Poulista and Xera are the most important snap bean cultivars growing
under El- Fayoum conditions, for both local market and export. Antioxidant
substances are organic compounds, i.e., organic acid or hormones. Recent
studies concentrated on the beneficial effects of these antioxidant substances to
improve plants performance. Therefore, an experiment was carried out during
the fall seasons of 2016 and 2017 in a private farm at El-Fayoum Governorate,
Egypt to study the effect of 7 antioxidant substances, i.e., indole -3- acetic acid,
indole -3- butyric acid, ascorbic acid, citric acid, salicylic acid, tartaric acid and
oxalic acid as a foliar application, each at the rate of 500 ppm, on growth
characters, green pods yield and pod qualities of Poulista and Xera plants.
Seeds of both cultivars were sown in September; experimental design was spilt
plot. Antioxidant applications were done after 20, 30 and 40 days from planting
and plant samples were taken after 50 and 70 days for growth characters and for
green pods yield and quality parameters, respectively. Results showed that Xera
variety was the higher in pod length, pods weight/ plant-1, chlorophyll a, b and
total chlorophyll content in leaves and amino acid content in pods compared
with Poulista variety. Moreover, Poulista variety was higher in plant height,
carbohydrates content in stem and pods and amino acid content in stem
compared with Xera cultivar.
All foliar antioxidant applications significantly increased all growth
characters, pods yield and pod quality and chemical composition of carotenoids,
chlorophyll a, b and total chlorophyll, as well as, carbohydrates and amino acid
contents in leaves, stem and pods of snap bean plants compared with the control
treatment. The superior application was oxalic acid followed by ascorbic acid,
respectively, while citric acid gave the highest content of amino acid in stem.
The remarkable growth and production improvement in Xera or Poulista
cultivar obtained when plants treated with oxalic or ascorbic acid 3 times (20,
30, 40 days) from planting at the concentration of 500 ppm.