The effects of salinity stress and rootstock on the growth, photosynthetic rate, nutrient and sodium concentrations of almond (Prunus dulcis Mill.)

Salinity tolerance is one of the major factor influencing crop productivity in arid and semi-arid areas. The salinity tolerance of fruit trees can be enhanced through the use of tolerant rootstocks. This experiment was conducted to investigate the effects of salinity stress and rootstock on the growth, photosynthetic rate and nutrient concentrations of almond (Prunus dulcis Miller.) cv. “Ferragnes” grown in the soilless culture and controlled environment. Three levels of NaCl (0, 50, 100 mM) and two rootstock (GF677, Tuono) was factorially combined in a randomized complete block design with four replications. The results showed that the salinity stress had a significant diminish effects on vegetative and physiological characteristics and nutrient concentrations of almond. The severity of the adverse effects of salinity varied among rootstocks. Fresh and dry weights of leaf and root, leaf number and chlorophyll index was increased in F/GF677 at 50 mM salinity level and then decreased compare to that in control, however it was decreased at 100 mM salinity concentration in F/Tuono. Photosynthetic rate, leaf area and K/Na ratio was decreased with increasing salinity in both rootstocks, it became more pronounced in F/Tuono. With increasing NaCl levels, leaf concentrations of N, P, K was decreased and Na concentration was increased in both rootstocks. This results imply that GF677 have a exclusion mechanism such as restrict either the uptake or transport of Na from root to shoot or maintain sufficient level of K, have a higher salt tolerance than Tuono hence, under salinity conditions can be useful salt-tolerant rootstock for different almond cultivars.