Ozone-induced reductions in below-ground biomass: an anatomical approach in potato

[EN] Potato plants were grown in open-top chambers under three ozone concentrations during two complete cropping seasons (93 and 77 d in 2004 and 2005, respectively). The effects of chronic exposure to ozone on leaf anatomy, cell ultrastructure and crop yield were studied. Severe cell damage was found, even at ambient ozone levels, mainly affecting the spongy parenchyma and areas near the stomata. Damage to the cell wall caused loss of cell contact, and loss of turgor pressure due to tonoplast disintegration, contributed to cell collapse. Phloem sieve plates were obstructed by callose accumulation, and damaged mesophyll cells increased their starch stores. Tuber yield fell sharply (24–44%), due to the biggest tubers becoming smaller, which affected commercial yield. These anatomical findings show the mechanisms of ozone effect on assimilate partitioning, and thus crop yield decrease, in potato. Further implications of ozone causing reductions in belowground biomass are also discussed.The authors thank Prof Secundino del Valle (Valencia University, Spain) for his helpful comments. We are also grateful to Mr Duncan Gates for revising the English style of the text. AAF was supported by a grant from the Generalitat Valenciana's FPI programme (Government of Valencia, Spain).Asensi-Fabado, A.; García-Breijo, F.; Reig Armiñana, J. (2010). Ozone-induced reductions in below-ground biomass: an anatomical approach in potato. Plant, Cell and Environment. 33(7):1070-1083. doi:10.1111/j.1365-3040.2010.02128.xS1070108333

Estudio anatómico-histológico de las flores del endemismo Lamottea diania (Asteraceae) y de los efectos del ozono troposférico sobre su desarrollo.

"Estudio anatómico-histológico de las flores del endemismo Lamottea diania (Asteraceae) y de los efectos del ozono troposférico sobre su desarrollo". Lilloa 53 (2). Plantas del endemismo Lamottea diania se expusieron en cámaras OTC (Open Top Chambers) a aire ambiente filtrado y a aire ambiente no filtrado más 30 ppb de ozono para observar el efecto de este contaminante sobre el desarrollo de sus flores, particularmente sobre su androceo. Hemos comprobado, mediante estudios de microscopía óptica y electrónica, que el ozono afecta el proceso de desarrollo y maduración de los estambres y del polen. Las anteras se ven afectadas, en unos casos al abortar algunos estambres en su desarrollo y, en otros, impidiéndose el desarrollo correcto de los sacos polínicos en el interior de las mismas. Asimismo, el ozono impide la formación correcta del polen encontrando numerosos granos de polen sin desarrollar o desarrollados y madurados de forma anómala en el interior de los sacos polínicos. Los resultados indican que el ozono es el responsable del desarrollo anormal del androceo y del polen en plantas de L. diania. Anatomical and histological study of endemism flowers of Lamottea diania (Asteraceae) and the effects of tropospheric ozone on their development'. Lilloa 53 (2). Plants of endemism Lamottea diania were exposed in cameras OTC (Open Top Chambers) to filtered ambient air and ambient air unfiltered over 30 ppb ozone to observe the effect of this pollutant on the development of its flowers, particularly on its androecium. We have found, through studies of optical and electron microscopy, that ozone affects the process of development and maturation of stamens and pollen. The anthers are affected, in some cases by aborting some stamens in their development and in other, prevented the proper development of the pollen sacs within them. In addition, ozone prevents proper formationand maturation of pollen found many undeveloped pollen grains or developed abnormally inside the pollen sacs. Results indicate that ozone was responsible for the abnormal development of androecium and pollen in L. diania

