ECOFISIOLOGIA DE PROGÊNIE DE CUPUAÇUZEIRO SUBMETIDA A DÉFICIT HÍDRICO E REIDRATAÇÃO

Abstract

The objective of this work was to evaluate the growth, biomass allocation and the ability of young plants of Theobroma grandiflorum to recover their water status and gas exchange after water deficit. Plants with 180 days, irrigated (control) and non-irrigated, were evaluated after water was withheld for 18 days, and after one, three and six days of irrigation resumption (rehydration). The drought reduced the production of biomass, and the leaves presented more significant reduction (28%). There was also a reduction in leaf area, plant height and stem diameter. Only the length of roots was not affected by soil water deficit. On the 18th, the leaf water potential of predawn (Ψam) of stressed plants was reduced to -3.07 MPa. With water deficit, significant reductions were observed in the relative water content in the predawn (25% reduction), stomatal conductance (78%) and sweating (90%). During rehydration, the water status of stressed plants was recovered after three days. Gas exchange was also recovered, but in a slower rate than water status. Under water deficit, the total soluble carbohydrate concentrations, total soluble amino acids and proline increased. Plants young are tolerant to moderate water deficit.