Two distinct plant respiratory physiotypes might exist which correspond to fast-growing and slow-growing species

The origin of the carbon atoms in CO2 respired by leaves in the dark of several plant species has been studied using 13C/12C stable isotopes. This study was conducted using an open gas exchange system for isotope labeling that was coupled to an elemental analyser and further linked to an isotope ratio mass spectrometer (EA-IRMS) or coupled to a gas chromatography-combustion-isotope ratio mass spectrometer (GC-C-IRMS). We demonstrate here that the carbon, which is recently assimilated during photosynthesis, accounts for nearly ca. 50% of the carbon in the CO2 lost through dark respiration after illumination in fast-growing and cultivated plants and trees and, accounts for only ca. 10% in slow-growing plants. Moreover, our study shows that fast- growing plants, which had the largest percentages of newly fixed carbon of leaf-respired CO2 , were also those with the largest shoot/root ratios, whereas slow-growing plants showed the lowest shoot/root values.

Prediction of crude protein and classification of the growth stage of wheat plant samples from NIR spectra

Near-infrared spectroscopy (NIRS) was used to analyse the crude protein content of dried and milled samples of wheat and to discriminate samples according to their stage of growth. A calibration set of 72 samples from three growth stages of wheat (tillering, heading and harvest) and a validation set of 28 samples was collected for this purpose. Principal components analysis (PCA) of the calibration set discriminated groups of samples according to the growth stage of the wheat. Based on these differences, a classification procedure (SIMCA) showed a very accurate classification of the validation set samples : all of them were successfully classified in each group using this procedure when both the residual and the leverage were used in the classification criteria. Looking only at the residuals all the samples were also correctly classified except one of tillering stage that was assigned to both tillering and heading stages. Finally, the determination of the crude protein content of these samples was considered in two ways: building up a global model for all the growth stages, and building up local models for each stage, separately. The best prediction results for crude protein were obtained using a global model for samples in the two first growth stages (tillering and heading), and using a local model for the harvest stage samples.

Cultivation of black truffle to promote reforestation and land-use stability

Cultivation of black truffle, Tuber melanosporum Vitt., has become an important agricultural alternative in rural Mediterranean regions due to its success in relatively harsh conditions, its high market value and diminishing production in natural areas. In addition, truffle cultivation requires relatively low agricultural inputs, promotes reforestation and economic restoration of rural lands and land-use stability. However, there remain major issues regarding the management practices to ensure successful black truffle production. We therefore conducted an experiment to evaluate 3 levels of irrigation based on monthly water deficit and the effects of currently applied weed control systems and fertilization. Treatment effects were evaluated by examining the mycorrhizal status of out-planted 1-yr-old Quercus ilex L. seedlings and seedling growth parameters after 18 months in 3 distinct experimental truffle plantations located in the foothills of the Spanish Pyrenees. We found that replacing one-half of the water deficit of the driest month (moderate irrigation) promoted the proliferation of T. melanosporum mycorrhizae, while high irrigation reduced fine root production and truffle mycorrhizae. Glyphosate weed control improved seedling survival by up to 16% over control seedlings without jeopardizing truffle mycorrhizae in the first year. Fertilization did not improve seedling growth or influence its mycorrhizal status. We describe the persistent relationship between this ectomycorrhizal fungus and Q. ilex by quantifying old and new mycorrhizae and we discuss the ecological implications of the symbiosis.

Clonal growth and demography of a hemicryptophyte alpine plant: Leontopodium alpinum Cassini

Clonally reproducing hemicryptophytic rosette plants are common in the alpine belt. However, their demography, and indirectly their growth and reproductive strategy in these harsh conditions, was rarely studied. We analysed the morphology, clonal reproduction and demography of one such species, Leontopodium alpinum, in two populations of the Swiss Alps. The species forms small colonies of 1-5 (maximum 30) sterile rosettes with a few flowering stalks. After flowering, the apical meristem dies and one or two new axillary buds grow below the previous rosette in the following year, developing into short rhizomes (<2 cm), which decay after four years. The new stalk produces sterile rosettes before flowering after two to four years, depending on climatic conditions. The apical meristem often dies during the sterile stage, and is replaced by a new axillary bud. Levkovitch matrices on two stages (sterile and flowering rosettes) showed that rosette survival and clonal reproduction maintain long-lived populations (λ = 0.96). Elasticities indicated that a change in the survival of sterile rosettes had the strongest effect on population dynamics, and this stage lasts, on average, 6.8 years at 2480 m. Altogether, L. alpinum is following Tomlinson's architectural model. This growth form appears perfectly adapted to harsh alpine conditions: the clonal ramification ensures longevity to genets and the semelparous behaviour of the rosettes allows an efficient flowering, whatever the climatic conditions. L. alpinum appears to follow a common growth model among rosette possessing hemicryptophytes in the alpine belt.

