Morpho-physiological and biochemical responses in the floating lamina of Trapa natans exposed to molybdenum

摘要: The response to molybdenum (Mo) was studied in the metal-tolerant hydrophyte Trapa natans L. Previously, it shown that plant accumulates Mn floating lamina by means of phenolic compounds and responded with acclimation responses chloroplast. Since involvement phenolics has been proposed also Mo resistance, we tested T. increasing doses (5, 50, 150, 600 µM) using photosynthetic apparatus as an indicator cellular stress. Only 5 μM did not cause evident modifications respect controls. Conversely, 50 600 μM induced progressively marked alterations morphology. chloroplast ultrastructure showed disorganisation thylakoid system, correspondingly, pigment pattern altered a fall-down photosynthesis. Microspectrofluorimetry indicated photosystem II, differences among three cell layers (first second palisade spongy tissues). While highest dose caused death, 150 μM Mo-treated plants underwent partial recovery, survived up end vegetative season. However, reproduction unsuccessful. treatment induce increase total phenolics, but only anthocyanin. In contrast Mn, detoxification chelation inside vacuoles, possibly anthocyanins, is suggested be insufficient mechanism reduce toxicity, which probably includes impairment nitrogen metabolism. metal accumulated lamina. On whole, limited capabilities survive excess compared Mn.