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Rafael Calama - One of the best experts on this subject based on the ideXlab platform.

  • resistance of Pinus pinea l bark to fire
    International Journal of Wildland Fire, 2019
    Co-Authors: Javier Madrigal, Rafael Calama, Jennifer Soutogarcia, Mercedes Guijarro, Juan Picos, Carmen Hernando
    Abstract:

    The stone pine (Pinus pinea L.) has thick bark as an adaptation to wildfire. In this study, laboratory tests were carried out to quantify the influence of bark thickness on flammability and fire resistance in this species. Heating rate in the cambium and the time to reach lethal temperatures in living tissues were determined using a mass loss calorimeter. In addition, data from permanent plots were used to generate linear mixed models to predict bark thickness along the trunk in stone pine stands. The combination of laboratory and field data provided information about the critical threshold of bark thickness (2 cm) below which the heat transmission rate would increase, decreasing the time to reach lethal temperatures in the cambium and therefore the resistance to fire. A new model was developed to calculate critical thresholds of charring height that guarantee efficient protection from fire along the trunk. Predicting whether the bark is thick enough to help trees survive may have important applications in the field of forest fuel management and in the ecology of these pine forests, as well as in preventive silviculture to assess critical heights of trunks likely to be affected during wildfire and prescribed burning.

  • spatiotemporal variability of stone pine Pinus pinea l growth response to climate across the iberian peninsula
    Dendrochronologia, 2016
    Co-Authors: Fabio Natalini, Rafael Calama, Marta Pardos, Javier Vazquezpique, Reyes Alejano, Ulf Buntgen
    Abstract:

    Climate warming and increasing aridity have impacted diverse ecosystems in the Mediterranean region since at least the 1970s. Pinus pinea L. has significant environmental and socio-economic importance for the Iberian Peninsula, so a detailed understanding of its response to climate change is necessary to predict its status under future climatic conditions. However, variability of climate and uncertainties in dendroclimatological approach complicate the understanding of forest growth dynamics. We use an ensemble approach to analyze growth-climate responses of P. pinea trees from five sites along a latitudinal gradient in Spain over time. The growth responses to April-June precipitation totals were stronger in the north than in the south. Since the 1950s, the sensitivity of growth to April-June precipitation increased in the north and decreased in the south. Meteorological drought usually started in May in the southern sites, but in June-July in the northern sites. The water deficit in the southern sites is thus greater and more limiting for tree growth, and this likely accounts for the lower growth sensitivity during these months. Our results indicate that P. pinea has a high degree of plasticity, suggesting the species will withstand changing climatic conditions. However, growth response to drought regimes varies among P. pinea populations, suggesting that different populations have different capacities for acclimation to warmer and drier climate, and this may influence future vegetation composition.

  • Defining the optimal regeneration niche for Pinus pinea L. through physiology-based models for seedling survival and carbon assimilation
    Trees - Structure and Function, 2015
    Co-Authors: Rafael Calama, Ruben Manso, Jaime Puértolas, Marta Pardos
    Abstract:

    Seedling survival in Pinus pinea is controlled by both water status and photosynthetic performance. Optimal regeneration niche for the species is found at mid-shaded sites. Summer survival has been identified as the main bottleneck preventing natural regeneration in Mediterranean forests, although the physiological processes resulting in seedling mortality are not sufficiently known. In the present work, the effect of water status and photosynthetic performance on seedling survival and regeneration niche in a Mediterranean pine (Pinus pinea L.) was analyzed by means of a modeling approach. Midday water potential was modeled as a nonlinear function of environmental factors, and this model was coupled with an existing model for carbon assimilation. A model for seedling survival was then constructed using lifetime analysis techniques, including predicted values of daily and cumulative net assimilation and probability for critical midday water potentials as predictors. The model was applied over a wide range of irradiance environments in order to identify the optimal regeneration niche for the species. Results indicate that midday water potential for P. pinea seedlings is affected by relative soil water content, leaf temperature, and irradiance, with younger seedlings being more likely to reach critical values. Seedling survival in P. pinea is controlled by both water status and photosynthetic performance, with mortality being triggered by the joint occurrence of low water potentials and negative assimilation rates, although photoassimilates stored during the spring season increase survival in older seedlings. Simulations indicated that seedling survival is optimized in shaded environments, while carbon assimilation reaches maximum values on more open sites, thus the optimal regeneration niche for the species is found on mid-shaded locations.

