Abstract Potato plants are often subjected to heat stress during growth and development, resulting in loss of yield and quality. However, the possibility exists that commercially important genotypes show tolerance to heat stress. In this study, we aim to investigate the morphological and physiological effects of moderate conditions of heat stress on tuberization in nine potato genotypes, and how it affects propagation using an ex vitro and in vitro system. The plant material came from the In Vitro Germplasm Bank of the International Potato Center (CIP). The incubation temperatures of the cultures in in vitro and ex vitro conditions were the ambient in the laboratory and greenhouse, respectively. In in vitro system a randomized complete block design was employed in nine genotypes, two treatments: multiplication culture medium and the same culture medium supplemented with 8.0% sucrose and 500 mg/L-1 CCC, six flasks and five explants per experimental unit. Among all genotypes evaluated, Leona and Liberteña did not form tubers under ex vitro treatment conditions. Under in vitro conditions, Amarilis, Capiro, Perricholi and Tacna showed no evidence of tuberization, and Canchán was the only genotype where 100% formation of tuberous structures were produced in all evaluations. The findings concluded in this study showed that of all the potatoes evaluated, Canchán best responded to the evaluations under both in ex vitro and in vitro conditions, at maximum temperatures between 22.4 to 26.9 and 27.0 to 28.2 oC, respectively. Therefore, it is vitally important to consider its development potential in different producing locations around the world, which are directly and indirectly affected by climate change.

Resumen Ficus americana y F. obtusifolia, se encuentran entre las especies arbóreas más importantes de los Bosques Tropicales Estacionalmente Secos (BTES) por su condición de siempre verdes y sus altos niveles de biomasa. Sin embargo, el BTES de Lambayeque y el norte de Perú está disminuyendo enormemente debido al avance de la agricultura migratoria, la minería ilegal y la deforestación. El objetivo de este trabajo fue estudiar los aspectos taxonómicos de ambas especies, así como la germinación de semillas, la micropropagación y la conservación de germoplasma in vitro. La germinación de semillas fue de 100 % en ambas especies hasta tres meses después de la recolección. Respecto a la micropropagación, el enraizamiento y la conservación de germoplasma, el medio de cultivo de Piper resultó efectivo, el cual está conformado por sales minerales MS con IAA 0.02 mg.L-1 y GA3 0.02 mg.L-1. La conservación in vitro de germoplasma duró más de 24 meses en ambas especies. La aclimatación en condiciones de invernadero alcanzó 50 % de supervivencia en ambas especies.

Abstract Ficus americana and F. obtusifolia are among the most important tree species in Seasonally Dry Tropical Forests (SDTF) due to their evergreen condition and high levels of biomass. However, the SDTF of Lambayeque and northern Peru is greatly diminishing due to the advance of migratory agriculture, illegal mining, and deforestation. The objective of this work was to study the taxonomic aspects of both species, as well as seed germination, micropropagation, and in vitro germplasm conservation. Seed germination was 100% for both species up to three months after collection. As for micropropagation, rooting, and germplasm conservation, the Piper culture medium was effective, as it was constituted by MS mineral salts with 0.02 mg.L-1 IAA and 0.02 mg.L-1 GA3. In vitro germplasm conservation lasted more than 24 months for both species. Acclimatization under greenhouse conditions reached 50% survival for both species.

SUMMARY Indiscriminate deforestation is one of the anthropic activities that most impacts global biodiversity. Its immediate effects mainly reach vulnerable species with high commercial value, such as Cedrela odorata, so the development of biotechnological studies is a crucial element for the genetic conservation of its populations. In this context, this work aimed to analyze the seed germination, micropropagation, and germplasm conservation of C. odorata in one of the most arid regions in northern Peru. Seed germination reached 76.6 % development, with germination time between 9 and 12 days. Likewise, micropropagation produced seedlings with stem tips up to 5.4 cm in height, 12 nodes, and 83 % rooting. Finally, the conservation of germplasm resulted in individuals that reached up to 12 cm in height, 19 nodes, and presented an optimal root system. The positive results regarding seed germination, micropropagation, and germplasm conservation of C. odorata in northern Peru could offer new approaches to the development and genetic conservation of its populations, and provide a more efficient alternative for the management and local conservation of the species.

