Comparison Of The Mineral Nutrition Of The Ferns Cyathea Aurea, C. Delgadii, Dicranopteris Flexuosa And Pteridium Arachnoideum In La Gran Sabana, Venezuela

Essential and non-essential elements were investigated in aerial and subterranean organs of the tree ferns Cyathea aurea and C. delgadii in Canaima National Park, Venezuela, as well as in the herbaceous ferns Dicranopteris flexuosa and Pteridium arachnoideum, two species with different position in the phylogenetic tree. The maximum foliar concentrations of Al, P, Mg and Fe were higher in C. delgadii than that in C. aurea; however, the maximum concentration of Mn, Zn and Cu was lower in C. delgadii. The aerial organs of the tree ferns showed lower Ba concentrations than those in the herbaceous species and a significant positive lineal correlation Ba-Ca was found, as well as a relation Ba:K with negative tendency. The highest Pb concentrations in aerial and subterranean organs correspond to C. delgadii. Between the four studied species, the phylogenetically most ancient fern, D. flexuosa, showed the highest foliar concentrations of Al, Mn and REE, as well as the lowest concentrations of P and Mg. On the contrary, the more recent fern, P. arachnoideum showed the lowest concentrations of Al. It is concluded that the tree ferns show Al accumulation and although the element levels may be affected by several factors, we found patterns in the elemental composition in the four studied species, such as: a) higher concentration of Al and REE in D. flexuosa, b) contrast in the molar stoiquiometric ratios Ca:Ba in tree ferns and herbaceous ferns and c) the highest Pb concentration in C. delgadii.