Effect of biostimulants on germination, growth and metabolism indicators in Lactuca sativa seedlings under heat stress

Treatment of seeds with biostimulants is an important technology to deal with heat stress during planting and improve yield, which all starts with seed germination. Therefore, the current study aims to investigate the effect of seaweed and amino acid-derived biostimulants, on the improvement of heat stress in the seed germination stage of cool-season plants (lettuce). The experiment was set up in a completely randomized design, with treatments repeated three times. For this purpose, seeds were pretreated for ۲ hours in an aqueous solution of ۰.۵ g/L Algabon® and ۲ g/L Bonamid®. Then, the seeds were incubated in the dark for ۷۲ hours at ۲۸°C (control) and ۳۵°C (heat stress). In cool-season seedlings (lettuce), pre-treatment with biostimulants Algabon and Bonamid led to an increase in indicators of germination percentage, root length, shoot length, fresh weight, dry weight, and also the activity of beta-amylase, protease and the amount of soluble sugars under heat stress (temperature of ۳۵°C). The results showed that heat stress has created conditions of oxidative stress (production of H۲O۲) in the seeds of cool-season plants, although pre-treatment of cool-season seeds with Algabon and Bonamid led to a decrease in H۲O۲ production under heat stress. On the other hand, the pre-treatment of the lettuce seeds with Algabon has increased the ability of the seeds to increase the scavenging of free radicals produced during heat stress. In general, it seems that the pre-treatment of seeds with Algabon by producing some compatible osmolyte compounds and stimulating the activity of enzymes involved in germination increases the germination performance and makes the seeds of lettuce resistant to thermal stress.

Keywords:

Algabon , Biostimulant , Bonamid , Heat stress , آلگابن , بنامید , تنش گرمایی , محرک های زیستی