Calcium Concentration and Distribution in Healthy and Decline Peach Tree Tissues1

Abstract

Most of the leaf Ca collected from healthy and declining peach trees (Prunus persica L. Batsch. cv. Loring) growing on both limed and unlimed field plots was found to be non-extractable in acetic acid irrespective of leaf age, health status, or lime treatment. The concentration of extractable leaf Ca was less than 100 parts per million. Concentration of total Ca was highest in leaves from declining trees but declining trees had fewer and smaller leaves resulting in less total Ca in decline as compared to healthy trees. Large numbers of Ca-oxalate crystals were observed throughout the leaf and stem tissues. Crystals were primarily concentrated in leaf midveins. Midvein sections of leaves from decline trees contained greater numbers of crystals per unit area than did those from healthy leaves from healthy trees.

Relative Aluminum Tolerance of Prunus Rootstocks

“…Typical A1 toxicity symptoms (Edwards et al, 1976) appeared within 21 days in plants at the 100 mg Al/liter treatment. The shoot Al concentration (Table 1) was higher than the 53 to 205 mg*kg-1 range reported for leaves, twigs, and roots of peach trees in the field by Weaver et al (1976), Gallager et al (1975), andJones (1974), and corresponds to the levels obtained by Ed wards et al (1976). The average relative shoot dry weight compared to the control was 46% at Al levels of 50 mgTiter-1 and 33% at the 100 mgTiter-1 level.…”

“…Many tropical soils are acidic and unsuitable for peach production, unless modified. In the southeastern United States, soil acidity is one of the factors contributing to short peach tree life and depressed yields and growth (Cummings, 1983;Gallager et al, 1975;Jones and Jones, 1974;Weaver et al, 1976). At soil pH 5.0 and below, where Al becomes more soluble (Manrique, 1986), Al toxicity is a factor contributing to poor crop performance.…”