Mecanismos morfofisiológicos e bioquímicos determinantes da adaptação de palma de óleo ao alagamento.

Abstract

The oil palm (Elaeis guineensis Jacq.) Is a widely cultivated palm tree in the state of Pará, which has the largest planting area and largest national fruit production of the species. Soil flooding due to improper crop management operations associated with local edaphoclimatic conditions can affect crop growth and development, negatively affecting yield. Thus, the general objective of this research was to evaluate the capacity of tolerance of oil palm to flooding, seeking to evidence a possible relationship between frequency of pneumatophores emitted per plant and stress tolerance. In order to do so, One year old plants were submitted to full irrigation (field capacity) and flooding (77 days) to evaluate the impacts of stress on plant water status, gas exchange, chlorophyll fluorescence, biomass allocation. and pattern of carbohydrate distribution in the plant. These variables were obtained in plants grouped according to the number of pneumatophores emitted (2–10, 30–40, 60–70, and 90–120 pneumatophores per plant). Flooding did not induce significant changes in plant water status, gas exchange and chlorophyll fluorescence, regardless of the number of pneumatophores. However, the algal induced changes in shoot morphology and biomass accumulation of plant parts, with emphasis on an increase in bulb stem diameter and bulb biomass. The plants under flooding showed a strong reduction in root biomass, and such reductions were more significant in plants with less pneumatophores. In control and flooded plants, sucrose concentrations were higher in the bulb, roots and pneumatophores (when present) than in the stem. The starch storage was higher in the stem, bulb and roots and lower in the pneumatophores. It can be concluded that oil palm plants tolerate satisfactorily long-term flooding (77 days) and that the higher number of pneumatophores per plant should induce a higher stress tolerance in relation to plants with lower number of pneumatophores.