Valida M. Alizade

Plant Resistance to Anthropogenic Toxicants: Approaches to Phytoremediation

The problem of soil preservation and restoration has became more intense due to continued deterioration of the ecological systems of the world. This problem is especially important for Azerbaijan, where environmental pollution by heavy metals and oil products is increasing. Though the nature of toxicity of these two factors is different, they both affect plant productivity, including agricultural crops and human health. This review is devoted to the analysis of modern conceptions on fundamental physiological mechanisms of plant resistance to toxic levels of heavy metals and organic pollutants in soils, also of their uptake and translocation in plants. Different aspects of the nature of toxicity of metals and petroleum hydrocarbons and genetic basis of plant resistance to them, hyperaccumulation mechanisms of heavy metals by some plant species and approaches to phytoremediation of both inorganic and organic pollutants are discussed.

Multiple mechanisms of heavy metal tolerance are differentially expressed in ecotypes of Artemisia fragrans

Artemisia fragrans is a plant species with ability of growing on heavy metal-polluted soils. Ecotypes of this species naturally growing in polluted areas can accumulate and tolerate different amounts of heavy metals (HM), depending on soil contamination level at their origin. Heavy metal tolerance of various ecotypes collected from contaminated (AP, SP) and non-contaminated (BG) sites was compared by cultivation on a highly HM-contaminated river sediment and a non-contaminated agricultural control soil. Tissue-specific HM distribution was analyzed by laser ablation-inductively-coupled plasma-mass spectroscopy (LA-ICP-MS) and photosynthetic activity by non-invasive monitoring of chlorophyll fluorescence. Plant-mineral analysis did not reveal ecotype-differences in concentrations of Cd, Zn, Cu in shoots of Artemisia plants, suggesting no differential expression of root uptake or root to shoot translocation of HM. There was also no detectable rhizosphere effect on HM concentrations on the contaminated soil. However, despite high soil contaminations, all ecotypes accumulated Zn only in the concentration range of generally reported for normal growth of plants, while Cu and Cd concentrations were close to or even higher than the toxicity level for most plants. As a visible symptom of differences in HM tolerance, only the AP ecotype was able to enter the generative phase to complete its life cycle. Analysis of tissue-specific metal distribution revealed significantly lower concentrations of Cd in the leaf mesophyll of this ecotype, accumulating Cd mainly in the leaf petioles. A similar mesophyll exclusion was detectable also for Cu, although not associated with preferential accumulation in the leaf petioles. However, high mesophyll concentrations of Cd and Cu in the SP and BG ecotypes were associated with disturbances of the photosynthetic activity. The findings demonstrate differential expression of HM exclusion strategies in Artemisia ecotypes and suggest Cd and Cu exclusion from the photosynthetically active tissues as a major tolerance mechanism of the AP ecotype.

Evaluation of Wild Halophytes of Aralo-Caspian Flora Towards Soil Restoration and Food Security Improvement

Nowadays, due to an increase in the salinization induced by climate change and desertification process in the dryland ecosystems, evaluation of potential use of halophytes for soil remediation, forage and food supply, medicinal and other purposes is gaining wide attention and acceptability. Documentation of valuable knowledge about these plants is assuming urgent priority.