Ipomoea aquatica showed symptoms of stem necrosis when exposed to graded concentrations of copper (Cu) in 50 % Hoagland solution. The duration of exposure required to elicit necrotic response was concentration-dependent, where two stages, early necrosis (EN) and advanced necrosis (AN), could be visually distinguished. The apical parts of the exposed plant remained nonnecrotic (NN). NN pieces placed in normal Hoagland 50 % solution could grow and produce new roots, nodes and leaves. Comparisons of protein, carbohydrate and copper concentrations among control (CN), EN, AN, NN and regrown and recovered (RC) stem tissues revealed that AN tissue had the lowest protein and carbohydrate concentrations, while NN had the highest. On the contrary, Cu concentration was higher in EN and AN than that in NN and CN. RC tissue had comparable protein, carbohydrate and Cu concentrations to those of CN. Thus I. aquatica could sequester excess Cu in necrotic tissue to keep the apical parts largely free from Cu toxicity. At the same time, more proteins and carbohydrates were synthesized in the apical part, which in turn enabled the plant to survive and grow, even when under Cu stress. This was further aided by the ability of its stem to produce adventitious roots from nodes and give off lateral shoots that bore flowers and leaves. This could be exploited for Cu phytoremediation by growing the plant in Cu-rich medium and then removing the Cu-enriched necrotic portions for safe disposal. The unaffected NN portions could be regrown and reused.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.