Response of Roses (Rosa hybrida L. 'Herbert Stevens') to Foliar Application of Polyamines on Root Development, Flowering, Photosynthetic Pigments, Antioxidant Enzymes Activity and NPK.

The effect of foliar application of polyamines on roses (Rosa hybrida cv. 'Herbert Stevens') was investigated in a factorial experiment based on a completely randomized design with three replications in a greenhouse. Two factors were applied including polyamine type (putrescine, spermidine, and spermine) and polyamine concentration (0, 1, 2 and 4 mM). The recorded traits included root fresh and dry weight, root length, number of flowers, flower longevity, chlorophyll content, carotenoids, antioxidant enzymes activity (catalase, ascorbate peroxidase and guaiacol peroxidase) and some macronutrients such as nitrogen, phosphorus and potassium. The results showed that among polyamines, putrescine had the greatest effect on root dry weight; spermidine showed the greatest effect on root length, chlorophyll content, plant phosphorus and spermine affected root fresh weight and flower longevity most strongly. Polyamine concentration of 1 mM had the strongest effect on flower longevity, carotenoids, nitrogen and phosphorus content. The highest potassium rate was observed in treatments with the concentration of 4 mM. Polyamine treatments had no significant effect on the number of flowers per plant and antioxidant enzymes.

Sodium nitroprusside stimulated production of tropane alkaloids and antioxidant enzymes activity in hairy root culture of Hyoscyamus reticulatus L.

Hyoscyamus reticulatus L. is a herbaceous biennial belonging to the solanaceae family. Hyoscyamine and scopolamine as main tropane alkaloids accumulated in henbane are widely used in medicine to treat diseases such as parkinson's or to calm schizoid patients. Hairy roots media manipulation which uses elicitors to activate defense mechanisms is one of the main strategies for inducing secondary metabolism as well as increasing the production of valuable metabolites. Cotyledon-derived hairy root cultures were transformed by Agrobacterium rhizogenes. Sodium nitroprusside (SNP), a nitric oxide donor), was used in various concentrations (0, 50, 100, 200 and 300 µM) and exposure times (24 and 48 h). Treatment with SNP led to a significant reduction in fresh and dry weight of hairy roots, compared to control cultures. ANOVA results showed that elicitation of hairy root cultures with SNP at different concentrations and exposure times significantly affected the activity of as antioxidant enzymes such as catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX). The highest hyoscyamine and scopolamine production (about 1.2-fold and 1.5-fold increases over the control) was observed at 50 and 100 µM SNP at 48 and 24 hours of exposure time, respectively. This is the first report of SNP elicitation effects on the production of tropane alkaloids in hairy root cultures.