Erythrina velutina Willd. : modelagem de distribuição potencial em Sergipe e análises de sementes como ferramentas para conservação ex situ

• Autor(a) principal: Souza, Juliana Lopes
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/handle/riufs/3007
• topic: Agronomia; Erythrina velutina; Germinação; Diversidade biológica -- Sergipe; Germinação; Plantas da caatinga; Mulungu; Ocorrência; Estresse hídrico; Biodiversidade; Occurence; Germination; Water stress; Biodiversity; CIENCIAS AGRARIAS

The fragmentation of forests promotes the isolation of populations, the loss of genetic diversity of native species and the deterioration of its capacity to adapt to climate change. Even plants with high ecological plasticity are found in a situation of rarity in the Brazilian biomes, before the full knowledge of its properties and potentials, demanding urgent measures for its conservation. Nevertheless, for the establishment of this conservation, the knowledge about germination and tolerance to water restriction is fundamental. Erythrina velutina Willd. is a native species recommended for degraded areas recovery, found in the state of Sergipe in the biomes Atlantic Forest and Caatinga, in rareness in the area of Baixo São Francisco. In this context, it is proposed the identification of the geographic distribution of Erythrina velutina Willd. in Sergipe state through potential geographic distribution modelling technique and identify areas outside of Conservation Units of potential occurrence to with places for seed collecting. For the occurrence modelling, 395 registers of occurrence for the species and 38 variables were used and evaluated on the Maxent program. Using the model generated by the program, maps were created on the program ArcGis with the species occurrence prediction and contrasting against local land use were generated. Through the potential distribution model, 23 cities had the higher occurrence probabilities for E. velutina, and it was noticed that most part of the areas were occupied by pasture and the remaining forests were vastly fragmented, demanding measures to sample this diversity and to collect material for ex situ conservation. For the seeds analysis two seed lots from different origins were used, Sergipe state and Pernambuco state, stored since 2012 and 2008. The seeds were first evaluated through X Ray image analysis, after that the initial seed quality with the determination of morfometry, 1000 seeds weigh, germination on paper and on sand and electric conductivity. After this, the seeds were submitted to water restriction with polietilenoglycol (PEG 6000) at -0.8 MPa though 12, 24, 48 and 72 hours. Another part of the seeds lots were submitted to osmopriming though submersion in water and PEG at -0.8 MPa with constant airing during seven days. The germination percentage (%G), germination speed index (IVG), average germination time (TMG) and average germination speed (VMG) were estimated. There were no observed differences between the seed thought the X-Ray image analysis, both lots had full seeds, and then the initial quality analyses were held. The seeds from Pernambuco state were bigger and heavier, but had lower germination and vigor. For the water restriction, the seeds form Sergipe state had an increment on germination with the increased time under restriction and the seeds from Pernambuco had the hair germination value with 24 hours. With the restriction at 72 hours is possible to differentiate between the vigor of the two lots. The osmopriming results in a 11% increment in germination in low vigor seeds, such as the ones from Pernambuco with 11% increase.