  • climatic factors control rodent seed predation in Pinus pinea l stands in central spain
    Annals of Forest Science, 2014
    Co-Authors: Ruben Manso, Marta Pardos, Rafael Calama
    Abstract:

    Pinus pinea L. presents serious problems of natural regeneration in managed forest of Central Spain. The species exhibits specific traits linked to frugivore activity. Therefore, information on plant–animal interactions may be crucial to understand regeneration failure. Determining the spatio-temporal pattern of P. pinea seed predation by Apodemus sylvaticus L. and the factors involved. Exploring the importance of A. sylvaticus L. as a disperser of P. pinea. Identifying other frugivores and their seasonal patterns. An intensive 24-month seed predation trial was carried out. The probability of seeds escaping predation was modelled through a zero-inflated binomial mixed model. Experiments on seed dispersal by A. sylvaticus were conducted. Cameras were set up to identify other potential frugivores. Decreasing rodent population in summer and masting enhances seed survival. Seeds were exploited more rapidly nearby parent trees and shelters. A. sylvaticus dispersal activity was found to be scarce. Corvids marginally preyed upon P. pinea seeds. Survival of P. pinea seeds is climate-controlled through the timing of the dry period together with masting occurrence. Should germination not take place during the survival period, establishment may be limited. A. sylvaticus-mediated dispersal does not modify the seed shadow. Seasonality of corvid activity points to a role of corvids in dispersal.

  • modelling Pinus pinea forest management to attain natural regeneration under present and future climatic scenarios
    Canadian Journal of Forest Research, 2014
    Co-Authors: Ruben Manso, Timo Pukkala, Marta Pardos, Jari Miina, Rafael Calama
    Abstract:

    Natural regeneration-based silviculture has been increasingly regarded as a reliable option in sustainable forest management. However, successful natural regeneration is not always easy to achieve. Recently, new concerns have arisen because of changing future climate. To date, regeneration models have proved helpful in decision-making concerning natural regeneration. The implementation of such models into optimization routines is a promising approach in providing forest managers with accurate tools for forest planning. In the present study, we present a stochastic multistage regeneration model for Pinus pinea L. managed woodlands in Central Spain, where regeneration has been historically unsuccessful. The model is able to quantify recruitment under different silviculture alternatives and varying climatic scenarios, with further application to optimize management scheduling. The regeneration process in the species showed high between-year variation, with all subprocesses (seed production, dispersal, germin...

Gregorio Montero - One of the best experts on this subject based on the ideXlab platform.

  • modelos de masa para orientar la gestion de Pinus pinea l en el noreste de espana
    Forest Systems, 2011
    Co-Authors: Miriam Piquenicolau, Rafael Calama, Miren Del Rio, Gregorio Montero
    Abstract:

    Se ha desarrollado un modelo de masa como base para orientar la gestion de Pinus pinea L. en el noreste de Espana (Cataluna). El modelo integra diferentes funciones que permiten evaluar las principales variables forestales a nivel de rodal, incluyendo un sistema de desagregacion para la estimacion de las distribuciones diametricas. A partir de los datos de una red de 75 parcelas temporales y diferenciando dos tipologias de masa en funcion de la densidad, masas claras y densas, se ajustaron simultaneamente sistemas de ecuaciones utilizando el metodo de estimacion de minimos cuadrados en tres etapas. Las funciones obtenidas predicen las principales variables de masa para las dos tipologias. Las distribuciones diametricas se obtuvieron a partir de la funcion de distribucion de Weibull, utilizando el metodo de recuperacion de parametros (PRM) y el metodo de los momentos. Finalmente, se simularon dos alternativas selvicolas para cada tipologia de masa (claras, densas) y calidad de estacion, resultando 16 escenarios selvicolas. El modelo de masa y las alternativas selvicolas obtenidas se presentan como una herramienta util para el gestor y una guia para la gestion sostenible de las masas de Pinus pinea en esta region.

