EFFECT OF SOME PLANT GROWTH REGULATORS ON BIOCHEMICAL GENE EXPRESSION, GROWTH AND YIELD OF FABA BEAN

Abstract

In the greenhouse experiment Vicia faba L. cv. Giza 716 were treated with 25 and 50
ppm of paclobutrazol (PP333), kinetin (Kin), naphthalene acetic acid (NAA) and 50
and 100 ppm of ethephon (Et) as foliar spray at the onset of flowering and fruiting.
Plant height, branches and flowers number were recorded after 104 days from
sowing. Two samples were taken after 90 days from planting and at harvest. At the
1st sample date, biochemical analyses were conducted in leaves for determination of
total soluble sugars, phenols, indoles, free amino acids, water soluble protein and
isozymes. At harvesting time (2nd sample), number of pods, pods and seeds dry
weights/plant were taken. Total seed proteins and soluble carbohydrates were
evaluated in dry faba bean seeds. PP333 at 50 ppm had significant and negative effect
on plant height, flowers number, total phenols and indoles. The high concentration of
Kin, Et and NAA treatments increased the number of pods, the dry weight of pods
and seeds per plant whereas the opposite occurred in the same concentration of PP333
treatment. Seed yield was correlated with the number of pods per plant and the dry
weight of pods per plant. In general, NAA at 25 ppm has strongly stimulating effect
on total soluble sugars, phenols, indoles and free amino acids (in leaves), soluble
carbohydrates (in seeds) and seed index (100-seed weight). It seems that growth
promoter NAA enhance the mobilization of photoassimilates to filling seeds. Protein
banding patterns and isozymes of superoxide dismutase, peroxidase, catalase, , -
esterases, acid phosphatase separation by electrophoresis were successfully used to
faba bean subjected to PP333, Kin, Et and NAA. The applied plant growth regulators
affected the rate of gene expression in leaves more than in seeds. Their effects on
growth, fruit set, yield, correlated components, proteins SDS-PAGE and isozymes
were discussed below.