Responses of evergreen and deciduous Quercus species to enhanced ozone levels

Plants of one evergreen oak (Quercus ilex) and three deciduous oaks (Q. faginea, with small leaves; Q. pyrenaica and Q. robur, with large leaves) were exposed both to filtered air and to enhanced ozone levels in Open-Top Chambers. Q. faginea and Q. pyrenaica were studied for the first time. Based on visible injury, gas exchange, chlorophyll content and biomass responses, Q. pyrenaica was the most sensitive species, and Q. ilex was the most tolerant, followed by Q. faginea. Functional leaf traits of the species were related to differences in sensitivity, while accumulated ozone flux via stomata (POD1.6) partly contributed to the observed differences. For risk assessment of Mediterranean vegetation, the diversity of responses detected in this study should be taken into account, applying appropriate critical levels. © 2010 Elsevier Ltd. All rights reserved.We thank both the Ministerio de Medio Ambiente y Medio Rural y Maritimo (in collaboration with ICP-Forests), and the Conselleria de Medi Ambient, Aigua i Habitatge and Interreg III (ForMedOzone and VegetPollOzone projects) for supporting the OTC activity. Institut Universitario CEAM-UMH is also supported by Generalitat Valenciana and Fundacion Bancaja, benefiting from CONSOLIDER-INGENIO 2010 (GRACCIE) and Prometeo (Generalitat Valenciana) Programs. Filippo Bussotti and two anonymous referees are thanked for their useful comments. Carmen Martin is also thanked for taking care of the plants.Calatayud, V.; Cervero, J.; Calvo, E.; García Breijo, FJ.; Reig Armiñana, J.; Sanz, M. (2011). Responses of evergreen and deciduous Quercus species to enhanced ozone levels. Environmental Pollution. 159(1):55-63. doi:10.1016/j.envpol.2010.09.024S5563159

In Vivo Pollen Tube Growth and Evidence of Self-Pollination and Prefloral Anthesis in cv. Macabeo (Vitis vinifera L.)

[EN] Cultivar Macabeo is one of the most planted white grape varieties of northern Spain. A general agreement supports many Vitis vinifera cultivars possibly being self-fertile, although this seems to be a variety-dependent characteristic. No previous information about the mating system of cv. Macabeo was found. This study aimed to analyze its mating system and to compare the in vivo fertilization process with and without artificial cross-pollination. Two treatments were performed: emasculation and cross-pollination. The seed number was counted, and pollen tube growth was observed by microscopy. The results showed that cv. Macabeo is self-fertile and selfing probably occurs before the flower opens. Pollen was found over the stigma of flowers before capfall and ovule fertilization was observed even in emasculated flowers, which suggests that germination and pollen tube growth happened in a very early flower development stage. Cross-pollination increased the presence of the pollen tubes growing inside flowers but was not necessary for fruit set. Ovule fertilization was very fast as 24 h (h) were enough for pollen tubes to reach the end of stylar canals.This research was supported by the Asociacion