  • an empirical ecological type model for predicting stone pine Pinus pinea l cone production in the northern plateau spain
    Forest Ecology and Management, 2008
    Co-Authors: Rafael Calama, Sven Mutke, Fco Javier Gordo, Gregorio Montero
    Abstract:

    Abstract Data from a 10 year series of cone production taken from 755 trees were used to model individual cone production in stone pine (Pinus pinea L.) stands in the Northern Inland Plateau of Spain following three different approaches. The first step was the construction of a silvicultural model, including typical forest growth covariates as tree size, stand density, site index and distance independent competition indices. Remaining between-plot variability was related with ecological attributes, as winter rainfall and altitude, resulting in a hybrid model. The third approach attempted to develop an ecological-type based model by considering a previous stratification of stone pine forests based on altitude, soil, geology and climate characteristics. The best model in terms of likelihood, bias and accuracy on predictions was the ecological-type one, producing unbiased marginal estimates for the main part of the territory with an efficiency reaching up to 39%. Due to the hierarchical structure of data set, proposed model was formulated as a multilevel mixed model. Stochastic formulation allows simulating cone production under different changing scenarios and describing real distribution of cone production within a given stand. Developed model constitutes the cone yield module for pinea2, an integrated single tree model for the management of stone pine stands within the northern Plateau of Spain.

  • effects of fertilization on the production of an edible forest fruit stone pine Pinus pinea l nuts in south west andalusia
    Forest Systems, 2007
    Co-Authors: Rafael Calama, G Madrigal, J A Candela, Gregorio Montero
    Abstract:

    The pine nut from the stone pine (Pinus pinea L.) is the most important edible fruit in mediterranean forests. Despite this fact, there is a lack of knowledge regarding the application of agronomy techniques in stands of this species to increase pine nut production. Our study focuses on the effect of mineral fertilization on cone production and size, which in turn, are closely related to nut yield and quality. Cone production and quality was analysed in a randomized experiment installed in south west Spain, comparing the effect of different doses of lime superphosphate, dolomite and potassium. A significant short term increase in cone production and quality exists as a consequence of fertilization, especially in those treatments involving the addition of larger quantity of dolomite. Nevertheless, effect of mineral fertilization on cone yield and quality was lower than expected, so further increments might be achieved through nitrogenous and organic fertilizations to improve soil structure in these sandy soils.

  • effects of fertilization on the production of an edible forest fruit stone pine Pinus pinea l nuts in south west andalusia
    Forest Systems, 2007
    Co-Authors: R. Calama, G Madrigal, J A Candela, Gregorio Montero
    Abstract:

    El pinon de Pinus pinea L. es el fruto forestal comestible mas importante en los bosques mediterraneos. Pese a esto, existe una falta de conocimiento cientifico acerca de la aplicacion de practicas agronomicas sobre las masas forestales de la especie al objeto de mejorar la produccion de pinon. Nuestro trabajo se centra en el analisis del efecto de la fertilizacion mineral sobre la produccion y el tamano de las pinas, variables muy relacionadas con la cantidad y calidad de pinon. Entre 1993-1999 se realizo el seguimiento de la produccion y la calidad de la pina en un experimente aleatorizado instalado en el SO de Espana, donde se comparaban diferentes dosis de superfosfato de cal, dolomita y cloruro potasico. Se ha detectado una respuesta positiva a la fertilizacion en la cantidad y calidad de las pinas producidas, especialmente en los tratamientos que planteaban la incorporacion de una mayor cantidad de dolomita. El efecto de la fertilizacion mineral sobre la cantidad y calidad de pina ha sido menor que el esperado, por lo que futuros trabajos deben plantear la necesidad de incorporar fertilizantes nitrogenados y materia organica para mejorar la estructura en estos suelos arenosos.

