BUSCADOR RECOLECTA

Pearl millet (Pennisetum glaucum L.) is an important fodder and is a potential feedstock for fuel ethanol production in dry areas. Our objectives were to assess the effect of elevated CO2 and/or reduced irrigation on biomass production and levels of sugars and proteins in leaves of pearl millet and to test whether mycorrhizal inoculation could modulate the effects of these abiotic factors on growth and metabolism. Results showed that mycorrhizal inoculation and water regime most influenced biomass of shoots and roots; however, their individual effects were dependent on the atmospheric CO2 concentration. At ambient CO2, mycorrhizal inoculation helped to alleviate effects of water deficit on pearl millet without significant decreases in biomass production, which contrasted with the low biomass of mycorrhizal plants under restricted irrigation and elevated CO2. Mycorrhizal inoculation enhanced water content in shoots, whereas reduced irrigation decreased water content in roots. The triple interaction between CO2, arbuscular mycorrhizal fungi (AMF) and water regime significantly affected the total amount of soluble sugars and determined the predominant soluble sugars in leaves. Under optimal irrigation, elevated CO2 increased the proportion of hexoses in pearl millet that was not inoculated with AMF, thus improving the quality of this plant material for bioethanol production. By contrast, elevated CO2 decreased the levels of proteins in leaves, thus limiting the quality of pearl millet as fodder and primary source for cattle feed., This study has been supported by the ‘Ministerio de Ciencia e Innovación’ and ‘Gobierno de Aragón’ (Spain) (BFU2011-26989, Group A-44). Eliseu Geraldo dos Santos Fabbrin received a grant from CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) from the Brazilian Government.

A greater understanding of how climate change will affect crop photosynthetic performance has been described as a target goal to improve yield potential. Other concomitant stressors can reduce the positive effect of elevated atmospheric CO2 on wheat yield. Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi predicted to be important in defining plant responses to rising atmospheric CO2, but their role in response to global climatic change is still poorly understood. This study aimed to assess if increased atmospheric CO2 interacting with drought can modify the effects of mycorrhizal symbiosis on flag leaf physiology in winter wheat. The study was performed in climate-controlled greenhouses with ambient (400 ppm, ACO2) or elevated (700 ppm, ECO2) CO2 concentrations in the air. Within each greenhouse half of the plants were inoculated with Rhizophagus intraradices. When ear emergence began, half of the plants from each mycorrhizal and CO2 treatment were subjected to terminal drought. At ACO2 AMF improved the photochemistry efficiency of PSII compared with non-mycorrhizal plants, irrespective of irrigation regime. Mycorrhizal wheat accumulated more fructan than non-mycorrhizal plants under optimal irrigation. The level of proline in the flag leaf increased only in mycorrhizal wheat after applying drought. Mycorrhizal association avoided photosynthetic acclimation under ECO2. However, nitrogen availability to flag leaves in mycorrhizal plants was lower under ECO2 than at ACO2. Results suggest that the mechanisms underlying the interactions between mycorrhizal association and atmospheric CO2 concentration can be crucial for the benefits that this symbiosis can provide to wheat plants undergoing water deficit., This study has been supported by the Ministerio de Economía y Competitividad (MINECO) and Gobierno de Aragón (Spain) (AGL2011–30386-C02–02, BFU 2011-26989, Group A-44).

Previous studies have demonstrated that moderate water restrictions and enhanced CO2 concentration can maintain or improve yield and accumulation of secondary compounds in lettuce under greenhouse conditions. Therefore, the aim of this study was to evaluate the combination of reduced soil moisture and carbon fertilization in shoot fresh weight (FW) and antioxidant capacity of two Batavia lettuce cultivars (Batabia Rubia Munguia; BRM and Maravilla de Verano; MV). Moderate water restriction treatment was equivalent to 2/3 of the field capacity and elevated CO2 concentration (ECO2) was fixed at ~700 μmol mol-1. While CO2 enrichment exerted a positive effect on shoot FW of MV, especially in combination with water restrictions, the yield of the cultivar BRM was not affected by CO2 concentration, nor by irrigation regime. However, antioxidant capacity of BRM plants was increased under ECO2 conditions. These results demonstrate that carbon fertilization and/or moderate water limitations can be strategically used to enhance nutritional value and growth of greenhouse lettuce., Estudios previos han demostrado que la moderada reducción del riego y el aumento de la concentración de CO2 pueden mantener o incrementar la producción vegetal e inducir la acumulación de compuestos secundarios en lechuga bajo condiciones de invernadero. Por ello, el objetivo del presente estudio fue evaluar la combinación de la reducción del contenido de humedad del suelo y la fertilización carbónica sobre la materia fresca (MF) de la parte aérea y capacidad antioxidante de dos cultivares de lechuga Batavia (Batavia Rubia Munguia; BRM y Maravilla de Verano; MV). El tratamiento de déficit hídrico moderado fue equivalente a 2/3 de la capacidad de campo y la elevada concentración de CO2 (ECO2) se fijó en ~700 μmol mol-1. Mientras que el enriquecimiento de CO2 ejerció un efecto positivo sobre la MF de la parte área de MV, especialmente en combinación con la restricción del riego, la producción del cultivar BRM no se vio afectado ni por la concentración de CO2 ni por el régimen de riego aplicado. Sin embargo, la capacidad antioxidante de las plantas BRM se incrementó bajo condiciones de ECO2. Los resultados demuestran que la fertilización carbónica y/o una moderada limitación hídrica pueden estratégicamente ser utilizados para mejorar el valor nutricional y rendimiento de la lechuga bajo invernadero., This study has been supported by the Ministerio de Economía y Competitividad (MINECO, Spain) (AGL2011-30386-C02-02, BFU 2011-26989). Marcelle M. Bettoni received a grant from' Los CAPES y Coordenação do Programa de Pósgraduação em Agronomia - Produção Vegetal' from the Brazilian Government.