Time filter

Source Type

del Monte J.P.,Technical University of Madrid | Dorado J.,CSIC - Institute of Agricultural Sciences
Weed Research | Year: 2011

Bromus diandrus is an emerging problem in barley crops in temperate climates, owing to its ability to adapt to certain farming techniques, as well as the absence of an efficient means of control. The aim of this study was to evaluate the germination of B. diandrus as a function of light conditions, time after ripening, temperature and water potential. Our results indicate that light conditions were the principal factor affecting germination and that seeds had negative photoblastism. Darkness modified the hydrotime parameters of the seeds somewhat, for example, by decreasing the values of Ψb and by favouring dormancy loss. The after-ripening time significantly modified the hydrotime parameters of the seeds, causing Ψb to drift towards more negative values (greater dormancy loss) as the after-ripening time increased. The combination of both variables explains the dormancy dynamics of this species in Mediterranean climates that are characterised by two distinct germination flushes, coinciding with two periods when soil humidity and temperature are not limiting. The first and main cohort of seedlings would emerge in autumn, originating from young buried seeds. A second cohort would emerge in the spring, from mature seeds on the surface of the soil. © 2011 The Authors. Weed Research © 2011 European Weed Research Society.

Badenes-Perez F.R.,CSIC - Institute of Agricultural Sciences
Acta Horticulturae | Year: 2013

Yellow rocket, Barbarea vulgaris R. Br. (Brassicaceae), is a biennial plant naturally occurring in temperate regions worldwide. This plant has been proposed as a trap crop for the diamondbaek moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae). Since P. xylostella is the most damaging insect pest of cruciferous crops throughout the world and it can easily develop resistance to insecticides, trap cropping is a desirable technique for P. xylostella management as an alternative to insecticide use. Barbarea vulgaris has been used at a small scale as a vegetable and food medicine and it contains phytochemicals proven to be beneficial for human health, such as flavonoids, glucosinolates, and saponins. Here we study the capacity of vegetative regeneration of B. vulgaris after partial and full removal of its foliage, which would allow the use of B. vulgaris as a vegetable while also being used as a trap crop. The potential of B. vulgaris as a salad vegetable was assessed by a group of 30 inexperienced taste panelists. The capacity of vegetative regeneration combined with the positive evaluation of the plant as a salad vegetable indicates that the additional use of B. vulgaris as a marketable vegetable could improve its potential as trap crop because of economic reasons.

Sanchez-Pardo B.,Autonomous University of Madrid | Fernandez-Pascual M.,CSIC - Institute of Agricultural Sciences | Zornoza P.,Autonomous University of Madrid
Environmental and Experimental Botany | Year: 2012

Copper (Cu) is a heavy metal which, at high concentrations, is toxic to organisms. Some plants, however, possess systems for dealing with excess Cu, such as its cell localisation, and have antioxidant enzymes that help to reduce the oxidative stress. The present work examines the microlocalisation of Cu and the antioxidant enzyme activity present in the nodules of white lupin and soybean plants grown hydroponically for 35 days in the presence of 1.6μM (control) or 192μM (excess) Cu. The effect of these conditions on nodule (ultra)structure was also examined. Energy-dispersive X-ray microanalysis showed the cell walls to be the main area of Cu binding in the inner and outer cortex and infected zone of white lupin nodules grown under the excess Cu conditions, while in soybean a high Cu signal was detected inside cells (cytoplasm or vacuoles) both in the inner cortex and infected zone. At the tissue level, an increasing Cu gradient was seen from the outer towards the inner nodule cortex in white lupin nodules, while the opposite was seen in soybean. Cu excess also induced oxidative stress and promoted damage to the ultrastructure of nodules. In the white lupin infected cells, a breakdown of the peribacteroidal membrane was seen, along with an increased number of vesicles in the cytosol of these cells. In the infected cells of the soybean nodules, the bacteroidal membrane became degraded and precipitation was seen within the vacuoles of the infected and uninfected cells. Finally, the white lupin nodules seemed to be more sensitive to Cu excess than those of soybean, with the nodulation process, N 2 fixation, and the ultrastructure of bacteroids more strongly affected. A less effective antioxidative stress response against Cu was also seen in white lupin than in soybean nodules: the excess copper treatment induced a smaller increase in the total thiol content and ascorbate peroxidase activity in white lupin nodules than in soybean nodules, and promoted a greater reduction in catalase activity. © 2012 Elsevier B.V..

Badenes-Perez F.R.,Max Planck Institute for Chemical Ecology | Badenes-Perez F.R.,CSIC - Institute of Agricultural Sciences | Reichelt M.,Max Planck Institute for Chemical Ecology | Gershenzon J.,Max Planck Institute for Chemical Ecology | Heckel D.G.,Max Planck Institute for Chemical Ecology
New Phytologist | Year: 2011

Glucosinolates are plant secondary metabolites used in host plant recognition by insects specialized on Brassicaceae, such as the diamondback moth (DBM), Plutella xylostella. Their perception as oviposition cues by females would seem to require their occurrence on the leaf surface, yet previous studies have reached opposite conclusions about whether glucosinolates are actually present on the surface of crucifer leaves. DBM oviposits extensively on Barbarea vulgaris, despite its larvae not being able to survive on this plant because of its content of feeding-deterrent saponins. Glucosinolates and saponins in plant tissue and mechanically removed surface waxes from leaves of Barbarea spp. were analyzed with high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Surface waxes from leaves of Barbarea spp. contained glucosinolates, but not feeding-deterrent saponins. Our research is the first to show that glucosinolates are present on the leaf surface of Barbarea spp., but not in other crucifers investigated, resolving some conflicting results from previous studies. Our research is also the first to quantify glucosinolates on the leaf surface of a crucifer, and to show that the concentrations of glucosinolates found on the leaf surface of Barbarea spp. are sufficient to be perceived by ovipositing DBM. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

De La Pena T.C.,CSIC - Institute of Agricultural Sciences | Pueyo J.J.,CSIC - Institute of Agricultural Sciences
Agronomy for Sustainable Development | Year: 2012

Mineral nitrogen deficiency is a frequent characteristic of arid and semi-arid soils. Biological nitrogen fixation by legumes is a sustainable and environmentalfriendly alternative to chemical fertilization. Therefore, legumes have a high potential for the reclamation of marginal soils. Such issue is becoming more urgent due to the ever-rising requirement for food and feed, and the increasing extension of salinized and degraded lands, both as a consequence of global change and irrigation practices. This manuscript reviews current research on physiological and molecular mechanisms involved in the response and tolerance to environmental stresses of the Rhizobium- legume symbiosis. We report in particular recent advances on the isolation, characterization, and selection of tolerant rhizobial strains and legume varieties, both by traditional methods and through biotechnological approaches. The major points are the following. (1) Understanding mechanisms involved in stress tolerance is advancing fast, thus providing a solid basis for the selection and engineering of rhizobia and legumes with enhanced tolerance to environmental constraints. (2) The considerable efforts to select locally adapted legume varieties and rhizobial inocula that can fix nitrogen under conditions of drought or salinity are generating competitive crop yields in affected soils. (3) Biotechnological approaches are used to obtain improved legumes and rhizobia with enhanced tolerance to abiotic stresses, paying particular attention to the sensitive nitrogen-fixing activity. Those biotechnologies are yielding transgenic crops and inocula with unquestionable potential. In conclusion, the role of legumes in sustainable agriculture, and particularly, their use in the reclamation of marginal lands, certainly has a very promising future. © INRA and Springer Science+Business Media B.V. 2011.

Discover hidden collaborations