  • cone and seed production from stone pine Pinus pinea l stands in central range spain
    European Journal of Forest Research, 2006
    Co-Authors: Rafael Calama, Gregorio Montero
    Abstract:

    Natural regeneration of stone pine (Pinus pinea L.) stands in the Central Range of Spain can be difficult to attain. The success of this regeneration is affected by factors such as the total amount of seed available, the short dispersal ability of the pinyon, the conditions required for germination, specific problems associated with the establishment, early survival of the seedlings due to severe summer heat and drought, competition for water and mineral resources and grazing damage. This study focuses on seed availability. The amount of available seeds depends on the number and size of the cones and the number of viable pinyons within the cones. In stone pine stands, both variables show great year to year variability. Both cone and seed production, for a given year, are also conditioned by the vigour and health of the tree, its size, the condition and attributes of the stand and the loss of seed through pests or predation. In this study, the main factors which influence cone and pinyon production are identified and a multivariate model to predict annual cone and viable seed production is developed. To consider the correlation among observations coming from the same tree, stand or year, random components are included in the model. The multivariate random structure allows for future calibration of the model for a given year from a small additional sample of observations. It is important to know the total amount of viable seed produced in a stand for a given year since regeneration cuttings for Stone pine should be concentrated in high crop years.

Ricardo J Ordas - One of the best experts on this subject based on the ideXlab platform.

  • pcr based molecular markers for assessment of somaclonal variation in Pinus pinea clones micropropagated in vitro
    Biologia Plantarum, 2010
    Co-Authors: Candela Cuesta, Ricardo J Ordas, Ana Rodriguez, Belen Fernandez
    Abstract:

    Four different markers [random amplified polymorphic DNA (RAPD), inter simple sequence repeat (ISSR), amplified fragment length polymorphism (AFLP), and selective amplified microsatellite polymorphism length (SAMPL)] were applied for evaluating somaclonal variation of micropropagated genotypes of stone pine (Pinus pinea L.). The total number of primers tested was 130, with 223 combinations assayed. A high number of them amplified successfully (178), representing 79.82 % of the total, and the average number of amplified fragments ranged from 2.47 (ISSR) to 65.76 (SAMPL). Based on internal controls, no problem of reproducibility was detected. Almost no somaclonal variation was detected within the clones. Of the tested markers, ISSR, AFLP, and SAMPL showed monomorphic amplification profiles, with only RAPD markers showing some interclonal variation.

  • clonal micropropagation of six selected half sibling families of Pinus pinea and somaclonal variation analysis
    Plant Cell Tissue and Organ Culture, 2008
    Co-Authors: Candela Cuesta, Ricardo J Ordas, Belen Fernandez, Ana Rodriguez
    Abstract:

    Organogenesis response of six selected half-sibling families of stone pine (Pinus pinea L.) has been evaluated, showing genotype-dependent behaviour. The caulogenic phase was characterized by high values of Survival and Organogenesis, while the rooting phase (the bottleneck of many coniferous species) showed great variability among families. Provenance influence was also studied, and the rhizogenesis protocol was optimized for the selected families. The highest values were obtained with family 36, with 100% of Organogenesis, a Bud Formation Capacity (BFC) Index of 6.54 and 38.44% of Rooted Shoots; on the other hand, family 61 presented the worst results, with 83.64% Organogenesis, a BFC Index of 3.01 and a 29.69% Rooting Rate. According to these results, both families will be used in further experiments looking for the underlying bases of the different organogenic behaviour between both families under the same culture conditions. In addition to this, and for the first time in this species, random amplified polymorphism DNA (RAPD) analysis has been carried out to determine whether somaclonal variation had occurred. The results suggested an absence of variation during the whole in vitro process, although more thorough studies would be required for a conclusive answer.

