Rubisco activity in Mediterranean species is regulated by the chloroplastic CO2 concentration under water stress

Water stress decreases the availability of the gaseous substrate for ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) by decreasing leaf conductance to CO2. In spite of limiting photosynthetic carbon assimilation, especially in those environments where drought is the predominant factor affecting plant growth and yield, the effects of water deprivation on the mechanisms that control Rubisco activity are unclear. In the present study, 11 Mediterranean species, representing different growth forms, were subject to increasing levels of drought stress, the most severe one followed by rewatering. The results confirmed species-specific patterns in the decrease in the initial activity and activation state of Rubisco as drought stress and leaf dehydration intensified. Nevertheless, all species followed roughly the same trend when Rubisco activity was related to stomatal conductance (gs) and chloroplastic CO2 concentration (Cc), suggesting that deactivation of Rubisco sites could be induced by low Cc, as a result of water stress. The threshold level of Cc that triggered Rubisco deactivation was dependent on leaf characteristics and was related to the maximum attained for each species under non-stressing conditions. Those species adapted to low Cc were more capable of maintaining active Rubisco as drought stress intensified

Nota sobre la distribució actual i hàbitat de Melaraphe punctata (Gmelin, 1789) (Mollusca, Gastropoda) a Mallorca

Abstract not availabl

Drought effects on water flow, photosynthesis and growth of potted grapevines

In two consecutive years and under different environmental conditions, leaf gas exchange, sap flow and trunk diameter were measured to estimate transpiration of grapevine. Daily maxima of sap flow were lower than estimations obtained by gas exchange measurements. Sap flow was delayed with regard to variation of irradiance. For irrigated plants the correlation between transpiration rates of single leaves as determined by gas exchange and instantaneous sap flow was high (r2=0.84). However, the correlation of sap flow with the total daily water consumption was even higher (r2=0.98) and close to 1:1. At various water states, leaf photosynthetic rate was also correlated with sap flow (r2=0.78); the correlation coefficient increased to r2=0.91 when the daily balance was compared. Plant growth, estimated from linear variable displacement transducers was closely related to the daily sap flow.

The Mediterranean evergreen Quercus ilex and the semi-deciduous Cistus albidus differ in their leaf gas exchange regulation and acclimation to repeated drought and re-watering cycles

Plants may exhibit some degree of acclimation after experiencing drought, but physiological adjustments to consecutive cycles of drought and re-watering (recovery) have scarcely been studied. The Mediterranean evergreen holm oak (Q. ilex) and the semi-deciduous rockrose (C. albidus) showed some degree of acclimation after the first of three drought cycles (S1, S2, and S3). For instance, during S2 and S3 both species retained higher relative leaf water contents than during S1, despite reaching similar leaf water potentials. However, both species showed remarkable differences in their photosynthetic acclimation to repeated drought cycles. Both species decreased photosynthesis to a similar extent during the three cycles (20–40% of control values). However, after S1 and S2, photosynthesis recovered only to 80% of control values in holm oak, due to persistently low stomatal (gs) and mesophyll (gm) conductances to CO2. Moreover, leaf intrinsic water use efficiency (WUE) was kept almost constant in this species during the entire experiment. By contrast, photosynthesis of rockrose recovered almost completely after each drought cycle (90–100% of control values), while the WUE was largely and permanently increased (by 50–150%, depending on the day) after S1. This was due to a regulation which consisted in keeping gs low (recovering to 50–60% of control values after re-watering) while maintaining a high gm (even exceeding control values during re-watering). While the mechanisms to achieve such particular regulation of water and CO2 diffusion in leaves are unknown, it clearly represents a unique acclimation feature of this species after a drought cycle, which allows it a much better performance during successive drought events. Thus, differences in the photosynthetic acclimation to repeated drought cycles can have important consequences on the relative fitness of different Mediterranean species or growth forms within the frame of climate change scenarios

Apreciación estética de estímulos abstractos y figurativos: datos conductuales y registros cerebrales

