Diferenciação dos grãos de pólen da família poaceae entre espécies campestres e florestais e seu metabolismo: Floresta Nacional de Chapecó, SC, Brasil

Abstract

Palynology studies the pollen grains produced by higher plants and spores of cryptogams, for the analysis of the environment through paleopalinology. Pollen grains from the Poaceae family found in sediments are considered indicators of e Campos, but there are species of this family that are from Forests. The pollen grains of the Poaceae family have uniform morphological characteristics, being spheroidal and monoporous. The objective of this work was to differentiate palynomorphs of the Poaceae family in grassland and forest vegetation types. As well as, its metabolism from the size of pollen grains. The method consists of measuring the diameter (D) of pollen grains of the Poaceae family in its major axis under optical microscopy. Based on the measurements, the pollen grains were categorized into Poaceae – herbaceous grasslands , Poaceae – arboreal forests (Bambuseae) and herbaceous grassland and arboreal forest (indeterminate). As for the type of metabolism, they were also categorized, being type C3 and type C3/C4 (indeterminate). It was possible to separate the palynomorphs of the Poaceae family by the size of the pollen grains in a previously studied palynological profile, which presents three environmental phases. In the first phase (22,690 ± 80 years BP to 16,669 years BP) the highest pollen percentage was of Campo herbaceous (52% - sample 13) and Indeterminate (87% - sample 3). As well as, low pollen percentage of forest pollen types (3%) and exclusive C3. The second phase (16669 yr BP to 10952 yr BP) featured up to 50% of Poaceae – Grassland herbaceous, an increase to up to 27% of Poaceae – arboreal forests and a decrease in pollen grains of Poaceae classified as Indeterminate – herbaceous grassland and arboreal forest. Already the metabolism, on average close to 20% are classified as C3. In the third phase, the percentage of Poaceae – herbaceous grasslands ranged from 16.7% to 40%, Poaceae – arboreal forests increased to 73%, with an average of 55% and Indeterminate – grassland and arboreal forest ranged from 0% to 37%. %. As for the metabolism, on average 60% are classified as C3. Finally, it is a viable and applicable method for not overestimating the Fields in palynological diagrams, contributing to a more assertive paleoenvironmental description.