Root nutrient uptake, photosynthetic transients, growth and leaf anatomy of Citharexylum myrianthum suggest tolerance to soil cadmium toxicity.

Abstract

The increase in water and soil contamination by potentially toxic elements (PTEs) constitutes a major environmental concern. Amongst these elements, cadmium (Cd) stands out due to its high mobility in both soil and plant vascular tissue. Consequently, effective strategies for PTE removal are urgently needed. This study aimed to examine the growth, anatomical and cellular traits, chlorophyll fluorescence, macro- and micronutrients content of Pau-Viola (Citharexylum myrianthum Cham.) seedlings exposed to different Cd concentrations 0.25, 0.5, or 0.75 μmol/kg in soil. C. myrianthum seedlings exposed to Cd exhibited minimal alterations in morphophysiological attributes. Cadmium was predominantly retained in the root system with limited translocation to the shoots, thereby preserving growth and nutritional balance. The lower Cd accumulation in the leaves helped maintain the integrity of the photosynthetic electron transport chain and the chlorophyll index, resulting in only minor changes in chlorophyll a fluorescence transients. The observed tolerance of C. myrianthum to Cd-initiated toxicity suggests metallic potential use in reforestation programs for Cd-contaminated areas, as the species demonstrated resilience and physiological stability under such conditions.