INTERNAL BREAKDOWN IN MANGO FRUIT - SYMPTOMOLOGY AND HISTOLOGY OF JELLY SEED, SOFT NOSE AND STEM-END CAVITY

Fruit of many mango (Mangifera, indica L.) cultivars are susceptible t o an internal disorder often referred to as either jelly seed, soft no se, or stem-end cavity (SEC), depending on the symptoms that appear wh en fruit are cut open. It has not been determined if jelly seed, soft nose, and SEC are different disorders or different symptoms of the sam e disorder. Sections of fruit mesocarp from the cultivars Irwin, Tommy Atkins, and Van Dyke were examined by light microscopy to characteriz e the disorder and discern histological differences or similarities am ong fruit with each of the three types of symptoms. Jelly seed and SEC affected fruit during early fruit ontogeny, whereas soft nose symptom s were detected only in fully developed fruit. No major microscopic di fferences were detected among fruit with jelly seed, soft nose or SEC. In fruit with each type of symptom, disorganization of the cells and rupture of the cell walls were the first microscopic indicators of the disorder, followed by deterioration or dissolution of vascular connec tions between the stone and the mesocarp. Stem-end cavity resulted in necrosis of the mesocarp around the cavity. No cavity or tissue necros is developed around the stone in fruit affected with jelly seed or sof t nose. The presence of Ca oxalate crystals was observed only in fruit with SEC. Based on temporal and spatial differences in symptom develo pment within the fruit, it appears that soft nose, jelly seed and SEC may be classified as separate disorders. (C) 1998 Elsevier Science B.V . All rights reserved.