RESUMEN La deforestación indiscriminada es una de las actividades antrópicas que más impactan la biodiversidad global. Sus efectos inmediatos alcanzan principalmente especies vulnerables y con alto valor comercial, como Cedrela odorata, por lo que el desarrollo de estudios biotecnológicos es un elemento crucial para la conservación genética de sus poblaciones. En ese contexto, el objetivo de este trabajo fue analizar la germinación de semillas, micropropagación y conservación de germoplasma de C. odorata, en una de las regiones más áridas del norte del Perú. La germinación de semillas alcanzó una eficiencia de 76,6 %, con velocidades de germinación de entre 9 y 12 días. Asimismo, en ensayos de micropropagación se obtuvieron plántulas con ápices caulinares de hasta 5,4 cm de altura, 12 nudos y 83 % de eficiencia de enraizamiento. Por último, la conservación de germoplasma resultó en individuos que, a los 30 meses de cultivo, alcanzaron hasta 12 cm de altura, 19 nudos y presentaron un óptimo sistema radicular. Este estudio sugiere que los efectos positivos sobre la germinación de semillas, micropropagación y conservación de germoplasma de C. odorata en el norte del Perú, podrían ofrecer nuevos enfoques sobre el desarrollo y conservación genética de sus poblaciones, funcionando incluso como una alternativa más eficiente para el manejo y conservación local de la especie.

RESUMO A fragmentação de habitats é uma das principais causas da criação de bordas e seus efeitos. Características funcionais das árvores, como a densidade da madeira, altura e diâmetro, são variáveis essenciais que permitem inferir vários processos ecológicos. Este estudo avaliou a variabilidade das características funcionais das árvores em dois tipos de habitats (borda e interior) de um remanescente florestal. Foram testadas as hipóteses de que i) as características funcionais teriam menores valores nas bordas do que no interior, e que ii) as variáveis ambientais influenciam essas diferenças. Este estudo foi realizado no maior remanescente de Mata Atlântica dentro do Parque Estadual da Serra da Tiririca, Brasil, estabelecendo dez parcelas (50 × 20 m) entre diferentes habitats. Dentro de cada parcela foram retiradas amostras de madeira de todas as árvores com diâmetro ≥ 10 cm. Além disso, foram registradas a altitude, distância das parcelas até a borda e registros de queimadas como possíveis variáveis explicativas (variáveis ambientais). A densidade da madeira foi obtida através do método de imersão. Para verificar diferenças nas características funcionais por tipo de habitat, foi aplicado o teste de Wilcoxon. Adicionalmente, foi avaliada a influência das variáveis explicativas sobre as características funcionais por meio de modelos lineares generalizados. Cento e oitenta e cinco árvores foram registradas nas bordas e 218 árvores no interior do remanescente. A densidade da madeira e a altura das árvores foram significativamente menores nas bordas do que no interior. Além disso, os melhores modelos indicaram relações significativas entre densidade da madeira e o tipo de habitat; assim como, entre o diâmetro e distância até a borda. Este estudo foi eficaz em abordar variáveis adequadas para prever os efeitos de borda no remanescente.

ABSTRACT Habitat fragmentation is one of the leading causes of edge genesis and its effects. Functional tree traits such as wood density, height, and diameter are essential variables from which it is possible to infer several ecological processes. This study assessed the variability of the functional traits of trees over two habitats (edge and interior) of a forest remnant. The hypothesis tested were i) the functional traits would have lower values at the edges than the interior, and ii) environmental variables would influence such differences. This study was carried out in the largest Atlantic Forest remnant within Serra da Tiririca State Park, Brazil, by establishing ten plots (50 × 20 m) among different habitats. Within each plot, wood samples were taken from all trees with a diameter of ≥ 10 cm. It was recorded the altitude, distance from the plots to the edge, and fire records as possible explanatory variables (environmental variables). Wood density was obtained using the immersion method. To verify differences in functional traits by habitat, the Wilcoxon test was applied. Additionally, the influence of explanatory variables on functional traits through generalized linear models was evaluated. One hundred eighty-five trees were recorded at the edges and 218 trees at the interior of the remnant. Wood density and tree height were significantly lower in the edges than in the interior. Furthermore, the best models indicated significant relationships between wood density and habitats, as well as diameter and distance to the edge. This study was effective in raising suitable variables to predict edge effects.