  • identification of genes differentially expressed during adventitious shoot induction in Pinus pinea cotyledons by subtractive hybridization and quantitative pcr
    Tree Physiology, 2007
    Co-Authors: Pablo Alonso, Ana Rodriguez, Belen Fernandez, Millan Cortizo, Francisco R Canton, Maria Luz Centeno, Francisco M Canovas, Ricardo J Ordas
    Abstract:

    As part of a study aimed at understanding the physiological and molecular mechanisms involved in adventitious shoot bud formation in pine cotyledons, we conducted a transcriptome analysis to identify early-induced genes during the first phases of adventitious caulogenesis in Pinus pinea L. cotyledons cultured in the presence of benzyladenine. A subtractive cDNA library with more than 700 clones was constructed. Of these clones, 393 were sequenced, analyzed and grouped according to their putative function. Quantitative real-time PCR analysis was performed to confirm the differential expression of 30 candidate genes. Results are contrasted with available data for other species.

  • an improved micropropagation protocol for stone pine Pinus pinea l
    Annals of Forest Science, 2006
    Co-Authors: Pablo Alonso, Ana Rodriguez, Belen Fernandez, Maria Luz Centeno, Paloma Moncalean, Ricardo J Ordas
    Abstract:

    A protocol for micropropagation from isolated cotyledons from Pinus pinea L. has been developed. Major improvements are the increase in rooting rates and the description for the first time of a successful continuous multiplication procedure. For bud induction, isolated cotyledons were cultured on 1/2 LP with 44.4 µM BA during 4 days. Shoot development was obtained by transfer to 1/2 LP hormone-free medium with activated charcoal. Since an additional 20 weeks were required for shoot elongation and rooting, at least 70 plantlets can be expected per seed after 29 weeks based on a 70% success rate. Besides, shoots can be micropropagated successively by subculturing on 1/2 LPC.

  • organogenic responses of Pinus pinea cotyledons to hormonal treatments ba metabolism and cytokinin content
    Tree Physiology, 2005
    Co-Authors: Paloma Moncalean, Ana Rodriguez, Belen Fernandez, Pablo Alonso, Millan Cortizo, Maria Luz Centeno, Ricardo J Ordas
    Abstract:

    Isolated cotyledons from mature Pinus pinea L. embryos were cultured in vitro in a factorial combination of 4.4, 10 and 44.4 microM N6-benzyladenine (BA) for 2, 4, 8, 16 and 35 days to optimize shoot regeneration. Incubation of explants in 44.4 microM BA for 4 days, in place of the standard incubation in 4.4 microM BA for 35 days, reduced the entire culture period to 4 weeks. Shortening the culture period had no significant effect on the caulogenic response or the number of buds formed per cotyledon. To establish the relationship between key moments in the caulogenic process induced by 4.4 microM BA and the endogenous concentrations of the active forms of BA and other isoprenoid-type cytokinins (CKs), we examined uptake, metabolism and amount of BA, as well as the amounts of zeatin, dihydrozeatin and their ribosides in P. pinea cotyledons after 1, 2, 6, 12 and 24 h, and 2, 4, 8, 16 and 35 days of exposure to 8-[14C]BA. Uptake and release of BA were associated with water movement between explants and the medium during the first 8 days of culture. The interconvertible forms of BA were the main metabolites formed in the tissues. Inactivation of BA as a result of conjugation or oxidation was insignificant. The endogenous concentration of BA + N6-benzyladenosine was 20-fold higher than the exogenously applied BA during the competence acquisition phase (Days 0-3). The concentration of isoprenoid-type CKs also increased 16-fold and then decreased during this time. Induction of shoot buds (Days 4-8) was characterized by a second peak of BA uptake by explants that triggered the synthesis of N6-benzyladenosine-5 -monophosphate and by the maintenance of isoprenoid-type CKs. Reestablishment of CK homeostasis marked the shift from the induction phase to the shoot development phase in this organogenic process (Days 8-12).

