{"id":96005,"date":"2018-03-11T10:16:08","date_gmt":"2018-03-11T10:16:08","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/ecophysiological-significance-of-lutein-epoxide-cycle\/"},"modified":"2018-03-11T10:16:08","modified_gmt":"2018-03-11T10:16:08","slug":"ecophysiological-significance-of-lutein-epoxide-cycle","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/fisiologia-vegetal\/ecophysiological-significance-of-lutein-epoxide-cycle\/","title":{"rendered":"Ecophysiological significance of lutein epoxide cycle"},"content":{"rendered":"<h2>Tesis doctoral de <strong> Raquel Esteban Terradillos <\/strong><\/h2>\n<p>Las plantas deben ser capaces de regular la utilizaci\u00f3n de la luz y de ajustarla a las condiciones ambientales, con el fin de prevenir da\u00f1os en los tejidos fotosint\u00e9ticos. Este desaf\u00edo no ser\u00eda posible sin un completo sistema de mecanismos de fotoprotecci\u00f3n, entre los cuales el ciclo de las xantofilas juega un papel principal. Es por ello, que el presente trabajo se centr\u00f3 en dicha l\u00ednea de defensa, siendo el objetivo principal el estudio de los aspectos ecofisiol\u00f3gicos del ciclo, taxon\u00f3micamente restringido, de la lute\u00edna ep\u00f3xido (lx) y el de sus relaciones con el ciclo de la violaxantina (v), universal en el reino vegetal. Tras el estudio de la distribuci\u00f3n del ciclo de la lx en el reino plantae, y de los patrones ecol\u00f3gicos de su distribuci\u00f3n, se encontr\u00f3 lx en el 45% de las especies analizadas, siendo las angiospermas basales el grupo que mayores concentraciones present\u00f3. En este grupo est\u00e1 incluida la familia lauraceae. Por lo tanto, el funcionamiento del ciclo de la lx fue investigado en varias especies de laur\u00e1ceas, bajo condiciones controladas y en campo. Se concluy\u00f3 que el ciclo de la lx funciona de modo unidireccional e irreversible en la mayor\u00eda de las especies, como laurus nobilis y persea americana  (ciclo lx truncado), si bien lo puede hacer de manera reversible y bidireccional en algunas, como el til (ocotea foetens) (ciclo lx verdadero). Es por ello, que esta \u00faltima especie se utiliz\u00f3 para establecer la funci\u00f3n ecofisiol\u00f3gica del ciclo de la lx. Nuestros datos mostraron que la fotoconversi\u00f3n de la lx acelera el establecimiento de la disipaci\u00f3n t\u00e9rmica de la energ\u00eda, adem\u00e1s de responder pl\u00e1sticamente a las condiciones ambientales. Asimismo, se demostr\u00f3 una doble regulaci\u00f3n del ciclo de la lx en o. Foetens, donde el  grado de reversibilidad depende de la intensidad y duraci\u00f3n de la iluminaci\u00f3n. Todas estas observaciones confirman que este segundo ciclo de las xantofilas aporta un abanico de soluciones fisiol\u00f3gicas mucho m\u00e1s amplio y pl\u00e1stico. Este mecanismo puede ser de especial relevancia para la supervivencia y aclimataci\u00f3n de las pl\u00e1ntulas de especies le\u00f1osas a las condiciones ambientales del sotobosque.  summary plants survival depends on the ability to regulate and adjust the utilization of light with the aim to prevent damage in the photosynthetic tissues. This key challenge could not be possible without a complete set of photoprotection mechanisms, among which the xanthophyll cycles play a key role. Regarding this line of defence, this work focused on the ecophysiological aspects of the taxonomically-restricted lutein epoxide (lx) cycle and its relationships with the ubiquitous violaxanthin (v) cycle. Distribution of lx cycle among kingdom plantae was addressed in the present work. In addition, ecological patterns of its distribution were discussed. We found lx in 45% of the species analyzed with the highest concentration in basal angiosperms. This group includes lauraceae family. Therefore, the lx cycle operation was investigated in several tree species of the lauraceae family under controlled and field conditions. This led to find that lx cycle could operate as irreversible on a daily basis (truncated lx cycle) in some species (laurus nobilis and persea americana), or display a complete restoration of lx overnight (true lx cycle) in others (ocotea foetens). The last of these species was used as model to find an ecophysiological answer for the lx cycle. Our data demonstrate that the photoconversion of lx accelerates the establishment of the thermal energy dissipation and that the pool of lx responds plastically to changing environmental conditions. Furthermore, we have found that there is a dual regulation of lx cycle in o. Foetens, in which the extent of lx restoration depends on the intensity and duration of illumination. All these observations indicate that this second xanthophyll cycle opens wider and more plastic arrays of physiological solutions to environment, which could be of special relevance for the survival of seedlings in the forest understorey.<\/p>\n<p>&nbsp;<\/p>\n<h3>Datos acad\u00e9micos de la tesis doctoral \u00ab<strong>Ecophysiological significance of lutein epoxide cycle<\/strong>\u00ab<\/h3>\n<ul>\n<li><strong>T\u00edtulo de la tesis:<\/strong>\u00a0 Ecophysiological significance of lutein epoxide cycle <\/li>\n<li><strong>Autor:<\/strong>\u00a0 Raquel Esteban Terradillos <\/li>\n<li><strong>Universidad:<\/strong>\u00a0 Pa\u00eds vasco\/euskal herriko unibertsitatea<\/li>\n<li><strong>Fecha de lectura de la tesis:<\/strong>\u00a0 18\/09\/2009<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3>Direcci\u00f3n y tribunal<\/h3>\n<ul>\n<li><strong>Director de la tesis<\/strong>\n<ul>\n<li>Jos\u00e9 Mar\u00eda Becerril Soto<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tribunal<\/strong>\n<ul>\n<li>Presidente del tribunal: Mar\u00eda  soledad Jimenez parrondo <\/li>\n<li>Mar\u00eda  bego\u00f1a Gonzalez moro (vocal)<\/li>\n<li>Jos\u00e9 Fernando Moran juez (vocal)<\/li>\n<li>shizue Matsubara (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tesis doctoral de Raquel Esteban Terradillos Las plantas deben ser capaces de regular la utilizaci\u00f3n de la luz y de 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