Growth in elevated CO2 enhances temperature response of photosynthesis in wheat

The temperature dependence of C3 photosynthesis may be altered by the growth environment. The effects of long-term growth in elevated CO2 on photosynthesis temperature response have been investigated in wheat (Triticum aestivum L.) grown in controlled chambers with 370 or 700 µmol mol-1 CO2 from sowing through to anthesis. Gas exchange was measured in flag leaves at ear emergence, and the parameters of a biochemical photosynthesis model were determined along with their temperature responses. Elevated CO2 slightly decreased the CO2 compensation point and increased the rate of respiration in the light and Rubisco Vcmax, although the latter effect was reversed at 15 ºC. With elevated CO2, Jmax decreased in the 15 ºC-25 ºC temperature range and increased at 30 ºC and 35 ºC. The temperature response (activation energy) of Vcmax and Jmax increased with growth in elevated CO2. CO2 enrichment decreased the RuBP-limited photosynthesis rates at lower temperatures and increased Rubisco- and RuBP-limited rates at higher temperatures. The results show that the photosynthesis temperature response is enhanced by growth in elevated CO2. We conclude that if temperature acclimation and factors such as nutrients or water availability do not modify or negate this enhancement, the effects of future increases in air CO2 on photosynthetic electron transport and Rubisco kinetics may improve the photosynthetic response of wheat to global warming.Spanish National Research and Development Programme (Project BFI2003-01277).Peer reviewe

Fructan synthesis is inhibited by phosphate in warm-grown, but not in cold-treated,excised barley leaves.

The inhibition by phosphate of fructan accumulation has been investigated in warm3 grown and cold-treated barley (Hordeum vulgare L.) plants. • Detached leaves were incubated in water or phosphate for 24 h under lighting or in darkness. Fructosyltransferase, sucrose phosphate synthase (SPS) and cytosolic fructose- 1, 6 - bisphosphatase (FBPase) activities were subsequently analysed, as well as the content of carbohydrates, hexose-phosphates, phosphate, amino acids and protein. • In warm-grown leaves, phosphate decreased fructan accumulation and total carbon in carbohydrates and did not affect protein contents. Phosphate increased hexose phosphates, phosphate and amino acids. Fructosyltransferase and FBPase activities were not affected by phosphate feeding, while SPS activity was inhibited by phosphate in incubations both in light and in darkness. In cold-treated leaves, which prior to incubation had higher SPS activities than warm-grown leaves, phosphate had no inhibitory effect on fructan accumulation, carbohydrate content or total carbon in carbohydrates. SPS and FBPase activities were unaffected by phosphate. • The results indicate that phosphate decreases fructan accumulation through an inhibition of SPS whenever this activity is not high prior to a rise in phosphate content.R. M. had a Ramón y Cajal research contract, and S.K. was the recipient of a grant for stays of foreign researchers in Spain, both from the Ministry of Education, Science and Sport. This work has been funded by the Junta de Castilla y León (Project CSI19/03).Peer reviewe

Diurnal changes of Rubisco in response to elevated CO2, temperature and nitrogen in wheat grown under temperature gradient tunnels.

Growth at elevated CO2 and temperature often leads to decreased Rubisco activity. We investigated the effects of increased CO2, temperature and nitrogen on the diurnal changes in the control of ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activity in wheat (Triticum aestivum L.). Spring wheat was grown at ambient and 700 μmol mol-1 CO2, under ambient and 4 ºC warmer temperatures, and with two levels of nitrogen supply in field tunnels in a Mediterranean environment. At ear emergence, elevated CO2 increased Rubisco activation, but decreased Rubisco protein and, with high nitrogen, Rubisco specific activity, and had no effect on the rbcS transcript. Warmer temperatures tended to decrease the rbcS mRNA level and Rubisco protein, although the effect on Rubisco activity was small. High nitrogen decreased Rubisco activation or specific activity, depending on the CO2 concentration. It increased Rubisco protein at the end of the night, but accelerated its diurnal loss. The main changes after anthesis were the disappearance of the decrease in Rubisco specific activity caused by elevated CO2, an increase in this activity with above-ambient temperatures combined with high nitrogen, and that high temperature and nitrogen did not affect Rubisco protein contents. This study suggests that decreased leaf protein and increased levels of a Rubisco inhibitor, rather than gene repression by sugars, are involved in acclimation to elevated CO2. High nitrogen increases this down regulation. Changes during growth in levels of leaf metabolites and protein may alter the relative importance of levels of inhibitors and Rubisco amounts for Rubisco regulation.The technical cooperation of Libia Hernandez and Angel Verdejo is acknowledged. The staff of the IRNASA experimental farm helped with crop sowing and fertilizer application. The Northern blots analyses were made at the laboratory of Prof. M. Stitt (Botanical Institute, University of Heidelberg, Germany) with Marina Bueno CSIC-DFG funds granted to R. Morcuende. This work was funded by the Spanish Plan Nacional de Investigación y Desarrollo (grant no. CLI96-0396). We thank Dr. Christine Raines (Dept. of Biological Sciences, John Tabor Laboratories, University of Essex, UK) for the generous gift of the Rubisco cDNA.Peer reviewe

Acclimatory responses of stomatal conductance and photosynthesis to elevated CO2 and temperature in wheat crops grown at varying levels of N supply, in a Mediterranean environment.