Joan Pera - One of the best experts on this subject based on the ideXlab platform.

  • effects of ectomycorrhizal inoculation and the type of substrate on mycorrhization growth and nutrition of containerised Pinus pinea l seedlings produced in a commercial nursery
    Annals of Forest Science, 2005
    Co-Authors: Ana Rincon, Javier Parlade, Joan Pera
    Abstract:

    Spore inocula of Melanogaster ambiguus (Vittad.) Tul. & C. Tul., Pisolithus tinctorius (Pers.) Coker & Couch, Rhizopogon luteolus Fr., Rhizopogon roseolus (Corda) Th. M. Fr. and Scleroderma verrucosum (Bull.) Pers., and two substrates (a mixture of peat-vermiculite and a mixture of peat-composted pine bark) were evaluated for producing mycorrhizal Pinus pinea L. seedlings in a commercial nursery in NE Spain. Inocula of all fungi were effective to obtain containerised mycorrhizal P. pinea seedlings although seedling mycorrhization rates were reduced in the peat/pine-bark mixture. Neither inoculation nor the type of substrate modified the first-year growth of seedlings. Rhizopogon spp. increased the levels of N and P and, in general inoculation reduced the concentration of Mn in needles. Symptoms of chlorosis were detected in all seedlings growing in the peat/pine-bark mixture, probably due to nutritional deficiencies caused by the substrate high pH. Among the fungi tested, R. roseolus is proposed as the best candidate for its application in nursery inoculation programmes destined to produced containerised mycorrhizal P. pinea. Pinus pinea / substrate / mycorrhization / ectomycorrhizal fungi / seedling nursery production Resume - Effets d'une inoculation ectomycorhizienne et du type de substrat sur la mycorhization, la croissance et la nutrition de semis de Pinus pinea L. en containers produits en pepiniere commerciale. Des inoculums sporaux de Melanogaster ambiguus (Vittad.) Tul. & C. Tul., Pisolithus tinctorius (Pers.) Coker & Couch, Rhizopogon luteolus Fr., Rhizopogon roseolus (Corda) Th. M. Fr. et Scleroderma verrucosum (Bull.) Pers., et deux substrats (un melange de tourbe-vermiculite et un melange de tourbe-ecorce compostee de pin) ont ete evalues pour produire des jeunes plants mycorhizes de Pinus pinea L. dans une pepiniere commerciale au Nord-Est de l'Espagne. Les inoculums de tous les champignons ont ete efficaces pour obtenir des semis mycorhizes de pin pignon en conteneur, bien que les taux de mycorhization ont diminue dans le substrat vermiculite-ecorce de pin. Ni l'inoculation ni le type de substrat n'ont modifie la croissance en premiere annee des jeunes plants. Les especes de Rhizopogon ont augmente les niveaux d'azote et de phosphore dans les aiguilles des plants et, en general, l'inoculation a reduit la teneur en manganese de ces feuilles. Des symptomes de chlorose ont ete detectes dans tous les plants croissant dans le substrat vermiculite- ecorce de pin, probablement en raison des carences nutritionnelles provoquees par le pH eleve du substrat. Parmi les champignons etudies, on propose R. roseolus comme le meilleur candidat pour son application dans des programmes d'inoculation en pepiniere destines a produire des plants de pin pignon mycorhizes en conteneur. Pinus pinea / substrat / mycorhization / champignons ectomycorhiziens / production des semis en pepiniere

  • Inoculation of containerized Pinus pinea L. seedlings with seven ectomycorrhizal fungi
    Mycorrhiza, 2001
    Co-Authors: Ana Rincon, Isabel F. Alvarez, Joan Pera
    Abstract:

