Differential tolerance to iron deficiency of chickpea varieties and Fe resupply effects.

The consequences of direct iron deficiency and iron resupply were evaluated during development stages of two Tunisian chickpea varieties (INRAT88 and Chetoui) cultivated in continuously aerated solution with or without 20 muM Fe. The chlorosis score was estimated during culture. Growth parameters, chlorophyll concentration, acidification capacity and Fe concentration were measured every three days during the 21-day treatment. After three weeks of treatment, the chlorosis index was 3-fold higher in Chetoui than in INRAT88, and a considerable decrease of chlorophyll concentration was observed in Chetoui plants since the 6th day of -Fe deprivation. Iron deficiency significantly inhibited whole-plant biomass deposition in both varieties. However, the growth reduction appeared earlier, and was more pronounced in Chetoui than in INRAT88. The whole-plant Fe content decreased dramatically under deficient conditions, and we note an Fe enrichment in shoots at the expense of roots. The sensitivity of Chetoui as compared to INRAT88 was confirmed by the behaviour of resupplied (-Fe/+Fe) plants. In fact, the addition of iron to deficient plants had no significant effect in Chetoui, whereas it led to a total recovery in INRAT88. The capacity of INRAT88 to maintain plant growth and to preserve adequate chlorophyll synthesis under limited iron conditions is related to its better Fe-use efficiency, in addition to its capacity to rapidly recover from this stress.