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Uptake of mineral nutrients in chickpea cultivars might be an important response in drought tolerance. An experiment under controlled conditions was carried out to study the genotypic response of 11 chickpea (Cicer arietinum L.) cultivars to drought and its relations with N, P, K, Ca, Mg, Fe, Zn, Mn and B uptake and uptake efficiency. Plants were grown either optimal or drought stress implemented at pre- (early drought stress, EDS) and post-anthesis (late drought stress, LDS) stages. Growth reduction of the cultivars as a response to drought significantly differed. The results of the study indicated that EDS had less detrimental effects on growth and nutrient uptake than LDS conditions. In general, drought tolerant chickpea cultivars accumulated more N, P, K, Ca, Zn, Mn and B in both drought stress treatments except for Zn and Mn uptake in LDS treatment. The total nutrient uptake efficiency of the cultivars were also very significantly correlated with the growth reduction ration (GR) both in EDS and LDS treatments giving correlation coefficients (r) of –7859 and –0.7678, p < 0.01, respectively.

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The effect of interspecific complementary and competitive root interactions and rhizosphere effects on primarily phosphorus (P) and iron (Fe) but also nitrogen (N), potassium (K), calcium (Ca), zinc (Zn), and manganese (Mn) nutrition between mixed cropped peanut (Arachis hypogaea L.) and barley (Hordeum vulgare L.). In order to provide more physiological evidence on the mechanisms of interspecific facilitation, phosphatase activities in plant and rhizosphere, root ferric reducing capacity (FR), Fe-solubilizing activity (Fe-SA), and rhizosphere pH were determined. The results of the experiment revealed that biomass yield of peanut and barley was decreased by associated plant species as compared to their monoculture. Rhizosphere chemistry was strongly and differentially modified by the roots of peanut and barley and their mixed culture. In the mixed cropping of peanut/barley, intracellular alkaline and acid phosphatases (AlPase and APase), root secreted acid phosphatases (S-APase), acid phosphatases activity in rhizosphere (RS-APase), and bulk soil (BS-APase) were higher than that of monocultured barley. Regardless of plant species and cropping system, the rhizosphere pH was acidified and concomitantly to this available P and Fe concentrations in the rhizosphere were also increased. The secretion Fe-solubilizing activity (Fe-SA) and ferric reducing (FR) capacity of the roots were generally higher in mixed culture relative to that in monoculture treatments which may improve Fe and Zn nutrition of peanut. Furthermore, mixed cropping improved N and K nutrition of peanut plants, while Ca nutrition was negatively affected by mixed cropping.