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

Antimicrobial activity of xanthatin from Xanthium spinosum L

[EN] Dichloromethane extracts from Xanthium spinosum L. were fractionated and the fractions tested for their bactericidal and fungicidal activity. From the active fraction, a compound was isolated and identified as xanthatin (I). Xanthatin was active against Colletotrichum gloesporoides, Trichothecium roseum, Bacillus cereus and Staphylococcus aureus.Ginesta Peris, E.; García-Breijo, F.; Primo Yúfera, E. (1994). Antimicrobial activity of xanthatin from Xanthium spinosum L. Letters in Applied Microbiology. 18(4):206-208. doi:10.1111/j.1472-765X.1994.tb00848.xS20620818

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

Gibberellic acid in Citrus spp. flowering and fruiting: A systematic review

[EN] Background In Citrus spp., gibberellic acid (GA) has been proposed to improve different processes related to crop cycle and yield. Accordingly, many studies have been published about how GA affects flowering and fruiting. Nevertheless, some such evidence is contradictory and the use of GA applications by farmers are still confusing and lack the expected results. Purpose This review aims to collate, present, analyze and synthesize the most relevant empirical evidence to answer the following questions: (i) how does gibberellic acid act on flowering and fruiting of citrus trees?; (ii) why is all this knowledge sometimes not correctly used by farmers to solve yield problems relating to flowering and fruit set? Methods An extensive literature search to obtain a large number of records about the topic was done. Searches were done in five databases: WoS, Scopus, Google Academics, PubMed and Scielo. The search string used was "Gibberellic acid" AND "Citrus". Records were classified into 11 groups according to the development process they referred to and initial data extraction was done. Records related with flowering and fruit set were drawn, and full texts were screened. Fifty-eight full text records were selected for the final data extraction. Results Selected studies were published from 1959 to 2017 and were published mainly in Spain, USA, Brazil and Japan. Twelve species were studied, and Citrus sinensis, C. reticulata and C. unshiu were the principal ones. Most publications with pre-flowering treatments agreed that GA decreases flowering, while only 3 out of 18 did not observe any effect. In most of these studies, the effect on fruit set and yield was not evaluated. Studies with treatments at full bloom or some weeks later mostly reported increased fruit set. However, these increases did not imply higher yields. The results on yield were highly erratic as we found increases, decreases, no effects or variable effects. Conclusions Despite some limitations, the action of GA related to cell division and growth, stimulating the sink ability of the organ and discouraging its abscission, has been clearly established through reviewed studies. GA applications before flowering counteract the floral induction caused by stress reducing flowering. However, on adult trees under field conditions, reducing flowering by applying GA would be difficult because it would be necessary to previously estimate the natural floral induction of trees. During flowering and fruit set, many problems may arise that limit production. Only when the problem is lack of fruit set stimulus can GA applications improve yields. However, much evidence suggests that the main factor-limiting yield would be carbohydrate availability rather than GA levels. 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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

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

Trebouxia lynnae sp. nov. (Former Trebouxia sp. TR9): Biology and Biogeography of an Epitome Lichen Symbiotic Microalga

[EN] Simple Summary In this work, we present the formal description of a new species of lichen photobiont (i.e., Trebouxia lynnae) isolated from the lichen Ramalina farinacea. The findings reported here provide an exhaustive characterization of the cellular ultrastructure, physiological traits and genetic and genomic diversity of the new species. Our results contribute to the knowledge of lichen-forming symbiotic green microalgae with their diversity and distribution. Two microalgal species, Trebouxia jamesii and Trebouxia sp. TR9, were detected as the main photobionts coexisting in the thalli of the lichen Ramalina farinacea. Trebouxia sp. TR9 emerged as a new taxon in lichen symbioses and was successfully isolated and propagated in in vitro culture and thoroughly investigated. Several years of research have confirmed the taxon Trebouxia sp. TR9 to be a model/reference organism for studying mycobiont-photobiont association patterns in lichen symbioses. Trebouxia sp. TR9 is the first symbiotic, lichen-forming microalga for which an exhaustive characterization of cellular ultrastructure, physiological traits, genetic and genomic diversity is available. The cellular ultrastructure was studied by light, electron and confocal microscopy; physiological traits were studied as responses to different abiotic stresses. The genetic diversity was previously analyzed at both the nuclear and organelle levels by using chloroplast, mitochondrial, and nuclear genome data, and a multiplicity of phylogenetic analyses were carried out to study its intraspecific diversity at a biogeographical level and its specificity association patterns with the mycobiont. Here, Trebouxia sp. TR9 is formally described by applying an integrative taxonomic approach and is presented to science as Trebouxia lynnae, in honor of Lynn Margulis, who was the primary modern proponent for the significance of symbiosis in evolution. The complete set of analyses that were carried out for its characterization is provided.PROMETEO 2021/005 (Excellence in research, Generalitat Valenciana) and the Grants New Generation EU (Ministry of Universities) to Salvador Chiva (MS21-058) and Cesar Bordenave (ZA21-046)Barreno, E.; Muggia, L.; Chiva, S.; Molins, A.; Bordenave, C.; García-Breijo, F.; Moya, P. (2022). Trebouxia lynnae sp. nov. (Former Trebouxia sp. TR9): Biology and Biogeography of an Epitome Lichen Symbiotic Microalga. Biology. 11(8):1-19. https://doi.org/10.3390/biology1108119611911

Multidisciplinary approach to describe Trebouxia diversity within lichenized fungi Buellia zo-haryi from the Canary Islands.