Abstract The Amazonian ecosystem is one of the most important in the world and also one of the least studied, especially in regard to its vegetation and its phenophases. The objective of this study was to identify and describe the phenological patterns of the most frequent large tree species in the Tambopata National Reserve, Madre de Dios, Peru. The study was conducted between the years 2010 to 2017; by establishing five 50 × 30 m plots for each forest type: Aguajal Forest, Bajío Forest, Successional Forest and Tierra Firme Forest. In each plot, all tree individuals with a diameter ≥ 10 cm were marked and identified at 1.30 m above the ground. An analysis of indicator species by habitat was performed, and the resulting taxa were periodically observed to evaluate the flower bud, flower, immature fruit and mature fruit phenophases. In addition, the influence of precipitation and temperature variables on their phenological responses was evaluated. A total of 1 958 individuals were recorded, belonging to 57 families, 173 genera and 300 species; the Fabaceae, Moraceae and Annonaceae families stand out with the highest number of taxa and Arecaceae, with the highest number of individuals. Eight indicator species were analyzed, two for each forest type. Except in the Aguajal forest, the flower bud and mature fruit phenophases reached their maximum values in September and December-January. This information will contribute to a better understanding of the phenodynamics of each of the forest types in the Tambopata National Reserve.

Resumen El ecosistema amazónico es uno de los más importantes del mundo y también uno de los menos estudiados, en especial su vegetación y sus fenofases. El objetivo del presente trabajo fue identificar y describir los patrones fenológicos de las especies arbóreas de gran porte más frecuentes de la Reserva Nacional Tambopata, Madre de Dios, Perú. El estudio se realizó entre los años de 2010 a 2017; mediante el establecimiento de cinco parcelas de 50 × 30 m por cada tipo de bosque: Bosque de Aguajal, Bosque de Bajío, Bosque Sucesional y Bosque de Tierra Firme. En cada parcela se marcaron e identificaron todos los individuos arbóreos con diámetro ≥ 10 cm, a 1.30 m por encima del suelo. Se hizo un análisis de especies indicadoras por hábitats y los taxones resultantes se observaron periódicamente, para evaluar las fenofases de botón floral, flor, fruto inmaduro y fruto maduro. Además, se evaluó la influencia de las variables precipitación y temperatura sobre sus respuestas fenológicas. Se registraron 1 958 individuos, pertenecientes a 57 familias, 173 géneros y 300 especies; destacan las familias Fabaceae, Moraceae y Annonaceae con el mayor número de taxa y Arecaceae con más individuos. Se analizaron ocho especies indicadoras, dos por cada tipo de bosque. Con excepción del Bosque de Aguajal, las fenofases botón floral y fruto maduro alcanzaron sus máximos valores en septiembre y diciembre-enero. Esta información contribuirá a un mejor entendimiento de la fenodinámica de cada uno de los tipos de bosques de la Reserva Nacional Tambopata.

RESUMEN Introducción: La situación actual de la COVID-19 es un gran problema para la población humana. En la actualidad, no hay medicamentos curativos disponibles en el mercado. Los investigadores están haciendo todo lo posible para producir fármacos con que luchar contra la enfermedad. Se están considerando varios esfuerzos basados en diferentes orientaciones del conocimiento científico y en las tecnologías para el tratamiento de la enfermedad. Desafortunadamente, ninguno de estos medicamentos funciona absolutamente contra la corriente pandémica. Por lo tanto, las moléculas bioactivas de plantas, animales y microorganismos podrían ser una mejor opción para tratar la COVID-19. Objetivo: Revisar la literatura sobre especies de la flora del Perú utilizadas en el tratamiento de enfermedades respiratorias y destacar las plantas con posible producción de metabolitos secundarios y lectinas vegetales potencialmente útiles como alternativa frente a la COVID-19. Métodos: Se revisaron artículos de literatura científica relacionados con el uso de la medicina tradicional en Perú, China e India para el tratamiento de enfermedades respiratorias, así como la información sobre lectinas vegetales y metabolitos secundarios con potencial utilidad contra la COVID-19. Resultados: Se presenta una amplia relación de géneros y especies de la flora del Perú con gran potencial contra la COVID-19. La mayoría de estas especies pertenecen a las familias Asteraceae, Loranthaceae, Piperaceae, Viscaceae y Zingiberaceae. Numerosas especies son endémicas del Perú. Conclusiones: La flora del Perú tiene más de 22 000 especies de plantas. Muchas de estas especies se utilizan tradicionalmente en el tratamiento de enfermedades respiratorias y pueden ser potencialmente útiles en el tratamiento de la COVID-19.

