EFFECTS OF 2,4,5-T ON ANATOMICAL AND HISTOLOGICAL PROPERTIES OF FRUIT AND LEAF OF "POZEGACA" PRUNES

Previously investigations showed that 2,4,5-T in conc. 50 and 100 ppm applied 2–3 days after pollination significantly stimulated an increase of size of "Pozegaca" fruits. Relatively good, but significantly smaller effects were obtained by spraying trees in later phenophases when synthesis of natural growth substances has been completed. These data suggested that 2,4,5-T provoked natural synthesis of growth regulators, but also stimulated nutrition of the fruits.

We expected to get a partial answer to this question from the investigations of mineral composition and anatomical and histological properties of leaves and fruits. These investigations showed that 2,4,5-T induced a number of negative effects for the relatively short time during the vegetation period but it was useful for increasing fruit weight.

Determination of morphological and chemical aspects of these alternations could have a theoretical and practical significance because of the possibility for inducing the same morphological alterations using other non-toxic substances.

The alterations mentioned were: on the treated trees the leaf hairs were increased, stomata openings were greater and stomata were more numerous; epidermis was thicker, mesocarp cells significantly larger, and there was more surface wax on the fruits. The contents of N, P₂O₅ and K₂O in the leaves were changed. But there is no clear connexion and significance of these alterations on growing and maturation of fruit.