PREETY RANI, SARITA DEVI*, SATPAL, SUKHAM MADAAN, PANKAJ, GAYATRI AND AJEEV KUMAR
Department of Botany & Plant Physiology,
Department of G&PB (Forage Section), 3Department of MBB,
CCS Haryana Agricultural University, Hisar-125 004 (Haryana), India
*(e-mail: devisaritaa@gmail.com)
(Received: 1 July 2025; Accepted: 5 September 2025)

SUMMARY

Biostimulants are natural or synthetic substances applied to plants to enhance their growth, development, and stress tolerance without providing essential nutrients. Their use in agriculture has gained significant attention as a sustainable strategy to boost crop productivity, enhance quality, and reduce dependency on chemical fertilizers and pesticides. With growing concerns over climate change and resource limitations, biostimulants offer an eco-friendly solution to optimize crop performance and improve resilience in challenging environments. This study was conducted at the Dryland Research Farm, Forage Section, CCS HAU, Hisar, to evaluate the physiological effects of various bio-stimulants on the cowpea genotype CS-88 (Vigna unguiculata L.) under rainfed summer conditions in 2019. Specifically, the experiment aimed to assess how these bio-stimulants influenced the plant responses when applied exogenously at the flower initiation stage. The physiological parameters in cowpea plant like gaseous exchange studies chlorophyll content (SPAD units) and photochemical quantum yield showed declining trend in rainfed condition. Values ranged from control to biostimulant application in assimilation rate (23.31 – 29.73 μmol CO₂ m^-2 s^-1), transpiration rate (1.70 – 2.07 mmol H₂O m^-2 s^-1) and stomatal conductance (0.02 – 0.03 mmol H₂O m-2 s-1). Similarly, chlorophyll content (SPAD units) and photochemical quantum yield also showed the increasing trend after foliar application of different biostimulants and the values varied from (41.0 – 51.4) and (0.678 – 0.718), respectively. Soil analysis was also done to find the best response of these biostimulants.

Key words: Biostimulants, cowpea, glycine betaine, proline content and RWC

231-236