ABSTRACT Introduction: The current situation of COVID-19 is a big issue for the human population. At present, no healing drug is available in the market. Researchers are doing their best to produce drugs to fight the disease. Various efforts are being considered based on different directions of scientific knowledge and technologies for the treatment of the disease. Unfortunately, none of these drugs works absolutely against the pandemic. Therefore, bioactive molecules from plants, animals and microorganisms could be a better option to treat COVID-19. Objective: Review the literature about species of the flora of Peru used for the treatment of respiratory diseases and highlight the plants with potential in the production of secondary metabolites and plant lectins as an alternative against COVID-19. Methods: A review was conducted of scientific articles related to the use of traditional medicine in Peru, China, and India for the treatment of respiratory diseases, as well as information about plant lectins and secondary metabolites potentially useful against COVID-19. Results: A long list is presented of genera and species of the flora of Peru with great potential against COVID-19. Most of these species belong to the Asteraceae, Loranthaceae, Piperaceae, Viscaceae and Zingiberaceae families. Numerous species are endemic to Peru. Conclusions: The flora of Peru has more than 22 000 plant species. Many of these species are traditionally used in the treatment of respiratory diseases and are potentially useful for the treatment of COVID-19.

Abstract Loxopterygium huasango Spruce ex Engl., of the Anacardiaceae family, classified critically endangered, is a forest tree with considerable value in the Seasonally Dry Tropical Forest (SDTF) in the northwest of Peru and south of Ecuador. The aim of the study was callus induction, propagation and germplasm conservation using in vitro tissue culture techniques. In vitro seed germination (90%) was obtained on Murashige and Skoog (MS) medium supplemented with 5.0 mg/L-1 GA3. The cotyledonal nodes of seedlings were used as explants to initiate the growth of the apical shoots, in culture medium with the IAA-GA3 interactions, without observing growth of the axillary buds. The highest rate of friable callus induction (100%) was recorded on MS medium containing 0.1 to 5.0 mg/L-1 2,4-D in cotyledons and hypocotyls explants after 30 to 45 days of culture. The profuse roots formation was the only morphogenic response (10.8 to 13.8%) on MS medium with 0.5 mg/L-1 IAA, 0.5 mg/L-1 IAA 2.0 mg/L-1 BAP, KIN or 2iP or 2.0 mg/L-1 BAP, KIN or 2iP. The germplasm conservation of apical buds and nodal segments was achieved with 2.0 mg/L-1 AgNO3. This method could be used to conserve elite genotypes, rapid production of roots and establishment of cellular suspension for secondary compounds production.

Abstract Plant biotechnology is one of the most important tools presently available and methods to genetically manipulate plants to exhibit greater productivity, tolerance to physical and chemical stress, and resistance to pests and diseases have been developed in recent decades. In vitro plant tissue culture has contributed significantly to this purpose. The objective of this study is to apply various techniques developed by in vitro tissue culture in seed germination, meristem culture for virus elimination, micropropagation, conservation, international transfer of germplasm, and induction of various morphogenic processes that lead to the genetic variability known as somaclonal variation. The application of this set of biotechnological techniques, in crops such as cassava, sweet potato, potato, native forest species as Cedrela odorata, Ficus spp. Loxopterygium huasango, and others, sugar cane, rice, pineapple, among other haves made it possible to meet, as a matter of improvement, several of the essential needs of farmers in the region of northern Peru. The development of these technologies will allow their wide application not only in the propagation, genetic improvement and conservation of species of economic importance, food and medicine, but also in the forest species of the seasonally dry tropical forest of northern Peru.

