Distribuição do alumínio (Al) em folhas de espécies acumuladoras de Al do cerrado
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Data
2018-08-30
Autores
Nogueira, Matheus Armelin [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As espécies arbóreas do Cerrado podem ser divididas em acumuladoras de alumínio (Al) e não-acumuladoras. Ambos os grupos crescem bem em solos distróficos que são ácidos e ricos em Al. Não há evidências do papel fisiológico do Al nessas plantas, diferentemente do que é conhecido sobre a maioria das plantas cultivadas. Nós comparamos a área foliar específica (AFE) e os conteúdos foliares de Ca e Al de duas espécies acumuladoras de Al (Qualea grandiflora Mart. e Qualea. Parviflora Mart.) que crescem em dois tipos de solos distintos. Um desses, foi distrófico típico do Cerrado, e o outro, de características únicas, calcário, com alta disponibilidade de Ca e baixa saturação de Al. As folhas também foram separadas em limbo e nervura foliar. A AFE foi similar para plantas da mesma espécie, independentemente do solo em que cresceram, indicando que o Al não influencia neste parâmetro. O conteúdo de Ca na folha refletiu sua disponibilidade entre os tipos de solo e foi mais acumulado nas nervuras foliares. No entanto, o acúmulo de Al foi independente de sua disponibilidade nos diferentes tipos de solos e sua concentração foi maior no limbo foliar de ambas as espécies, o que foi confirmado por análises químicas e histoquímicas. Concluímos que Ca e Al não parecem competir em espécies acumuladoras de Al e o padrão da distribuição e alocação de Al nas folhas merece novos estudos.
The wood species of Cerrado can be classified in Al-accumulators and non-accumulators. Both groups grow well on acidic and Al rich distrophic soils. There is no evidence of physiological role for Al in these plants, regardless of what is known in cultivated plants. We compared the specific leaf area (SLA), Ca and Al contents in leaves of two Al-accumulating species (Qualea grandiflora and Q. parviflora) growing in two distinct soil types. One from a typical dystrophic cerrado soil, and another one with unique features, a calcareous soil with high Ca and low Al availabilities. The leaves were also divided into leaf blade and leaf veins. The SLA was similar in the same plant species, regardless of the soil in which they grew, indicating that this parameter is not affected by Al. The leaf Ca content reflected its availability between the soil types, and was higher in the leaf veins when compared to the leaf blade. However, the Al accumulation was independent of its availability between the different soil types, and Al concentration was higher in the leaf blade of both species, which was confirmed by chemical and histochemical analyses. We concluded that Ca and Al do not seem to compete in Al-accumulating species and the distribution pattern and Al allocation in the leaves deserve further studies.
The wood species of Cerrado can be classified in Al-accumulators and non-accumulators. Both groups grow well on acidic and Al rich distrophic soils. There is no evidence of physiological role for Al in these plants, regardless of what is known in cultivated plants. We compared the specific leaf area (SLA), Ca and Al contents in leaves of two Al-accumulating species (Qualea grandiflora and Q. parviflora) growing in two distinct soil types. One from a typical dystrophic cerrado soil, and another one with unique features, a calcareous soil with high Ca and low Al availabilities. The leaves were also divided into leaf blade and leaf veins. The SLA was similar in the same plant species, regardless of the soil in which they grew, indicating that this parameter is not affected by Al. The leaf Ca content reflected its availability between the soil types, and was higher in the leaf veins when compared to the leaf blade. However, the Al accumulation was independent of its availability between the different soil types, and Al concentration was higher in the leaf blade of both species, which was confirmed by chemical and histochemical analyses. We concluded that Ca and Al do not seem to compete in Al-accumulating species and the distribution pattern and Al allocation in the leaves deserve further studies.
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Palavras-chave
Alumínio, Limbo foliar, Qualea sp, Cálcio, Al, Calcium, Leaf blade