Anatomical and structural changes in response to application of silicon (Si) in vitro during the acclimatization of banana cv. ‘Grand Naine’

Abstract

This study aimed at evaluating possible effects of silicon application during in vitro culture of banana plants (cv. ‘Grand Naine’) on structural and anatomical characteristics of leaves of acclimatized plants. Shoots previously established in vitro were inoculated on Murashige and Skoog (MS) medium with addition of 30 g L-1 sucrose and 1 mg L-1 NAA (naphthalene acetic acid) and supplemented with three sources of silicon (sodium silicate, potassium silicate and calcium silicate) at a dosage of 1 g L-1 . Medium without any source of silicate was used as a control treatment. The cultures were maintained for 45 days at the rooting stage. After this phase, the plants were transferred to the greenhouse where they were held for 60 days. The experimental design was completely randomized with five replicates (a total of fifteen plants per treatment). The presence of silicate in the culture medium favored increased stomatal density on both sides of the leaves and increased the polar diameter/equatorial diameter ratio on the abaxial side. The thicknesses of mesophyll and chlorophyll content were also enhanced in the presence of silicon, mainly when the source used was the calcium silicate. The use of sodium silicate increased the contents of cellulose, hemicellulose and tannins. The application of silicon during the in vitro culture provides improvements on anatomical and physiological characteristics of leaves of banana plants on acclimatization phase.