Resumo O trabalho desenvolveu se no Cerro Três Pontas de Pilasca no distrito de Salas-Motupe, região Lambayeque, Perú. O objetivo de estudo foi determinar a sua biomassa arbórea, o carbono aglomerado e a valoração econômica. Com este fim estabeleceram se quatro transeptos linhares que abrangeram 11,4 ha duma totalidade de 2 975 há da extensão de estudo. Em cada uns dos transeptos avaliados, a altura e o diâmetro (a 1,30 cm por acima do terreno) ≥ 5,0 cm de todos os indivíduos arbóreos. Mesmo assim, realizaram se coletas botânicas para a identificação dos mesmos. Registraram se 140 indivíduos, compreendidos em 17 espécies, 17 gêneros e 10 famílias. A biomassa estimada nos quatro transeptos resultou uma meia de 796,62 t ha-1, que transformada em toneladas de carbono, trouxe como resultante 1 460,6 t CO2 ha-1, o que significa uma valoração econômica de 28 963,70 USD por há. As famílias que aportaram maior biomassa ao Cerro Três Pontas de Pilasca, foram Moraceae e Lauraceae, com 8 457,95 t ha-1 y 5 738,79 tha-1 simultaneamente, mesmo que no resto das famílias, a biomassa foi menor de 1 000 t ha-1. O Cerro Três Pontas de Pilasca demostrou ser uma importante floresta com altos valores com altos valores de biomassa para a região de Lambayeque.

Abstract The work was developed in the Cerro Tres Puntas de Pilasca, in the district of Salas-Motupe, Lambayeque region, Perú. The objective of the study was to determine its tree biomass, accumulated carbon and economic valuation. For this purpose, four linear transects were established covering 11.4 ha of the total 2,975 ha of the study area. In each transect were evaluated the height and diameter (1.30 cm above the ground) ≥ 5.0 cm of all tree individuals. Also, botanical collections were made for their identification. 410 individuals were registered, comprised of 17 species, 17 genera and 10 families. The estimated biomass in the four transects gave an average of 796.62 t ha-1, which transformed into tons of carbon gave 1 460.6 t CO2 ha-1, meaning an economic valuation of 28 963.70 USD per ha. The families that contribute more biomass to the Cerro Tres Puntas de Pilasca were Moraceae and Lauraceae, with 8 457.95 t ha-1 and 5 738.79 t ha-1 respectively, while in the rest of the families the biomass was less than 1 000 t ha-1. Cerro Tres Puntas de Pilasca proved to be an important forest with high biomass values for the region of Lambayeque.

Resumen El trabajo se desarrolló en el cerro Tres Puntas de Pilasca, en el distrito de Salas-Motupe, región Lambayeque, Perú. El objetivo del estudio fue determinar su biomasa arbórea, el carbono acumulado y la valoración económica. Para ello, se establecieron cuatro transectos lineares que abarcaron 11,4 ha del total de 2 975 ha del área de estudio. En cada transecto fueron evaluados la altura y el diámetro (a 1,30 cm por encima del suelo) ≥ 5,0 cm de todos los individuos arbóreos. Asimismo, se realizaron colectas botánicas para la identificación de los mismos. Se registraron 410 individuos, comprendidos en 17 especies, 17 géneros y 10 familias. La biomasa estimada en los cuatro transectos arrojó una media de 796,62 t ha-1, la que transformada en toneladas de carbono arrojó 1 460,6 t CO2 ha-1, significando una valoración económica de 28 963,70 USD por ha. Las familias que aportan mayor biomasa al cerro Tres Puntas de Pilasca fueron Moraceae y Lauraceae, con 8 457,95 t ha-1 y 5 738,79 t ha-1 respectivamente, mientras que en el resto de familias la biomasa fue menor de 1 000 t ha-1. El cerro Tres Puntas de Pilasca demostró ser un importante bosque con altos valores de biomasa para la región de Lambayeque.

ABSTRACT Peperomia albovittata and P. galioides are two herbaceous species, belonging to the Piperaceae family, collected in the Andean district of Kañaris (1128 to 1550 m above sea level), in Lambayeque region, Perú. These species are recalcitrant to propagation by conventional vegetative methods, whereby the present study aims to in vitro propagate of Peperomia albovittata and P. galioides through by organogenesis. Single nodes with axillar buds, stem segments (internodes), leaves and petioles were cultured on gellified basal culture medium and was added IAA-GA3, NAA-GA3 and NAA-BAP at different concentrations. Only in the NAA-GA3 combination clonal propagation from nodal segments and direct organogenesis in internodes were observed. Callus induction and proliferation was observed in some interactions of NAA-BAP, although all explants from leaves turned dark brown and died. On the other hand, shoot regeneration was observed only in P. galioides. Both species, especially P. albovittata, showed a high degree of recalcitrance to the induction of in vitro morphogenic processes.

