Effect of commercial seaweed and amino acid-derived biostimulants on germination, metabolism indices and growth of canola, green bean, barley and lettuce under heat stress

The current study aimed to determine the role of two commercial biostimulants, Algabon® (seaweed extract-derived) and Bonamid® (containing amino acid (۸۵%)), on improving heat stress during the germination stage and seedling growth of ۴ different crops, canola, green bean, barley and lettuce, using a factorial design within a completely randomized design. 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). The results showed that heat stress (temperature of ۳۵°C) significantly reduced all germination and growth indices, the activity of α-amylase and protease enzymes and radical scavenging activity (RSA), while increasing the amount of soluble carbohydrates and H۲O۲ content in the seedlings of barley and lettuce. In contrast to the results for barley and lettuce seedlings, heat stress caused an increase in all germination and growth indices, the activity of α-amylase and protease enzymes and RSA, however reduced H۲O۲ content in the seedlings of canola and green beans. In all the four species examined, under both control and stress conditions, the germination and growth indices, the activity of α-amylase and protease enzymes and RSA, and the amount of soluble carbohydrates were increased by the Algabon®. The reduction of H۲O۲ production under heat stress was observed in the seedlings of canola, green bean, barley and lettuce pre-treated with Algabon® and Bonamid®. In this study, we observed a composition-dependent effect of biostimulants in diminishing the effects of heat stress, so that Algabon® was more effective than Bonamid®. According to the results of the absolute decrease index, the lowest inhibition index and the highest relative heat tolerance index were observed in canola seeds pre-treated with Algabon®, which were identified as the most heat-resistant seedlings. 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 canola, green bean, barley, and lettuce resistant to heat stress.

کلیدواژه ها:

Amylase ، Biostimulant ، Heat stress ، Protease ، Resistance indices ، Amylase ، Biostimulant ، Heat stress ، Protease ، Resistance indices