Marooned plants : vernacular naming practices in the Mascarene Islands

This article explores possible histories of plant exchanges and plant naming tied to the slave trade between East Africa, Madagascar and the Mascarene Islands. The subsequent 'marronnage' of slaves on these islands - their escape from captivity, sometimes to live in mountain hideouts - continues to inspire cultural references. Inspired by the use of the adjective 'marron/marronne' for a number of plants on Reunion Island, we compile evidence of plant exchanges and plant naming from ecological records, historical accounts and the use of descriptive, emotive or symbolic vernacular names as clues for deepening our knowledge of historical societies and environments. The evidence from the Mascarenes opens a window into the role of the African diaspora in plant introduction, diffusion, domestication and cultivation. We document that maroons relied on a variety of wild, escaped and cultivated plants for their subsistence. We also highlight the role of marronnage in the popular and literary imaginary, with the result that many plants are named 'marron/marrone' in a metaphorical sense. Finally, we identify a few plants that may have been transported, cultivated, or encouraged in one way or another by maroons. Along the way, we reflect on the pitfalls and opportunities of such interdisciplinary work.

Background, current status and future prospects of transgenic crop plant development

Les plantes transgèniques són una part integral de l’agricultura contemporània. Durant l’any 2006 més de noranta milions d’hectàrees de plantes transgèniques van ser cultivades en vint-i-un països. Des de la comercialització de la primera planta transgènica el 1996 els nivells d’adopció d’aquests cultius han augmentat anualment amb percentatges de dos dígits. El desenvolupament i la comercialització de les plantes transgèniques van lligats estretament al comerç mundial, a la globalització, a la disponibilitat de suficient menjar, a la protecció del medi ambient i del consumidor i a la propietat intel·lectual. En aquest article exposem els avenços més recents i les tendències actuals en el desenvolupament dels cultius transgènics i de la seva utilització. També ens fem ressò d’alguns assumptes no científics que s’han de solucionar abans que aquests cultius arribin al màxim del seu potencial, proporcionant una agricultura més sostenible i ecològica. Finalment, ressaltarem la importància de com les plantes transgèniques poden contribuir en la disponibilitat de menjar i en la millora de la pobresa en els països en vies de desenvolupament.

Un nuevo problema en espacios verdes urbanos: el pulgón Myzocallis (Lineomyzocallis) walshii (Hemiptera: Aphididae) y el roble americano (Quercus rubra)

Myzocallis (Lineomyzocallis) walshii (Monell) es un pulgón nativo del este de Nor- teamérica que se detectó por primera vez en España en 1995 y cuyo principal huésped es el roble americano (Quercus rubra L.). Los robles americanos se emplean como árbol ornamental en ambientes urbanos en diversas ciudades españolas, donde las proliferaciones del pulgón generan gran cantidad de melaza provocando daños estéticos y de confort. Durante 2008 y 2009 se efectuó el seguimiento de la fenología y de la densidad de población de M. walshii y de otros pulgones en robles americanos plantados en alineación en la ciudad de Girona y se estimaron los daños producidos. Asimismo se valoró la relación entre la abundancia de pulgones y los daños ocasionados. Finalmente se identificaron los principales grupos de enemigos naturales, a la vez que se cuantificó su abundancia. M. walshii fue la única especie de pulgón que afectó a los robles americanos. Este pulgón pasa el invierno en forma de huevo, las primeras ninfas surgen a la salida de hojas y las distintas generaciones de individuos partenogenéticos se mantienen a niveles variables hasta mediados de otoño, cuando aparecen las formas sexuales. Existe una correlación positiva entre la abundancia del pulgón y los daños de confort, incluso cuando la densidad es baja. Parasitoides y coccinélidos fueron los enemigos naturales más frecuentemente registrados, aunque su abundancia fue relativamente escasa. Se discute el papel de las condiciones climáticas y de los enemigos naturales en la determinación de la abundancia de M. walshii.

