Summary: In the ecosystems of arid and semi-arid zones, food production is increasingly complex. One of the most important effects is desertification where water plays a key role. Therefore, seeking strategies for the production of safe and sustainable food is the current challenge. The production of food through aquaponics is an alternative to respond to this problem. In the Baja California Peninsula, the low annual rainfall and the geographical characteristics naturally make water scarce; but if also add anthropogenic factor, we have as a result, mostly brackish aquifers. In this context, was analyzed, the efficiency in the use of snook culture effluent, in the growth of chard, in a aquaponic system. Were measured the parameters physicochemical of the snook culture effluent and how they influence the morphometric response in chard under hydroponic system. Was compared the response with a traditional system with well water effluent and conventional fertilization. Obtained greater growth in the plants in the hydroponic system, but with snook culture effluent (with a significant difference in length, biomass, leaf area and number of leaves). This study demonstrates the efficiency of the use of snook culture effluent in the growth and development of chard. This knowledge will generate future research with application in biotechnological innovation that can be used by society, with benefits due to the ability to grow species of quality in density, take advantage of nutrients, control water availability, take advantage and improve climatic conditions. We believe that this model snook-chard is ideal for sustainable production systems.

Resumen: En los ecosistemas de zonas áridas y semiáridas la producción de alimentos es cada vez más compleja. Uno de los efectos más importantes es la desertificación donde el agua tiene un papel primordial. Por lo que, buscar estrategias de producción de alimento inocuo y de forma sustentable, es el reto actual. La producción de alimento mediante acuaponía es una alternativa para dar respuesta a esta problemática. En la Península de Baja California, las bajas precipitaciones anuales y las características geográficas hacen de forma natural que el agua sea escasa; pero si a esto se le suma el factor antropogénico, tenemos como resultado, acuíferos en su mayoría salobres. Bajo este contexto se analizó la eficiencia en el uso del efluente del cultivo de robalo, en el crecimiento de la acelga, en un sistema acuapónico. Se midieron los parámetros fisicoquímicos del efluente del robalo y cómo influyen en la respuesta morfométrica en la acelga bajo sistema hidropónico. La respuesta se comparó con un sistema tradicional con efluente de agua de pozo y con fertilización convencional. Se obtuvo mayor crecimiento en las plantas en sistema hidropónico, pero con efluente de agua de cultivo de robalo (con diferencia significativa en longitud, biomasa, área foliar y número de hojas). Este estudio demostró la eficiencia del uso del efluente del cultivo de robalo en el crecimiento y desarrollo de la acelga. Este conocimiento generará futuras investigaciones con aplicación en innovación biotecnológica que podrán ser empleadas por la sociedad, con beneficios por la capacidad de cultivar especies de calidad en densidad, aprovechar los nutrientes, controlar la disponibilidad de agua, aprovechar y mejorar las condiciones climáticas. Consideramos que este modelo robalo-acelga es ideal para los sistemas de producción con sustentabilidad.

ABSTRACT. The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

ABSTRACT. The objective of this study was to evaluate the the ability of foliar application of potassium nitrate (KNO3) to induce water deficit tolerance in sorghum plants (Sorghum bicolor cv. P898012) subjected to water deficit at pre-flowering. The experiment was conducted under greenhouse conditions with 4 treatments: field capacity (FC), water deficit (WD), field capacity + KNO3 (FC + KNO3), and water deficit + KNO3 (WD + KNO3). Two foliar applications of 3% (m/v) KNO3 were made, the first on day zero of stress and the second on the fifth day. All analyses were performed after 12 days of stress (end of stress). Foliar application of KNO3 to irrigated plants led to increases in relative chlorophyll content, photosynthetic rate, stomatal conductance, transpiration, and carboxylation efficiency. It also induced increases in leaf concentrations of P, Mg, S, Cu, and Fe, in addition to height growth. Under water deficit conditions, plants treated with KNO3 presented higher relative chlorophyll content, leaf area, photosynthetic rate, stomatal conductance, transpiration, carboxylation efficiency, and higher levels of P, K, Mg, S, Cu, and Fe than those not treated with KNO3. The morphometry of the root system was not altered by the treatments. In addition, plants treated with KNO3 under water deficit conditions showed higher growth and a grain yield 32.2% higher than those that did not receive KNO3. These results demonstrated that KNO3 applied to the leaves induced water deficit tolerance in sorghum plants subjected to severe water stress at pre-flowering.

