%0 Journal Article
%T Germination and development of jatropha seedlings under water stress conditions Germina  o e desenvolvimento de plantulas de pinh o manso sob condi  es de estresse h¨ªdrico simulado
%A M¨¢rcio Dias Pereira
%A Jos¨¦ Carlos Lopes
%J Semina : Ci¨ºncias Agr¨¢rias
%D 2011
%I Universidade Estadual de Londrina
%X The first step sequence that involves the germination process is imbibition. The limitation of water to the seed at planting time can reduce germination and velocty as well as the development of the seedling. Hence, the objective of this study was to evaluate the germination and seedling development of jatropha under conditions of water stress by polyethylene glycol (PEG6000). The study was conducted at the Research Laboratory of the Department of Crop Seeds, Federal University of Vi osa. We used seeds of jatropha in temperature de 30 ¡ãC under osmotic potential levels of 0.0, -0.2, -0.4, -0.6, -0.8, -1.0 and -1.2. The performance of seed germination and seedling development were evaluated by germination (first and second count), index of germination velocity, time of germination, length and primary root and hypocotyl length. The experimental design was completely randomized design with six levels of osmotic potential to more witnesses and four replications. We conducted the analysis of variance and regression of the data and curves fitted by quadratic polynomial model for all variables. The reduction in osmotic potential of the substrate caused a significant reduction in germination of seeds of jatropha, as well as the speed of germination and seedling performance of this species. The fall of germination and seedling performance is enhanced and levels considered critical to -0.2 MPa and inhibits germination from -1.2 MPa. A primeira etapa da seq¨¹¨ºncia que envolve o processo germinativo ¨¦ a embebi  o. A limita  o de ¨¢gua para a semente no momento da semeadura pode diminuir a germina  o e sua velocidade, bem como o desenvolvimento da plantula. Diante disto, o objetivo deste trabalho foi avaliar o desempenho germinativo e o desenvolvimento de plantulas de pinh o manso sob condi  es de estresse h¨ªdrico simulado por polietilenoglicol (PEG6000). O trabalho foi desenvolvido no Laborat¨®rio de Pesquisa em Sementes do Departamento de Fitotecnia da Universidade Federal de Vi osa. Utilizaram-se sementes de pinh o manso em temperatura de 30oC sob os n¨ªveis de potencial osm¨®tico de 0,0; -0,2; -0,4; -0,6; -0,8; -1,0 e -1,2. O desempenho germinativo das sementes e o desenvolvimento das plantulas foram avaliados pelos testes de germina  o (primeira e segunda contagem), ¨ªndice de velocidade de germina  o, tempo m¨¦dio de germina  o, comprimento de raiz prim¨¢ria e comprimento do hipoc¨®tilo. O delineamento estat¨ªstico utilizado foi o inteiramente casualizado com seis n¨ªveis de potencial osm¨®tico mais a testemunha com quatro repeti  es. A redu  o do potencial osm¨®tico do sub
%K Jatropha curcas
%K Salinidade
%K Sementes
%K Vigor.
%U http://www.uel.br/revistas/uel/index.php/semagrarias/article/view/5224