Effect of the position of the needles in the crown of the tree on the foliar anatomy of Pinus caribaea Morelet var. caribaea Barrett and Golfari

Abstract

Variations in the structure of plant leaves are mainly due to environmental variability. In many cases the way to acclimatize to unfavorable conditions. It is documented that in Cuba the anatomical and morphological characteristics of P. caribaea needles differ between ecotopes with different edaphoclimatic conditions. In this study, the effect of the position in the tree crown on the anatomy of the needles is analyzed. For this purpose, needles were collected from the lower, middle and upper part of 30 trees. The variables analyzed were thickness of the chlorophyll parenchyma, thickness of the transfusion parenchyma, height of the conduction tissue and width of the conduction tissue, cuticle thickness, epidermis thickness, hypodermis thickness, number of layers of hypodermis cells, number of channels and number of stomat. The results of the analyzes show a greater differentiation of the morphology of the needles towards the upper part of the tree, which is expressed by the increase in the thickness of the protective tissues and related to the greater exposure to the sun and lower relative humidity than they are exposed. The variables that contribute the most to differentiate the needles according to their position in the tree are the number of stomata and the number of cells in the hypodermis.

Keywords

• acícula, variación anatómica, copa del árbol, canal de resina.