پاسخ پایه های ‘به’ (Cydonia oblonga Mill.)، گلابی و زالزالک به کمبود آهن

Iron (Fe) chlorosis is an important nutritional problem in quince trees. But, quince rootstocks differ in their tolerance to Fe deficiency in calcareous soils. Tolerance to Fe deficiency of seedling rootstocks of quince, pear and crataegus and clonal rootstock of quince A was evaluated by exposure to two levels of Fe (3 and 50 µM) in the presence or absence of 10 mM bicarbonate in soilless culture. According to results of this study different rootstocks had various responses to Fe deficiency stress. In Fe-deficiency stress conditions, rootstocks of pear and crataegus showed the lowest severity of chlorosis among the studied rootstocks and had the highest plant height, number of leaves and Fe concentration in leaves and roots. Activity of guaiacol peroxidase enzyme in these two Fe-tolerant rootstocks was less affected by Fe deficiency. In contrast, seedling rootstock of quince showed the highest severity of chlorosis along with the decrease in activity of guaiacol peroxidase (-74.19%) and ascorbate peroxidase (-52.35%). Quince A rootstock showed better performance than seedling rootstock of quince under Fe deficiency. Results also revealed that despite sufficient Fe level in the media (50 µM), seedling rootstocks exposed to bicarbonate showed Fe deficiency symptoms. In general, it was found out that rootstocks of pear and crataegus were more tolerance to Fe deficiency stress