Measurement of chlorophyll fluorescence can be a useful tool for detecting changes in the photosynthetic apparatus of plants. With the understanding that early detection of zinc (Zn) contamination is fundamental in environmental monitoring, the aim of this study was to assess Zn stress in castor bean (Ricinus communis) plants using X-ray chlorophyll fluorescence. The changes brought about by Zn in photosynthetic pigments and in the mineral composition of plants were also studied. Castor bean plants were grown for 28 days in a nutrient solution with five Zn rates (100, 200, 300, 400, and 600 µmol L-1), as well as a control with 0.380 µmol L-1 of Zn. Chlorophyll fluorescence detected temporal changes from Zn accumulation in plants and proved to be useful in early detection of Zn toxicity in castor bean. Despite negative effects on nutritional status, castor bean was relatively tolerant to Zn toxicity, indicating that the species is an attractive alternative for revegetation or remediation of Zn contaminated areas.
Ricinus communis; trace elements; soil pollution; photosynthesis
