Efeitos da inundação no crescimento, trocas gasosas e porosidade radicular da carnaúba (Copernicia prunifera (Mill.) H.E. Moore)

Abstract

Carnaúba, Copernicia prunifera (Mill.) H.E. Moore, is a common Brazilian palm from the Northeast region, which is usually found in saline and poorly drained soils. To evaluate the degree of tolerance to flooding, 4 month-old plants were grown in soil submerged by a 80mm water layer, for 60 days. During this period, shoot height was measured weekly. After 60 days of flooding, root intercellular air volume (porosity) was measured. Porosity was 25,3% on flooded plants and 21,8% on control plants. Photosynthetic rate, stomatal conductance and transpiration were measured in 10 month-old plants, during 35 days of flooding. After this period of flooding, internal CO2 and O2 concentrations were quantified on roots. Flooded plants had higher concentration of CO2, and lower concentration of O2, compared to control plants. While a reduction in photosynthesis and stomatal conductance occurred, shoot height improvement was not affected and no visible flooding symptoms were seen in carnaúba shoots, indicating that this species displays tolerance to flooding, which is probably related to the high root porosity.