Plant responses to hypoxia: Signaling and adaptation

Molecular oxygen deficiency leads to altered cellular metabolism and can dramatically reducecrop productivity. Nearly all crops are negatively affected by lack of oxygen (hypoxia) due to adverseenvironmental conditions such as excessive rain and soil waterlogging. Extensive efforts to fullyunderstand how plants sense oxygen deficiency and their ability to respond using different strategiesare crucial to increase hypoxia tolerance. It was estimated that 57% of crop losses are due to floods. Progress in our understanding has been significant in the last years. This topic deserved moreattention from the academic community; therefore, we have compiled a Special Issue including fourreviews and thirteen research articles reflecting the advancements made thus far.Fil: Loreti, Elena. Institute of Agricultural Biology and Biotechnolog; Italia. Consiglio Nazionale delle Ricerche; ItaliaFil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

A quantitative review of soybean responses to waterlogging: agronomical, morpho-physiological and anatomical traits of tolerance

The impact of waterlogging on crops has increased during the last decades due to climate change, being considered the second most important abiotic stress after drought in soybean, with yield reductions of up to 80%. In this review, we performed a quantitative review from 54 papers about waterlogging effects in soybean. Yield losses are greater (57%) with waterlogging occurring at reproductive stages between R1 and R3 compared to vegetative stages, which is mostly related to a diminished number of pods per plant. Waterlogging impacts on biological nitrogen fixation, with losses of about 30 and 50% in nodule number and weight, with the greatest reductions in reproductive stages. The nitrogenase activity is drastically reduced with water excess but can quickly restore after. Losses in photosynthesis are about 30–50%, mostly related to reduced stomatal conductance and poor N status. Soybean can also develop aerenchymatous tissue in roots, hypocotyls and nodules, which may alleviate the anoxia generated by waterlogging by facilitating oxygen transport. Further efforts should be invested in investigating the effect of waterlogging on nodulation and the impact and subsequent recovery of root growth.Fil: Ploschuk, Rocio Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Miralles, Daniel Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. University of Western Australia; Australi

Seed-borne diseases in pasture grasses and legumes: state of the art and gaps in knowledge

Information on fungal seed-borne diseases on main pasture grasses and legumes from the literature was reviewed. These diseases reduce biomass production, quality of forage, and persistence due to progressive plant mortality. The main fungal pathogens associated with forage seeds belong to the orders Hypocreales, Pleosporales, and Helotiales in the phylum Ascomycota. Hypocreales includes the genus Fusarium, which reduces seedling establishment, and contaminates plant tissues with mycotoxins. Pleosporales includes many genera associated with seeds of legumes (Leptosphaerulina and Ascochyta), grasses (Bipolaris, Pyrenophora, Curvularia, Drechslera, Alternaria, Exserohilum, and Phoma), and both (Stemphylium). Some fungal genera within this order induce the accumulation of coumestans (leafspot-producing fungi) or produce secondary metabolites that contaminate tissues (Alternaria). Within Helotiales, the main genera are Sclerotinia (affecting mainly legumes), Clarireedia and Gloeotinia (affecting grasses). Pyricularia (order Magnaporthales), Colletotrichum (order Glomerellales), and Cercospora (order Mycosphaerellales) also include seed-borne fungi that provoke diseases on forage species as well as Rhizoctonia (order Cantharellales) and Ustilago (order Ustilaginales) which belong to the phylum Basidiomycota. These pathogens affect pastures by (i) compromising seedling establishment at early stages and (ii) constraining growth by reducing yield and seed quality at later stages. Future research should address (i) generation of reliable data on forage yield loss due to seed-borne diseases, (ii) assessment of the interaction between seed-borne pathogens and other biotic and/or abiotic stresses, (iii) delve into the study of the role of wild and/or cultivated forage species as inoculum reservoirs of pathogens, and (vi) shed light on the contamination issue due to mycotoxins generation.Fil: Pérez Pizá, María Cecilia. Universidad del Salvador; ArgentinaFil: Striker, Gustavo Gabriel. Universidad de Buenos Aires; Argentina. University of Western Australia; Australia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Stenglein, Sebastian Alberto. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentin

Waterlogging of Winter Crops at Early and Late Stages: Impacts on Leaf Physiology, Growth and Yield

