A field experiments were carried out during the two successive
seasons of 2007 and 2008 in the Experimental Farm at Demo ( a newly
reclaimed soil with a moderately salinity level), Faculty of Agriculture,
Fayoum University to investigate the effect of foliar application of
citrine (15% citric acid, 2% Fe, 2% Mn and 2% Zn) at the rates of 0,
0.3, 0.4, and 0.5% and active dry yeast at the rates of 0, 1, 1.5 and 2 g /
L, each alone or together on growth, yield and some chemical
constituents of roselle plants (Hibiscus sabdariffa L. var. sabdariffa).
The studied growth characters were plant height, number of branches/
plant, number of leaves/plant, leaf area and dry weight of leaves /plant,
as well as yield and its components, (i.e. number of flowers /plant,
fresh and dry weights of sepals/ plant, yield of dry sepals/fed). The
chemical constituents of leaves included total chlorophyll, carotenoids
& antioxidants enzyme activity and those of sepals, i.e., pH,
anthocyanin and total carbohydrates. The obtained results indicated
that, all studied characters were affected positively by the foliar
application of citrine and active dry yeast at all applied different rates
either alone or together (except, pH values that were decreased by the
applied treatments). The best results were obtained by the application
of the highest rates of citrine (0. 5%) or active dry yeast (2 g / L) alone
or together. At the same time, the oxidative enzyme activities such as
peroxidase and catalase were recorded the highest values when
spraying with the highest rates of citrine or active dry yeast alone or
together.
In view of these results, it could be recommended that foliar
spraying roselle plants (Hibiscus sabdariffa L. var. sabdariffa) with
citrine or active dry yeast should be counteracted the adverse
conditions, particularly at salinity condition of the soil, and
consequently producing an economic yield.