Abstract

Scarce drainage, abundant precipitations or inadequate irrigation of soils could generate oxygen (O 2 ) deficient conditions in plants roots. The O 2 concentration deficiency in plant roots provokes physiological changes in plants. In turn, toxic product accumulation and rapid organic compound depletion occur due to slower water and nutrient translocation in root produced by an energetic limitation. In fruit-trees, O 2 deficiency resistance in roots is determined by the rootstock characteristics. Prunus trees present rootstocks with diverse tolerance features to flooding conditions. It has been described that different rootstocks could provide higher tolerance or sensitivity to hypoxia conditions. The aim of this study was to evaluate the plant physiology and root respiration of two Prunus rootstocks, Mariana 2624 and CAB 6P, under hypoxic water solution in a hydroponic system. When gas interchange was evaluated, it was observed that photosynthesis decreased in short-term experiments during the first 14 days in both species. Stomatal conductance (gs) presented an earlier reaction than photosynthesis, presenting a decrease from day 3 of treatment. Root respiration was increased in both rootstocks, being more drastic in CAB 6P at the end of treatments. However, no effects were found in the relative water content and chlorophyll contents of both plant leaves. In summary, plants under a hypoxic solution presented a decrease on photosynthetic rates, stomatal conductance and roots respiration, showing that the oxygen deficiency induced a short time effects on plant physiology. However, these changes did not incited effects on water contents and did not affect the chlorophyll contents after 14 days of treatment. Acknowledgments: CONICYT-REGIONAL/GORE O´HIGGINS/CEAF/R08I1001.