Nitrate Seed Priming Modulates Germination Physiology of Rice var. Sahabhagi and MTU 1010

Abstract

Rice (Oryza sativa L.) often suffers from poor germination under normal as well as various adverse climatic conditions, in this context seed priming can be considered as an important strategy for improving seed germination and seedling stand establishment of different crops. This study evaluated the effects of magnesium nitrate [Mg(NO₃)₂] and calcium nitrate [Ca(NO₃)₂] priming on germination physiology of rice varieties Sahabhagi and MTU‑1010. Seeds were primed with varying concentrations (1–20 mM for both nitrate salts) and assessed for germination percentage as well as α‑ and β‑amylase (free and bound form) activity over 24–120 h. Results showed that both nitrate salts significantly enhanced germination compared to controls, with Sahabhagi responding faster at early stages and MTU‑1010 exhibiting delayed but uniform germination. varieties. Enzyme activity generally increased during the early germination period and reached its highest values at 72–96 h. Under magnesium nitrate priming, Sahabhagi recorded a maximum α-amylase activity of 680.90 mg maltose g−1 h−1 at 72 h. Calcium nitrate produced a maximum free β-amylase activity of 402.32 mg maltose g−1 h−1 in Sahabhagi and a maximum bound β-amylase activity of 270.91 mg maltose g−1 h−1 in MTU-1010 at 72 h. Treatment effects were significant at the 1% level. These findings indicate that nitrate priming can enhance germination and reserve mobilisation, although responses vary with genotype, salt concentration, and assessment time.