The short and long-term responses of flag leaf stomatal conductance (gs) and rate of photosynthesis (An) to elevated CO2 (757 μmol mol-1), 4 ºC warmer temperatures and N supply were investigated in spring wheat (Triticum aestivum L. cv. Alcalá) crops grown in two seasons in field conditions under temperature gradient tunnels, in a Mediterranean environment. Plants grown at elevated CO2 had lower gs and An measured at 700 μmol mol-1 CO2 than ambient CO2-grown plants, indicating acclimatory responses to elevated CO2. N supply, which was lower in 2003 than 2002, reduced this acclimation in both years. Warmer temperatures at high nitrogen supply also decreased An acclimation. Acclimatory responses of An and gs were highly correlated. The analysis of the gs – An relationship indicated that both parameters are probably linked and respond in parallel to elevated CO2 at ambient temperatures, but non-parallel responses were observed at above-ambient temperatures.This work was funded by the Spanish Programme of Research and Development (grant No. BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements and chlorophyll determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe

Acclimatory responses of stomatal conductance and photosynthesis to elevated CO2 and temperature in wheat crops grown at varying levels of N supply, in a Mediterranean environment.

The short and long-term responses of flag leaf stomatal conductance (gs) and rate of photosynthesis (An) to elevated CO2 (757 μmol mol-1), 4 ºC warmer temperatures and N supply were investigated in spring wheat (Triticum aestivum L. cv. Alcalá) crops grown in two seasons in field conditions under temperature gradient tunnels, in a Mediterranean environment. Plants grown at elevated CO2 had lower gs and An measured at 700 μmol mol-1 CO2 than ambient CO2-grown plants, indicating acclimatory responses to elevated CO2. N supply, which was lower in 2003 than 2002, reduced this acclimation in both years. Warmer temperatures at high nitrogen supply also decreased An acclimation. Acclimatory responses of An and gs were highly correlated. The analysis of the gs – An relationship indicated that both parameters are probably linked and respond in parallel to elevated CO2 at ambient temperatures, but non-parallel responses were observed at above-ambient temperatures.This work was funded by the Spanish Programme of Research and Development (grant No. BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements and chlorophyll determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe

Perfil antropométrico, somatotipo y composición corporal de jóvenes jugadores de tenis de mesa

El objetivo de este trabajo es determinar las características cineantropométricas de jóvenes jugadores españoles de tenis de mesa de nivel nacional e internacional. Un total de sesenta y tres jugadores (treinta y ocho chicos y veinticinco chicas), fueron divididos en tres grupos atendiendo a sus edades (G1, hasta 11 años; G2, 11 y 12 años; G3, 13-14 años). Se registraron diferentes medidas corporales: peso, talla, pliegues cutáneos (bíceps, tríceps, subescapular, suprailiaco, supraespinal, abdominal, muslo anterior y pierna medial), perímetros (brazo relajado, brazo tensado y flexionado, muslo medio y pierna) y diámetros (biepicondíleo de húmero, biestiloideo de muñeca y bicondíleo de fémur). Además del correspondiente análisis antropométrico, se realizaron cálculos para determinar la composición corporal y el somatotipo de los sujetos participantes en el estudio. Así, el somatotipo general del grupo resultó ser de tipo endomórfico-mesomórfico, coincidiendo con el de los grupos G2 y G3. El análisis teniendo en cuenta el factor género, puso de manifiesto un somatotipo mesomórfico balanceado en el grupo de varones, y meso-endomórfico en el de mujeres. Los datos correspondientes a la composición corporal y contrastados según el factor género mostraron un mayor porcentaje graso en mujeres respecto a varones y un porcentaje óseo más alto en el grupo de varones con respecto al de mujeres. Estos resultados coinciden, en parte, con los encontrados en otros estudios realizados con jugadores de tenis de mesa, en los que se ha observado, de forma global, un predominio equilibrado de los componentes mesomórfico y endomórfico sobre el componente ectomórfico

Quantitative RT-PCR Platform for Transcript Profiling of C-N Metabolism Related Genes in Durum Wheat: Study under a Future Climate Change Scenario

4 figuras. -- Póster presentado en el congreso: BIT's 6th Annual World Congress of Molecular & Cell Biology 2016. Theme: Unlocking the Secrets of Cells. Dalian (China), 25-28 de abril de 2016.Climate change is a major challenge to global food supply, thus is important understanding the mechanisms of crop responses to future environmental conditions. To achieve this goal, we developed a qRT-PCR platform for the expression analysis of more than a hundred C and N metabolism genes in durum wheat, based on available bread wheat genes and the identification of orthologs of known genes in other species. Additionally, we investigated the effect of elevated CO2 and temperature on primary metabolism of durum wheat grown in field chambers at two levels of N supply by combining transcript level analysis, using the qRT-PCR platform, with biochemical and physiological parameters in flag leaves at anthesis.This work was supported by the Spanish National R&D&i Plan of the Ministry of Economy and Competitiveness (grants AGL2006-13541-C02-02, AGL2009-11987 and BES-2010-031029 to R.V.).N