Club de Variedades Vegetales Protegidas as part of a project undertaken with the Universitat Politecnica de Valencia (Spain, UPV 20190822), of which H. Merle was the principal researcher. There was no additional external funding received for this study.García-Breijo, F.; Reig Armiñana, J.; Garmendia, A.; Cebrián, N.; Beltrán, R.; Merle Farinós, HB. (2020). In Vivo Pollen Tube Growth and Evidence of Self-Pollination and Prefloral Anthesis in cv. Macabeo (Vitis vinifera L.). Agriculture. 10(12):1-13. https://doi.org/10.3390/agriculture10120647S1131012FAO Resource Database, Crops http://www.fao.org/faostat/en/#data/Coito, J. L., Silva, H. G., Ramos, M. J. N., Cunha, J., Eiras-Dias, J., Amâncio, S., … Rocheta, M. (2019). Vitisflower types: from the wild to crop plants. PeerJ, 7, e7879. doi:10.7717/peerj.7879Bordeu, E., & Gil, G. (1983). Fructificación de la vid, cv. Moscatel Rosado, sometida a polinización artificial y eliminación manual de caliptras. Ciencia e investigación agraria, 10(3), 279-281. doi:10.7764/rcia.v10i3.728Sampson, B., Noffsinger, S., Gupton, C., & Magee, J. (2001). Pollination Biology of the Muscadine Grape. HortScience, 36(1), 120-124. doi:10.21273/hortsci.36.1.120Munoz-Rodriguez, A. F., Tormo, R., & Silva, M. I. (2011). Pollination Dynamics in Vitis vinifera L. American Journal of Enology and Viticulture, 62(1), 113-117. doi:10.5344/ajev.2010.10047PETRIE, P. R., & CLINGELEFFER, P. R. (2005). Effects of temperature and light (before and after budburst) on inflorescence morphology and flower number of Chardonnay grapevines (Vitis vinifera L.). Australian Journal of Grape and Wine Research, 11(1), 59-65. doi:10.1111/j.1755-0238.2005.tb00279.xEltom, M., Trought, M. C. T., Agnew, R., Parker, A., & Winefield, C. S. (2017). Pre-budburst temperature influences the inner and outer arm morphology, phenology, flower number, fruitset, TSS accumulation and variability of Vitis vinifera L. Sauvignon Blanc bunches. Australian Journal of Grape and Wine Research, 23(2), 280-286. doi:10.1111/ajgw.12260Culley, T. M., & Klooster, M. R. (2007). The Cleistogamous Breeding System: A Review of Its Frequency, Evolution, and Ecology in Angiosperms. The Botanical Review, 73(1), 1-30. doi:10.1663/0006-8101(2007)73[1:tcbsar]2.0.co;2Lord, E. M. (1981). Cleistogamy: A tool for the study of floral morphogenesis, function and evolution. The Botanical Review, 47(4), 421-449. doi:10.1007/bf02860538Pereira, M. R., Ribeiro, H., Cunha, M., & Abreu, I. (2018). Comparison of pollen quality in Vitis vinifera L. cultivars. Scientia Horticulturae, 227, 112-116. doi:10.1016/j.scienta.2017.09.038Agricolae: Statistical Procedures for Agricultural Research https://CRAN.R-project.org/package=agricolaeHESLOP-HARRISON, Y., & SHIVANNA, K. R. (1977). The Receptive Surface of the Angiosperm Stigma. Annals of Botany, 41(6), 1233-1258. doi:10.1093/oxfordjournals.aob.a085414Mesejo, C., Martínez-Fuentes, A., Reig, C., & Agustí, M. (2007). The effective pollination period in ‘Clemenules’ mandarin, ‘Owari’ Satsuma mandarin and ‘Valencia’ sweet orange. Plant Science, 173(2), 223-230. doi:10.1016/j.plantsci.2007.05.00