Waterlogging is expected to increase as a consequence of global climate change, constraining crop production in various parts of the world. This study assessed tolerance to 14-days of early- or late-stage waterlogging of the major winter crops wheat, barley, rapeseed and field pea. Aerenchyma formation in adventitious roots, leaf physiological parameters (net photosynthesis, stomatal and mesophyll conductances, chlorophyll fluorescence), shoot and root growth during and after waterlogging, and seed production were evaluated. Wheat produced adventitious roots with 20–22% of aerenchyma, photosynthesis was maintained during waterlogging, and seed production was 86 and 71% of controls for early- and late-waterlogging events. In barley and rapeseed, plants were less affected by early- than by late-waterlogging. Barley adventitious roots contained 19% aerenchyma, whereas rapeseed did not form aerenchyma. In barley, photosynthesis was reduced during early-waterlogging mainly by stomatal limitations, and by non-stomatal constraints (lower mesophyll conductance and damage to photosynthetic apparatus as revealed by chlorophyll fluorescence) during late-waterlogging. In rapeseed, photosynthesis was mostly reduced by non-stomatal limitations during early- and late-waterlogging, which also impacted shoot and root growth. Early-waterlogged plants of both barley and rapeseed were able to recover in growth upon drainage, and seed production reached ca. 79–85% of the controls, while late-waterlogged plants only attained 26–32% in seed production. Field pea showed no ability to develop root aerenchyma when waterlogged, and its photosynthesis (and stomatal and mesophyll conductances) was rapidly decreased by the stress. Consequently, waterlogging drastically reduced field pea seed production to 6% of controls both at early- and late-stages with plants being unable to resume growth upon drainage. In conclusion, wheat generates a set of adaptive responses to withstand 14 days of waterlogging, barley and rapeseed can still produce significant yield if transiently waterlogged during early plant stages but are more adversely impacted at the late stage, and field pea is not suitable for areas prone to waterlogging events of 14 days at either growth stage

La aplicación de nanoparticulas de SiO2 como pretratamiento disminuye el impacto de la sequía en la performance fisiológica de Prunus mahaleb (Rosaceae)

La aplicación de nanoparticulas de SiO2 como pretratamiento disminuye el impacto de la sequía en la performance fisiológica de Prunus mahaleb (Rosaceae). En este trabajo se estudiaron respuestas fisiológicas de Prunus mahaleb (Mahaleb) a la sequía luego de la aplicación de diferentes concentraciones de nanoparticulas de SiO2 (SNPs) por irrigación como pretratamientos. Se aplicaron 4 concentraciones de SNPs (0, 10, 50 and 100 mg L-1) durante 45 días y, a posteriori, las plantas fueron sujetas a tres regímenes hídricos que incluyeron control (300 mL cada 3 días), estrés hídrico moderado (150 mL cada 3 días) y estrés hídrico severo (sin riego) por 19 días. El intercambio de gases – fotosíntesis, conductancia estomática y transpiración –se redujo menos frente a la sequía en las plantas que recibieron pretratamientos con SNPs. El estado nutricional de las plantas tratadas con SNPs visto por la concentración de N, P y K se mantuvo bajo sequía moderada. Las plantas pretratadas con SNPs mantuvieron el largo de sus raíces y sufrieron menor impacto en su biomasa radical ante sequía. Se concluye que la aplicación de SNPs como pretratamiento podría ser una práctica agronómica para sitios propensos a déficit hídricos en épocas cercanas a la plantación.We studied the physiological responses of Prunus mahaleb (Mahaleb) seedlings to drought stress when previously irrigated (or not) with different concentrations of SiO2 nanoparticles (SNPs). SNPs were applied at four concentrations (0, 10, 50 and 100 mg L-1) for 45 days, and then seedlings were subjected to three watering treatments including low (300 mL water every 3 d), moderate (150 mL water every 3 d) and severe drought stress (no irrigation) for 19 days. Results showed that gas exchange ? photosynthesis, stomatal conductance, and transpiration rate ? were signifcantly less impacted by severe drought stress when seedlings were pretreated with SNPs at high concentrations. Benefcial effects of SNPs pretreatment were evident in the nutritional status of the plants as the concentration of N, P and K, were maintained at similar levels than in well-watered seedlings. Pretreated seedlings were able to maintain the root length and to reduce the impact of severe drought on root dry mass accumulation. Therefore, application of SNPs as pretreatment should be considered as a promising agronomic practice in sites prone to suffer from water defcitFil: Ashkavand, Peyman. Tarbiat Modares University; IránFil: Zarafshar, Mehrdad. Agricultural Research, Education and Extension Organization; IránFil: Tabari, Masoud. Tarbiat Modares University; IránFil: Mirzaie, Javad. University of Ilam; IránFil: Nikpour, Amirreza. Gorgan University; IránFil: Bordbar, Seyed Kazem. Ohio State University; Estados UnidosFil: Struve, Daniel. Department Of Horticulture And Crop Science; Estados UnidosFil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Eco-physiological traits related to recovery from complete submergence in the model legume Lotus japonicus

