Anatomical analyses of Tabebuia roseo-alba (Bignoniaceae) seedlings during acclimatization process

Abstract

The knowledge on morphological changes of plants grown in vitro is essential for establishing effective protocols for the survival of plants from controlled environments under natural conditions. This study aimed to examine the acclimatization of ipê-branco seedlings produced in vitro and also to compare the anatomical structure between leaves of seedlings grown in vitro and those acclimatized to different substrates. For acclimatization, ipê-branco seedlings were taken from in vitro cultivation and transferred to tubes containing Plantmax TM, vermiculite, sand and Plantmax TM + vermiculite + sand mixture. About 100% of fixation was verified, and seedlings acclimatized in Plantmax TM were those showing the best development. For the anatomical study, transversal and paradermal sections were performed in the leaf blades of seedlings derived from in vitro cultivation and seedlings already acclimatized to the different substrates. Anatomical differences were observed in the leaf blades of seedlings from the in vitro environment when compared to those acclimatized to different substrates. The stomatal density and polar and equatorial diameter of leaves derived from the in vitro environment were higher than those acclimatized to different substrates. The PD / ED ratio was lower for leaves derived from the in vitro environment, and comparing the different substrates, it was greater in seedlings acclimatized with vermiculite. The mesophyll and adaxial and abaxial epidermises were smaller in plants grown in vitro and among substrates, seedlings acclimatized to Plantmax TM were higher, with increased thickness of palisade and spongy parenchyma.