RESUMO
Field peas (Pisum sativum L.) are widely cultivated throughout the world as a cool season grain and forage crop. Boron (B) toxicity is caused by high B concentration in the soil or irrigation water, and is particularly problematic in medium or heavier textured soil types with moderate alkalinity and low annual rainfall. Previous studies have indicated that B-toxicity increases oxidative stress in plants, and B-tolerance has been considered an important target in field pea plant breeding programmes. Inducers of tolerance may be a promising alternative for plant breeding. Little research has been conducted on the combined use of silicon (Si) and salicylic acid (SA) to remediate B-toxicity in field peas. The present study revealed the physiological and biochemical plant responses of applying Si + SA under B-toxicity (15 mg B L-1) on two Brazilian field pea cultivars (Iapar 83 and BRS Forrageira). A semi-hydroponic experiment was conducted using a completely randomized factorial design (2 × 5): with two field pea cultivars and five treatments which were formed by individual and combined applications of Si and SA under B-toxicity plus a control (control, B, B + Si, B + SA, and B + Si + SA). Si (2 mmol L-1) was applied to plants in two forms (root and leaf), while for SA (36⯵molâ¯L-1) only foliar applications were applied. Our results demonstrated that the combined use of exogenous Si + SA in field peas increased tolerance to B-toxicity through an intensified antioxidant plant defence system, resulting in a better regulation of reactive oxygen species (ROS) production and degradation. It significantly increased total chlorophyll and carotenoids contents, the activities of major antioxidant enzymes, and reduced MDA and H2O2 contents, resulting in increased fresh shoot and total plant dry biomass. The application of Si + SA alleviated the inhibitory effects of boron toxicity in field peas, resulting in greater plant growth by preventing oxidative membrane damage through an increased tolerance to B-excess within the plant tissue. Therefore, the use of Si + SA is an important and sustainable strategy to alleviate B-toxicity in field pea cultivation.
Assuntos
Antioxidantes/metabolismo , Boro/toxicidade , Pisum sativum/fisiologia , Ácido Salicílico/metabolismo , Silício/metabolismo , Poluentes do Solo/toxicidade , Brasil , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Pisum sativum/efeitos dos fármacos , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
RESUMEN Los agroecosistemas muestran una gran heterogeneidad en cuanto a las prácticas y características, debido a que dependen de las lógicas de la agricultura familiar, convirtiéndose en un recurso potencialmente valioso, cuando se estudia el uso y el soporte del medio productivo. Es por ello, que esta investigación evaluó el sistema de arveja (Pisum sativum L.) en el municipio de Ipiales, a través de una metodología multidimensional, usando 26 indicadores, agrupados en cuatro dimensiones de sustentabilidad agroecológica. La estimación, se realizó sobre 30 fincas, que representaron tres tipos de campesinos, previamente descritos, como C1, C2 y C3; los resultados permitieron identificar los Puntos Críticos de Sustentabilidad (PCS) y el Índice General de Sustentabilidad (IGS) del sistema, estableciendo que las diferentes situaciones sociales, ambientales, económicas y técnico-productivas determinan la existencia de PCS específicos. El IGS tuvo una calificación de 2,65, para C1; 2,90, para C2 y 2,62, para C3, evidenciando medidas de monitoreo y de manejo, que se deberían discutir en la región, para disminuir las externalidades generadas por el modelo productivo.
ABSTRACT Agroecosystems present great heterogeneity in terms of practices and characteristics, since they depend on the logic of family farming, which makes them a potentially valuable resource when studying the use and support of the productive environment. For this reason, this research evaluated the pea system (Pisum sativum L.) in the municipality of Ipiales, through a multidimensional methodology that uses 26 indicators grouped into four dimensions of agroecological sustainability. The estimation was made on 30 farms that represented three types of farmers previously described as C1, C2 and C3; the results allowed identifying the Critical Points of Sustainability (CPS) and the General Index of Sustainability (GIS) of the system. It was established that the different social, environmental, economic and technical-productive situations determine the existence of specific CPS, the GIS had a rating of 2.65 for C1, 2.90 for C2 and 2.62 for C3, this evidenced monitoring and management measures that should be discussed in the region to reduce the externalities generated by the production model.
RESUMO
RESUMEN La arveja, una fuente económica para pequeños y medianos agricultores de la zona andina, evidencia un incipiente manejo pos-cosecha y un nulo nivel de transformación. Tras la cosecha y debido a su naturaleza temporal y perecedera, la arveja acelera su metabolismo, disminuyendo su calidad y vida útil. Una opción económica y que esté disponible para los productores y LOS comercializadores para conservar sus características es el uso de empaques y la refrigeración. El objetivo fue evaluar tipos de empaques (bolsa de polietileno de baja densidad -PE-LD-, envase plástico termoformado perforado -PE-HD- y bandeja de poliestireno -PS-) y temperaturas de almacenamiento (0°C, 4°C y 18°C) en dos variedades de arveja, Sureña y Obonuco Andina. Se utilizó un diseño irrestrictamente al azar con arreglo factorial 3x3x2, teniendo como factores temperatura, empaque y variedad y como variables de estudio, las constantes cinéticas (K) de porcentaje de brotación, firmeza, pérdida de peso e índice de color. Los resultados mostraron que, para la brotación, se presentó el valor más bajo de K en Sureña, en PE-LD, a 0°C. La temperatura afectó la firmeza de los granos, conservándose a 0°C. La menor pérdida de peso se evidenció en PE-HD, a 0°C, independiente de la variedad. Para el índice de color, la K más baja se encontró en PS, a 0°C, en Obonuco Andina. Con la ecuación de Arrhenius en la variable índice de color, se estimó tiempos de vida útil de 13; 7; 5 y 2 días a temperaturas de 0°C, 6°C, 10°C y 24°C, respectivamente.