Desarrollo larvario y número de estadios larvarios de "Pseudaletia unipuncta" alimentada con dos variedades de maíz y dos dietas semisintéticas

Pseudaletia ( Mythimna) unipuncta (Haworth) es una plaga defoliadora del maíz presente año tras año en la Cuenca del Ebro, que realiza en el maíz daños esporádicos pero a veces devastadores. La implantación creciente de maíz resistente a taladros ha producido, en la zona del presente estudio, la disminución casi total de los daños debidos a los taladros Sesamia nonagrioides (Lefebvre) y Ostrinia nubilalis (Hübner). Sin embargo, no se sabe aún cómo el incremento de maíz transgénico puede afectar a las poblaciones de P. unipuncta. Actualmente no hay datos sobre biología o parámetros del desarrollo de la especie en la Península Ibérica necesarios para evaluar los posibles efectos de las nuevas variedades utilizadas. Para ello es necesario primero establecer un método de cría adecuado y posteriormente iniciar los estudios sobre la biología de la misma. En el presente trabajo se planteó conocer diferentes parámetros del desarrollo larvario de poblaciones locales de P. unipuncta alimentada sobre hoja de maíz (variedades Tietar y PR33P66) y sobre dos dietas semisintéticas, una a base de alubias. Phaseolus vulgaris, y otra a base de maíz, Zea maya. Los resultados mostraron que las larvas desarrolladas en dieta a base de alubias sufrieron menor mortalidad, que las desarrolladas con planta o sobre la otra dieta, además el peso de las pupas resultantes fue mayor y presentaron menos malformaciones. En cuanto al numero de estadios larvarios, la mayoría pupó tras seis mudas larvarias, necesitando, las de dieta de maíz, estadios larvarios adicionales. Estos resultados indican que la dieta a base de alubias es la más adecuada para posteriores trabajos con esta especie.

Plant-derived phenolics inhibit the accrual of structurally characterised protein and lipid oxidative modifications

Epidemiological data suggest that plant-derived phenolics beneficial effects include an inhibition of LDL oxidation. After applying a screening method based on 2,4-dinitrophenyl hydrazine- protein carbonyl reaction to 21 different plant-derived phenolic acids, we selected the most antioxidant ones. Their effect was assessed in 5 different oxidation systems, as well as in other model proteins. Mass-spectrometry was then used, evidencing a heterogeneous effect on the accumulation of the structurally characterized protein carbonyl glutamic and aminoadipic semialdehydes as well as for malondialdehyde-lysine in LDL apoprotein. After TOF based lipidomics, we identified the most abundant differential lipids in Cu++-incubated LDL as 1-palmitoyllysophosphatidylcholine and 1-stearoyl-sn-glycero-3-phosphocholine. Most of selected phenolic compounds prevented the accumulation of those phospholipids and the cellular impairment induced by oxidized LDL. Finally, to validate these effects in vivo, we evaluated the effect of the intake of a phenolic-enriched extract in plasma protein and lipid modifications in a well-established model of atherosclerosis (diet-induced hypercholesterolemia in hamsters). This showed that a dietary supplement with a phenolic-enriched extract diminished plasma protein oxidative and lipid damage. Globally, these data show structural basis of antioxidant properties of plant-derived phenolic acids in protein oxidation that may be relevant for the health-promoting effects of its dietary intake. that a dietary supplement with a phenolic-enriched extract diminished plasma protein oxidative and lipid damage. Globally, these data show structural basis of antioxidant properties of plant-derived phenolic acids in protein oxidation that may be relevant for the health-promoting effects of its dietary intake.