RESUMEN Peperomia albovittata and P. galioides son dos especies herbáceas, pertenecientes a la familia Piperaceae, colectadas en el distrito andino de Kañaris (1128 a 1150 msnm, en la región Lambayeque, Perú. Estas especies son recalcitrantes a la propagación por métodos vegetativos convencionales, por lo que el objetivo de este trabajo de investigación fue propagar Peperomia albovittata y P. galioides, mediante organogénesis. Nudos con yemas axilares, segmentos de tallos (entrenudos), hojas y peciolos fueron cultivados en medio de cultivo semisólido y complementado con diferentes concentraciones de AIA-AG3, ANA-AG3 y ANA-AG3 y ANA-BAP. Solamente en la combinación ANA-AG3, fue observada la propagación clonal, a partir de segmentos nodales, y la organogénesis directa en entrenudos. La inducción y proliferación de callos fue observada en algunas interacciones de ANA-BAP, aunque todos los explantes de hojas tomaban un color marrón oscuro y morían. Por otro lado, la regeneración de brotes fue observada solamente en P. galioides. Ambas especies, especialmente P. albovittata, mostraron un alto grado de recalcitrancia a la inducción de procesos morfogénicos in vitro.

Abstract From March to June, 2018 the seasonally dry forest Cerro Tres Puntas of Pilasca (Salas-Motupe, Lambayeque, Perú) was studied, in order to obtain information on its structure and its floristic composition. In a linear transect, about 11.4 ha, specimens of woody plants with DBH ≥ 5.0 cm were assessed. 410 individuals representing 17 species, 17 genera and 10 families were recorded. The most abundant species were Vachellia macracantha (Fabaceae 154 individuals) and Celtis iguanaea (Cannabaceae 55 individuals). The families with the highest number of species were Fabaceae (7) and Malvaceae (2). The basimetric area was 343.86 m2 ha-1 highlighting Ficus obtusifolia with 139.23 m2 ha-1 and Beilschmiedia sulcata with 120.90 m2 ha-1. The Importance Value Index for the species reached the main values in F. obtusifolia (49.34), V. macracantha (46.75) and B. sulcata (41.57), while the Family Value Index was widely higher in the Fabaceae family (111.86). While these results show that this forest is a precarious version of the region’s, F. obtusifolia individuals between 35-39.9 m high and 210-219.9 cm DBH were found. This study will help to accomplish an efficient conservation and reforestation program in order to improve the Cerro Tres Puntas forest, located in one of the poorest areas of the nation.

Resumen De marzo a junio de 2018 se estudió el bosque estacionalmente seco en Cerro Tres Puntas de Pilasca (Salas-Motupe, Lambayeque, Perú) con la finalidad de obtener información sobre su estructura y composición florística. En un transecto lineal de 11.4 ha, aproximadamente, se evaluaron especímenes de plantas leñosas con DAP ≥ 5.0 cm. Se registraron 410 individuos que representan a 17 especies, 17 géneros y 10 familias. Los taxones más abundantes fueron Vachellia macracantha (Fabaceae 154 individuos) y Celtis iguanaea (Cannabaceae 55 individuos) y las familias mejor representadas corespondieron a Fabaceae, con siete especies y Malvaceae, con dos. El área basal total fue de 343.86 m2 ha-1, en la que destacan Ficus obtusifolia con 139.23 m2 ha-1 y Beilschmiedia sulcata con 120.90 m2 ha-1. El Índice de Valor de Importancia alcanzó los mayores valores en F. obtusifolia (49.34), V. macracantha (46.75) y C. ruizii (41.57); en tanto que el Índice de Valor de la Familia fue más alto para Fabaceae, con 111.86, seguida de Moraceae (46.74) y Lauraceae (45.33). Si bien, los resultados muestran que este bosque es una versión precaria de los existentes en la región, todavía se identificó la presencia de individuos de F. obtusifolia entre 35 - 39.9 m de altura y DAP de 210 a 219.9 cm. El presente estudio contribuirá a desarrollar un programa de conservación, y de reforestación eficaz para mejorar el bosque del Cerro Tres Puntas, ubicado en una de las áreas más pobres del país.