Abstract The tara (Caesalpinia spinosa (Mol.) Kuntze) is a non-timber forest species whose pods are of economic importance to various industries; however, attacks by pests such as Tanaostigmodes sp. the leaves and young stems decrease the production of this species. The aim of this study was to determine the morphological and biological characteristics of Tanaostigmodes sp. and percentage of incidence in C. spinosa. 1399 insects were identified in which evaluations of the duration of the stages, the morphometry and the damage to the plant were carried out. The egg, larva, pupa and adult measure 0.2, 2.0, 2.1 and 2.0 to 2.3 mm long, last 13.1, 71.8, 20.6 and 10.1 days respectively, totaling its development cycle in 115.1 days; the larvae when feeding make mines in the rachis of the leaves and in young stems, reaching maximum attacks of up to 84.5% causing defoliation. Tanaostigmodes sp. it is a major tare pest, with average attack records of 24.6% on leaves. Knowing its biological aspects and its interaction with tara phenology will allow the adoption of efficient strategies for its integrated management and control.

Resumen La tara (Caesalpinia spinosa (Mol.) Kuntze) es una especie forestal no maderable cuyas vainas son de importancia económica para diversas industrias; sin embargo, ataques de plagas como Tanaostigmodes sp. a las hojas y tallos jóvenes disminuye la producción de esta especie. El objetivo de este estudio fue determinar las características morfológicas y biológicas de Tanaostigmodes sp. y porcentaje de incidencia en C. spinosa. Fueron identificadas 1399 puestas del insecto en las cuales se realizaron evaluaciones de la duración de los estadios, la morfometría y los daños en la planta. El huevo, larva, pupa y adulto miden 0,2; 2,0; 2,1 y de 2,0 a 2,3 mm de largo, duran 13,1; 71,8; 20,6 y 10,1 días respectivamente, totalizando su ciclo de desarrollo en 115,1 días; las larvas al alimentarse realizan minas en los raquis de las hojas y en tallos jóvenes, alcanzando ataques máximos de hasta 84,5% provocando defoliación. Tanaostigmodes sp. es una plaga principal de tara, con registros de ataques medios de 24,6% en hojas. Conocer sus aspectos biológicos y su interacción con la fenología de tara, permitirá adoptar estrategias eficientes para su manejo integrado y control.

Resumen Introducción: Los manglares representan cerca del 11 % de la superficie forestal de Cuba. No existen estudios previos que describan sus características foliares, a pesar de que estas variables pueden constituir indicadores del estado de los ecosistemas boscosos. Objetivo: En el presente trabajo se describen las características morfométricas de las hojas en cuatro manglares periurbanos de la ciudad de La Habana: Bajos de Santa Ana, Cojímar, Rincón de Guanabo y la laguna El Cobre-Itabo. Métodos: Se emplearon 1 472 muestras de hojas de Rhizophora mangle, Avicennia germinans y Laguncularia racemosa, recolectadas entre abril y julio 2019, a las cuales se les extrajeron ocho variables: largo de la lámina, ancho máximo, área, perímetro, asimetría lateral, ángulos interiores anterior y posterior y un índice de forma. Resultados: Se detectaron diferencias geográficas en varias de las dimensiones de las hojas en R. mangle y A. geminans, pero L. racemosa mostró características altamente constantes entre localidades. Las diferencias se relacionaron con las características geográficas y ambientales de las localidades. Las dimensiones de las hojas fueron consistentes con estudios realizados en otros países. Conclusiones: Es necesario continuar evaluando de forma precisa estos indicadores foliares para sustentar su uso en futuros monitoreos o investigaciones, y para ello el empleo de fotografías digitales presenta numerosas ventajas, que fundamentan su uso.

Abstract Introduction: Mangroves represent 11 % of the emerged land of Cuba. There is no previous research describing foliar characteristics, but these variables can be used as health indicators in forest ecosystems. Objective: In the current study we describe folial morphometry in four mangroves around Havana city: Bajos de Santa Ana, Cojímar, Rincón de Guanabo and El Cobre - Itabo lagoon. Methods: We collected 1 472 leaves´ samples of Rhizophora mangle, Avicennia germinans and Laguncularia racemosa, between April and July in 2019, to extract eight foliar variables: length, width, area, perimeter, lateral asymmetry, inner angles and shape index. Results: Geographic differences several variables of leaves in R. mangle and A. germinans were detected, but L. racemosa showed high similarity among localities. Differences can be explained by environmental differences in localities. Conclusions: There is a need for more extensive research on these kinds of foliar indicators to support it use in future monitoring or researches, and for that using digital pictures fotografías pose many advantages.

