Ecologia morfofuncional de plântulas e modos de dispersão de espécies arbóreas da caatinga.

Abstract

Morphofunctional ecology of seedlings and modes of dispersal of tree species in the caatinga. The native plant species of the Caatinga are still little studied and there are information gaps ranging from seed germination to seedling stage description. This stage is decisive phase for the survival and establishment of the plant and for the spatial distribution of the populations. The objective of this study was to determine the morphofunctional classification of ten native Caatinga tree species; to describe the morphology of the seedling stage to the Tirodendro of the species and to elaborate the dendrological key based on the characteristics of this last stage; characterize the dispersion modes; to relate the modes of dispersion with the morphological types and to classify the weight of the seeds and to relate them to the morphological types. The morphofunctional types determined were phanero-epigenefoliaceous (PER): Aspidosperma pyrifolium, Cynophalla flexuosa, Jatropha molíssima, Vitex gardneriana, Pseudobombax marginatum, Ziziphus joazeiro and Tocoyena sellowiana; phytoepigene- storing (PEF): Leutzelburgia auriculata, Tabebuia aurea; and crypto-hypogeumstoring (CHR): Combretum leprosum. There was morphological difference of the seedlings in relation to other works probably by polymorphism of the species, adopted terminologies or different stages. The anemocoria occurred in five species: Aspidosperma pyrifolium, Combretum leprosum, Luetzelburgia auriculata, Pseudobombax marginatum and Tabebuia aurea; the zoocoria in four: Cynophalla flexuosa, Tocoyena sellowiana, Vitex gadneriana and Ziziphus joazeiro; and autocoria in Jathopha molissima. In the correlation of the modes of dispersion to morphofunctional types occurred in PEF: 40% zoocoria, 30% anemocoria and 10% autocoria; in PER and CHR both showed 10% in anemocoria. Regarding seed weight, 50% of the species presented light seeds, S ≤ 0.1g with 40% PEF seedlings and 10% CHR. The others, 50%, were weighed, 0.1 <S <1.5g, between the morphofunctional types PEF (40%) and PER (10%).