Effectiveness of sulfur-modified wheat straw biochar in alleviating vanadium stress in rice: impacts on growth, photosynthesis, and redox regulation.

Altaf, Muhammad Mohsin; Ashraf, Sahrish; Khan, Muhammad Qaisar Naeem; Sun, Xiaoyan; Li, Dong; El-Sheikh, Mohamed A.; Xu, Shunqing; Zhu, Zhiqiang

Vanadium (V) is recognized as an environmental contaminant that adversely affects plant growth and development. The main objective of this study was to investigate the effects of sulfur-modified biochar (SBC) compared to standard biochar (BC) on rice under V suppression (35 mg L−1). Our findings revealed that V stress significantly suppressed rice seedling growth, evidenced by reductions in shoot fresh weight, chlorophyll pigment content, photosynthetic assimilation, and root attributes, with higher V accumulation observed in both shoots and roots of V-stressed plants compared to BC- and SBC-treated plants. SBC application improved rice growth more effectively than BC, exhibiting increases of 61.41% in fresh weight, 63.04% in root length, 66.66% in chlorophyll a, 52.20% in chlorophyll b, and 52.95% in carotenoids, alongside enhanced gas exchange attributes. Notably, SBC reduced V accumulation by 58.33% in shoots and 43.79% in roots compared to V-stressed plants. SBC also induced V stress tolerance in rice by elevating antioxidant enzyme activities in roots and shoots, including superoxide dismutase (SOD, 85.25/89.41%), catalase (CAT, 119.04/100.01%), glutathione peroxidase (GPX, 82.20/79.82%), glutathione S-transferase (GST, 123.74/114.67%), ascorbate peroxidase (APX, 86.56/63.74%), glutathione reductase (GR, 204.87/60.36%), dehydroascorbate reductase (DHAR, 53.60/62.06%), and monodehydroascorbate reductase (MDHAR, 87.09/88.88%), while simultaneously reducing hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels. Furthermore, SBC increased the activities of glyoxalase enzymes (Gly I by 96.15/77.14% and Gly II by 115.78/104.25%), mitigating methylglyoxal (MG) induced toxicity, and enhanced the expression of metal-tolerant (OsFSD1) genes and antioxidant-glyoxalase systems. Overall, SBC application was found to be more effective than raw BC in alleviating V-induced toxic effects and improving rice plant growth. Nonetheless, further studies must be performed to determine exactly driving mechanism involved in the promotion of growth. Highlights: Vanadium (V) toxicity impairs rice growth through severe oxidative damage. Wheat straw biochar modified with sulfur (SBC) sustained plant growth under V-stress. SBC reduced V deposition in both roots and leaves of rice. SBC enhanced antioxidant enzyme activities and upregulated metal-resistant genes in rice.

BIOCHAR; VANADIUM compounds; RICE farming; POLLUTANTS; PHOTOSYNTHESIS; OXIDATIVE stress; ANTIOXIDANTS

Biochar, 2025, Vol 7, Issue 1, p1

2524-7972

Academic Journal

10.1007/s42773-025-00462-2