Effect of moisture stress on Nitrate Reductase Activity (NRA) in PEA (Pisum sativum L.) [C3] and sorghum (Sorghum vulgare Pers.) [C4] plants

Nitrate reductase activity (NRA) was studied in pea, a C₃ plant, and sorghum, a C₄ plant, at various stages of growth and development. Influence of moisture stress and nitrogen application was also observed since these factors have profound influence on growth and development.

In pea, NRA was maximum at pod maturity stage and minimum at flowering stage. In sorghum plant there was gradual increase in NRA upto grain formation followed by a fall in activity at maturity.

Nitrogen treatment as nitrate and ammonia significantly increased nitrate reductase activity over control in both pea and sorghum. Treatment with potassium nitrate was found to stimulate more NRA in pea than with ammonium sulphate. In sorghum, both forms of nitrogen did not differ much in their influence on NRA.

Influence of moisture stress in reducing NRA was more clear in sorghum, a C₄ plant than in pea, a C₃ plant. In general, control plants recorded low NRA in both the crops when compared to nitrogen treated plants except at pod formation stage in pea.