STUDIES ON FACTORS AFFECTING IRON AVAILABILITY IN THE RHIZOSPHERE

Abstract

Iron deficiency chlorosis (Lime induces chlorosis) is a widespread in higher plants grown in calcareous soils. In recent years, considerable progress has been made in identification of adaptive mechanisms which plant species and genotypes developed to overcome iron deficiency in soils which have low availability of iron A particular adaptive mechanism has been found in graminaceous species under Fe deficiency .In response to iron deficiency, root of graminaceous species release so-called phytosiderophores, which are highly effective to solubilize, by chelation, the sparingly soluble inorganic Fe compounds such a

Fe3

hydroxides, oxides and phosphates.

The present work was undertaken to study iron mobility and

availability in either rhizosphere or non rhizosphere zone of Fe - efficient barley as affected by root exudates, soil pH, CaC0 3 content and iron fertilizer. Straw and grain yields of barley as well as nutrient concentration were also determined. Moreover, root exudates and their content from amino acids organic acids and phytosiderophores released from Fe-efficient barley cultivar, using solution culture technique were evaluated. For this purpose, two experiments using hydroponics

technique, as well as a pot experiment under greenhouse conditions were carried out. Hydroponic experiments: