Scholarlink

<p>Cyanobacteria play a vital role in rice-field ecosystems by contributing to nitrogen fixation, organic matter recycling, and soil fertility. However, the widespread use of the chloroacetamide herbicide pretilachlor, together with increasing ultraviolet radiation (UVR), poses a serious threat to cyanobacterial survival and metabolism. Although the individual effects of herbicides and UVR on cyanobacteria are known, their combined impact, particularly in rice-field species, remains poorly understood. The present study investigated the individual and combined impacts of pretilachlor and UVR (PABP) stress on the morphology, physiological responses, and biochemical composition of the rice-field cyanobacterium <i>Fischerella</i> sp. HKAR-24. Microscopic analyses (brightfield, scanning electron, and fluorescence microscopy) revealed that PABP exposure caused pronounced cell deformation, pigment loss, filament disruption, and enhanced intracellular ROS accumulation compared to individual treatments. In vivo DCFH-DA fluorescence and Nile red fluorescent microscopy analysis further revealed that PABP exposure induced severe oxidative stress as evidenced by a 4.9-fold increase in the G/R ratio (<i>p</i> &lt; 0.05) and a 7.4-fold decline in chlorophyll <i>a</i> (Chl <i>a</i>) content as compared to the control. This oxidative damage was accompanied by enhanced lipid peroxidation and activation of antioxidant enzymes (SOD, POD, CAT, and APX), indicating an oxidative stress-mediated toxicity mechanism. Notably, the PABP exposure caused a greater reduction in major macromolecular constituents of the rice-field cyanobacterium <i>Fischerella</i> sp. HKAR-24. The exposure conditions used in this study were selected to reflect environmentally relevant concentrations of pretilachlor reported in rice-field ecosystems and high UVR levels experienced under field conditions. Overall, the study provides novel insights into the synergistic effects of UVR and herbicide stress on cyanobacteria, emphasizing the need for sustainable herbicide management to protect agroecosystem stability under changing climatic conditions.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Interactive effects of ultraviolet radiation and herbicide pretilachlor on the morpho-physiological and biochemical attributes of the rice-field cyanobacterium Fischerella sp. HKAR-24

  • 期刊论文

  • 发表日期：

    2026年2月26日

查看全文
  • Riya Tripathi,
  • Ashish P. Singh,
  • Palak Rana,
  • Varsha K. Singh,
  • Sapana Jha,
  • Rajeshwar P. Sinha

摘要

Cyanobacteria play a vital role in rice-field ecosystems by contributing to nitrogen fixation, organic matter recycling, and soil fertility. However, the widespread use of the chloroacetamide herbicide pretilachlor, together with increasing ultraviolet radiation (UVR), poses a serious threat to cyanobacterial survival and metabolism. Although the individual effects of herbicides and UVR on cyanobacteria are known, their combined impact, particularly in rice-field species, remains poorly understood. The present study investigated the individual and combined impacts of pretilachlor and UVR (PABP) stress on the morphology, physiological responses, and biochemical composition of the rice-field cyanobacterium Fischerella sp. HKAR-24. Microscopic analyses (brightfield, scanning electron, and fluorescence microscopy) revealed that PABP exposure caused pronounced cell deformation, pigment loss, filament disruption, and enhanced intracellular ROS accumulation compared to individual treatments. In vivo DCFH-DA fluorescence and Nile red fluorescent microscopy analysis further revealed that PABP exposure induced severe oxidative stress as evidenced by a 4.9-fold increase in the G/R ratio (p < 0.05) and a 7.4-fold decline in chlorophyll a (Chl a) content as compared to the control. This oxidative damage was accompanied by enhanced lipid peroxidation and activation of antioxidant enzymes (SOD, POD, CAT, and APX), indicating an oxidative stress-mediated toxicity mechanism. Notably, the PABP exposure caused a greater reduction in major macromolecular constituents of the rice-field cyanobacterium Fischerella sp. HKAR-24. The exposure conditions used in this study were selected to reflect environmentally relevant concentrations of pretilachlor reported in rice-field ecosystems and high UVR levels experienced under field conditions. Overall, the study provides novel insights into the synergistic effects of UVR and herbicide stress on cyanobacteria, emphasizing the need for sustainable herbicide management to protect agroecosystem stability under changing climatic conditions.