According to Bayuelo-Jimenez et al. (2011) [3], under P deficiency, P-efficient accessions of maize plants (Zea mays L.) had greater root to shoot ratio, nodal rooting, nodal root laterals, nodal root hair density and length of nodal root main axis, and first-order laterals. In our experiments, we also found differential root system morphology among three Greek olive cultivars (the root systems of ‘Koroneiki’ and ‘Chondrolia Chalkidikis’ were less branched and more lateral, and with less root hair development and density, than that of ‘Kothreiki’, which was richly-branched and with much greater root hair development and density), something which was probably the main reason for the great genotypic variations in nutrient uptake and growth among the three cultivars (Chatzistathis, unpublished data). Singh et al. (2010) [37] found that great differences existed among 10 multipurpose tree species, grown in a monoculture tree cropping system on the sodic soils of Gangetic alluvium in north India, concerning plant height, diameter e. t.c.