Ameliorative effects of foliar polyamines on leaf traits of guava (Psidium guajava L.) cv. Hisar Safeda under saline water irrigation

Abstract

Salinity stress poses a significant constraint to guava production, particularly in arid and semi-arid regions where saline irrigation is prevalent. This study investigated the mitigating effects of exogenous polyamine application on guava leaves parameters under saline water irrigation conditions. The experiment was conducted at the Experimental Orchard, Department of Horticulture, CCS Haryana Agricultural University, Hisar during 2023-2025 using a Factorial Completely Randomized Design with three replications. Treatments included four irrigation water salinity levels (Canal water, 6.0, 7.0 and 8.0 dSm⁻¹) and seven polyamine treatments (Putrescine at 0.5 and 1.0 mM, Spermidine at 0.5 and 1.0 mM, Spermine at 0.5 and 1.0 mM, and Control). Results demonstrated that increasing salinity levels significantly reduced most of le f traits. However, exogenous application of polyamines, particularly Putrescine at 0.5 mM, significantly ameliorated salt stress effects. The highest values for number of leaves (51.56), leaf area (359.79 cm²), fresh leaf weight (7.39 g) and dry leaf weight (1.66 g) were recorded with Putrescine 0.5 mM treatment. The study demonstrates that foliar application of polyamines, especially Putrescine at 0.5 mM, can serve as an effective strategy to enhance guava tolerance to salinity stress and maintain productive growth under challenging irrigation conditions.