The organic air pollutant cumene hydroperoxide interferes with NOantioxidant role in rehydrating lichen

Organic pollutants effects on lichens have not been addressed. Rehydration is critical for lichens, a burst of free radicals involving NO occurs. Repeated dehydrations with organic pollutants could increase oxidative damage. Our aim is to learn the effects of cumene hydroperoxide (CP) during lichen rehydration using Ramalina farinacea (L.) Ach., its photobiont Trebouxia spp. and Asterochloris erici. Confocal imaging shows intracellular ROS and NO production within myco and phycobionts, being the chloroplast the main source of free radicals. CP increases ROS, NO and lipid peroxidation and reduces chlorophyll autofluorescence, although photosynthesis remains unaffected. Concomitant NO inhibition provokes a generalized increase of ROS and a decrease in photosynthesis. Our results suggest that CP induces a ompensatory hormetic response in Ramalina farinacea that could reduce the lichen s antioxidant resources after repeated desiccation-rehydration cycles. NO is important in the protection from CP.This project was funded by the Spanish Ministry of Education and Science [project numbers CGL2012-40058-C02-01 and CGL2009-13429-C02-01], project Prometeo 2008/174 of the Generalitat Valenciana and the project AECID PCI/A/024755/09 of the Spanish Ministry of Foreign Affaires.Catalá, M.; Gasulla Vidal, F.; Pradas Del Real, A.; García Breijo, FJ.; Reig Armiñana, J.; Barreno Rodriguez, E. (2013). The organic air pollutant cumene hydroperoxide interferes with NOantioxidant role in rehydrating lichen. Environmental Pollution. 179:277-284. https://doi.org/10.1016/j.envpol.2013.04.015S27728417

Physiological,anatomical and biomass partitioning responses to ozone in the Mediterranean endemic plant Lamottea dianae

Ozone effects on the perennial forb Lamottea dianae were studied in an open-top chamber experiment. Ozone was found to induce reductions in CO 2 assimilation and water use efficiency in the leaves of this species. These reductions were mainly related to a decline in the in vivo CO 2 fixation capacity of Rubisco (V c,max), rather than to stomatal limitations or photoinhibitory damage (F v:F m). In addition to chloroplast degeneration, other observed effects were callose accumulation, formation of pectinaceous wart-like cell wall exudates and phloem alterations. Moreover, ozone exposure significantly reduced root dry biomass. The possible relevance of these adverse effects for Mediterranean forbs is commented. These results show that endemic plants can be very sensitive to ozone, suggesting that risks associated with this pollutant should be taken into account for conservation purposes. © 2011 Elsevier Inc.We thank the Conselleria de Medi Ambient, Aigua, territory i Habitatge and FEDER funds (project VegetPollOzone, Interreg IIIb, Meddoc) for supporting parts of this study. The Instituto Universitario CEAM-UMH is partly supported by Generalitat Valenciana, Fundacion Bancaja, and benefits form the projects CONSOLIDER-INGENIO 2010 (GRACCIE) and Prometeo Program (Generalitat Valenciana). Emilio Laguna and Mari Carmen Escriva are also thanked for providing us the plants and, together with Joan Perez, for their comments on aspects of the biology of this species. Carmen Martin is thanked for taking care of the plants. Four anonymous referees provided very useful comments for improving the manuscript.Calatayud, V.; García Breijo, FJ.; Cervero, J.; Reig Armiñana, J.; Sanz Sánchez, MJ. (2011). Physiological,anatomical and biomass partitioning responses to ozone in the Mediterranean endemic plant Lamottea dianae. Ecotoxicology and Environmental Safety. 74(5):1131-1138. doi:10.1016/j.ecoenv.2011.02.023S1131113874

