Intraspecific Variation in Pinus Pinaster PSII Photochemical Efficiency in Response to Winter Stress and Freezing Temperatures

As part of a program to select maritime pine (Pinus pinaster Ait.) genotypes for resistance to low winter temperatures, we examined variation in photosystem II activity by chlorophyll fluorescence. Populations and families within populations from contrasting climates were tested during two consecutive winters through two progeny trials, one located at a continental and xeric site and one at a mesic site with Atlantic influence. We also obtained the LT50, or the temperature that causes 50% damage, by controlled freezing and the subsequent analysis of chlorophyll fluorescence in needles and stems that were collected from populations at the continental trial site

Análisis económico financiero del grupo Nextil (2018-2020)

El objetivo principal en el que se basa la elaboración de este trabajo es realizar un análisis económico financiero del Grupo Nueva Expresión Textil, S.A, más conocido por la abreviatura Nextil, centrándonos en la empresa matriz y en el Grupo en conjunto, para el periodo comprendido entre 2018-2020. Se hará una breve reseña histórica del grupo contando cómo ha evolucionado desde su creación como una empresa familiar hasta convertirse en un holding, incidiendo en las situaciones de crisis que ha atravesado a lo largo del tiempo. Interpretaremos y analizaremos porcentajes verticales y horizontales del balance de situación y los ratios más importantes, estudiaremos el recorrido del grupo a lo largo de los años y el entorno externo con los factores que le influyen, centrándonos en los efectos sobre su actividad causados por la pandemia del Covid-19. Una vez obtenidos los datos, analizados e interpretados podemos concluir que el grupo Nextil se encuentra en una situación en la que todavía tiene que enfrentarse a un importante desequilibrio financieroGrado en Administración y Dirección de Empresa

Phenotypic plasticity in

• Carbon isotope composition (δ13C) is a complex trait involved in acclimation, adaptive processes and related to water use efficiency (WUE) and/or productivity. • To estimate the genetic variation in δ13C and growth (h), their relationship, and the genotype by environment interaction effect in both variables, we analyzed three Pinus pinaster populations and six to ten families per population, in two experimental trial sites and in two consecutive years. • δ13C increased in the drier site (from –27.15  ±  0.18 to –24.53  ±  0.22) and was more affected by environment (62% of variance) than by genotype. • All populations and families exhibited a high phenotypic plasticity in δ13C and increased WUE in the xeric site. • As expected, significant height differences between sites, years, populations and families were displayed. Smaller trees were associated to higher water use efficiency (δ13C) in both, mesic and xeric trial sites. • Aridity and continentality enhanced population differences in δ13C, therefore, in afforestation programs of arid and continental zones, the selection at the population level would be more efficient than at the family level. In the mesic site, the presence of a high genetic variation in δ13C and h between families allows the possibility of a selection for growth and water use efficiency within populations in sub-humid sites

Phenotypic plasticity in mesic populations of Pinus pinaster improves resistance to xylem embolism (P-50) under severe drought

The objectives of the study were to assess the phenotypic variation in the vulnerability to water stress-induced cavitation (estimated by P-50, or the xylem water potential which causes a 50% loss of conductivity) and the trade-offs between P-50 and related hydraulic traits, i.e., stem specific conductivity (K-s), slope of the vulnerability curve (slope), wood density and branch size. Variability was examined for six Pinus pinaster populations covering the latitudinal range of the species and plasticity was tested through two provenance-progeny trial sites (xeric/mesic). As expected, the overall values of P-50, K-s and branch size decreased in the xeric site. Variation in P-50 and K-s among populations was mainly the result of phenotypic plasticity, while wood density was genetically controlled and not affected by the environment. Stress conditions in the xeric site promoted a convergence in P-50 and K-s as a result of the high phenotypic plasticity of the populations from mesic origins. In the mesic site, the ranking of populations for cavitation resistance and hydraulic capacity was consistent with the geographic location of the seed source. Higher resistance to cavitation was related to lower K-s, branch size and slope, mainly at the population level, but also as a general trend across individuals. In a warmer and drier climate, there could be a potential selection of Pinus pinaster populations from mesic origins, which showed a great responsiveness and adjustment to drought conditions (similar or higher P-50 than the populations from dry origins), in addition to a high wood density and growth

Population variation in the freezing tolerance of needles and stems.

<p>The relationship between the temperature (°C) and maximum potential PSII efficiency (<i>F</i>_v/<i>F</i>_m) in the needles (A) and stems (B) of <i>Pinus pinaster</i> populations is shown: <i>Oria</i> (filled circles), <i>Mimizan</i> (open circles), <i>Tamrabta</i> (squares) and <i>Arenas</i> (triangles). Error bars indicate standard errors of the mean values.</p

Seasonal changes in photosynthesis and photoprotection in a Quercus ilex subsp. ballota woodland located in its upper altitudinal extreme in the Iberian Peninsula

Quercus ilex L. subsp. ballota (Desf.) Samp., a Mediterranean evergreen species growing in a continental Mediterranean climate, did not experience water stress and showed greater sensitivity to winter stress than to summer stress over a 12-month period. Net CO2 assimilation rates and photosystem II (PSII) efficiency decreased markedly during the cold months and recovered completely in spring. Lutein, neoxanthin and β-carotene to chlorophyll (Chl) molar ratios all showed the same trend throughout the year, increasing from September to March. This increase was a result of increases in carotenoid concentrations, because Chl concentration per unit leaf area remained stable, and was higher at the end than at the beginning of the first growing season. Lutein-epoxide was a minor component of the total lutein pool. Thermal energy dissipation and non-photochemical quenching (NPQ) were associated with the de-epoxidated forms of the xanthophyll cycle pigments in the warm months. Photosynthetic rates decreased slightly at midday in summer. These changes were accompanied by decreases in maximum potential PSII efficiency (which recovered during the night), actual and intrinsic PSII efficiencies, photochemical quenching and increases in NPQ. Overall, our data indicate down-regulation of photosynthesis during the summer. The diurnal de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin occurred throughout the year, except in January. Antioxidant enzymatic activity increased in the winter months, especially during the coldest months, highlighting its key role in photoprotection against photo-oxidation. Structural and functional modifications protected PSII from permanent damage and allowed 1-year-old leaves to photosynthesize at high rates when temperatures increased in spring.This work was supported by the projects 1FD97-0911-C03-01.SUBP1 and SC96-086 to E.G-P and a postgraduate INIA grant to L.C.Peer Reviewe

Percentages of variance by <i>site</i> and <i>winter</i> (%).

<p>Abbreviations are the same as those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028772#pone-0028772-t002" target="_blank">Table 2</a>.</p

Summary of ANOVA significances.

<p><i>F</i>_v/<i>F</i>_m: maximum potential PSII efficiency. Φ_PSII: actual PSII efficiency. <i>qP</i>: photochemical quenching. <i>NPQ</i>: non-photochemical quenching. <i>Winter</i>: studied period (winter 2005–06, winter 2006–07). <i>Site</i>: location of the provenance-progeny trials. Num <i>DF</i>: number of degrees of freedom. Den <i>DF</i>: Denominator of degrees of freedom. Pr: Probability. <i>F</i>: F-values. Bold numbers denote values for which Pr>0.05.</p

Population heritabilities (<i>h²</i>) with non-zero significance, by <i>site</i> and <i>winter</i>.

<p>Abbreviations are the same as those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028772#pone-0028772-t002" target="_blank">Table 2</a>.</p