We investigated the effect of moderate Cu 2+ and Cd 2+ stress by applying chlorophyll (Chl) fluorescence and P 700 absorbance measurements to monitor the photosynthetic electron transport activity of 3-week-old Pisum sativum L. cv. Petit Provençal plants grown in a modified Hoagland solution containing 50 μM CuSO 4 or 5 μM CdCl 2. Both heavy metals caused a slight inhibition in PSII photochemistry as indicated by the decrease in the effective quantum efficiency of PSII (Φ PSII), the maximum electron transport capacity (ETR max), and the maximum quantum yield for electron transport (α). PSI photochemistry was also affected by these heavy metals. Cu 2+ and Cd 2+ decreased the quantum efficiency of PSI (Φ PSI) as well as the number of electrons in the intersystem chain, and the Cu 2+ treatment significantly reduced the number of electrons from stromal donors available for PSI. These results indicate that PSII and PSI photochemistry of pea plants are both sensitive to moderate Cu 2+ and Cd 2+ stress, which in turn is easily detected and monitored by Chl fluorescence and P 700 absorbance measurements. Therefore, monitoring the photochemistry of pea plants with these noninvasive, yet sensitive techniques offers a promising strategy to study heavy metal toxicity in the environment.
ASJC Scopus subject areas
- Plant Science