Standardization of Seed Testing Protocol and Seed Germination Improvement Treatment in Henna (Lawsonia inermis Linn.).

A research endeavor aimed at standardizing the seed germination process for Henna involved a comprehensive exploration of various germination media, temperature regimes, and dormancy - breaking treatments. Three distinct media - top of paper, between paper and sand-were evaluated alongside constant temperatures of 20°C, 25°C, and 30°C, as well as an alternating temperature of 20/30°C. An array of pre-treatments, including water soaking, KNO3, thiourea, leaching, GA3, and chilling treatment, were administered with the objective of enhancing seed germination. The findings highlighted the top of paper method and an alternate temperature of 20/30°C as the most conducive for seed germination, yielding remarkable outcomes viz., 80% germination rate, root length of 1.4cm, shoot length of 1.6cm, dry matter production of 3.0 mg 10 seedlings-1, and a vigor index of 240. Furthermore, specific timelines for key germination stages were delineated: 5.5days for initiation of germination, 7.8 days for 50% seed germination, 16.0days for the onset of seedling withering, and 17.8days for the initiation of seedling mortality. As a result, it recommended that the first count on 8th day and final count on 16th day for evaluation. Further investigation found that soaking seed in a 1% Thiourea solution for 24 hours was highly effective, resulting in an impressive 94% germination rate, with minimal abnormal seedlings (3%), fresh ungerminated seeds (2%), and dead seeds (1%). Additionally, it significantly improved speed of germination (4.6), root length (1.5cm), shoot length (1.4cm), dry matter production (3.43 mg 10 seedlings-1), vigor index I (277), and Vigor index II (324). In contrast, untreated seeds only attained a 64% germination rate.