Resumo: O objetivo deste trabalho foi verificar a possibilidade de indução de haploidia em milho superdoce tropical (Zea mays L. var. saccharata) por meio de indutor maternal, bem como identificar métodos alternativos para seleção de haploides. Um híbrido simples de milho comum e 11 populações de milho superdoce tropical foram cruzados com o indutor de haploidia. Os haploides foram pré-selecionados pelo marcador R1-navajo e diferenciados em haploides ou falsos positivos, no estágio V2-V3, com base na cor da primeira bainha foliar e no comprimento das células-guarda dos estômatos foliares. Os resultados obtidos são indicativos da possibilidade de induzir haploides maternos em populações de milho superdoce tropical. Contudo, muitos haploides falso-positivos foram selecionados incorretamente pelo marcador R1-navajo. A coloração da primeira bainha foliar foi eficiente na identificação de haploides em populações de milho superdoce, e o método baseado na morfometria dos estômatos pode ser usado quando não há distinção de cor da primeira bainha foliar.

Abstract: The objective of this work was to determine the possibility of haploid induction in tropical supersweet corn (Zea mays L. var. saccharata) using a maternal inducer, as well as to identify alternative methods for haploid selection. A single-cross hybrid of field corn and 11 tropical supersweet corn populations were crossed with the haploid inducer. The haploids were pre-selected using the R1-navajo marker and were differentiated into haploids or false positives at the V2-V3 stage, based on the color of the first leaf sheath and on the length of stomata guard cells. The obtained results are indicative of the possibility of inducing maternal haploids in populations of tropical supersweet corn. However, a large number of false-positive haploids were incorrectly selected by the R1-navajo marker. The color of the first leaf sheath was efficient for haploid identification in supersweet corn populations, and the method based on stomata morphometry can be used when there is no color distinction on the first leaf sheath.

RESUMO: Oaxaca é umas das regiões de maior diversidade de espécies de pimentas do México. Os agricultores selecionam sementes da maneira tradicional; informações sobre sua qualidade são desconhecidas. O objetivo desta pesquisa foi comparar a qualidade física e fisiológica de sementes e mudas de três tipos nativos de pimenta (Huacle, De Agua e Pasilla) e pimenta verde comercial como controle. Quinze variáveis foram avaliadas em sementes e doze em mudas. As experiências de laboratório foram estabelecidas sob um delineamento inteiramente casualizado. As médias das variáveis foram comparadas pelo teste de Tukey (α=0.05). Os resultados mostraram que o Pasilla apresentou os maiores valores em tamanho e peso de sementes, 1,44 g mais pesado que o controle e 2,09 a 3,73 g maior que os demais tipos de pimenta nativa. A pimenta Huacle e a pimenta verde tiveram 90% de germinação de 90%, enquanto que De Agua e Pasilla foi de 51 e 38%, respectivamente. A pimienta Huacle apresentou os maiores índices de taxa de germinação (29,89) e de vigor de plântulas (992,25). Os maiores valores máximos no número de mudas normais foram obtidos no controle e na pimenta Huacle (72 e 88%). Além disso, este último apresentou os maiores valores de plúmula (3,36 cm) e radícula (7,67 cm). As mudas do Huacle e Pasilla apresentaram maiores valores em altura, espessura do caule, número de folhas, área foliar e índice de esbelto em relação à pimenta, De agua e ao controle. O Huacle apresentou boa qualidade física e fisiológica, semelhante às sementes da pimentão comercial.

ABSTRACT: The diversity of chilis in Oaxaca is one of the most extensive in Mexico. Growers select seeds in the traditional manner; information on its quality is unknown. The aim of this research was to compare the physical and physiological quality of seeds and seedlings of three native types to chili (Huacle, De agua and Pasilla) and of the commercial Green pepper as control. Fifteen variables were evaluated in seed and twelve in seedlings. The laboratory experiments were established under a completely randomized design. Means of the variables were compared using the Tukey test (α=0.05). Results showed that Pasilla chili had the highest values in seed size and weight, which was 1.44 g heavier than the control and 2.09 to 3.73 g higher than native types. Haucle chili and green pepper had a 90% germination rate, while chili De agua and Pasilla chili had germination rates of 51 and 38%, respectively. Huacle chili had the highest germination rate index (29.89) and seedling vigor index (992.25). The top highest values of number of normal seedlings were obtained in the control and Huacle chili seedlings (72 and 88%); also, the latter had the longest plumule (3.36 cm) and radicle (7.67 cm) values. Both Huacle and Pasilla chili seedlings had larger values in height, stem thickness, number of leaves, leaf area and slenderness index than De agua and Green pepper. Huacle chili had good physical and physiological quality similar to the seeds of the commercial Green pepper.