RESUMEN Las plantas hemiparásitas o 'mistletoe' o 'muérdago' son comunes en varios grupos vegetales o árboles, perteneciendo a las familias Santalaceae and Loranthaceae y muchas plantas hemiparásitas son usadas como medicina en varios lugares del mundo. El objetivo del presente trabajo realizado en Psittacanthus linearis or 'suelda con suelda', especie representativa en el bosque estacionalmente seco (BES) del norte del Perú, fue estudiar algunos aspectos en el cultivo de tejidos in vitro, el análisis fitoquímico preliminar y su actividad antibacterial. Semillas de P. linearis teniendo a Prosopis pallida 'algarrobo' como hospedero, fueron colectadas y utilizadas en la germinación in vitro, propagación clonal, inducción de callos y procesos organogénicos. Tallos, hojas y frutos de plantas silvestres fueron secados, pulverizados y sometidos a extracción con etanol y el extracto fue recuperado primero con etanol y el remanente con cloroformo formando las fraciones etanólica y clorofórmica. Se realizó un estudio fitoquímico y antibacteriano preliminar utilizando Staphylococcus aureus, Escherichia coli y Pseudomonas aeruginosa y los resultados son discutidos. Este trabajo es el primer estudio sobre cultivo de tejidos, análisis fitoquímico y actividad antibacteriana de P. linearis. Los resultados obtenidos tienen importantes implicancias para el conocimiento de las interacciones fisiológicas y bioquímicas entre las especies hospederas y las plantas hemiparásitas, como P. linearis con P. pallida y otras especies del BES.

ABSTRACT Hemiparasitic plants commonly known as mistletoe (muérdago in Spanish) in the families Santalaceae and Loranthaceae are common in various kinds of plants or trees, and many hemiparasitic plants are used for medicinal purposes in various parts of the world. The objective of the present work, carried out in Psittacanthus linearis (suelda con suelda), a representative species in the seasonally dry forest (SDF) from the north of Perú, was to study aspects of in vitro tissue culture, carry out preliminary phytochemical analysis, and assess antibacterial activity. Seeds of individuals of P. linearis, which used Prosopis pallida (algarrobo) as host plant, were collected and used to induce in vitro seed germination, clonal propagation, callus induction and organogenesis. Stems, leaves and fruits of individuals of P. linearis were dried, powdered, and subjected to ethanol extraction. Posteriorly the extract was first recovered with ethanol and the remnant with chloroform, which formed the ethanolic and chloroformic fraction. A preliminary phytochemical screening was performed and preliminary antibacterial studies with Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were carried out and their results are discussed. This is the first report about in vitro tissue culture, phytochemical analysis and antibacterial activity of P. linearis. The results may have important implications for understanding physiological and biochemical interactions between host and hemiparasitic species as well as P. linearis with P. pallida and other SDF species.

El fertilizante de origen natural Sulpomag, o sulfato de potasio y magnesio, constituido por K2O 22%, MgO 22%, S 18% y Cl (cloruro) 2,5% y los complejos orgánicos agua de coco 10 y 20% y caseína hidrolizada 250 y 500 mg.l-1, como sustitutos parciales de las sales minerales de Murashige y Skoog (MS), fueron utilizados en la propagación in vitro de banano, Musa sp., cv. Cavendish. El objetivo de esta investigación fue inducir el crecimiento y desarrollo de plantas in vitro en condiciones mínimas de sales minerales inorgánicas, prohibidas en el reglamento técnico para los productos orgánicos. Ápices caulinares, cultivados en medio de cultivo MS, fueron transferidos a 10 formulaciones de multiplicación de brotes suplementadas con KH2PO4 (170 mg.l-1), CaCl2.2H2O (150 mg.l-1), NH4NO3 y KNO3, a 1/5 y 1/10 de la concentración MS, micronutrientes MS y Sulpomag 0,1096 g.l-1, AIA 0,2 mg.l-1 y BAP 5 mg.l-1. El medio de cultivo de enraizamiento fue de igual formulación de sales minerales, con variaciones en los reguladores de crecimiento. Los mejores resultados se obtuvieron con NH4NO3 y KNO3 a 1/5 de la concentración MS, Sulpomag 0,1096 g.l-1 y agua de coco 10 y 20%. Los resultados obtenidos posibilitan la utilización del Sulpomag y el agua de coco como sustitutos parciales de las sales minerales MS en la propagación in vitro de Musa sp., cv. Cavendish en la agricultura orgánica.

