Limit between stages I and II of a seed imbibition curve

• Autor(a) principal: Pinho,Sheila Zambello de
• Data de Publicação: 2004
• Outros Autores: Carvalho,Lídia Raquel de, Delachiave,Maria Elena Aparecida
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Scientia Agrícola (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000100003
• topic: water absorption; non-linear regression; germination

A knowledge of the imbibition stages shown by different species, is essential in research projects aiming at improvement of seed quality by treatments such as osmotic conditioning, initial wetting, and the use of bioregulators. The objective of this study was to establish a methodology to determine the limit between the first and second stages of the process, considering the model W = f(t) - (a - w0)exp(-kt), using statistical tests. This limit was determined using an asymptotic distribution of an estimator function. The data point beyond which the difference (W*) is no longer significant was determined using Student's T statistics. The model is <img border=0 id="_x0000_i1026" src="../../../img/revistas/sa/v61n1/a03img01.gif" align=absmiddle > or = (0.434 + 0.00162 t) - (0.434 - w o)exp(-0.121 t), with r² = 0.98 and W* = (0.434 - w o)exp(-0.121 t) fits the utilized data. The calculated t value (27.2 hours) is smaller than the value that was determined considering a 1% value difference between the asymptote and the estimated model as a criterion for the stage change. This two-hour difference corresponds to 0.28% in absorbed water.