Absence of aluminium compromises root integrity, reduces leaf hydration and Rubisco performance in Qualea grandiflora, an Al-accumulating species.

Aluminium (Al) is toxic to most plants. Nevertheless, some species accumulate Al without showing toxicity symptoms. Previous studies have evidenced Al in chloroplasts of Al-accumulating species from the Cerrado vegetation in South America. We ask whether Al increases carbon assimilation through enhanced apparent efficiency of Rubisco. Seedlings of the Al-accumulator Qualea grandiflora (Vochysiaceae) were grown in nutrient solution with 0, 740, and 1480 µm Al. Growth parameters, relative leaf water content, Al concentration in organs, gas exchange and apparent carboxylation efficiency (measured from A/Ci curves) were evaluated for 60 days. Plants without Al showed no root growth, necrotic roots, low gas exchange rates, and decreased apparent carboxylation efficiency. Al-treated plants, however, showed new white roots and increased root biomass leading to higher leaf hydration, and apparent carboxylation efficiency was higher in these plants. Increased Al available in the nutrient solution increased Al accumulation in plant organs. Absence of Al compromised root integrity in Q. grandiflora, thus limiting leaf hydration. No positive direct effect of Al on Rubisco was evidenced in Al-treated plants.

Non-destructive equations to estimate the leaf area of Styrax pohlii and Styrax ferrugineus.

We developed linear equations to predict the leaf area (LA) of the species Styrax pohlii and Styrax ferrugineus using the width (W) and length (L) leaf dimensions. For both species the linear regression (Y=α+bX) using LA as a dependent variable vs. W × L as an independent variable was more efficient than linear regressions using L, W, L2 and W2 as independent variables. Therefore, the LA of S. pohlii can be estimated with the equation LA=0.582+0.683WL, while the LA of S. ferrugineus follows the equation LA=-0.666+0.704WL.

Non-destructive equations to estimate the leaf area of Styrax pohlii and Styrax ferrugineus / Equações lineares para estimativa de área foliar de Styrax pohlii e Styrax ferrugineus

We developed linear equations to predict the leaf area (LA) of the species Styrax pohlii and Styrax ferrugineus using the width (W) and length (L) leaf dimensions. For both species the linear regression (Y=α+bX) using LA as a dependent variable vs. W × L as an independent variable was more efficient than linear regressions using L, W, L2 and W2 as independent variables. Therefore, the LA of S. pohlii can be estimated with the equation LA=0.582+0.683WL, while the LA of S. ferrugineus follows the equation LA=−0.666+0.704WL.

Foram determinadas equações lineares para estimar a área foliar (AF) de Styrax pohlii e Styrax ferrugineus utilizando dimensões do limbo foliar (C – comprimento, L – largura). O modelo linear (Y=α+bX), utilizando AF vs. C × L, foi mais eficiente que os modelos lineares utilizando C, L, C2 e L2 como variáveis independentes na determinação da área foliar de S. pohlii e S. ferrugineus. Assim, a AF de S. pohlii pode ser estimada pelo modelo AF=0,582+0,683CL e a AF de S. ferrugineus pode ser estimada pelo modelo AF=−0,666+0,704CL.

Non-destructive equations to estimate the leaf area of Styrax pohlii and Styrax ferrugineus / Equações lineares para estimativa de área foliar de Styrax pohlii e Styrax ferrugineus

We developed linear equations to predict the leaf area (LA) of the species Styrax pohlii and Styrax ferrugineus using the width (W) and length (L) leaf dimensions. For both species the linear regression (Y=α+bX) using LA as a dependent variable vs. W × L as an independent variable was more efficient than linear regressions using L, W, L2 and W2 as independent variables. Therefore, the LA of S. pohlii can be estimated with the equation LA=0.582+0.683WL, while the LA of S. ferrugineus follows the equation LA=−0.666+0.704WL.(AU)

Foram determinadas equações lineares para estimar a área foliar (AF) de Styrax pohlii e Styrax ferrugineus utilizando dimensões do limbo foliar (C comprimento, L largura). O modelo linear (Y=α+bX), utilizando AF vs. C × L, foi mais eficiente que os modelos lineares utilizando C, L, C2 e L2 como variáveis independentes na determinação da área foliar de S. pohlii e S. ferrugineus. Assim, a AF de S. pohlii pode ser estimada pelo modelo AF=0,582+0,683CL e a AF de S. ferrugineus pode ser estimada pelo modelo AF=−0,666+0,704CL.(AU)

Efeito de fungicidas no controle da ferrugem do feijoeiro causada por uromyces appendiculatus em condições de campo / Fungicides effects on the control of leaf bean rust caused by uromyces appendiculatus under field conditions

RESUMO Avaliou-se a eficácia de fungicidas no controle da ferrugem do feijoeiro, em condições de campo. O experimento foi conduzido em Marília, SP, com plantas de feijão do grupo Carioca. Foram realizadas 3 pulverizações a cada 14 dias, utilizando-se 300 L de calda/ha, com os ingredientes ativos: trifloxystrobin + propiconazole (75 mL/ha), prothioconazole (100 mL ha-1); azoxystrobin (50 g ha-1) + nimbus 0,25% v/v e trifloxystrobin + tebuconazole (50 + 100, 60 + 120 e 75 + 150 mL ha-1). O controle proporcionado pelos ingredientes ativos foi avaliado nas folhas, sendo o índice de infecção calculado através de escala de notas dividida em nove níveis. Constatou-se q ue todos os fungicidas e doses utilizados foram eficientes no controle da ferrugem (Uromyces appendiculatus), proporcionando mais de 90% de eficiência. Na testemunha o índice de infecção chegou a 52% na terceira avaliação.

ABSTRACT The efficacy of fungicides for the controlof bean rust was evaluated, under field conditions. The experiment was conducted in Marília, SP (Brasil), using bean plants of the 'Carioca' group. Three sprayings were applied, each 14 days, with spray volume of 300 liters ha-1, with the following active ingredients: trifloxystrobin + propiconazole (75 mL ha-1), prothioconazole (100 mL ha-1), azoxystrobin (50 g ha-1) + nimbus 0,25% v/v and trifloxystrobin + tebuconazole (50 + 100, 60 + 120 and 75 + 150 mL ha-1). The disease control provided by active ingredients was evaluated on leaves, with its infection index calculated from a 9-degree disease index. All the fungicides and their doses used were efficient in controlling leaf bean rust (Uromyces appendiculatus), reaching more than 90% efficiency. In the control treatment the leaf infection index reached 52% at the third evaluation.