Objectives: This study describes Zinc biofortification of wheat using a rhizospheric isolate, Pseudomonas fluorescens strain Psd.Methods: The strain was used as a bio-ionculant in soil deficient in zinc and the plant-growth promoting potential and biofortification was assessed using a number of physical and biochemical parameters. The enzymatic studies indicated towards the zinc supply mediated by the strain Result: This plant-growth-promoting strain, apart from the Zn accumulation potential, has the ability to solubilise Zn and was also able to leach out Zn from ore-tailings. The application of a Zn-laden biomass of the strain in soil resulted in increased growth and productivity of wheat crop as demonstrated by pot experiments. The beneficial effect was also reflected in increased activities of some enzymes. In addition, grain Zn 2+ content was enhanced by ~85% in comparison to wheat grown in Zn 2+ -deficient soil.

Diverse environmental stimuli largely affect the ionic balance of soil, which have a direct effect on growth and crop yield. Details are fast emerging on the genetic/molecular regulators, at whole-genome levels, of plant responses to mineral deficiencies in model and crop plants. These genetic regulators determine the root architecture and physiological adaptations for better uptake and utilization of minerals from soil. Recent evidence also shows the potential roles of epigenetic mechanisms in gene regulation, driven by minerals imbalance. Mineral deficiency or sufficiency leads to developmental plasticity in plants for adaptation, which is preceded by a change in the pattern of gene expression. Notably, such changes at molecular levels are also influenced by altered chromatin structure and methylation patterns, or involvement of other epigenetic components. Interestingly, many of the changes induced by mineral deficiency are also inheritable in the form of epigenetic memory. Unravelling these mechanisms in response to mineral deficiency would further advance our understanding of this complex plant response. Further studies on such approaches may serve as an exciting interaction model of epigenetic and genetic regulations of mineral homeostasis in plants and designing strategies for crop improvement.

An attempt was made to investigate the effect of water stress treatment on the components of photosynthesis and water relations of triticale (Triticale octoploide), Russian rye (Secale cereale) and wheat, (Triticum aestivum var. Sonalika). The results revealed that there was no significant adverse effect of water stress on the photosynthesis of triticale compared to wheat and rye. The maintenance of photosynthetic productivity under water stress in triticale has been accomplished by (a) reduction in water loss by stomatal behaviour and (b) by maintenance of water uptake through continued transpirational flow. Both these mechanisms served to maintain high water potential as stress occures. This ameliorates the onset of stress and helps to maintain photosynthesis. The rye also consists of another type of adaptability to drought through significant recovery of photosynthesis and chlorophyll development on reirrigation particularly at post‐anthesis stage, when other species failed to recover. However, in wheat Sonalika both these adaptive characteristics did not exist in such intensity.

The carbondioxide compensation point (Γ), dry matter production, and the activities of nitrate reductase (NR), glycolate oxidase (GO), ribulose 1,5-bisphosphate carboxylase (RuBPC) and phosphoenolpyruvate carboxylase (PEPC) were measured in wheat, grown on media, containing nitrate or ammonium. Significantly higher Γ and lower dry matter was observed in plants supplied with ammonium-nitrogen (NH4-N), as compared to those supplied with nitrate-nitrogen (NO3-N). The activities of NR and PEPC were higher in plants grown on NO3-N than to those grown on NH4-N. There were no significant differences in the activities of GO and RuBPC irrespective of whether NO3-N or NH4-N was supplied. None of the enzymes was found to be associated directly with the Γ.PEPC activity accounted the measured differences in the Γ and biomass production between NH4-N and NO3-N supplied plants. The relationship between PEPC and the Γ is discussed.