Dormancy in seeds of brazilian cerrado and dense Ombrophilous forest

Abstract

The Cerrado and the Dense Ombrophilous Forest are important brazilian biomes that together cover more than half of the country's territory. They have a vast and rich plant diversity which often has a block in the germination process called dormancy. Dormancy can be defined as an obstruction in the germination of viable and intact seeds, even when all the favorable conditions are present. This work aimed to verify, through a literature survey, the occurrence of dormancy in seeds of plant species of the Brazilian Cerrado and Dense Ombrophilous Forest, comparing its occurrence between ecological groups of species, biomes and types of dormancy. The results showed that in Cerrado dormancy was observed in 56% of the species, whereas in Dense Ombrophilous Forest this number reduces to 42%. These data revealed an association between the presence of dormancy and the Cerrado. Also, in this biome, it was possible to verify a higher occurrence of physical dormancy in the seeds, with up to 63% of its dormant species presenting this type of dormancy. Pioneer species of Cerrado exhibited a greater dormancy percentage when comparing to climax, while this fact was not noticed in the forest, which resulted in an association between the ecological group of pioneer species from Cerrado and the dormancy process. These results show that dormancy may be related to more arid biomes and physical dormancy appears to be the most common type in these environments. Moreover, dormancy seems to be correlated with pioneer species of Cerrado, but not Forest