Direct effects of Al in leaves of sensitive and Al-accumulating species and al role in roots of Al-accumulating species

• Grant number: 18/15359-8
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): December 01, 2019
• Effective date (End): June 30, 2022
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal researcher: Gustavo Habermann
• Grantee: Brenda Mistral de Oliveira Carvalho Bittencourt
• Home Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

The first and most evident symptom of aluminum (Al) toxicity is the decrease in root growth, which can occur in a matter of hours. In addition, Al may cause decreased shoot growth and reduced gas exchange and photochemical reactions. Most of the studies try to show that damage caused by Al in the aerial part is of indirect character (long-distance) due to the water deficiency, consequence of the smaller root growth. There is no evidence in the literature that Al has a direct effect on photosynthetic apparatus or foliar gas exchange mechanisms. On the other hand, there are species that accumulate a considerable amount of Al in the leaves without causing damage to the tissues. Interestingly, some studies have shown that the presence of Al may increase the growth of several Al accumulator species from Cerrado. The presence of Al is detected in the chlorophyllic parenchyma of these species, suggesting that Al may be involved in the photosynthetic processes of these plants. On the other hand, given the deep root system of these Cerrado species and the fact that some of them show significantly higher root growth when grown in the presence of Al, it is possible that Al also plays some role in the roots of these plants. We chose Vochysia tucanorum (Vochysiaceae), Al accumulator native from Cerrado, and Citrus limonia (Rutaceae), sensitive to Al. We will cultivate these species in absence of Al and we will insert a solution with and without Al in the petiole with a syringe needle, to test the hypothesis that the presence of Al directly in the leaves causes an increase in photosynthetic performance in V. tucanorum and a reduction in C. limonia. The photosynthetic performance of the leaf in question will be evaluated over time, every three minutes, allowing the evaluation of the immediate and direct effect of Al on the leaves of these species. In other study, we will cultivate V. tucanorum in presence and absence of Al in same individuals ("split root" experiment) to test the hypothesis that V. tucanorum roots exposed to Al have higher growth and lower concentration of auxin (IAA) in relation to those not exposed to Al. At the end of the study [90 Days After Planting (DAP)], we will measure the concentration of IAA in the root apex. Root growth and plant height, gas exchange and chlorophyll a florescence will be evaluated at 1, 7, 15, 30, 45, 60 and 90 DAP. To verify if there is interference (not only association) of Al concentration on root growth, IAA concentration and photosynthetic performance of this species, we will also cultivate V. tucanorum in four Al concentrations (separate individuals), also for 90 days. The same variables in the same DAP of the split-root experiment will be evaluated. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

BRESSAN, ANNA CAROLINA GRESSLER; DE OLIVEIRA CARVALHO BITTENCOURT, BRENDA MISTRAL; SILVA, GISELLE SCHWAB; HABERMANN, GUSTAVO. Could the absence of aluminum (Al) impair the development of an Al-accumulating woody species from Brazilian savanna?. THEORETICAL AND EXPERIMENTAL PLANT PHYSIOLOGY, v. 33, n. 3 JUL 2021. Web of Science Citations: 0.