Control of hyperhydricity in embryogenic callus induced in Robusta coffee leaf explants (Coffea canephora P.)

Abstract

During the induction of embryogenic callus in Coffea canephora Pierre, problems with the production of hyperhydrated callus with little potential for embryo formation are common. This work aimed to study the morphogenic response and water relations of explants from three sections of tender and young leaves of Robusta coffee (INIFAP 95-9), subjected to different concentrations of sucrose and gelling agent, as osmotic agents. For this, two types of leaves (tender and young leaves) and the section of the leaf blade (basal, middle, and apical) were evaluated, each type subjected to three concentrations of sucrose: 30, 50 and 80 g L-1 and three concentrations of phytagel: 5.2, 8 and 16 g L-1. For the three sections of the leaf, the concentration of 8 g L-1 of phytagel produced callus of quality consistency (compact sandy or easily dispersed); in young leaves, the treatments with 5.2 and 8 g L-1 of phytagel were the best to produce this type of embryogenic callus. The calluses of the different sections had the capacity for osmoregulation by maintaining the turgor potential (Ψp) with positive values due to the active accumulation of solutes. Based on the results obtained, it was possible to identify the type and leaf section, in turn the agent osmotic and the most efficient concentration to reduce hyperhydration and generate callus with embryogenic potential.