ABSTRACT The pea, an economic source for small and medium farmers in the Andes zone, evidences an incipient postharvest handling and a null level of transformation. After the harvest and due to its temporary and perishable nature, the pea accelerates its metabolism, decreasing its quality and shelf life. An economic option that is available to producers and marketers to preserve their characteristics is the use of packaging and refrigeration. The objective was to evaluate types of packaging (low density polyethylene bag (PE-LD), perforated thermoformed plastic container (PE-HD) and polystyrene tray (PS)) and storage temperatures (0°C, 4°C and 18°C) in two pea varieties (Sureña and Obonuco Andina). An unrestricted random design with a 3x3x2 factorial arrangement was used, taking as factors temperature, packing and variety; and as study variables the kinetic constants (K) of percentage of sprouting, firmness, weight loss and color index. The results showed that, for the sprouting, the lowest value of K was shown in Sureña, in PE-LD at 0°C. The temperature affected the firmness of the grains, remaining at 0°C. The lowest weight loss was evidenced in PE-HD at 0°C, regardless of the variety. For the color index, the lowest K was found in PS at 0°C, in Obonuco Andina. With the Arrhenius equation in the variable color index, useful life times of 13; 7; 5 and 2 days were estimated at temperatures of 0°C, 6°C, 10°C and 24°C respectively.
RESUMO
Research on soybean seed has revealed that conductivity test results may be influenced by storage temperature and that an apparent direct relationship between deterioration at low temperatures and loss of cellular membrane integrity is not evident. The objective of this study was to verify the influence of low storage temperatures on electrical conductivity results in other species, such as seeds of two pea cultivars studied temperatures were: 10, 20, 25, 20/10 and 25/10ºC. The physiological potential of the seeds was evaluated every three months during an 18 month storage period using germination, accelerated aging and electrical conductivity tests. The electrical conductivity test was not a good indicator for the degree of seed deterioration stored at low temperatures. Seed deterioration at 10ºC did not seem to be directly related to the loss of membrane integrity, possibly due to membrane repair or reorganization during storage at this temperature.
Pesquisas com sementes de soja têm revelado que os resultados do teste de condutividade elétrica podem ser influenciados pela temperatura de armazenamento, sugerindo que a deterioração das sementes em temperaturas baixas parece não estar relacionada diretamente com a perda da integridade das membranas celulares. O presente estudo foi conduzido com o objetivo de verificar se a influência de baixas temperaturas de armazenamento nos resultados da condutividade elétrica ocorre também para outra espécie, sendo utilizadas para tanto, sementes de dois cultivares de ervilha. O efeito das seguintes temperaturas foi estudado: 10, 20, 25, 20/10 e 25/10ºC. A cada três meses, num total de 18 meses de armazenamento, foi avaliado o potencial fisiológico das sementes usando-se os testes de germinação, envelhecimento acelerado e condutividade elétrica. O teste de condutividade elétrica não se mostrou um bom indicador da intensidade do processo de deterioração de sementes armazenadas a baixas temperaturas. A deterioração das sementes a 10ºC parece não estar relacionada diretamente com a perda da integridade das membranas, possivelmente devido ao reparo ou à reorganização das mesmas durante o período de armazenamento nesta temperatura.
RESUMO
Research on soybean seed has revealed that conductivity test results may be influenced by storage temperature and that an apparent direct relationship between deterioration at low temperatures and loss of cellular membrane integrity is not evident. The objective of this study was to verify the influence of low storage temperatures on electrical conductivity results in other species, such as seeds of two pea cultivars studied temperatures were: 10, 20, 25, 20/10 and 25/10ºC. The physiological potential of the seeds was evaluated every three months during an 18 month storage period using germination, accelerated aging and electrical conductivity tests. The electrical conductivity test was not a good indicator for the degree of seed deterioration stored at low temperatures. Seed deterioration at 10ºC did not seem to be directly related to the loss of membrane integrity, possibly due to membrane repair or reorganization during storage at this temperature.
Pesquisas com sementes de soja têm revelado que os resultados do teste de condutividade elétrica podem ser influenciados pela temperatura de armazenamento, sugerindo que a deterioração das sementes em temperaturas baixas parece não estar relacionada diretamente com a perda da integridade das membranas celulares. O presente estudo foi conduzido com o objetivo de verificar se a influência de baixas temperaturas de armazenamento nos resultados da condutividade elétrica ocorre também para outra espécie, sendo utilizadas para tanto, sementes de dois cultivares de ervilha. O efeito das seguintes temperaturas foi estudado: 10, 20, 25, 20/10 e 25/10ºC. A cada três meses, num total de 18 meses de armazenamento, foi avaliado o potencial fisiológico das sementes usando-se os testes de germinação, envelhecimento acelerado e condutividade elétrica. O teste de condutividade elétrica não se mostrou um bom indicador da intensidade do processo de deterioração de sementes armazenadas a baixas temperaturas. A deterioração das sementes a 10ºC parece não estar relacionada diretamente com a perda da integridade das membranas, possivelmente devido ao reparo ou à reorganização das mesmas durante o período de armazenamento nesta temperatura.