[EN] The Canary Islands are famous for their extraordinary biodiversity; however, lichenized algae have only been studied partially. Buellia zoharyi is a circum-Mediterranean/Macaronesian species that usually occurs in semi-arid areas of the Mediterranean, but occasionally some interesting communities of this species grow on basaltic lava flows in Lanzarote, Fuerteventura and Tenerife. Those three locations showed similar ecological conditions, but different mean annual temperatures. Here we applied a multidisciplinary approach to describe microalgae diversity from B. zoharyi covering the entire described range of distribution in the Canary Islands. Photobionts were characterized in symbiosis using molecular and microscopic techniques. Different Trebouxia spp. were detected as primary photobiont in each island (Trebouxia cretacea-Fuerteventura, T. asymmetrica-Lanzarote and Trebouxia sp. `arnoldoi '-Tenerife). Coexistence of various Trebouxia spp. within a thallus were detected by using specific primers-PCR. Those three photobionts were isolated and cultured under laboratory conditions. Different phytohormone profiles were obtained in the isolated strains which suggest different internal signalling needs. In addition, we characterized the response of the isolated strains to different temperatures using chlorophyll fluorescence. T. asymmetrica did not modify their F-v/fm values with respect to temperature acclimation. In contrast, Trebouxia sp. `arnoldoi'and T. cretacea were more sensitive to changes in growing temperature decreasing Fv/fm at 17 degrees C. Our results indicate that B. zoharyi is flexible regarding the photobiont choice depending on the region, and suggest that bioclimatic factors could influence the myco/photobiont association patterns.Funding for field and laboratory work for this study was provided by the Ministerio de Economia y Competitividad (MINECO and FEDER, Spain) (CGL2016-79158-P) and Prometeo Excellence in Research Program (Generalitat Valenciana, Spain) (PROMETEOII/2013/021; PROMETEO/2017/039). Daniel Sheerin revised the English manuscriptMolins, A.; Chiva, S.; Calatayud, A.; Marco, F.; García-Breijo, F.; Reig-Arminana, J.; Carrasco, P.... (2020). Multidisciplinary approach to describe Trebouxia diversity within lichenized fungi Buellia zo-haryi from the Canary Islands. 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Forced Flowering in Mandarin Trees Under Phytotron Conditions

[EN] Phytotron has been widely used to assess the effect of numerous parameters on the development of many species. However, less information is available on how to achieve fast profuse flowering in young fruit trees with this plant growth chamber. This study aimed to outline the design and performance of a fast clear methodology to force flowering in young mandarin trees (cv. Nova and cv. Clemenules) and to analyze the influence of induction intensity on inflorescence type. The combination of a short water stress period with simulated spring conditions (day 13 h, 22 °C, night 11 h, 12 °C) in the phytotron allowed flowers to be obtained only after 68-72 days from the time the experiment began. Low-temperature requirements were adequately replaced with water stress. Floral response was proportional to water stress (measured as the number of fallen leaves): the greater the induction, the larger the quantity of flowers. Floral induction intensity also influenced inflorescence type and dates for flowering. Details on artificial lighting (lumens), photoperiod, temperatures, plant size and age, induction strategy and days for each stage are provided. Obtaining flowers from fruit trees at any time, and also several times a year, can have many advantages for researchers. With the methodology proposed herein, three, or even four, flowering periods can be forced each year, and researchers should be able to decide when, and they will know, the duration of the entire process. The methodology can be useful for: flower production and in vitro pollen germination assays; experiments with pests that affect early fruit development stages; studies on fruit physiological alterations. All this can help plant breeders to shorten times to obtain male and female gametes to perform forced-crosses.The authors thank Jose Javier Zaragoza Dolz for providing technical assistance and helping in the management tasks. This research was partially supported by the Asociacion Club de Variedades Vegetales Protegidas as part of a project undertaken with the Universitat Politecnica de Valencia (UPV 20170673).Garmendia, A.; Beltrán, R.; Zornoza, C.; García-Breijo, F.; Reig, J.; Raigón Jiménez, MD.; Merle Farinós, HB. (2019). Forced Flowering in Mandarin Trees Under Phytotron Conditions. Journal of Visualized Experiments. (145):1-9. https://doi.org/10.3791/59258S1914