Response of 'Star Ruby' grapefruit on two rootstocks to NaCl salinity

摘要

An experiment with seven year old field-grown 'Star Ruby' grapefruit trees (Citrus paradisi Macf.) grafted on 'Cleopatra' mandarin (Citrus reticulata Blanco (CM)) and 'Carrizo' citrange (C. sinensis L., Osb X Poncirus trifoliata L. Ref. (DC) (CC) was designed to evaluate the long-term effect on fruit yield (1998/2001), fruit quality and leaf mineral composition of three irrigation waters having sodium chloride concentrations of 3, 15 and 30 mM NaCl, respectively. Fruit yield was progressively decreased by salinity in all treatments, but the effect was influenced by rootstock. 'Cleopatra' mandarin appeared to be a better rootstock than 'Carrizo' citrange for 'Star Ruby' grapefruit trees, since in the control and in 30 mM NaCl treatment, 'Cleopatra'mandarin had a higher fruit yield than 'Carrizo' citrange. On the other hand, fruit from 'Carrizo' had impaired quality in the saline treatment, due to a decrease in juice percentage and an increase in pulp and peel percentage. Chloride concentration inleaves from 'Cleopatra' was significantly lower than for those of 'Carrizo'. The opposite effect was observed for Na~+ concentration, where leaves from 'Carrizo' accumulated less Na~+ than those from 'Cleopatra'. Foliar concentrations of nitrate-N wereincreased and K~+ were decreased in the saline treatments, for trees grafted on both rootstocks.