Duration-dependent Seed Priming: A Strategy to Trigger Amylase and Protease-mediated Food Reserve Mobilization during Seed Germination and Seedling Growth of Pea (Pisum sativum L)

An in vitro study was carried out under controlled environmental conditions in the Laboratory of Plant Physiology, Department of Agronomy, School of Agriculture, Lovely Professional University, to assess the impact of duration-dependent seed priming on the mobilization of food reserve based on amylase and protease enzymes during seed germination and seedling growth of pea (Pisum sativum L).

The present study was laid out in a complete randomized design (CRD) comprising three priming durations and four seed priming agents. Wherein the duration of seed priming ranged from 5 to 15 hours, while the deionized water (T₁), magnesium nitrate 7.5 mM (T₂), calcium nitrate 7.5 mM (T₃), potassium nitrate 15 mM (T₄) and biopriming with Rhizobium (T₅) were used as a priming agent.

Results indicated that among the priming durations, 10 hours was the most effective in terms of seed germination, speed and uniformity of germination, compared to 5 and 15 hours. Additionally, the activity of key enzymes viz., amylase and protease, was also markedly enhanced at 10 hours, reflecting the optimum activity. Among the seed priming agents, hydro-priming with deionized water was noticed to be the most effective for the evaluated parameters at 5 h priming duration, followed by magnesium nitrate (T₂)> potassium nitrate T₄ > biopriming with Rhizobium (T₅) and calcium nitrate (T₃). Conversely, potassium nitrate (15 mM) proved to be the most effective priming agent at 10 hours of priming, followed by magnesium nitrate (T₂) > calcium nitrate (T₃)> Hydro-priming with deionized (T₁) and biopriming with Rhizobium (T₅). However, similar trends with fewer magnitude were observed at 15 hours of seed priming, A per cent increase or decrease analysis over control clearly indicated that 10 hours of priming with potassium nitrate resulted in the maximum percent increase in seed germination (27.8%), germination index (GI, 38.8%), vigour index (VI, 49.6%), amylase activity (45.1%) and protease activity (44.8%) along with the reduction in time to 50% germination was (-16.7%). The findings of the results suggest that the use of 10 hours of seed priming with potassium nitrate (15 mM) significantly triggers the activity of hydrolytic enzymes, thereby promoting faster seed germination and vigorous seedling establishment in pea.