- Introducció Les investigacions d’aquesta tesi s’emmarquen en la feina del grup Evolució i Cognició Humana (EvoCog), centrat en l’estudi dels trets específics dels éssers humans des d’un enfocament evolutiu-cognitiu. La capacitat moral i l’apreciació estètica són dos dels principals trets funcionals exclusius de l’espècie humana, i degut a que no deixen indicis fòssils directes, suposen un repte per a l’estudi de la cognició humana i la seva evolució. Per això el grup EvoCog centra els seus esforços en algunes de les incògnites d’aquests dos trets a través del projecte “La naturalesa moral i estètica humana. Caracterització sistemàtica dels trets derivats humans de moral i estètica” (FFI2010-20759). El projecte, en el qual s’emmarca aquest treball doctoral, es planteja aprofundir en la naturalesa dels valors de moral i estètica, així com estudiar els seus possibles trets evolutius comuns. - Contingut de la investigació Els treballs del doctorant han esdevingut en l’elaboració de diversos articles, la majoria ja publicats, que segueixen la línia esmentada. Com aproximació a l’estudi de la cognició moral a través del plantejament de dilemes morals (1–3), es va estudiar un grup de dones cristianes i es varen comparar les seves respostes comportamentals i cerebrals amb les d’un grup de dones atees (4). Quant a la neuroestètica, la revisió de Nadal et al. (5) fa una síntesi dels resultats previs en aquest camp com a marc de reflexió teòrica per aquest treball doctoral. Com a continuació de l’article de Cela-Conde et al. (6), que estudia mitjançant Magnetoencefalografia (MEG) l’activació cerebral diferencial de la resposta estètica “bell” respecte de “no bell”, es varen dur a terme dues línies d’investigació: una d’elles comportà noves anàlisi (7); mentres que l’altra replicà el mateix mètode d’anàlisi però amb l’objectiu d’explorar el contrast invers, “no bell” contra “bell” (8), i ens donà pistes que suggereixen que la resposta estètica és relativa. Per això dissenyàrem un experiment de priming (9) que tracta d’incrementar el nostre coneixement sobre l’efecte dels processos afectius i la seva influència sobre l’apreciació estètica. Això no obstant, una altra variable que sembla influir en la relativitat de l’experiència estètica és el nivell d’abstracció dels estímuls. La literatura ha descrit la tendència que tenen els participants sense formació artística per considerar bells els quadres figuratius i no bells els quadres abstractes (10–15). Tot i així, no s’ha explorat a fons aquesta tendència, i expecialment no s’ha analitzat la interacció entre el tipus d’estímul (abstracte/figuratiu) i la resposta (bell/no bell). Què succeeix quan hom considera bell un quadre abstracte, i no bell a un quadre figuratiu o una fotografia? L’article de Flexas et al. (16) és una primera aproximació a la resposta d’aquesta pregunta, i els resultats de Cattaneo et al. (17) suposen anàlisis addicionals sobre aquesta qüestió. Finalment, l’article de Cela-Conde et al. (18) suggereix que existeix una xarxa d’apreciació estètica primerenca i una xarxa d’apreciació estètica tardana, aquesta darrera estretament relacionada amb la xarxa cerebral per defecte (Default Mode Network) (19). - Conclusió Els nostres resultats, presos en conjunt i en consonància amb la majoria d’estudis actuals de neuroestètica, suggereixen que la capacitat d’apreciació estètica es serveix d’un conjunt de processos i components cognitius i neuronals, cada un dels quals sembla imprescindible però no suficient per configurar el tret de l’apreciació estética, i que pot ser compartit per altres xarxes cerebrals i trets funcionals. En definitiva, el conjunt de treballs presentats ha contribuït significativament a desvetllar possibles components cognitius i neurals del tret d’apreciació estètica i la potencial sinèrgia entre ells. A més, els resultats permeten apuntar possibles mecanismes comuns entre els trets derivats de moral i estètica.- Introducción Las investigaciones de esta tesis se enmarcan en el trabajo del grupo de investigación Evolución y Cognición Humana (EvoCog), centrado en el estudio de los rasgos específicamente humanos desde un enfoque evolutivo-cognitivo. La capacidad moral y la apreciación estética son dos de los principales rasgos funcionales exclusivos de la especie humana, y debido a que no dejan indicios fósiles directos, suponen un reto para el estudio de la cognición humana y su evolución, por lo que el grupo EvoCog centra sus esfuerzos en algunas de las incógnitas de estos dos rasgos a través del proyecto “La naturaleza moral y estética humana. Caracterización sistemática de los rasgos derivados humanos de moral y estética” (FFI2010-20759). Dicho proyecto, en el que se enmarca este trabajo doctoral, se plantea profundizar en la naturaleza de los valores de moral y estética, así como estudiar sus posibles rasgos evolutivos comunes. - Contenido de la investigación Los trabajos del doctorando han devenido en la elaboración de varios artículos, la mayoría ya publicados, que siguen la línea arriba expuesta. Como aproximación al estudio de la cognición moral a través del planteamiento de dilemas morales (1–3), se estudió un grupo de mujeres cristianas y se compararon sus respuestas comportamentales y cerebrales con las de un grupo de mujeres ateas (4). En cuanto a la neuroestética, la revisión de Nadal et al. (5) hace una síntesis de los resultados previos en este campo, sirviendo de marco de reflexión teórica para este trabajo doctoral. Como continuación del artículo de Cela-Conde et al. (6), que estudia mediante Magnetoencefalografía (MEG) la activación cerebral diferencial de la respuesta estética “bello” respecto de “no bello”, se llevaron a cabo dos líneas de investigación: una de ellas comportó nuevos análisis (7), mientras que la otra replicó el mismo método de análisis pero con el objetivo de explorar el contraste inverso, “no bello” versus “bello” (8), proporcionando pistas que sugieren que la respuesta estética es relativa. Por eso diseñamos un experimento de priming (9) que trata de incrementar nuestro conocimiento del efecto de los procesos afectivos y su influencia sobre la apreciación estética. Otra variable que parece influir en la relatividad de la experiencia estética es el nivel de abstracción de los estímulos. La literatura ha descrito la tendencia que tienen los participantes sin formación artística por considerar bellos los cuadros figurativos y no bellos los cuadros abstractos (10–15). Sin embargo, no se ha explorado a fondo esta tendencia, y especialmente no se ha analizado la interacción entre el tipo de estímulo (abstracto/figurativo) y la respuesta (bello/no bello). ¿Qué sucede cuando se considera bello un cuadro abstracto, y no bello un cuadro figurativo o una fotografía? El artículo de Flexas et al. (16) es una primera aproximación a la respuesta a esa pregunta, y los resultados de Cattaneo et al. (17) suponen análisis adicionales sobre esta cuestión. Finalmente, el artículo de Cela-Conde et al. (18) sugiere que existe una una red de apreciación estética temprana y una red de apreciación estética tardía, esta última estrechamente relacionada con la red cerebral por defecto (Default Mode Network) (19). - Conclusión Nuestros resultados, tomados en conjunto y en consonancia con la mayoría de estudios actuales de neuroestética, sugieren que la capacidad de apreciación estética se sirve de un conjunto de procesos y componentes cognitivos y neuronales, cada uno de los cuales parece imprescindible pero no suficiente para dar cuenta del rasgo de apreciación estética, y que puede ser compartido por otras redes cerebrales y rasgos funcionales. En definitiva, el conjunto de los trabajos presentados ha contribuido significativamente a desvelar posibles componentes cognitivos y neurales del rasgo de la estética y la potencial sinergia entre ellos; y además permite apuntar posibles mecanismos comunes entre los rasgos de moral y estética.- Introduction The research of this thesis is part of the work of the research group 'Human Evolution and Cognition' (EVOCOG), focused on the study of human-specific traits from a cognitive-developmental approach. Moral capacity and aesthetic appreciation are two major functional traits that are unique to the human species, but they didn't left direct fossil evidence. Thus, their study is a challenge, and EVOCOG group focuses its efforts on some of the questions about these two traits through the project "The moral and aesthetic nature of humans. Systematic characterization of derived human traits of moral and aesthetics" (FFI2010-20759). This project, which is the base of this doctoral work, explore the nature of moral and aesthetic values, and their possible common evolutionary features. - Research content The work of the candidate have become the ellaboration of several papers, most already published, which follow the line stated above. As an aproximation to the study of moral cognition through the moral dilemmas approach (1-3), we studied a group of Christian women and compared their behavioral and brain responses with those of a group of atheist women (4). About neuroaesthetics, the review of Nadal, Flexas et al. (5) is a summary of previous results from researches in this field and serves as theoretical framework for this doctoral work. Following the paper of Cela-Conde et al. (6), which studied, by means of magnetoencephalography (MEG), the differential brain activity between the aesthetic responses "beautiful" and "not beautiful", we carried out two lines of research: one of them with new analysis (7) and the other replicating the same method of analysis but with the aim of exploring the reverse contrast, "not beautiful" versus "beautiful" (8). This revealed some indications that aesthetic response is relative. Thus, we designed an experiment with affective priming (9) to increase our knowledge about the effect of affective processes and their influence on aesthetic appreciation. Another variable that appears to influence the relativity of aesthetic experience is the level of abstraction of stimuli. The literature describes the trend that participants without artistic training consider beautiful the representational paintings and not beautiful the abstract paintings (10-15). However, it is not fully explored this trend. In fact, the interaction between type of stimulus (abstract / figurative) and response (beautiful / not beautiful) has not been analyzed to date. What happens when an abstract painting is considered beautiful? The paper by Flexas et al. (16) is a first approximation to answer that question, and the results of Cattaneo et al. (17) represent additional analysis on this issue. Finally, the article by Cela-Conde et al. (18) suggests that there is an initial aesthetic appreciation network and a delayed aesthetic appreciation network, the latter closely related to the Default Mode Network (19). - Conclusion Our results, taken together and in line with most current neuroaesthetics studies, suggest that the capacity for aesthetic appreciation uses a bunch of cognitive and neural processes and components, each of which seems essential but not sufficient to account of aesthetic appreciation trait, and can be shared by other brain networks and functional traits. In short, all of the papers of this work contribute significantly to uncover potential cognitive and neural components of the aesthetic appreciation and suggest synergy between them. Moreover, this work brings some potential common mechanisms between moral and aesthetic features

