evaluation of peach, bitter almond, gf677 and gn15 rootstocks for bicarbonate or iron deficiency-induced chlorosis

in order to evaluate tolerance of four prunus rootstocks to fe-deficiency-induced chlorosis,  an experiment was carried out in bu-ali sina university in 2012 using a rcbd design with four replications. four rootstocks were used, including gf677, gn15, bitter almond and peach and nutritional treatments were: hoagland solution without fe (ph = 6), hoagland solution containing 90µm fe as control (ph = 6), and hoagland solution containing 90 µm fe + 10 mm khco3 (ph = 8). at the end of experiment, total and active content of iron in leaves and roots, chlorophyll content, hydrogen peroxide levels as well as catalase and ascorbate peroxidase enzyme activity were measured. based on the results, peach was the most sensitive rootstock to iron deficiency and bicarbonate treatments, while almond was the most tolerant rootstock. comparing two peach × almond hybrid rootstocks showed that gf677 had better performance under iron deficiency and in the presence of bicarbonate rather than gn15. bicarbonated nutrient solution inhibited the fe absorption and transport by peach roots, whiles other rootstocks uptake high amount of iron and transferred it to shoots. in this condition, on both peach-almond hybrids, gf677 and gn15, large amounts of iron in leaves were in inactive form but on bitter almond rootstock in addition to high iron uptake and transport, large amounts of this element was active and utilizable by leaves.