Two Trebouxia algae with different physiological performances are ever-present in lichen thalli of Ramalina farinacea. Coexistence versus Competition

Ramalina farinacea is an epiphytic fruticose lichen that is relatively abundant in areas with Mediterranean, subtropical or temperate climates. Little is known about photobiont diversity in different lichen populations. The present study examines the phycobiont composition of several geographically distant populations of R. farinacea from the Iberian Peninsula, Canary Islands and California as well as the physiological performance of isolated phycobionts. Based on anatomical observations and molecular analyses, the coexistence of two different taxa of Trebouxia (working names, TR1 and TR9) was determined within each thallus of R. farinacea in all of the analysed populations. Examination of the effects of temperature and light on growth and photosynthesis indicated a superior performance of TR9 under relatively high temperatures and irradiances while TR1 thrived at moderate temperature and irradiance. Ramalina farinacea thalli apparently represent a specific and selective form of symbiotic association involving the same two Trebouxia phycobionts. Strict preservation of this pattern of algal coexistence is likely favoured by the different and probably complementary ecophysiological responses of each phycobiont, thus facilitating the proliferation of this lichen in a wide range of habitats and geographic areas. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.This study was funded by the Spanish Ministry of Education and Science (CGL2006-12917-C02-01/02), the Spanish Ministry of Science and Innovation (CGL2009-13429-C02-01/02), the AECID (PCI_A/024755/09) and the Generalitat Valenciana (PROMETEO 174/2008 GVA). We are grateful to Dr J. Gimeno-Romeu (University of California, Davis, USA) and to Dr P. J. G. de Nova (IREC, Ciudad Real, Spain), who were the first to isolate DNA from Ramalina farinacea thalli in our group. Wendy Ran revised the manuscript in English.Casano, L.; Del Campo, E.; García Breijo, FJ.; Reig Armiñana, J.; Gasulla, F.; Del Hoyo, A.; Guéra, A.... (2011). Two Trebouxia algae with different physiological performances are ever-present in lichen thalli of Ramalina farinacea. Coexistence versus Competition. Environmental Microbiology. 13(3):806-818. https://doi.org/10.1111/j.1462-2920.2010.02386.xS806818133Angert, A. L., Huxman, T. E., Chesson, P., & Venable, D. L. (2009). Functional tradeoffs determine species coexistence via the storage effect. Proceedings of the National Academy of Sciences, 106(28), 11641-11645. doi:10.1073/pnas.0904512106Baker, N. R., & Oxborough, K. (s. f.). Chlorophyll Fluorescence as a Probe of Photosynthetic Productivity. Advances in Photosynthesis and Respiration, 65-82. doi:10.1007/978-1-4020-3218-9_3Barreno , E. Herrera-Campos , M. García-Breijo , F. Gasulla , F. Reig-Armiñana , J. 2008 Non photosynthetic bacteria associated to cortical structures on Ramalina and Usnea thalli from Mexico http://192.104.39.110/archive/IAL6abstracts.pdfBECK, A., FRIEDL, T., & RAMBOLD, G. (1998). Selectivity of photobiont choice in a defined lichen community: inferences from cultural and molecular studies. New Phytologist, 139(4), 709-720. doi:10.1046/j.1469-8137.1998.00231.xBilger, W., & Bj�rkman, O. (1991). Temperature dependence of violaxanthin de-epoxidation and non-photochemical fluorescence quenching in intact leaves ofGossypium hirsutum L. andMalva parviflora L. Planta, 184(2), 226-234. doi:10.1007/bf01102422Bj�rkman, O., & Demmig, B. (1987). Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77 K among vascular plants of diverse origins. Planta, 170(4), 489-504. doi:10.1007/bf00402983Bold, H. C., & Parker, B. C. (1962). Some supplementary attributes in the classification of chlorococcum species. 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T. (2004). Early Molecular Investigations of Lichen-Forming Symbionts: 1986–2001. Annual Review of Microbiology, 58(1), 273-301. doi:10.1146/annurev.micro.58.030603.123730DOERING, M., & PIERCEY-NORMORE, M. D. (2009). Genetically divergent algae shape an epiphytic lichen community on Jack Pine in Manitoba. The Lichenologist, 41(1), 69-80. doi:10.1017/s0024282909008111Friedl, T. (1989). Comparative ultrastructure of pyrenoids inTrebouxia (Microthamniales, Chlorophyta). Plant Systematics and Evolution, 164(1-4), 145-159. doi:10.1007/bf00940435Gasulla, F., de Nova, P. G., Esteban-Carrasco, A., Zapata, J. M., Barreno, E., & Guéra, A. (2009). Dehydration rate and time of desiccation affect recovery of the lichenic algae Trebouxia erici: alternative and classical protective mechanisms. Planta, 231(1), 195-208. doi:10.1007/s00425-009-1019-yGasulla, F., Guéra, A., & Barreno, E. (2010). “A simple and rapid method for isolating lichen photobionts“. Symbiosis, 51(2), 175-179. doi:10.1007/s13199-010-0064-4Gauze, G. F. (1934). The struggle for existence, by G. F. Gause. doi:10.5962/bhl.title.4489Genty, B., Briantais, J.-M., & Baker, N. R. (1989). The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence. Biochimica et Biophysica Acta (BBA) - General Subjects, 990(1), 87-92. doi:10.1016/s0304-4165(89)80016-9Gross, K. (2008). Positive interactions among competitors can produce species-rich communities. Ecology Letters, 11(9), 929-936. doi:10.1111/j.1461-0248.2008.01204.xGUZOW-KRZEMIŃSKA, B. (2006). Photobiont flexibility in the lichen Protoparmeliopsis muralis as revealed by ITS rDNA analyses. The Lichenologist, 38(5), 469-476. doi:10.1017/s0024282906005068Haruta, S., Kato, S., Yamamoto, K., & Igarashi, Y. (2009). Intertwined interspecies relationships: approaches to untangle the microbial network. 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Coexistence of different intrathalline symbiotic algae and bacterial biofilms in the foliose Canarian lichen Parmotrema pseudotinctorum

