The knowledge of the germination responses of seeds from plants growing along river margins or in areas susceptible to flooding is an important factor in the adoption of restoration practices. Considering that maturation of fruits of Genipa Americana L. when river margins are flooded, we raised some questions: Is seed germination of this species affected by water submersion, and, do distinct seed populations present differences in germination? Seeds of G. Americana were submerged in water for different periods to assess the germination and growing responses, using populations from different locations. Water submersion decreased the germination percentage and the germination speed index, and increased seed mean germination time in both populations. Growth was found to be hampered for most variables in the different seed populations. The adaptation of G. Americana to flooding involves the seeds being tolerant to submersion, with this factor not being effective in distinguishing populations studied here.

No abstract

Soil flooding restricts the availability of the oxygen necessary to activate the embryonic physiological processes that characterize seed germination. However, some species have adaptations that allow them to grow naturally in areas prone to flooding, such as Ormosia arborea, a native species of the Atlantic forest and the Cerrado. The objective of this work was to evaluate how seed germination and emergence in this species were affected by submersion in water and scarification. In experiment 1, the seeds were scarified by 15 minutes in sulfuric acid and was subsequently sown in tubes submerged in water for 0, 15, 30 and 45 days. In experiments 2 and 3, seeds were submerged in running water for the same period and, after each time of submersion, were scarified by 0, 5, 10 and 15 minutes in sulfuric acid and sown either in tubes and in Germitest® paper. It was found that, after breaking the tegumental dormancy, 15 days of flooding is enough to derail the germination of O. arborea seeds that tolerate submersion in water when they are intact. This response indicates that the hard, impermeable seed coat is an important seed characteristic for this response.

Fires have taken a central role in the discussions on environmental conservation in Brazil and worldwide. In this study, we investigated the temporal evolution of soil cover and the restoration of vegetation in a burned area (BA) and another unburned area (UBA) in a Cerrado stricto sensu, using aerial images and the ImageJ® software. Soil cover changed little over time and there was no difference between the areas regarding restoration of vegetation. Otherwise, the ImageJ® software proved useful in evaluating the evolution of soil cover and, due to its simplicity and free access, it can be used in the processing of individual images for the calculation of exposed soil area.