Abstract
To study the influence of phytosiderophores (PS) released from some Egyptian wheat cultivars on mobilization and absorption of iron (Fe) and zinc (Zn) from pre-amended calcareous soils, three selected wheat cultivars (Sids 10, Giza 162, and Baniswaif 2) were used. The cultivars were pre-cultured for 17 days in nylon bags as the control root compartment (RC) and filled with fine sand and provided with nutrient solution +/- Fe-EDTA. The nylon bags with roots of the seedlings were brought in contact for further 4 days with pre-amended calcareous soils. DTPA-extractable Fe and Zn from amended calcareous soils with sludge was much higher than from untreated soils. Relative increases in extractable Fe or Zn were found in Fe-deficient wheat (-Fe pretreatment) compared with Fe-sufficient plants. The extractable amounts of Fe- and Zn-DTPA from different calcareous soils were affected by the distance from the central root compartment where minimum values were reached at distance of more than 4 mm. Release of PS and mobilization of Fe and Zn were highest with, Sids 10 and Baniswaif 2 cultivare while Giza 162 was lower particularly under sufficient seedlings. Moreover, increasing CaCO
3
content in calcareous soils minimized the growth differences among wheat cultivars. The status of Fe and Zn contents was improved in roots compared with shoots during the 4-day growth period. Furthermore, nutrient status was generally higher in soils amended with sludge compared with untreated soils. Sids 10 have the highest values of Fe content particularly under Fe-deficient conditions while Giza 162 was inferior. Zinc content in Sids 10 was superior in high calcareous soil (53% CaCO
3
content) while Baniswaif 2 was superior in low calcareous soil (14% CaCO
3
content).