[EN] Parmotrema pseudotinctorum (des Abb.) Hale is a foliose lichen able to colonize large areas on rock surfaces in semiarid and warm localities in the Canary Islands. In this contribution, we investigate the phycobionts of this successful lichen under these extreme environmental conditions using ultrastructural and genetic methodologies. Two populations from La Gomera and La Palma islands were analyzed. After TEM analyses, three algal types were clearly distinguished in intrathalline symbiosis, provisionally named Ph1, Ph2, and Ph3. Two of them (Ph1 and Ph2) were Trebouxia showing a well visible pyrenoid corticolatype the chloroplast thylakoids being very different in both. The type Ph3 could be a taxon included in the genus Asterochloris. Our molecular approach consisted in sequencing two different DNA loci: a portion of the chloroplast psbA gene and nuclear ITS. Sequences of the psbA gene resulted in electrophoretograms showing double peaks when DNA extracted from the whole lichen thallus was used as template. Such double peaks were interpreted as single nucleotide polymorphisms (SNPs). This interpretation was confirmed by cloning. However, no intrathalline polymorphisms were detected among the nrITS sequences. Phylogenetic analyses on the basis of the psbA gene revealed three distinct clades. It is likely that these clades corresponded to the the three different morphotypes revealed by TEM. One of these clades, was closely related to T. corticola, other was related to Asterochloris glomerata and the third did not grouped with any specific taxa. These results are the first piece of evidence that algal coexistence may even be established between species of different genera of the Trebouxiophyceae (Asterochloris and Trebouxia at least). Moreover, the coexistence of several microalgal taxa evidenced in this study appears as a consistent character among the populations of this foliose lichen. Further isolation and cultivation of the three different algal types and physiological studies should shed light on the ecological plasticity of the entire holobiont. Along with such variety of intrathalline coexisting algae, another unexpected result was the observation of an almost continuous layer of bacterial-communities coating the lower cortex in all the studied samples of P. pseudotinctorum. The function of these biofilms in the lichen symbiosis remains to be elucidated. The existence of such particular symbiosis involving different algal species and bacteria could be explained by an increased fitness in particular habitats or under specific environmental conditions[ES] Parmotrema pseudotinctorum (des Abb.) Hale es un liquen foliáceo que coloniza roquedos volcánicos y es frecuente en localidades semiáridas y cálidas de las islas Canarias. En este trabajo, se investigan los ficobiontes de este liquen utilizando métodos ultraestructurales y genéticos. Se analizaron dos poblaciones de La Gomera y La Palma. Mediante análisis TEM, se han distinguido claramente tres tipos de algas en simbiosis intratalinas, llamados provisionalmente Ph1, Ph2 y Ph3. Dos de ellas (Ph1 y Ph2), pertenecientes al género Trebouxia, muestran un pirenoide bien visible del tipo corticola, pero los tilacoides del cloroplasto son muy diferentes en ambos. El tipo Ph3 podría ser un taxón incluido en el género Asterochloris. El enfoque molecular consistió en la secuenciación de dos loco diferentes de ADN: una porción del gen psbA del cloroplasto e ITS nuclear. Las secuencias del gen psbA proporcionaron electroforetogramas que mostraban dobles picos cuando se usó como patrón el ADN extraído de los talos completos. Estos dobles picos se interpretaron como polimorfismos de nucleótido simple (SNP). Esta interpretación se confirmó mediante técnicas de clonación. Sin embargo, no se detectaron polimorfismos intratalinos con las secuencias nrITS. Los análisis filogenéticos basados en las secuencias del gen psbA constataron la presencia de tres clados diferenciados. Es probable que éstos correspondan a los tres diferentes morfotipos puestos en evidencia por TEM. Uno de ellos está estrechamente relacionado con T. corticola, otro con Asterochloris glomerata, y el tercero no se agrupaba a ningún taxón especifico. Estos resultados son la primera evidencia de que en los líquenes la coexistencia de algas intratalinas se puede establecer incluso entre especies de difierentes géneros de Trebouxiophyceae (Asterochloris y Trebouxia al menos). Por otra parte, la coexistencia de varios taxones de microalgas, constatada en este estudio, puede considerarse como una sólida característica entre las poblaciones de este liquen foliáceo. Posteriores aislamientos y el cultivo de los tres tipos de algas, además de estudios fisiológicos, podrán explicar la plasticidad ecológica que muestra el holobionte. Otro resultado inesperado fue la observación de una capa casi continua de comunidades bacterianas que recubren el córtex inferior en todas las muestras estudiadas de P. pseudotinctorum. Está por determinar la función que estos biofilms puedan tener en las simbiosis liquénicas. La existencia de estos tipos de simbiosis tan particulares, que involucran tanto a diferentes especies de algas como a bacterias, podría explicarse por un incremento en la capacidad de colonizar hábitats peculiares o con condiciones ambientales específicasThis study was funded by the Spanish Ministry of Economy and Innovation (MINECO CGL2012-40058-C02-01/02), FEDER and the Generalitat Valenciana (PROMETEO 021/2013 GVA).Molins, A.; García-Breijo, F.; Reig Armiñana, J.; Del Campo, EM.; Casano, L.; Barreno Rodriguez, E. (2013). Coexistence of different intrathalline symbiotic algae and bacterial biofilms in the foliose Canarian lichen Parmotrema pseudotinctorum. Vieraea. Folia Scientarum Biologicarum Canariensium. 41:349-370. http://hdl.handle.net/10251/77348S3493704

