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Abstract(s)
As alterações climáticas são um tema de extrema importância nos dias de hoje sendo um tópico que preocupa a população mundial. Alguns fatores humanos são responsáveis por este fenómeno, tais como a queima de combustíveis fósseis, nomeadamente a queima de petróleo, carvão ou gás que liberta CO2 e N2O para a atmosfera, o uso de fertilizantes, aumento da atividade pecuária e causas associadas à desflorestação. O impacto cada vez mais acentuado do CO2 atmosférico, assim como da temperatura, tem desencadeado um avanço de fenómenos naturais desde secas e precipitação intensa, até à evidência de perda nutricional de proteína, ferro (Fe) e zinco (Zn) em diversos vegetais, incluindo as leguminosas como soja (Glycine max. L.) e feijão (Phaseolus vulgaris L.). Em particular, as populações de países em desenvolvimento, que tenham grande dependência nas leguminosas como fontes de nutrientes, poderão vir a ser especialmente impactadas devido ao CO2 elevado. Neste projeto estudaram-se duas leguminosas, a soja cv. Thorne e o cv. Papo de rola. Realizaram-se dois ensaios: o primeiro a 400 ppm (CO2 ambiental), e o segundo a 800 ppm (valores previstos para 2050) e, em cada um destes, as plantas foram crescidas na presença e na ausência de Fe. As plantas foram mantidas em câmaras de fitoclima com temperatura, humidade e CO2 controlado. Após a recolha de dados e análise estatística percebeu-se que na soja existe um aumento do peso seco a alto CO2 (+ 52,09 % em folhas e + 60,47 % em raízes). Também se verifica que as amostras de soja e feijão que que cresceram com Fe desenvolvem-se mais (+ 67,49 % em peso seco das folhas e + 60,70 % em raízes de soja; + 91,11 % em folhas e + 77,95 % em raízes de feijão). No entanto, houve reduções na atividade da redutase férrica radicular (94,79 % em soja e 72,19 % para feijão), no teor de clorofila foliar (75,42 % em soja e 73,39 % em feijão) e na taxa fotossintética (90,46 % em soja e 58,13 % em feijão) quando comparadas com as plantas crescidas a CO2 ambiental e na ausência de Fe. Nas análises nutricionais, verifica-se maior teor proteico (55,32 %), retenção mineral (especialmente Fe e Zn), assim como, maior teor de ácidos e açúcares a CO2 ambiental com Fe. Em síntese, a soja e o feijão crescidos com Fe indicam melhores condições de sobrevivência para a planta, sendo que o maior crescimento a alto CO2 não determina necessariamente maior teor nutricional.
Climate change is a topic of great importance these days being a subject of concern to the world´s population. Several human factors are responsible for this event, such as the burning of fossil fuels, namely of oil, coal or gas -that release CO2 and N2O to the atmosphere, the use of fertilizers, increased livestock production and deforestation. The increasing impact of atmospheric CO2, as well as temperature has triggered an advance of natural phenomena from droughts and intense precipitation to the evidence of nutritional loss of protein, iron (Fe) and zinc (Zn) in several plants, including legumes such as soybean (Glycine max. L.) and common bean (Phaseolus vulgaris L.). Populations in developing countries which are highly reliant on legumes as main sources of nutrients may be especially vulnerble in the future due to elevated CO2. Here, two legume grains, soybean cv. Thorne and common bean cv. Papo de rola were analyzed. Plants were grown in growth chambers, with controlled temperature, humidity and CO2. Two experiments were carried out, the first one at 400 ppm (environmental CO2) and the second at 800 ppm (values predicted for 2050). In each experiment, a set of plants grew with Fe and another set without this mineral. After data collection and statistical analysis it was observed that in soybean there is an increased dry weight at high CO2 (52.09 % in leaves and 60.47 % in roots). It is also verified that the samples of soybean and beans that grew with Fe had higher biomass (67.49 % in leaves and 60.70 % in roots of soybean; 91.11 % in leaves and 77.95 % in roots of common beans). However, there was a reduction in the activity of the root iron reductase (94.79 % in soybeans and 72.19 % in beans), in leaf chlorophyll content (75.42 % in soybean and 73.39 % in bean) and photosynthetic rate (90.46 % in soybean and 58.13 % in beans) when compared to plants that grew at ambient CO2 and in the absence of Fe. With regards to the nutritional analysis, a higher protein concentration (55.32 %), mineral retention, especially Fe and Zn, was verified, as well as a higher content of organic acids and sugars at ambient CO2 with Fe. In summary, Fe promotes better survival conditions for soybean and bean, and the higher growth at high CO2 does not reflect in higher nutritional content.
Climate change is a topic of great importance these days being a subject of concern to the world´s population. Several human factors are responsible for this event, such as the burning of fossil fuels, namely of oil, coal or gas -that release CO2 and N2O to the atmosphere, the use of fertilizers, increased livestock production and deforestation. The increasing impact of atmospheric CO2, as well as temperature has triggered an advance of natural phenomena from droughts and intense precipitation to the evidence of nutritional loss of protein, iron (Fe) and zinc (Zn) in several plants, including legumes such as soybean (Glycine max. L.) and common bean (Phaseolus vulgaris L.). Populations in developing countries which are highly reliant on legumes as main sources of nutrients may be especially vulnerble in the future due to elevated CO2. Here, two legume grains, soybean cv. Thorne and common bean cv. Papo de rola were analyzed. Plants were grown in growth chambers, with controlled temperature, humidity and CO2. Two experiments were carried out, the first one at 400 ppm (environmental CO2) and the second at 800 ppm (values predicted for 2050). In each experiment, a set of plants grew with Fe and another set without this mineral. After data collection and statistical analysis it was observed that in soybean there is an increased dry weight at high CO2 (52.09 % in leaves and 60.47 % in roots). It is also verified that the samples of soybean and beans that grew with Fe had higher biomass (67.49 % in leaves and 60.70 % in roots of soybean; 91.11 % in leaves and 77.95 % in roots of common beans). However, there was a reduction in the activity of the root iron reductase (94.79 % in soybeans and 72.19 % in beans), in leaf chlorophyll content (75.42 % in soybean and 73.39 % in bean) and photosynthetic rate (90.46 % in soybean and 58.13 % in beans) when compared to plants that grew at ambient CO2 and in the absence of Fe. With regards to the nutritional analysis, a higher protein concentration (55.32 %), mineral retention, especially Fe and Zn, was verified, as well as a higher content of organic acids and sugars at ambient CO2 with Fe. In summary, Fe promotes better survival conditions for soybean and bean, and the higher growth at high CO2 does not reflect in higher nutritional content.
Description
Keywords
Alterações climáticas Ferro Leguminosas Proteína Climate change Iron Legume grains Protein