干旱区生态环境知识资源中心

The seeds in the soil play an important role in promoting the plant regeneration and acts on the local biodiversity conservation, but despite their importance, they are subject to biotic and abiotic factors that may inhibit their germination, including allelopathic effects triggered by the plants that are present in the soil environment. In this study we tested the hypothesis that the germination of seeds of seedbeds from Semidecidual Seasonal Forest (SSF) is inhibited under the canopy of exotic trees. Fifty (50) single samples of soil were collected (0.25 x 0.25 x 0.05 m) in a fragment of SSF; the samples were homogenized and from that new samples were taken and submitted to four (4) treatments: 10 samples were deposited in the greenhouse (SMN-CV); other 10 were returned to the forest fragment understory (SMN-MN); 10 were deposited on the soil under homogeneous canopy of Pinus elliottii (SMN-P) and the last 10 samples were allocated under homogeneous plantation of Eucalyptus sp (SMN-E). We also collected samples of soil under the canopies of P. elliottii (SP-CV) and Eucalyptus sp.(SE-CV) that were transferred to a greenhouse. The number of seedlings was counted at intervals of 15 days in each seedbed sample and the plants obtained were identified when possible. We obtained 515 plants from 15 botanical families, 21 genera and 13 morphospecies. The analysis of variance and comparison of means by Tukey-Kramer 0.01% showed no statistical differences between the treatements. Outcomes indicate that the low density and diversity of plants in P. elliottii and Eucalyptus sp understory are not directly corelated to suppressive effects promoted by the presence of these species, supporting recent data from literature that stands out the forest plantations of exotic species as possible areas for biodiversity conservation, in opposition to the designation of "green deserts" that are assigned to them.