Maize growth and physiological dynamics: Arsenic uptake modulation under combined abiotic stresses of salinity, boron and arsenic

Soil salinity and relatively high boron (B), frequently co-occur in agricultural environments, posing significant challenges to crop growth and productivity. This inhibitory effect on plant growth can be further exacerbated when crops like maize ( Zea mays L.) are exposed to the arsenic (As) contaminated soils and irrigation water, along with elevated salinity and B levels. Understanding these combined effects is crucial for optimizing crop resilience. A hydroponic study was conducted to assess the interactive effects of high B and As under saline conditions on maize. Plants were stressed with salinity (60 mM NaCl), boron (3 mM H 3 BO 3 ) and arsenic (40 µM Na 3 AsO 4 ) alone and in combination. A 20-day stress period caused significant reduction in overall growth, with more pronounced effect under combined stress. Root and shoot dry biomass was decreased by 63.45 and 57.84 % while leaf area and chlorophyll index (SPAD value) were diminished by 56.34 and 64.23 %, membrane stability index (MSI) and leaf relative water contents (RWC %) were reduced by 63.92 and 61.59 % upon exposure to these combined stressors as compared to the control treatment. Arsenic stress increased the shoot and root As accumulation by 52.4 and 84.6-fold, respectively. However, high B and salinity effectively suppressed these levels due to their negative correlation with As uptake. Further in-depth phytometric profiling is needed to understand the underlying mechanisms of plant stress tolerance and nutrient homeostasis under these combined stresses. • Expended use of contaminated sources for agriculture reduces crop productivity. • First report on the combined effects of arsenics, boron and salinity on maize. • Combined arsenic, boron and salinity stress is highly detrimental to plant health. • Salinity and high boron moderated the arsenic uptake and translocation.