Aminolevulinic acid-induced changes in yield and seed-oil characteristics of sunflower (Helianthus annuus L.) plants under salt stress

Effectiveness of a potential plant growth regulator,5-aminolevulinic acid (ala) on improving yield and regulating some potential physio-chemical attributes of seed and oil of two sunflower cultivars was examined in a greenhouse experiment. four varying levels of ala 20,50 and 80 mg l-1 were applied foliarly to the two sunflower cultivars (hysun-33 and s-278) grown under saline (150 mm nacl) and non-saline (0 mm nacl) conditions. salt stress adversely affected the achenes/plant,total achene yield,100-achene weight,seed moisture content,seed oil percentage,seed k+ and p concentrations of both sunflower cultivars,while in contrast,salt-induced increase in the accumulation of cl- and na+ in seed as well as α-tocopherols in oil of both sunflower cultivars. however,no significant change in seed organic and inorganic contents,oil refractive index (ri) and seed ca2+ content was observed due to salt stress in both sunflower cultivars. foliar-applied varying levels ala remained ineffective in improving all yield variables,oil refractive index and seed inorganic nutrients (na+,cl-,k+ and p) of both sunflower cultivars under saline and non-saline regimes. however,a significant increase in seed oil concentration,accumulation of oil α-tocopherols and seed p of both sunflower cultivars was observed due to foliar-applied 20 and 80 mg l-1 of ala under saline conditions. overall,ala was ineffective in ameliorating the salt-induced adverse effects on yield and different seed-oil characteristics except of seed p and oil α-tocopherols in sunflower plants.