Integration of Zinc Oxide in In Vitro Culture and Plant Improvement

Zinc oxide (ZnO), especially in the nanoparticulate form, has shown to be one of the most important agents in the current plant biotechnology, particularly in tissue culture and plant development strategies. Zinc, as a vital micronutrient, is involved in plant metabolism, activation of enzyme systems, synthesis of proteins, and modulation of growth regulators. Inclusion of ZnO in in vitro systems presents a strategy that can be used to optimize tissue culture efficiency, to stimulate organogenesis, and to improve plant health. Recent reports have demonstrated that ZnO applied at the optimum concentration could enhance callus induction, shoot regeneration, and somatic embryogenesis, and decrease microbial contamination through its antimicrobial activities. In addition, their antioxidant impact can decrease oxidative stress of cultured tissues and enhance the general survival and vigor of explants. This chapter will also address the functional aspects of zinc in plant physiology, the particularities of ZnO, and how it exploits its actions at the cellular and molecular levels, both in vitro. We evaluate ZnO’s role as a genetic transformation effector, and its effect on plant metabolic pathways. Case studies on individual plant species illustrate the various uses and effects of ZnO supplementation in growth media. Yet phytotoxicity, nanoparticle stability and safety in the environment are also critically discussed as issue. Given the growing interest in nanobiotechnology, the incorporation of ZnO in plant tissue culture represents an exciting opportunity for improved crop productivity, stress tolerance, and genetic enhancement and a new way forward in sustainable agriculture and rapid plant improvement.