (3) 45Ca supply to basal leaves, and (4) 45Ca application to apical leaves. After three months, plants were harvested for biomass and Ca content determination. The recovery of 45Ca in different plant parts was measured with a liquid scintillation counter and leaf traits were observed by scanning electronic microscopy. In general, the highest 45Ca concentrations were recovered in treated organs and root applications led to highest 45Ca translocation rates which however varied between chili pepper and cherry plants. For chili pepper, 45Ca applied to the soil was principally detected in roots (44 %) followed by leaves (36.6%) stems (17.4 %) and fruits (2 %). In sweet cherry trees, soil-applied 45Ca was principally recovered in roots (45.3 %), shoots (28.5%), leaves (14.3 %) and trunks (11.9%). The results provide evidence for the increased absorption of root-applied Ca, and the different degree of Ca mobility between species. Foliar application led to major Ca increases in treated leaves, with Ca being transported to other plant organs after apical leaf Ca supply chiefly in cherry trees.