Isoleucine treatment of seeds increased the content of 4-hydroxyisoleucine and affected the anatomy properties of Trigonella persica Boiss. At different developmental stages

Non-protein amino acid 4-hydroxyisoleucine (4HIL) from Trigonella persica Boiss., the only endemic species in Iran from the Fabaceae family, is known for its anti-diabetic property. 4HIL content was evaluated by HPTLC (High-performance thin-layer chromatography) method in seedlings (every 24 h for 6 days), 21-day plantlets, and 42-day mature plants growing from seeds treated with 5 and 7.5 mM isoleucine (Ile) compared to those growing from untreated seeds. The content of 4HIL showed an increasing trend during germination as it reached the highest level of 717 µg 100 mg − 1 FW on day 5 at 7.5 mM. The Ile significantly increased the growth parameters and anatomical properties of T. persica . Besides, Ile increased the carbohydrate content and the membrane stability of T. persica . Histochemical tests were also accomplished as evidenced by the maximum presence of starch on day 3, and lipids on day 5 in the mesophyll of cotyledons. In this research, the seedlings of T. persica . growing from treated seeds with 7.5 mM Ile were found to be a promising source of 4HIL on day 5 after imbibition.