ABSTRACT The excess of heavy metals, such as copper, causes toxicity in plants, consequently, it generates changes in their aerial tissues, affecting their stomata whose main function is gas exchange. However, the density and morphometry of these stomata could vary to compensate for the water content caused by these environmental changes. The purpose of this study was to determine the leaf area, density and morphometry of leaf stomas of Gochnatia arequipensis Sandwith (Asteraceae) in relation to leaf copper content, determined by atomic absorption spectrophotometry, collected at different sampling points. In this research, a stratified design was carried out, for which leaves of the study plant developed in the district of Quequeña were collected at different distances from the tailings belonging to the Kiowa PAM and also in the Characato district. The leaf area was lower in plants from the points closest to the Kiowa PAM (55.8 ± 11.27 mm2) than the leaf area of the Characato district plants (62.72 ± 6.94 mm2). On the other hand, the stomatal density (154.2 ± 32.9 stomata / mm2) was greater in the plants of the points near the Kiowa PAM while its stomatal area decreased (315.02 ± 31.114 fim2). The stomatal opening was greater in the Characato plants (73.04 ± 8.3 fim2). When the amount of leaf copper is greater, the leaf area suffers a decrease, the stomatal density decreases as the plants move away from the Kiowa PAM.

RESUMEN El exceso de metales pesados, como el cobre, provoca toxicidad en las plantas, en consecuencia, genera cambios en sus tejidos aéreos, afectando sus estomas cuya principal función es el intercambio gaseoso. Sin embargo, la densidad y morfometría de estos estomas podrían variar para compensar el contenido hídrico provocado por los cambios ambientales. El propósito de este estudio fue determinar el área foliar, la densidad y la morfometria de los estomas de hojas de Gochnatia arequipensis Sandwith (Asteraceae) en relación al contenido de cobre foliar, determinado mediante espectrofotometría de absorción atómica, colectadas en diferentes puntos de muestreo. En esta investigación se realizó un diseño estratificado, para lo cual se recolectaron hojas de la planta en estudio desarrolladas en el distrito de Quequeña a diferentes distancias del relave perteneciente al PAM Kiowa y también en el distrito de Characato. El área foliar fue menor en plantas de los puntos más próximos al PAM Kiowa (55.8 ± 11.27 mm2) que el área foliar de las plantas del distrito de Characato (62.72 ± 6.94 mm2). Por otro lado, la densidad estomática (154.2 ± 32.9 estomas/mm2) fue mayor en las plantas de los puntos próximos al PAM Kiowa mientras que su área estomática disminuyó (315.02 ± 31.114 μm 2). La apertura estomática fue mayor en las plantas de Characato (73.04 ± 8.3 μm 2). Cuando la cantidad de cobre foliar es mayor, el área foliar sufre una disminución, la densidad estomática disminuye conforme las plantas se alejan del PAM Kiowa.

ABSTRACT The national poultry production has acquired great importance for being an activity of high socioeconomic impact and generates high demand for ingredients. Moringa oleifera has acquired great importance as a nutritional supplement and medicinal plant; therefore, it could represent an alternative as an immune stimulant. The effects of the inclusion of the M. oleifera leaf on the immunological constants of broiler chickens were evaluated. 180 chickens (females) Cobb genetic line were used, distributed in 3 treatments: Control, M10, and M20. Intestinal morphometry and the content of IgY were determined at 21 and 42 days. A completely randomized statistical design was used: ANOVA and comparison of Tukey's means were performed. At 42 days, the height of villi of the duodenum of the Control group obtained the lowest values (1485 μm) with respect to M10 and M20 groups. The height of the jejunum villi was significantly higher (P<0.05) in the M10 group, with respect to the M20 and Control groups. In the depth of the jejunum crypts, there was a difference (P<0.05) between the Control and M20, the latter being the least. The IgY content at 21 days was significantly higher (P<0.05) in the M10 and M20 than in the Control. M. oleifera has a positive effect as an immunostimulant and can be used in animal feeding.

