Distribution of С4 Plants of the Chenopodiaceae Family According to the Salinization Profile of the Kyzylkum Desert

Resumo

The peculiarities of the prevalence of C₄ species in the relief of the Kyzylkum Desert were revealed based on botanical and geographical descriptions. In the lowlands (0–50 m above sea level), a predominance of C₃ halophytes was found, while halophytes with C₄ photosynthesis began to predominate at medium elevations (50–200 m above sea level). Above 200 m above sea level, a sharp decline in the contribution of halophilic flora to the biodiversity of native vegetation was detected. Thus, the penetration of halophytes above 200 m is limited by the presence of C₄ photosynthesis as an adaptive characteristic to soil desalinization. A decrease in the succulence of leaf morphology in edificatory perennial plants of the Kyzylkum Desert (tamarix, saxaul, and camel thorn) was noted with a decrease in soil salinization. In the summer dry period, C₄ photosynthesis provides a competitive advantage over C₃ halophytes for survival on desalinated soils of elevated parts of the terrain desiccated during the summer. It was concluded that the acquisition of C₄ photosynthesis by halophilic species is an adaptation of the photosynthesis of halophilic flora to seasonal desalinization and drying of the soil of the elevated parts of the Kyzylkum Desert.