De micronutrientes a elementos potencialmente tóxicos: crescimento e produção de biomassa de Canavalia ensiformis e Leucaena leucocephala em resposta ao excesso de Cu e Fe no solo

• Ano de defesa: 2024
• Autor(a) principal: Bomfim, Nayane Cristina Pires [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Tolerância; Biomassa; Toxicidade; Leguminosa; Acúmulo; Translocação; Tolerance; Biomass; Toxicity; Legumes; Accumulation; Translocation
• Link de acesso: https://hdl.handle.net/11449/257829; https://orcid.org/0000-0003-1446-5274

The increase in potentially toxic elements (PTEs) in the soil is worrying, especially in agricultural soils due to the bioaccumulation factor. Copper (Cu) and iron (Fe) are micronutrients, responsible for important functions in the plant body, but the high availability of these elements in the soil can cause soil contamination and toxicity in plants. Canavalia ensiformis and Leucaena leucocephala have been the target of studies that explore their tolerance and phytoremediation potential to some PTEs, and the focus of this study is to understand the physiological responses (gas exchange, growth, tolerance, biomass, accumulation, translocation) of these species to high Cu and Fe contents in the soil, separately, and evaluate the growth of L. leucocephala in excess of these elements in the soil for 12 and 24 months of cultivation (long-term cultivation) in a greenhouse. Treatments 50, 150, 250 and 350 mg dm-3 of each element (CuSO4*5H2O and FeSO4*7H2O), separately, were incorporated into the soil (Oxisol) of each experimental unit (six replications per treatment), in addition to the control. Seeds of C. ensiformis and L. leucocephala were sown in the soil enriched with the treatments in pots of 4 and 10 dm3 of soil, respectively and after emergence they were cultivated in a greenhouse for 90 days (C. ensiformis); 12 and 24 months (L. leucocephala) in a completely randomized design. Biometric assessments (length, diameter) gas exchange was performed; fresh and dry weight of the organs (roots, leaves and stems), quantification of Cu and Fe in plant organs and quantification of the bioavailability of the elements in the soil. Based on these data, calculations of tolerance, accumulation and translocation were carried out. C. ensiformis was tolerant to Fe treatments and as for Cu, it showed tolerance up to treatment 150 mg dm-3. The tolerance of the species is dependent on chlorophyll levels and gas exchange. There was accumulation of both PTEs in the roots and translocation to the shoot. L. leucocephala showed tolerance to Cu and Fe up to treatment 50 and 250 mg dm-3, respectively, at both cultivation times. The time of exposure to PTE negatively influenced the biomass of L. leucocephala subjected to Cu, unlike Fe. L. leucocephala accumulated more Cu over time, the same did not happen for plants subjected to Fe.