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Dodd I.C.,Lancaster University | Perez-Alfocea F.,CSIC - Center of Edafology and Applied Biology of the Segura
Journal of Experimental Botany | Year: 2012

The use of soil and irrigation water with a high content of soluble salts is a major limiting factor for crop productivity in the semi-arid areas of the world. While important physiological insights about the mechanisms of salt tolerance in plants have been gained, the transfer of such knowledge into crop improvement has been limited. The identification and exploitation of soil microorganisms (especially rhizosphere bacteria and mycorrhizal fungi) that interact with plants by alleviating stress opens new alternatives for a pyramiding strategy against salinity, as well as new approaches to discover new mechanisms involved in stress tolerance. Although these mechanisms are not always well understood, beneficial physiological effects include improved nutrient and water uptake, growth promotion, and alteration of plant hormonal status and metabolism. This review aims to evaluate the beneficial effects of soil biota on the plant response to saline stress, with special reference to phytohormonal signalling mechanisms that interact with key physiological processes to improve plant tolerance to the osmotic and toxic components of salinity. Improved plant nutrition is a quite general beneficial effect and may contribute to the maintenance of homeostasis of toxic ions under saline stress. Furthermore, alteration of crop hormonal status to decrease evolution of the growth-retarding and senescence-inducing hormone ethylene (or its precursor 1-aminocyclopropane-1-carboxylic acid), or to maintain source-sink relations, photosynthesis, and biomass production and allocation (by altering indole-3-acetic acid and cytokinin biosynthesis) seem to be promising target processes for soil biota-improved crop salt tolerance. © 2012 The Author. Source

Syvertsen J.P.,University of Florida | Garcia-Sanchez F.,CSIC - Center of Edafology and Applied Biology of the Segura
Environmental and Experimental Botany | Year: 2014

Citrus, one of the most important fruit crops in the world, is sensitive to many environmental stresses including salt stress. The negative effects of stresses often lead to poor tree growth and reductions in fruit yield and quality. Under natural conditions, citrus trees often experience multiple stresses at the same time so there are direct and indirect interactions between salinity and almost all physical abiotic stresses that include flooding, drought, nutrient deficiency, high irradiance, high temperature, and high atmospheric evaporative demand. In addition, salinity stress also has direct effects on roots predisposing trees to biotic environmental stresses including attack by root rot, nematodes and bacterial disease. The agronomical and physiological responses of citrus exposed to two or more stress factors, can differ depended on stress intensity or duration. Since citrus leaf Cl- accumulation has been linked to water use, for example, other environmental factors including high CO2 concentration, lowered temperature and high relativity humidity which decrease leaf transpiration, can improve the salt tolerance. Citrus rootstocks known to be tolerant to root rot and nematode pests, can become more susceptible to these biotic stresses when irrigated with high salinity water. Root pests can, in turn, affect the salt tolerance of citrus roots and may increase salt uptake. Moderate salinity stress, however, can reduce physiological activity and growth allowing citrus seedlings to survive cold stress and can even enhance flowering after the salinity stress is relieved. In this review, we discuss the currently available information about the effects of salinity in citrus trees from an agronomic and physiological point of view, and how these responses interact with other abiotic/physical and biotic environmental factors. Short-term potential benefits of moderate stresses including salinity, will also be discussed. © 2013 Elsevier B.V. Source

Suzuki N.,University of North Texas | Rivero R.M.,CSIC - Center of Edafology and Applied Biology of the Segura | Shulaev V.,University of North Texas | Blumwald E.,University of California at Davis | Mittler R.,University of North Texas
New Phytologist | Year: 2014

Contents: 32 I. 32 II. 34 III. 38 IV. 39 41 References 41 Summary: Environmental stress conditions such as drought, heat, salinity, cold, or pathogen infection can have a devastating impact on plant growth and yield under field conditions. Nevertheless, the effects of these stresses on plants are typically being studied under controlled growth conditions in the laboratory. The field environment is very different from the controlled conditions used in laboratory studies, and often involves the simultaneous exposure of plants to more than one abiotic and/or biotic stress condition, such as a combination of drought and heat, drought and cold, salinity and heat, or any of the major abiotic stresses combined with pathogen infection. Recent studies have revealed that the response of plants to combinations of two or more stress conditions is unique and cannot be directly extrapolated from the response of plants to each of the different stresses applied individually. Moreover, the simultaneous occurrence of different stresses results in a high degree of complexity in plant responses, as the responses to the combined stresses are largely controlled by different, and sometimes opposing, signaling pathways that may interact and inhibit each other. In this review, we will provide an update on recent studies focusing on the response of plants to a combination of different stresses. In particular, we will address how different stress responses are integrated and how they impact plant growth and physiological traits. © 2014 New Phytologist Trust. Source

Tomas-Barberan F.A.,CSIC - Center of Edafology and Applied Biology of the Segura | Andres-Lacueva C.,University of Barcelona
Journal of Agricultural and Food Chemistry | Year: 2012

During the 5th International Conference on Polyphenols and Health that was held in Sitges (Spain) in October 2011, the latest advances in this area of active research were presented. Sessions on polyphenol effects on cardiovascular disease, polyphenols as ingredients of functional foods, the role of polyphenols in preventing obesity and diabetes, the interaction of polyphenols with gut microbiota, bioavailability and metabolism of polyphenols in humans, the mechanisms of action of these metabolites in different models, new methodologies for the study of the role of polyphenols in health, polyphenols and cancer, recent developments in phenolic compounds and neuroscience, and polyphenols in epidemiology and public health were organized. This highlight issue presents a selection of papers from invited speakers, oral presentations, and poster prize winners. The perspectives for this exciting area of very active research were also discussed at the meeting and are summarized in this introductory paper. © 2012 American Chemical Society. Source

Martinez-Ballesta M.D.C.,CSIC - Center of Edafology and Applied Biology of the Segura | Carvajal M.,CSIC - Center of Edafology and Applied Biology of the Segura
Plant Science | Year: 2014

Recent advances concerning genetic manipulation provide new perspectives regarding the improvement of the physiological responses in herbaceous and woody plants to abiotic stresses. The beneficial or negative effects of these manipulations on plant physiology are discussed, underlining the role of aquaporin isoforms as representative markers of water uptake and whole plant water status. Increasing water use efficiency and the promotion of plant water retention seem to be critical goals in the improvement of plant tolerance to abiotic stress. However, newly uncovered mechanisms, such as aquaporin functions and regulation, may be essential for the beneficial effects seen in plants overexpressing aquaporin genes. Under distinct stress conditions, differences in the phenotype of transgenic plants where aquaporins were manipulated need to be analyzed. In the development of nano-technologies for agricultural practices, multiple-walled carbon nanotubes promoted plant germination and cell growth. Their effects on aquaporins need further investigation. © 2013 Elsevier Ireland Ltd. Source

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