Increasing poly phenols in Coleus blumei at the cellular and intact plantlevels using PEG stress

摘要

An expermen was carried out in order to of increase poly phenols in Coleus blumei using elicitation at the intact and cellular levels. The abiotic elicitor used to achieve this aim was polyethylene glycol at the concentrations 4, 8 or 12%.Total phenols in the whole plant and callus tissues were estimated using Folin-ciocalteu and spectrophotometric methods. Induction and maintenance of Coleus callus was carried out on the Gamborg medium (B5) for 21 days supplemented with the growth regulators 0.8 mg.l-1 2,4 dichlorophenoxy acetic acid (2-4-D), 2 mg.l-1 Benzyl adenine (BA) and 0.5 mg.l-1 Naphthalene acetic acid (NAA) using stem explants for callus induction. Results exhibited a significant decrease in fresh and dry weights of shoots and roots in intact plants of Coleus in vivo after treatment with PEG. The fresh weight reachedl0.56g at 12%PEG compared with the control which recorded 35.87g.while the fresh weights of the root decreased to 0.767g at 0.12% PEG compared with the control which recorded 3.73 g. Callus cultures accumulated higher polyphenols compared with mother plants after treatment with PEG. Total phenols were also evaluated in both callus cultures and liquid medium then compared with the whole plant and control treatments. The highest mean of total phenols was recorded in callus cultures supplemented with PEGrecording73.3 ug.l-1 at the concentration 12%PEG in both liquid medium and callus tissues. The intact plants recorded the highest mean in poly phenols in plants grown in vivo (55.423) ug.l-1 at 8% of PEG.