Effect of some antioxidants on growth, yield and some chemical constituents of onion (allium cepa l.)‎ plants

الملخص EN

The present investigation was conducted during the two successive seasons 2004/2005 and 2005 / 2006 on onion (Allium cepa L.

cv.

Giza 20) grown at the experimental station of the Faculty of Agriculture, Fayoum University, Egypt, to study the effect of some antioxidants (ascorbic acid, citric acid, oxalic acid and salicylic acid) foliar spray at the rate of 0, 2.5, 5 and 10 mM on the possibility of improving growth, yield and some chemical constituents of onion plants.

Significant positive influences of all antioxidants treatments used in this study were observed on growth, yield of bulb and some chemical composition characters in both tested seasons.

The obtained results indicated that, the growth characters, i.

e.

plant height, number of leaves / plant, and fresh and dry weight of leaves / plant were affected positively by the application of all antioxidants used at all studied rates.

The maximum increase in this respect was obtained by the treatment of 10 mM followed by 5 mM treatment as compared to the control untreated plants in both seasons.

The same treatments increased bulb yield and its components (bulb diameter, as well as fresh and dry weight of bulb).

In addition the most effective treatments for enhancing the concentration of chlorophyll a and b, total caroteniods, total free amino acid, total indoles, and total soluble phenols on fresh leaves, and total carbohydrates, total and reducing sugars, anthocyanin concentration, crude protein and some nutrients i.

e.

N, P and K in dry matter of leaves and the content of bulbs from total soluble solids (T.

S.

S.%), total soluble carbohydrates and protein was observed at higher concentration (10mM) of all antioxidants used especially Ascorbic acid and Salicylic acid.

Thus, the highest application of antioxidants is recommended for improving growth, yield and chemical composition of onion plants.