GROWTH AND PHYSIOLOGICAL RESPONSES OF TREE SPECIES (Hymenaea courbaril L., Peltophorum dubium (Spreng.) Taub. and Myroxylon peruiferum L. F.) EXPOSED TO DIFFERENT COPPER CONCENTRATIONS IN THE SOIL

Abstract

-Copper (Cu) is an essential micronutrient for plants. However, when in excess, it becomes phytotoxic. In this context, the objective of this study was to evaluate the growth and physiological responses of tree species exposed to different copper concentrations in the soil. Three experiments were carried out, one for each forest species under study: Myroxylon peruiferum ("Óleo Bálsamo"), Hymenaea courbaril ("Jatobá") and Peltophorum dubium ("Canafístula"), with the same doses of copper (0, 50, 100, 200 and 400 mg kg -1 ). The experimental design was in randomized blocks (DBC), with five copper concentrations and four replicates. The plants were grown on soil substrate packed in 8-dm 3 pots and kept in a greenhouse for 90 days. Biometric measurements, chlorophyll, antioxidant enzymes and copper content in tissues were evaluated. Copper did not influence the vegetative growth of the species studied. The content of chlorophyll "a" was reduced with increasing copper concentrations in the soil. H. courbaril had 56 to 92% copper retained in the roots, and the same behavior was observed for P. dubium (77-91%) and M. peruiferum (19-64%). In the three species studied, there was copper bioaccumulation, mainly in the roots, possibly as a metal tolerance strategy, preserving the most active tissues and the photosynthetic machinery. Cu translocation from roots to shoot was very restricted in all species. This behavior, associated with the increase in the activity of some antioxidant enzymes in plants, may indicate the phytoremediation potential of the studied species.Keywords: Antioxidant enzymes; Bioaccumulation; Heavy metal. CRESCIMENTO E RESPOSTAS FISIOLÓGICAS DAS ESPÉCIES ARBÓREASHymenaea courbaril L., Peltophorum dubium (Spreng.) Taub. e Myroxylon peruiferum L. F. EXPOSTAS A DIFERENTES CONCENTRAÇÕES DE COBRE NO SOLORESUMO -O cobre (Cu) é um micronutriente essencial aos vegetais, mas em excesso torna-se fitotóxico para as plantas. Nesse contexto, o objetivo deste trabalho foi avaliar o crescimento e as respostas fisiológicas de espécies arbóreas expostas a diferentes concentrações de cobre no solo. Foram realizados três experimentos, sendo um para cada espécie florestal em estudo: Myroxylon peruiferum (Óleo Bálsamo), Hymenaea courbaril (Jatobá) e Peltophorum dubium (Canafístula), com as mesmas doses de cobre (0, 50, 100, 200 e 400 mg kg -1 ). O delineamento para os experimentos foi em blocos casualizados (DBC) com cinco concentrações de Cu e quatro repetições. As plantas foram cultivadas em substrato de solo acondicionados em vasos de 8 dm 3 e mantidas em casa-de-vegetação por 90 dias. Foram avaliadas medidas biométricas, clorofila, enzimas

Negative Effects on Photosynthesis and Chloroplast Pigments Exposed to Lead and Aluminum: A Meta-Analysis

“…When toxic metals substitute elements of its chain it restricts the capacity to capture energy and the possibility of producing organic matter. Chlorophyll b is also reduced when the plant is exposed to toxic metals, since the metals damage the thylakoid membranes and substitute compounds of the chlorophyll metabolic pathway (Fu and Wang 2015;Marques et al 2018). Toxic metals may interfere with chlorophyll biosynthesis by inhibiting the formation of α-aminolevulinic acid (ALA), as well as protochlorophyllide reductase, the key enzyme of phototransformation.…”

“…Thus, the plant compensates for this damage using chlorophyll b as an electron donor for chlorophyll a, which explains the reduction in chlorophyll b since this pigment is not replaced. However, chlorophyll b is a pigment that assists in the uptake of light and is an accessory pigment with a photoprotective effect; it reduces the harmful effects of light in the photosynthetic apparatus, avoiding damage to photosynthetic membranes (He et al, 2018;Marques et al, 2018). The Fv/Fm decline reflects the structural damage to photosystem II and an increase in the dissipation of nonphotochemical energy as heat.…”

“…It is the second largest economically important family of angiosperms and includes many plants of food importance. Also, it has many taxa of great ornamental potential, is commonly planted in urban areas and, for this reason, suffers from contamination by toxic metals (Marques et al, 2018). Pereira et al (2012), when studying the use of this family in the reforestation of contaminated areas, concluded that metals in the soil were at concentrations above the safe values established by legislation and that the plants established in the contaminated site were tolerant.…”

“…Photosynthesis of plants exposed to toxic metal contamination is also compromised, since these elements can reduce the levels of chlorophyll and carotenoids due to the inactivation of the enzymes responsible for the biosynthesis of these pigments. Harmful effects on the electron transport chain, inactivation of the Calvin cycle enzymes and reduction of stomatal conductance have also been reported (Marques et al, 2018).…”

Effects of Fertigation with Untreated and Treated Leachates from Municipal Solid Waste on the Microelement Status and Biometric Parameters of Viola × wittrockiana

“…The specific leaf area was reduced in the treatment with phytodepurated water, which could be due to the concentration of Cu and Zn in the substrate solution. It has been demonstrated that the content of chlorophyll "a" was reduced with increasing Cu concentrations in the soil [74]; in maize, the application of only Zn showed better effects than Zn + Cu under Fe limitation [75].…”