Hydrography and dynamics of Port Foster, Deception Island, Antarctica

The circulation and water masses of Port Foster, Deception Island, were studied using conductivity-temperature-depth stations inside and outside the semi-enclosed bay and an array of bottom temperature sensors moored around the perimeter of the bay over two weeks in the summer of 2012. Inside Port Foster, the water column is divided into two layers separated by a temperature-forced, seasonal pycnocline at ~40–60 m. The circulation of the upper layer is in an anticlockwise direction, with mean geostrophic currents of ~0.04–0.10 ms^(-1). The lower layer, from ~60 m to the seabed, shows coastal-trapped waves travelling in a clockwise direction, possibly triggered by local wind gusts. Local sea ice melt in areas surrounding the underwater hot springs of Pendulum Cove appears as a fresh, warm anomaly down to 30 m

Distribution of leaf photosynthesis and transpiration within grapevine canopies under different drought conditions

The effects of seasonal drought on the distribution of leaf area, photosynthesis and transpiration within the canopy were evaluated for two Spanish grapevine cultivars. Both varieties were cultivated according to their typical training system.At early stages of drought, reduction of photosynthesis and transpiration was only observed in sun-exposed leaves. As drought intensified, even less sun-exposed leaves were affected. Severe drought reduced photosynthesis and transpiration in all locations of the canopy except for most shaded leaves in the inner part. However, those leaves were almost unproductive, and seemed to be insensitive to variation of both light intensity and drought. Leaf area was also reduced by drought, but the distribution of these reductions within the canopy differed between cultivars, possibly reflecting differences in the training system.Leaves from all locations of the canopy except those in the central part showed a similar radiation use efficiency, suggesting that the observed variation in photosynthesis within the canopy was mostly related to different light interception, while other factors such as different leaf age should play only a minor role. Photosynthetic radiation use efficiency strongly depended on both, pre-dawn leaf water potential and light-saturated stomatal conductance. The interest of these results for modeling purposes is discussed.

Mesophyll conductance to CO2, assessed from online TDL-AS records of 13CO2 discrimination, displays small but significant short-term responses to CO2 and irradiance in Eucalyptus seedlings

Mesophyll conductance (gm) is now recognized as an important limiting process for photosynthesis, as it results in a significant decrease of CO2 diffusion from substomatal cavities where water evaporation occurs, to chloroplast stroma. Over the past decade, an increasing number of studies proposed that gm can vary in the short term (e.g. minutes), but these variations are still controversial, especially those potentially induced by changing CO2 and irradiance. In this study, gm data estimated with online 13C discrimination recorded with a tunable diode laser absorption spectrometer (TDL-AS) during leaf gas exchange measurements, and based on the single point method, are presented. The data were obtained with three Eucalyptus species. A 50% decrease in gm was observed when the CO2 mole fraction was increased from 300 μmol mol−1 to 900 μmol mol−1, and a 60% increase when irradiance was increased from 200 μmol mol−1 to 1100 μmol mol−1 photosynthetic photon flux density (PPFD). The relative contribution of respiration and photorespiration to overall 13C discrimination was also estimated. Not taking this contribution into account may lead to a 50% underestimation of gm but had little effect on the CO2- and irradiance-induced changes. In conclusion, (i) the observed responses of gm to CO2 and irradiance were not artefactual; (ii) the respiratory term is important to assess absolute values of gm but has no impact on the responses to CO2 and PPFD; and (iii) increasing irradiance and reducing the CO2 mole fraction results in rapid increases in gm in Eucalyptus seedlings

Contribution to the knowledge of the flora and fauna of the sea bed of Cala Rafeubetx (SW of Mallorca, Balearic Islands)

Abstract not availabl