    Containerized Pinus pinea L. seedlings are commonly used for reforestation in the Mediterranean area. While there is an increasing knowledge of the potential ectomycorrhizal fungi associated with Pinus pinea , few studies exist of inoculation techniques with selected ectomycorrhizal fungi. We tested seven ectomycorrhizal fungi for their effectiveness with containerized Pinus pinea seedlings. Hebeloma crustuliniforme , Laccaria laccata and Pisolithus tinctorius were applied as vegetative inocula while Melanogaster ambiguus , Pisolithus tinctorius , Rhizopogon luteolus , Rhizopogon roseolus and Scleroderma verrucosum were tested as spore inocula. The inoculum of each fungus was tested at several application rates. Among the fungi tested as vegetative inocula, the highest percentages of ectomycorrhizas were obtained with H. crustuliniforme at all rates tested. The ectomycorrhizas formed by L. laccata varied from 11% to 40% depending on the inoculum rate applied. Vegetative inoculum of Pisolithus tinctorius was only effective at the highest inoculum rates and gave mycorrhization percentages around 60%. Pisolithus tinctorius applied as a spore inoculum formed ectomycorrhizas at a frequency of about 50% at the effective inoculum rates. The rest of the fungi applied as spore inocula produced more than 50% of ectomycorrhizas at the effective spore concentrations. These included the highest percentages of ectomycorrhizas (>80%) obtained with both Rhizopogon species. Differences in growth due to inoculation with the different fungi were not detected and in some cases inoculation even reduced the total biomass accumulated by seedlings. All seedlings reached a size suitable for transplantation.

Schuyler S. Korban - One of the best experts on this subject based on the ideXlab platform.

  • Effects of salt formulations, carbon sources, cytokinins, and auxin on shoot organogenesis from cotyledons of Pinus pinea
    2015
    Co-Authors: Iii-whan Sul, Schuyler S. Korban
    Abstract:

    Adventitious shoots were induced on cotyledons of Pinus pinea. Among seven salt formulations, three carbon sources (sucrose, glucose and fructose), and two cytokinins [6-benzyladenine (BA) and thidiazuron (TDZ)] with and without [a-naphthaleneacetic acid (NAA)], cotyledons grown on 1/2 MS medium con-taining sucrose and 30 lM BA produced the highest frequency of shoot organogenesis (>90%) and mean number of shoots/explant (>40 % of cotyledons produced over 20 shoots/cotyledon). As for the site of shoot organogenesis along the cotyledonary explant, the highest number of shoots per explant was ob-served along the basal segment of the cotyledon (distal to the hypocotyl) over all cytokinin and auxin treatments tested. Shoots were elongated on a growth regulator-free medium containing activated charcoal. Abbreviations: BA – 6-benzyladenine; NAA – a-naphthaleneacetic acid; TDZ – thidiazuron (N-phenyl-N¢-1,2,3-thidiazol-5yulera

  • Effects of salt formulations, carbon sources, cytokinins, and auxin on shoot organogenesis from cotyledons of Pinus pinea L.
    Plant Growth Regulation, 2004
    Co-Authors: Schuyler S. Korban
    Abstract:

    Adventitious shoots were induced on cotyledons of Pinus pinea . Among seven salt formulations, three carbon sources (sucrose, glucose and fructose), and two cytokinins [6-benzyladenine (BA) and thidiazuron (TDZ)] with and without [α-naphthaleneacetic acid (NAA)], cotyledons grown on 1/2 MS medium containing sucrose and 30 μM BA produced the highest frequency of shoot organogenesis (>90%) and mean number of shoots/explant (>40% of cotyledons produced over 20 shoots/cotyledon). As for the site of shoot organogenesis along the cotyledonary explant, the highest number of shoots per explant was observed along the basal segment of the cotyledon (distal to the hypocotyl) over all cytokinin and auxin treatments tested. Shoots were elongated on a growth regulator-free medium containing activated charcoal.