Submergence is a severe form of stress for most plants. Lotus japonicus is a model legume with potential use in assisting breeding programs of closely related forage Lotus species. Twelve L. japonicus genotypes (10 recombinant inbred lines (RILs) and 2 parental accessions) with different constitutive shoot to root dry mass ratios (S:R) were subjected to 7 days of submergence in clear water and allowed to recover for two weeks post-submergence; a set of non-submerged plants served as controls. Relative growth rate (RGR) was used to indicate the recovery ability of the plants. Leaf relative water content (RWC), stomatal conductance (gs), greenness of basal and apical leaves, and chlorophyll fluorescence (Fv/Fm, as a measure of photoinhibition) were monitored during recovery, and relationships among these variables and RGR were explored across genotypes. The main results showed (i) variation in recovery ability (RGR) from short-term complete submergence among genotypes, (ii) a trade-off between growth during vs. after the stress indicated by a negative correlation between RGR during submergence and RGR post-submergence, (iii) an inverse relationship between RGR during recovery and S:R upon de-submergence, (iv) positive relationships between RGR at early recovery and RWC and gs, which were negatively related to S:R, suggesting this parameter as a good estimator of plant water balance post-submergence, (v) chlorophyll retention allowed fast recovery as revealed by the positive relationship between greenness of basal and apical leaves and RGR during the first recovery week, and (vi) full repair of the submergence-damaged photosynthetic apparatus occurred more slowly (second recovery week) than full recovery of plant water relations. The inclusion of these traits contributing to submergence recovery in L. japonicus should be considered to speed up the breeding process of the closely related forage Lotus spp. used in current agriculture.Fil: Buraschi, Florencia Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Mollard, Federico Pedro Otto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Grimoldi, Agustin Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Recordando a Silvia Burkart (07/12/1942-17/01/2018)

Tognetti, Pedro Maximiliano. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Omacini, Marina. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Oyarzabal, Mariano. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.Striker, Gustavo Gabriel. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.606-60

Réponses morphologiques, physiologiques et biochimiques au déficit en eau chez les jeunes plants de trois populations de poiriers sauvages (Pyrus boisseriana)

