SILICON IN THE ANATOMY AND PHYSIOLOGY OF BANANA PLANT LEAVES UNDER TEMPORARY IMMERSION BIOREACTORS

Abstract

Banana is a crop with outstanding economic and social expression throughout the world, therefore, it is important to use appropriate methods of propagation. The micropropagation is an appropriate method because it is disease-free, unlike traditional methods that spread pests and diseases. The objective of this study was to evaluate the effect of silicon on foliar anatomy and chlorophyll content of banana plants culturedin vitro using temporary immersion bioreactor technology. Explants of ‘Dwarf Cavendish’ banana established in vitro were inoculated in bioreactors containing MS liquid medium. Treatments included silicon concentration (0 and 1 mLL^-1) and frequency of immersions (every 4, 6, and 8 hours) lasting 1 minute per immersion. Cultures were maintained in a growth room at 27 ± 2 °C under LED light (50 μmol m^-² s^-¹) with a 16 h of photoperiod for 36 days. After that period, anatomical characteristics and chlorophyll content were evaluated. Higher values were observed for some characteristics validated in plants cultivated with silicon when compared to control. Silicon addition resulted in increased thickness of the leaf’s limb tissues, resulting in a larger mesophyll (563.122µm) which is the set of measurements of all leaf’s limb tissues, it also provided greater adaxial and abaxial stomatal density (0.108817µm and 0.305085µm) respectively, greater adaxial and abaxial polar diameter/equatorial diameter ratio (1.982 and 2.069) respectively, and increased chlorophyll a content (0.000134 mg·g^-1 fresh weight) and a/b ratio (1.710425) of plants of banana ‘Dwarf Cavendish’ cultured in bioreactors.