Características morfofisiológicas de abacaxizeiro ‘gomo de mel’ enraizado in vitro sob luz natural e substrato vermiculita

Abstract

This study aimed to evaluate the effect of vermiculite, agar, artificial light and natural light in the in vitro rooting of pineapple shoots ‘Gomo de Mel’ propagules, as well as, to characterize these plants anatomically. The study was performed at the Plant Tissue Culture Laboratory of the Department of Agriculture - UFLA, Lavras-MG. It was used shoots with 2 cm of length cultivated in MS medium added with 30g.L-1 of sucrose. Two physical supports were tested: 6g.L-1 of agar and 15 g.L-1 of vermiculite for the shoot rooting in two environments: growth room 25±1 ºC, 45 W.m-2.s-1 during 16 hours and greenhouse with radiation of 115,08 W.m-2.s-1 and 33 ºC (natural light). After 60 days, it was evaluated the aerial part length, fresh and dry mass of aerial part and roots, the thicknesses of foliar limb tissues, besides the number, polar and equatorial diameter of the stomata. The experiment was installed in a completely randomized design. The results showed significance in the interaction between physical supports and environment for all analyzed variables. The use of the vermiculite substrate in artificial light presented better results in all variables, except for number of stomata. For the anatomical characteristics, bigger thicknesses of the foliar limb tissues was verified when it was used vermiculite and natural light, being that, for the agar use, it also increased the thicknesses only when the environment of natural light was used. Regarding the number of stomata/mm2 , did not have significant difference between treatments. A greater polar and equatorial diameter was observed in stomata of leaves cultivated in artificial light and vermiculite and natural light and vermiculite respectively.