MAT RUSH (JUNCUS EFFUSUS L.) TROUNCES MANGANESE TOXICITY THROUGH ULTRA-MORPHOLOGICAL MODIFICATIONS AND MANGANESE RESTRICTION IN ROOTS

摘要

This study appraised phyto-remediation efficiency and tolerance mechanism of Juncus effusus as was evidenced by ultrastructuralmodification in its roots under manganese (Mn) toxicity. Three-week-old J. effusus plants were treated with differentconcentrations of Mn (50, 100 and 500 μM) in hydroponics. Although higher Mn levels caused modifications in growth,biomass, height and root morphological traits, J. effusus tolerated Mn toxicity without showing any obvious phyto-toxicsymptoms even under the highest level of Mn (500 μM). With incremental Mn levels in the growth media, the plants showed asteady increase in Mn uptake, while translocation factor (TF) for Mn declined. This illustrated the tendency of J. effusus plantsto avoid Mn-induced stress by restricting maximum Mn in root tissues. Electron microscopy of root tip cells elucidated planttolerance mechanism to Mn toxicity. Modification in cellular shape and size, and increased number of vacuoles andmitochondria appeared to play a major role in induction of tolerance against Mn toxicity, and ultimate survival of plant.