Cajanus cajan and Canavalia ensiformis as potential phytoremediation agents in soils contaminated with manganese

Abstract

Cajanus cajan (pigeon pea) and Canavalia ensiformis (jack bean) are commonly used in human and animal food, green manure and also for the recovery of degraded areas, due to the germination capacity of these species in compacted soils. Due to these characteristics, pigeon pea and jack bean are potential candidates for the application of phytoremediation, which aims to decontaminate soils with excess of potentially toxic elements through plants. In this work, the potential for decontamination of soils with high concentrations of Mn2 + will be investigated. We will use the Dystrophic Red Latosol for contamination with 1M aqueous solution of MnCl2 in the following concentrations; 0, 60, 80, 100, 120 and 140 mg / dm3 of soil. Soil samples will be collected and sent to the analysis of the available Mn concentration, and in each 4L pot, 5 seeds will be sown, obeying the completely randomized experimental design with 5 treatments and 4 repetitions totaling 20 experimental units for pigeon pea and 20 for the pork beans. The plants will be grown for 60 days and growth will be measured weekly by assessing the height and number of leaves. The behavior of the photosystems will be measured by means of gas exchange measurements, using a portable analyzer and the photosynthetic pigments will also be quantified. After the disassembly of the experiment, the fresh mass, dry mass, the nutritional status of the plants, and also the metabolic status will be gauged from biochemical tests related to the compounds of carbon metabolism and nitrogen metabolism. The data obtained will be subjected to analysis of variance and the averages will be adjusted to the regression models that suit the biological behavior. It is expected to determine the tolerance and potential for Mn extraction, and also to gather information on the effects of excess Mn on the carbon and nitrogen metabolism for pigeonpea and jack bean.