{The use of organic and inorganic cultures in improving vegetative growth, yield characters and antioxidant activity of roselle plants (Hibiscus sabdariffa L.)}

This study was conducted at the Experimental Farm of the Faculty of Agriculture, in May during the two
seasons of 2008 and 2009 on roselle plants (Hibiscus sabdariffa L.). The objective was to improve the
vegetative growth, yield characters and antioxidant activity of plants growing under different organic
and inorganic media conditions in response to the spray of amino acids, humic acids and micro
elements. The results showed great similarity which had been noticed with the majority of the studied
characters in both seasons. The highest values of plant height, number of branches per plant, stem
diameter, fresh and dry weights of leaves and branches per plant, number of days to flowering, number
of fruits per plant, fresh and dry weights of sepals per plant and seed yield per plant were obtained
when the plants were grew in a soil mixed with compost or magnetic iron and sprayed by humic acid in
comparison with the rest of the treatments. Comparing the values of the previous characters when
compost plus humic acid was used to that of magnetic iron plus humic acid, it could be stated that
these values were greater with the first treatment than that of the second one in both seasons. The
lowest values of the characters were noticed always with the mixture of compost or magnetic iron with
amino acids or with micro elements, although these values were still higher than that of the compost or
a single magnetic iron, or that of the control treatments in both seasons. The best scavenging activity
against DPPH radical was observed with plants treated with compost plus humic acid and this
correlated with the total anthocyanin content.