Fungal-associated NO is involved in the regulation of oxidative stress during rehydration in lichen symbiosis

[EN] Background Reactive oxygen species (ROS) are normally produced in respiratory and photosynthetic electron chains and their production is enhanced during desiccation/rehydration. Nitric oxide (NO) is a ubiquitous and multifaceted molecule involved in cell signaling and abiotic stress. Lichens are poikilohydrous organisms that can survive continuous cycles of desiccation and rehydration. Although the production of ROS and NO was recently demonstrated during lichen rehydration, the functions of these compounds are unknown. The aim of this study was to analyze the role of NO during rehydration of the lichen Ramalina farinacea (L.) Ach., its isolated photobiont partner Trebouxia sp. and Asterochloris erici (Ahmadjian) Skaloud et Peksa (SAG 32.85 = UTEX 911). Results Rehydration of R. farinacea caused the release of ROS and NO evidenced by the fluorescent probes DCFH2-DA and DAN respectively. However, a minimum in lipid peroxidation (MDA) was observed 2 h post-rehydration. The inhibition of NO in lichen thalli with c-PTIO resulted in increases in both ROS production and lipid peroxidation, which now peaked at 3 h, together with decreases in chlorophyll autofluorescence and algal photobleaching upon confocal laser incidence. Trebouxia sp. photobionts generate peaks of NO-endproducts in suspension and show high rates of photobleaching and ROS production under NO inhibition which also caused a significant decrease in photosynthetic activity of A. erici axenic cultures, probably due to the higher levels of photo-oxidative stress. Conclusions Mycobiont derived NO has an important role in the regulation of oxidative stress and in the photo-oxidative protection of photobionts in lichen thalli. The results point to the importance of NO in the early stages of lichen rehydration.This project was funded by the Spanish Ministry of Education and Science [project numbers CGL2006 12917 C02 0 and CGL2009 13429 C02 01], project Prometeo 2008/1/4 of the Generalitat Valenciana and the project AECID PCI/A/024755/09 of the Spanish Ministry of Foreign Affaires. We are grateful to F. Gasulla, J. Gimeno-Romeu, E. Barreno, (ICBIBE, University of Valencia) and A. Guera (Plant Biology, University of Alcala) for communicating unpublished data, to Dr. R. Catala (CIB, Madrid), Dr. P. D'Ocon (UVEG, Valencia) and Dr. J. Medina (INIA, Madrid) for critical revision of the manuscript, and J. L. Rodriguez Gil for MDA protocol optimization. English revision was done by Wendy Ran.Catalá, M.; Gasulla Vidal, F.; Pradas Del Real, AE.; García-Breijo, F.; Reig Armiñana, J.; Barreno Rodriguez, E. (2010). Fungal-associated NO is involved in the regulation of oxidative stress during rehydration in lichen symbiosis. BMC Microbiology. 10. https://doi.org/10.1186/1471-2180-10-297S1

Morphology, anatomy and germination response of heteromorphic achenes of Anthemis chrysantha J. Gay (Asteraceae), a critically endangered species

[EN] This study demonstrates that Anthemis chrysantha, a 'Critically Endangered' annual plant, produces two morphs of achenes: white and dark achenes, which differ in size, mass, anatomy and germination behaviour. Fresh white achenes germinated at all temperatures assayed from 10 to 25 degrees C in both continuous darkness and 12-h photoperiod, ranging between 24% at 25 degrees C in darkness and 89% at 12/20 degrees C in light, whereas fresh dark achenes did not germinate under any temperature or light conditions. To identify differences in dormancy type between the two morphs, germination of dry-stored achenes, and achenes stratified at 5 or 25 degrees C for 2 months were tested in both darkness and light at 5, 15 and 12/20 degrees C for dry-stored and warm-stratified (25 degrees C) achenes; and at 15, 25 and 12/20 degrees C for cold-stratified (5 degrees C) achenes. Of the white achenes, 90% germinated during the cold stratification period. In general, dry storage and warm stratification did not increase germination compared to fresh achenes. However, dark achenes did not germinate under any conditions. Dark achene dormancy was only broken by mechanical scarification or by excising the embryo (germination reached 71%). An anatomical study showed that the mesocarp of dark achenes had no intercellular spaces and was much thicker and stronger than that of white achenes, making the entry of water difficult, and also preventing germination by mechanical restriction. This study demonstrated that dormancy in the dark achenes is likely caused by the thickness of their pericarp, physically impeding germination and hampering imbibition of water.This work was financed by the Consejeria de Agricultura y Agua de la Comunidad Autonoma de la Region de Murcia and the Fundacion Seneca de la Region de Murcia (Project 1186/PI/09).Aguado, M.; Martinez-Sanchez, JJ.; Reig Armiñana, J.; García Breijo, FJ.; Franco, JA.; Vicente, MJ. (2011). Morphology, anatomy and germination response of heteromorphic achenes of Anthemis chrysantha J. Gay (Asteraceae), a critically endangered species. Seed Science Research. 21(4):283-294. doi:10.1017/S0960258511000183S28329421