Differential Mechanisms of Tolerance and Accumulation in Cajanus cajan (L.) Millsp. and Canavalia ensiformis (L.) DC in Response to Soil Manganese Concentration

Abstract

ABSTRACT Cajanus cajan and Canavalia ensiformis are commonly used as cover crops due to their high biomass production, in addition they are also applied in recovery strategies for degraded areas. The objective of this study is to compare the tolerance, accumulation and translocation of Mn in the tissues of C. cajan and C. ensiformis, based on biomass production and the effects on the photosynthetic apparatus between species. The experiment was carried out in Red Latosol, contaminated with MnCl2 in the following concentrations: 0 (control), 80, 100, 120, 140 and 160 mg kg−1. Mn doses resulted in differentiated absorption, translocation and accumulation in plant organs, generating changes in the photosynthetic apparatus, reduction in dry mass and growth, and variations in tolerance and translocation levels between species. According to the results obtained, both species proved to be tolerant Mn and can be used in manganese management systems, they’re able to accumulate Mn in tissues, and not only maintain but also improve biomass production at intermediate doses, C. cajan indicates to be a better option for phytostabilization of Mn, on the other hand C. ensiformis, indicates to be a better option for phytoextraction of Mn in soils with contents up to 160 mg kg−1.