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  • Author or Editor: R. N. Gallaher x
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Abstract

Mouse ear is an abnormal condition in pecans [Carya illinoensis (Wang.) K. Koch] in which the leaflets of the compound leaf fail to elongate in a normal manner and develop into a “mouse ear” shape. Mouse-ear trees had more Ca, Mn, Fe, Cu, Zn and Mo and less Mg in leaf and stem tissues than normal trees. In both normal and mouse ear pecan, 92–96% of total Ca in leaves and stems was nonextractable in 2% acetic acid solution, being in the form of Ca-oxalate crystals. Crystals of cross-sectional area as large as 2000 μm2 and 6000 μm2 were found in leaves and stems, respectively. Although only 600 to 1200 ppm of Ca was available for physiological functions in leaf tissue other than for precipitation of oxalic acid. There was no significant evidence to show that mouse ear is a Ca-deficiency problem.

Open Access

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.

Open Access