Preferential reproduction mode of hermaphrodite papaya plant (Carica papaya L; Caricaceae)

This research was done to study the reproductive system of papaya hermaphrodite plant based on the histochemical nature of pollen grain, stigma receptivity, in vivo pollen grain germination and pollen:ovule ratio. In the histochemical analysis, pollen grains were stained by using Sudan IV and I2KI solution ; the stigma receptivity was assessed by alpha-naphthtyl acetate solution in closed and opened flowers. Pollen germination and pollen tube growing were examined in flower buds near anthesis with 0.1% aniline blue. To estimate the pollen:ovule ratio , anthers from each flower bud were dissected and all pollen grains were counted; ovules were dissected from ovaries and were counted under stereomicroscope. The results indicated that papaya pollen grains are of lipidic nature; the stigmas were receptive before the opening and until 48 hours after opening; the pollen grains germinated and emitted polinic tube before flower opening and the pollen:ovule ratio indicated the predominance of autogamous reproductive system. These results indicate that hermaphrodite papaya trees is preferentially of optional autogamous with cleistogamy.

Sour orange bud regeneration and in vitro plant development related to culture medium composition and explant type

In order to evaluate the formation of adventitious buds and in vitro regeneration of sour orange plants (Citrus aurantium L.) two organogenesis-inducing experiments were conducted. In the first experiment, the induction and in vitro regeneration of adventitious buds were tested on epicotyl and internodal segments under the influence of BAP or KIN associated with NAA. The second experiment evaluated the in vitro regeneration of sour orange plants related to different explant types (epicotyls segments, internodal segments of in vitro germinated plantlets and internodal segments of greenhouse cultivated plants). Data collected on both experiments included the percentage of responsive explants (explants that formed buds), and the number of buds per explant. The addition of BAP showed the best organogenic response. In vitro germinated epicotyl segments and internodal segments are recommended as explants for sour orange in vitro organogenesis. Rooting of regenerated shoots was achieved without the need of auxin in the medium.

Anaerobic treatment of deinking pulp plant effluents

Anaerobic treatment as a first biological stage in wastewater treatment is nowadays a well-established technology in recycled paper processing mills using closed water circuits. Today further developed high-rate processes and especially high-tower reactors are also able to handle lower organic loads and become therefore feasible for deinking pulp plant effluents. The interest in the anaerobic method is based on a positive energy balance in form of biogas production and low biomass yield from the process. The anaerobic treatment method was researched and its suitability for the deinking pulp plant effluents was tested experimentally at Stora Enso Maxau mill. In the theory, the deinking pulp process is introduced and the effluents from the deinking process are characterized. The anaerobic treatment is brought up in depth in terms of its use for the deinking effluents, and different kind of reactor types are presented. In addition, other wastewater treatment methods are shortly introduced with the focus on tertiary treatment. Static biodegradability tests were carried out for the wastewaters both anaerobically and aerobically. Based on the results, the deinking effluents can be degraded anaerobically, and inhibition to the methanogenic bacteria was not noticed. In the aerobic static test a good performance of the existing wastewater treatment plant at Maxau mill was proved. Later on pilot trials with sequential anaerobic-aerobic treatment were carried out for the deinking effluents. The anaerobic reactor used was a so called internal circulation reactor. The results confirmed that the combination of the anaerobic treatment and the aerobic activated sludge process is a suitable method for deinking wastewaters with a COD reduction as good as with a two stage aerobic method. When combined with the outstanding quality of the produced biogas and the cost savings acquired from the lower sludge production, the anaerobic treatment was found to be an especially favorable treatment method.

Residual effect of growth regulators in etiolation and regeneration of in vitro pineapple plants

This work aimed to evaluate the influence of naphthaleneacetic acid (NAA) and gibberellic acid (GA3) plant regulators in in vitro etiolation and subsequent regeneration of the PE x SC-60 pineapple hybrid. Nodal segments of in vitro plants with approximately 5-7 cm height were incubated in basic MS culture medium supplemented with 0.0; 0.5 and 1.0 mg L-1 of naphthaleneacetic acid (NAA) in combination with gibberellic acid (GA3) in concentrations of 0.0; 0.5 and 1.0 mg L-1, and maintained at 27 ºC under dark condition. Evaluations were carried out at 90 and 180 days after incubation period. The best results for length of etiolated stems were obtained with 1.0 mg L-1 of NAA. In the experiment followed by the regeneration, stems with 3 cm from the etiolation treatment, were cultivated in proliferation medium and the number of regenerated plants per treatment was evaluated at 60 days of cultivation. The treatment that promoted the best etiolation of plants also promoted the worst regeneration rates, demonstrating the residual effect of the auxin used in the previous step in the regeneration of plants of the pineapple hybrid evaluated.

Plant growth regulators to manipulate oat stands

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