Stem and leaf anatomical and physiological characteristics of ‘Colín V-33’ avocado seedlings

Abstract

The anatomical and physiological structure of the ‘Colín V-33’ avocado stem and leaf is described from samples from plants obtained from seed in order to identify genotypes and early selection parameters in a rootstock improvement program for avocado. Eighty-nine plants of 12 months of age were used, where a total of 25 anatomical variables of the stem, leaf, and physiological of leaf were evaluated. A cluster analysis was conducted that generated a hierarchical dendrogram that suggested six groups of plants. Furthermore, from the 25 variables, eight were selected as discriminant when performing a canonical discriminant analysis, the variables that most discriminated for the first canonical component were: stem diameter and density of xylem vessels, for the second: thickness of the stem epidermis, temperature of the stem leaf and stomata length, while for the third: thickness of the cambium, transpiration rate, and stomatal conductance. The genotypes showed a great variation between the groups, the characteristics of these indicated that the genotypes of Group 4 showed some that could be related to small or dwarf plants (smaller stem diameter, high density of xylem vessels, a higher rate of transpiration and stomatal conductance). In contrast to the genotypes of Group 3 which presented opposite characteristics in the previous variables, being able to associate with vigorous plants. The anatomical traits of the stem showed to be highly related to the behavior of the avocado plants. Associating genotypes with physiological and anatomical variables in leaf and stem can have great value for the selection of rootstocks at an early stage of development.

Keywords

• gas exchange
• Persea americana Mill.
• stem anatomy
• stomatal conductance
• transpiration
• xylem vessels