GROWTH, YIELD AND CHEMICAL COMPOSITION OF

OENOTHERA    BIENNIS    AS    AFFECTED  BY YEAST,

BIOTIN AND RIBOFLAVIN FOLIAR APPLICATION

[65]

Hend E. Wahba¹

ABSTRACT

      Two field experiments were carried out during two successive seasons (1998 and 1999) to investigate the effect of yeast, biotin and riboflavin on growth, yield and chemical composition of Oenothera biennis. Three concentrations from each of yeast (2.5, 5.0 and 7.5 g/L), biotin or riboflavin (50, 100 and 150 ppm) along with control treatment  were  used.  Generally, the concentration of yeast, biotin and riboflavin increased most of growth parameters  and  chemical composition as compared to untreated plants. The best response was resulted from the highest concentration of yeast (7.5 g/L) and riboflavin at (150) ppm. The yield  of  seeds  and  fixed   oil,   potassium and total carbohydrates content increased with application of yeast at 7.5 g/L. GLC analysis of fatty acids showed that the major  components were linoleic, linolenic, oleic and palmitic. The highest content of linoleic (64.36 %) was obtained with riboflavin at 100 ppm. Yeast at 5.0 g/L was effective in increasing linolenic acid (12.30 %), while biotin at 150 ppm was effective in increasing oleic percentage (28.03 %).