The Sulpomag natural fertilizer, or potassium sulfate and magnesium, constituted by K2O 22%, MgO 22%, S 18% and Cl (chloride) 2.5% plus organic complexes of coconut water 10 to 20%, and casein hydrolyzate 250 and 500 mg.l-1, as partial substitutes for mineral salts of Murashige and Skoog (MS), were used in the in vitro propagation of banana, Musa sp., cv. Cavendish. The aim was that the in vitro plants grow and develop in minimum quantities of mineral salts, banned in the technical regulation for organic products. Shoot tips, established in vitro on MS medium, were transferred to 10 treatments for shoot multiplication supplemented with KH2PO4 (170 mg.l-1), CaCl2.2H2O (150 mg.l-1), NH4NO3 and KNO3, at 1/5 and 1/10 of the MS concentration, MS micronutrients and 0.1096 g.l-1 of Sulpomag, IAA (0.2 mg.l-l) and BAP (5 mg.l-1). The rooting medium was the same formulation of mineral salts, only varying on the growth regulators. Best results were obtained in culture media supplemented with NH4NO3 and KNO3 at 1/5 of MS concentration, 0.1096 g.l-1 Sulpomag and coconut water 10 y 20%. The results allow to consider the possibility of using Sulpomag and coconut water, as partial substitutes for MS mineral salts for in vitro propagation of Musa sp., cv. Cavendish for use in organic agriculture.

Cucurbit germplasm was collected in northern Perú. Sampling covered the Tumbes, Piura and Cajamarca regions and gathered 8 genera, 14 species and 202 accessions. The highest number of accesions came from Lambayeque. Genetic material has been conserved since 1988 to this date at 10 °C, with a seed viability rate of 90 %. Morphological characteristics of fruits and seeds of Cucurbita ficifolia, C. moschata, C. maxima, Cucurbita sp., a local variety known as "loche", and Lagenaria siceraria, were evaluated. The Cucurbita accesions showed variability in fruit shape, size and colour, and in seed size and shape. Lagenaria accesions stood out by their variability in fruit shape and size, in which the "calabazos", "lapas", "mates" and "checos" fruit types, and many intermediate shapes, were recognized. The possibility that the genotypes "chuyán" and "loche", traditionally classified as C. moschata, could be sub-species is discussed. It is concluded that the north coast of Perú is a center of high morphological diversity of C. moschata and L. siceraria, while the Andean region of Cajamarca and Piura is the diversity center for C. ficifolia.

Se colectó germoplasma de cucurbitáceas en el norte del Perú, en las regiones de Tumbes, Piura, Lambayeque y Cajamarca, para un total de 8 géneros, 14 especies y 202 accesiones, sobre todo de la región Lambayeque que tuvo el mayor número de accesiones. Este material genético se conserva desde 1988 hasta la actualidad a 10 °C de temperatura, con una tasa de viabilidad de las semillas de 90 %. Se evaluaron las características morfológicas de frutos y semillas de las especies Cucurbita ficifolia, C. moschata, C. maxima y Cucurbita sp., una variedad local conocida como "loche", y Lagenaria siceraria. Las accesiones de Cucurbita fueron muy variables en forma, tamaño y color de fruto, y forma y tamaño de semilla. Las accesiones de Lagenaria destacaron por la amplia variabilidad en forma y tamaño del fruto, en las que se reconocieron los tipos "calabazos", "lapas", "mates" y "checos", con numerosas formas intermedias. Se discute la posibilidad de que los genotipos "chuyán" y "loche", clasificados tradicionalmente como C. moschata, pudieran constituir subespecies. Se concluye que la costa norte del Perú es un centro de alta diversidad morfológica de C. moschata y L. siceraria, y la región altoandina de Cajamarca y Piura de C. ficifolia.