Studies on fruit pedicel concerning fruitlet abscission in kinnow mandarin

Abstract

Fruit drop is a major constraint for the production of kinnow mandarin. The present investigation comparedthe physical, biochemical and anatomical dynamics taking place in abscised and non-abscised fruit pedicelsof Kinnow mandarin at physiological and pathological fruit drop stages. The pedicel parameters (length, girthand weight) were higher in non-abscised than the abscised fruits. The activities of polygalacturonase (4.01μg D-glucose released g-1 FW min-1) and cellulase (4.34 μg D-glucose released g-1 FW min-1) enzymes weresignificantly low in non-abscised as compared to abscised fruit pedicels. The transverse sections of nonabscisedhealthy fruit pedicels revealed intact phloem and long xylem vessels in the vascular tissue. However,pedicels of abscised fruits showed degradation of cells and formation of the abscission zone. Fruit pedicelparameters had positive correlation with mineral nutrients, total soluble sugars and total soluble proteins,however, non-abscised fruit pedicels were negatively correlated with cell wall degrading enzymes. The fruitpedicel health has been found important and positively associated with the diminution in physiological andpathological fruit abscission in kinnow mandarin.