MODIFICATIONS IN LEAF ANATOMY OF BANANA PLANTS CULTIVAR 'MAÇÃ' SUBJECTED TO DIFFERENT SILICON SOURCES IN VITRO

In vitro plant culture under conventional heterotrophic conditions promotes the development of certain undesirable morpho-physiological characteristics, such as reduced epicuticular wax deposition and mesophyll differentiation, rudimentary vascular bundles and little control of stomata opening and closing. Silicon is a beneficial element for plants and affects anatomical characteristics of leaf surface. This study analyzed morphological differences in banana plant cultivar ‘Maç㒠plants as a result of the use of silicon added to the medium for in vitro cultivation. Shoots of banana plants cultivar ‘Maç㒠established in vitro were inoculated on MS, supplemented with 30 g L^-1 sucrose, 1 mg L^-1 NAA (naphthaleneacetic acid) and solidified with 1.8 g L^-1 Phytagel^TM. Three sources of silicate were added to the MS medium, sodium silicate, potassium silicate or calcium silicate at 1 g L^-1, and MS medium without silicate, as the control treatment. The experimental design was completely randomized with five replications. After 45 days, anatomical characteristics and photosynthetic and transpiration rates were evaluated. The addition of calcium silicate resulted in greater thickness of upper and lower epidermis, mesophyll, palisade parenchyma and increased photosynthetic rate. The use of silicon improved micropropagated anatomy of banana plant cultivar ‘Maç㒠leaves.