Chromium (Cr) contamination poses food safety and environmental challenges, yet the early-stage physiological and molecular responses to Cr(III) stress remain unclear. Citrus and tomato are economically important crops representing woody and herbaceous species, making them valuable models for studying heavy metal toxicity in plants. This study investigates the impact of Cr (III) exposure on citrus and tomato seedlings, with a focus on physiological phenotypes and transcriptional response. Citrus seed germination declines with increasing Cr(III) concentrations, while low Cr(III) levels promote tomato germination, with inhibition occurring above 1 g/L. Under hydroponic conditions, Cr (III) severely hampers root and leaf growth in both citrus and tomato plants, accompanied by decreased net photosynthetic rate. Using a GFP-based confocal microscopy system, we observed reduced fluorescence intensity within three days of Cr(III) exposure (100 mg/L and 500 mg/L), indicating early cellular damage. Biochemical assays revealed oxidative stress, marked by increased H2O2, malondialdehyde (MDA), and antioxidant enzyme activity. Additionally, low Cr (III) concentrations could result in the death of various microorganisms, including Escherichia coli, Agrobacterium rhizogenes, and Agrobacterium tumefaciens. Transcriptomic analysis identified differentially expressed genes related to MAPK signaling pathway and Plant hormone signal transduction pathway. Transcription of many transcription factors, such as bHLH, WRKY, and MYB, also underwent significant changes.

Farmland soil organisms frequently encounter pesticide mixtures presented in their living environment. However, the underlying toxic mechanisms employed by soil animals to cope with such combined pollution have yet to be explored. This investigation aimed to reveal the changes in cellular and mRNA levels under chlorpyrifos (CPF) and lambda -cyhalothrin (LCT) co-exposures in earthworms ( Eisenia fetida ). Results exhibited that the combination of CPF and LCT triggered an acute synergistic influence on the animals. Most exposures resulted in significant alterations in the activities of total superoxide dismutase (T -SOD), copper/zinc superoxide dismutase (Cu/Zn-SOD), caspase 3, and carboxylesterase (CarE) compared to the basal level. Moreover, when exposed to chemical mixtures, the transcription levels of four genes [heat shock protein 70 ( hsp70 ), gst , sod , and calreticulin ( crt )] also displayed more pronounced changes compared with their individual exposures. These changes in determined parameters indicated the occurrence of oxidative stress, cell death, detoxification dysfunction, and endoplasmic reticulum damage after co-exposure to CPF and LCT in E. fetida . The comprehensive examination of mixture toxicities of CPF and LCT at different endpoints would help to understand the overall toxicity they cause to soil invertebrates. The augmented deleterious effect of these pesticides in a mixture suggested that mixture toxicity assessment was necessary for the safety evaluation and application of pesticide mixtures.