Water shortage limits production of fruit orchards, like pear, in arid and semi-arid regions. The identification of wild pear germplasm for potential use as rootstock would be valuable for pear cultivation in semi-arid regions. Relative drought tolerance of wild pear germplasm (Pyrus boisseriana) from three different populations distributed along an elevational gradient (semi-arid 1000, semi-wet 1350 and semi-wet 1600 populations) was evaluated in a greenhouse trial. Established container-grown seedlings were exposed to 18 days of simulated drought, or not, followed by a seven day recovery. Biomass allocation and accumulation, physiological (stomatal conductance, photosynthesis, transpiration, xylem water potential) and biochemical parameters (leaf pigments, free proline, malondialdehyde and hydrogen peroxide production) were evaluated. Although all populations were able to recover from water shortage, thereby being relatively drought tolerant, some differences among populations were detected for gas exchange parameters, biomass accumulation and proline concentration in favor of the semi-arid 1000 elevation population, which was more drought tolerant; it had the most rapid and complete recovery of physiological activity (stomatal conductance and carbon fixation). In addition, all populations increased carotenoids in leaves. Overall, we showed that plants from semi-arid 1000 elevation greater tolerance to drought than those from higher elevations. Although the initial drought resistance response of the 1000 elevation source was promising, additional field studies are needed to confirm the greenhouse results and the benefit of a more drought resistant rootstock to commercial scions.En régions arides et semi-arides, la disponibilité en eau est le facteur limitant des vergers de production, comme en culture de poirier, par exemple. À cet égard, l’évaluation d’une collection de poiriers sauvages pourrait mettre en évidence du matériel potentiellement utilisable comme porte-greffe et tolérant à la sécheresse dans ces régions. Des poiriers sauvages (Pyrus boisseriana) originaires de trois populations différentes selon leur répartition en altitude (populations « semi-aride 1 000 m », « semi-humide 1350 m » et « semi-humide 1 600 m ») ont été évalués pour leur tolérance à la sécheresse dans un essai en serre. Des semis cultivés en pots ont été soumis à 18 jours de sécheresse, puis à une reprise de sept jours de croissance en conditions normales d’irrigation. La répartition et l’accumulation de la biomasse, les paramètres physiologiques (conductance stomatique, photosynthèse, transpiration, potentiel hydrique du xylème) et biochimiques (teneurs en pigments des feuilles, proline libre et malondialdéhyde ; production de peroxyde d’hydrogène) ont été évalués par rapport à des témoins non soumis au stress hydrique. Bien que toutes les populations de poirier aient pu se rétablir après la période sans irrigation et présentent de ce fait une certaine tolérance à la sécheresse, certaines différences de comportement entre celles-ci ont été détectées pour ce qui concerne les échanges gazeux, l’accumulation de la biomasse et la concentration de la proline dont les valeurs étaient en faveur de la population établie en zone semi-aride à une altitude de 1000 m. Celle-ci a d’ailleurs montré une reprise plus rapide et plus complète de son activité physiologique (conductance stomatique et fixation du carbone). À noter que le taux de caroténoïdes dans les feuilles a augmenté dans toutes les populations soumises au stress hydrique. De manière générale, nous avons montré que les plantes appartenant à la population établie en zone semi-aride à 1 000 m d’altitude présentaient une plus grande tolérance à la sécheresse que celles appartenant aux populations des altitudes plus élevées (populations semi-humides). Ces plantes constituent donc un matériel prometteur comme candidats porte-greffe pour les greffons commerciaux de poiriers destinés à la culture dans les régions soumises fréquemment à des déficits hydriques.Fil: Zarafshar, Mehrdad. Tarbiat Modares University. Faculty of Natural Resources and Marine Sciences. Department of Forestry; IránFil: Akbarinia, Moslem. Tarbiat Modares University. Faculty of Natural Resources and Marine Sciences. Department of Forestry; IránFil: Askari, Hossein. Shahid Beheshti University, G.C. Faculty of New Technologies and Energy Engineering. Biotechnology Department; IránFil: Hosseini, Seyed Mohsen. Tarbiat Modares University. Faculty of Natural Resources and Marine Sciences. Department of Forestry; IránFil: Rahaie, Mehdi. University of Tehran. Faculty of New Science and Technology. Department of Life Science Engineering; IránFil: Struve, Daniel. Ohio State University. Department of Horticulture and Crop Science.; Estados UnidosFil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

¿Qué puede pasar si se inunda un potrero durante la implantación de agropiro alargado?

Las inundaciones son disturbios naturales frecuentes que afectan el crecimiento de las plantas. En Argentina, la expansión de la frontera agrícola ha desplazado los sistemas ganaderos hacia ambientes marginales, que se caracterizan por tener suelos con problemas de drenaje, salinidad y/o alcalinidad. En la Pampa Deprimida los excesos de lluvia durante el invierno y los déficits hídricos en verano, el drenaje lento, y el carácter salino-sódico de los suelos dedicados a la ganadería, determinan que sea frecuente la alternancia de períodos de inundaciones y sequías estacionales. En ese sentido, estudios realizados en la cuenca baja del Río Salado han registrado eventos extremos de precipitación acumulada en todas las estaciones del año. Los anegamientos acontecidos en otoño e invierno han sido más prolongados que los ocurridos durante primavera y verano, siendo más recurrentes en los meses de abril y mayo.EEA BalcarceFil: Iturralde Elortegui, María del Rosario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Olavarría; Argentina.Fil: Berone, Germán Darío. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Martinefsky, María Julia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Olavarría; Argentina.Fil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina.Fil: Monterubbianesi, María Gloria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Assuero, Silvia Graciela. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina