Análise estrutural comparativa dos órgãos vegetativos em Zingiberaceae e implicações evolutivas do xilema

Abstract

Zingiberaceae is the largest family in the order Zingiberales, consisting of over 1,000 species divided into four subfamilies and six tribes, and widely distributed worldwide. Studies on the distribution, the level of specialization, and the functionality of vessel elements in several monocotyledon families have increased over the last decades. On the other hand, a few studies have focused both evolutionary and ecological aspects in Zingiberaceae tribes. This study aims to characterize and compare the anatomy of subterranean and aerial organs of eight Zingiberaceae species, as well as determine the specialization in vessel elements of twenty eight species of tribes Alpineae, Zingibereae, and Globbeae. Plant sampling was done both in protected areas in the Brazilian Atlantic Rain Forest, and in private cultivation areas. Samples of aerial and subterranean organs were processed for both optical and scanning electron microscopy. Results indicate anatomical aspects are similar among the eight species, which belong to genera Alpinia, Renealmia, Curcuma Hedychium and Zingiber. Some characters of vessel elements, like the type of perforation plate, the amount of bars, and the type of wall thickening were found to be important to establish a phylogenetic relationship between subfamilies and tribes. Vessel elements were found to be confined to the roots, presenting several basal characters in Zigibereae and Globbeae tribes and derivate characters in Alpinieae tribe