Role of Foliar Application of Nicotinic Acid and Tryptophan on Onion Plants Response to Salinity Stress

Abstract

This experiment was conducted at the National Research Centre, Dokki, Cairo, Egypt during 2006 and 2007 winter season to evaluate the effects of spraying with tryptophan (TP) and nicotinic acids (NA) on onion plants grown under varying degree of salinity stress (irrigation water with 3000 and 6000 ppm salinity) as compared to tap water (300 ppm) irrigation. Irrigation by high salinity water decreased the number of leaves, mean bulb diameter, fresh and dry weight of bulb and whole plant. Foliar application of TP and NA significantly increased the top height and fresh weight, and bulb dry weight. The above beneficial effects were greater in the plants sprayed with NA as compared to those of the plants received TP spray. At the lower salinity level (3000 ppm), TP was more effective than NA in mitigating the negative effects of salinity stress. At the high salinity stress (6000 ppm), however, the converse was evident. The electrolyte leakage (EL) was not influenced by 3000 ppm salinity irrigation water as compared to that of the plants which received tap water (300 ppm) irrigations. However, it increased significantly in the plants irrigated by 6000 ppm salinity water. Lipid peroxidation (LP) and EL were significantly lower in the plants sprayed with TP or tapwater. In addition, spraying of NA or TP increased the plant growth and biomass weight. Therefore, the above foliar sprays appear to mitigate the negative effects of increased salinity.

Developmentally controlled changes during Arabidopsis leaf development indicate causes for loss of stress tolerance with age

“…Nicotinic acid provides stress resistance in plants by protecting the cells against oxidative damage ( Hussein et al , 2014 ; Berglund et al ., 2016 , 2017 ). Dehydroascorbic acid plays an important role in plant adaptation to environmental stresses ( Akram et al , 2017 ; Chang et al , 2017 ; Hasanuzzaman et al , 2019 ) and, by means of the dehydroascorbate reductase (DHAR) reaction ( Smirnoff, 1996 ; Smirnoff and Wheeler, 2000 ), can be reduced to ascorbic acid, one of the most important antioxidants in plants ( Conklin and Barth, 2004 ; Akram et al , 2017 ).…”

Enhanced metabolic process to indole alkaloids in Clematis terniflora DC. after exposure to high level of UV-B irradiation followed by the dark

“…Additionally, it has been suggested that indoles have anti-oxidant and radical scavenging activities [58]. Tryptophan, produced from indole through L-tryptophan synthase, has important biological roles in stress-defense, such as against salinity [59] and water stresses [60]. Indole and tryptophan provide the skeletons for indole alkaloids [61] and IAA [62, 63].…”

Effect of Tryptophan and Ascorbic Acid on Yield and Some Chemical Constituents of Lupine ( Lupines termis L.) Plants

“…Tryptophan is an amazing amino acid, it might go about as an osmolyte, particle transport controller, adjusts stomatal opening and detoxify harmful effects of heavy metals (Orabi et al, 2014;Rai, 2002). In addition, the tryptophan pathway assumes a protective role in plants (Hussein et al , 2014). It was also found that using of amino acids as foliar spray enhances some of chemical components such as total free amino acids and total soluble sugars in Antholyza ethiopica .…”