Changes in osmoregulatory metabolism of cotton genotypes during water deficit and recovery period/ Mudancas no metabolismo osmorregulador de genotipos de algodoeiro durante deficit hidrico e periodo de recuperacao

The aim of this study was to evaluate the changes in osmoregulatory metabolism of cotton genotypes subjected to water deficit and recovery period. In a greenhouse, six cotton genotypes and two water managements were combined in a 6 x 2 factorial scheme, in a completely randomized design, evaluated after 14 and 22 days under water stress and recovery conditions, respectively. The water status, growth indicators and compatible solutes in the leaves were evaluated. The genotypes BRS Serido, BRS Aroeira and BRS 7MH withstand better the stress condition because they had lower variations in their water potentials due to the osmotic adjustment and maintained their growth under water deficit conditions. The BRS 286 is the most sensitive genotype to the water deficit condition, since it showed greater variations in its water potential, which ultimately stopped its growth. Water replacement during the recovery period allowed growth resumption in most of the genotypes, mainly CNPA 5M and BRS 286. After the recovery period, variations in the concentrations of osmoregulators indicate the plasticity of cotton in regulating the concentrations of osmoregulators under favorable and unfavorable water conditions. Key words: Gossypium hirsutum L., osmotic adjustment, compatible osmolytes, drought O objetivo do presente estudo foi avaliar as mudancas no metabolismo osmorregulador de genotipos de algodoeiro submetidos ao deficit hidrico e ao periodo de recuperacao. Em casa de vegetacao, seis genotipos de algodoeiro e dois manejos hidricos foram combinados em esquema fatorial 6 x 2, em delineamento inteiramente casualizado, avaliados apos 14 e 22 dias em condicoes de estresse hidrico e recuperacao, respectivamente. Foram avaliados o status hidrico, indicadores de crescimento e solutos compativeis em folhas. Os genotipos BRS Serido, BRS Aroeira e BRS 7MH suportam melhor a condicao de estresse por apresentarem menores variates nos seus potenciais hidricos devido ao ajustamento osmotico e por manterem seu crescimento em condicoes de deficit hidrico. O BRS 286 e o genotipo mais sensivel a condicao de deficit hidrico, pois apresentou maiores variates no seu potencial hidrico que repercutiu na paralizacao do seu crescimento. A reposicao hidrica durante o periodo de recuperacao permitiu a retomada do crescimento da maioria dos genotipos, principalmente CNPA 5M e BRS 286. Apos o periodo de recuperacao hidrica, as variates nas concentrates dos osmorreguladores indicam plasticidade do alg