Abstract
The potential of macroalgae as biostimulants in agriculture was proved worthy.
Vicia faba
and
Helianthus annuus
are socioeconomic crops owing to their increasing demand worldwide. In this work, we investigated the energetic role of seed presoaking and irrigation by the brown seaweed,
Sargassum polycystum
aqueous extract (SAE) on certain germination and growth traits, photosynthetic pigments, carbohydrates, phenolics, flavonoids, and the total antioxidant activity. Compared to the control plants, our consequences revealed that seeds that received the SAE improved all the germination and growth criteria for both crop plants. Furthermore, the SAE significantly increased the carotenoids, total photosynthetic pigments, and total carbohydrates by (14%, 7%, and 41%) for
V. faba
and (17%, 17%, and 38%) for
H. annuus
, respectively. Phenolics and flavonoids were significantly induced in
Vicia
but slightly promoted in
Helianthu
plants, whereas the total antioxidant activity in both crops non significantly elevated. Even though The NPK contents were significantly stimulated by the SAE in
Vicia
plants, the effect was different in
Helianthus
, where only nitrogen content was significantly enhanced, whereas phosphorus and potassium showed little enhancement. Thus, the SAE treatment is one of the superlative sustainable strategies for food, feed, and as excellent plant conditioner.