Along with other heavy metals, arsenic (As) is one among the substances most harmful to living organisms including humans. Owing to its morphological similarity to phosphorus, the uptake of As is influenced by photosynthesis and the phosphorus uptake pathway. In this study, we varied arsenic exposure and light intensity during nutrient solution cultivation of lettuce (Lactuca sativa L.) to determine the effect of these two factors on arsenic uptake, lettuce growth, and electron transfer in photosystem II. In the treatment exposed to 30 μmol L-1 of arsenic, the shoot arsenic concentration increased from 4.73 mg kg-1 to 18.97 mg kg-1 as the light intensity increased from 22 to 122 μmol m-2 s-1. The water content and ET2o/RC of the shoots were not affected by arsenic at low light intensity; however, at optimal light intensity, they decreased progressively with arsenic exposure. Increased light intensity stimulated the growth of plant roots and shoots; contrarily, the difference in growth decreased as the concentration of As exposure increased. The results of this study suggest that the effect of As on plant growth is dependent on light intensity; in particular, an increase in light intensity can increase the uptake of As, thereby affecting plant growth and As toxicity.

1. INTRODUCTION
2. MATERIALS AND METHODS
    2.1. Plant material and treatment conditions
    2.2. Measurement of fresh mass androot length
    2.3. Estimation of As content
    2.4. Estimation of photosynthetic activities
    2.5. Statistical analysis
3. RESULTS AND DISCUSSION
    3.1. Arsenic accumulation in lettuce shootsand roots
    3.2. Root and shoot growth
    3.3. Impact of arsenic exposure onphotosynthesis:Fluorescence of chlorophyll a
    3.4. Correlation coefficient withAs concentration in plant
4. CONCLUSION
CRediT authorship contribution statement
Declaration of Competing Interest
ACKNOWLEDGEMENTS
REFERENCES

• Hyun-Gi Min(Ojeong Resilience Institute, Korea University, Seoul 02841, Republic of Korea)
• Eunjee Kim(Division of Environmental Science and Ecological Engineering, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea)
• Min-Suk Kim(Waste Resources Management Division Resource Recirculation Bureau, Ministry of Environment, Sejong 30103, Republic of Korea)
• Jeong-Gyu Kim(Division of Environmental Science and Ecological Engineering, College of Life Science and Biotechnology, Korea University, Seoul 02841, Republic of Korea) corresponding author