RESUMEN La producción avícola tiene gran relevancia por su alto impacto socioeconómico, genera alta demanda de ingredientes. Moringa oleifera ha adquirido gran importancia como suplemento nutricional y planta medicinal, por tanto, podría representar una alternativa como estimulante inmunológico. Se evaluaron los efectos de la inclusión de la hoja M. oleifera sobre constantes inmunológicas de pollos de engorda. Se utilizaron 180 pollos (hembras) línea genética Cobb distribuídas en 3 tratamientos: Control, M10 y M20. Se evaluó morfometría intestinal y contenido de IgY a los 21 y 42 días. Se utilizó un diseño estadístico completamente al azar, se realizó ANDEVA y comparación de medias de Tukey. A los 42 días, la altura de vellosidades del duodeno del Control obtuvo valores más bajos (1485 μm) con respecto a los grupos M10 y M20. La altura de vellosidades de yeyuno fue significativamente mayor (P<0.05) en M10, con respecto a M20 y Control. En la profundidad de criptas de yeyuno existió diferencia (P<0.05) entre Control y M20, siendo este último el menor. El contenido de IgY a los 21 días fue significativamente mayor (P<0.05) en M10 y M20 con respecto a Control. M. oleifera tiene efecto positivo como inmunoestimulante y puede utilizarse en alimentación animal.

ABSTRACT Although in-feed antibiotics work for broiler chicken´s growth, they are a source of public health hazard. Therefore, there is a need for alternates which can act as growth promoter without deleterious effects on the health of meat consumers. Moringa oleifera is one such phytobiotic which is reported to possess antimicrobial and immuno-modulatory properties. This study investigated the effect of Moringa oleifera leaf powder (MOLP) supplementation on meat quality and bone morphometry of broiler. One-day-old chicks (n=100), divided into five groups (four replicates with n=5), were fed a basal diet (control group) or same diet supplemented with 6, 9, 12 or 15 g/kg MOLP. On d-35, two birds per replicate were euthanized to collect samples of breast muscle, blood and tibia bone. The MOLP supplementation significantly increased pH of breast muscle and ash percentage of tibia bone. The diameter of breast muscle fibres and also weight and weight length index of tibia bone significantly increased with 12 and 15 g/kg MOLP. The water holding capacity (WHC) of breast muscle was significantly higher with 9 and 15 g/kg MOLP; whereas robusticity index of tibia bone significantly decreased with 12 and 15 g/kg MOLP inclusion compared to the control group. In conclusion, dietary supplementation of Moringa oleifera leaf powder (12g/kg) increased pH, water holding capacity, and muscle fibre diameter of breast muscle and also weight, ash percentage and density indices of tibia bone in broiler chickens.

Resumo Os órgãos vegetativos aéreos estão consideravelmente mais expostos às condições ambientais e podem refletir as adaptações específicas das plantas ao seu habitat. A espécie Aldama grandiflora é amplamente distribuída no Brasil e, dessa forma, indivíduos de diferentes populações podem estar expostos a diferentes condições ambientais. Vários estudos anatômicos realizados com espécies brasileiras do gênero Aldama têm abordado, principalmente, as características anatômicas qualitativas dessas espécies, mas não em suas características quantitativas. Neste estudo avaliamos se as condições climáticas e do solo podem alterar a morfometria entre os indivíduos de A. grandiflora coletados em seis populações do Estado de Goiás. Foram avaliados os caracteres anatômicos foliares e caulinares, além da amostragem do solo e coleta de dados climáticos, para os seis locais. A análise indicou algumas diferenças estatísticas entre as populações avaliadas, mostrando que A. grandiflora apresentou características anatômicas foliares e caulinares bastante consistentes. As pequenas diferenças morfo-anatômicas encontradas entre indivíduos das diferentes populações avaliadas, refletiram as condições do solo nos quais essas populações se desenvolveram. Assim sendo, fatores ambientais relacionados ao clima e condições do solo têm uma influência significativa sobre a morfo-anatomia de Aldama grandiflora.

Abstract Vegetative aerial organs are considerably more exposed to environmental conditions and can reflect the specific adaptations of plants to their local environment. Aldama grandiflora species are known to be widely distributed in Brazil; therefore, individuals from different populations of this species are thought to be exposed to different abiotic and biotic conditions. Several anatomical studies conducted on Brazilian Aldama species have mainly focused on the qualitative anatomical characters or traits of these species, but not on their quantitative traits. In this study, we evaluated whether climate and soil conditions can change the morphometry among individuals of A. grandiflora collected from six sites in the Goiás State, Brazil, by assessing their anatomical characters. Further, soil sampling was performed, and climate data were collected from all the six sites. The analysis indicated few statistical differences among the populations evaluated, showing that A. grandiflora presented consistent leaf and stem anatomical characteristics. The small morpho-anatomical differences found among individuals of the different populations evaluated, reflected the soil conditions in which these populations were grown. Therefore, environmental factors have a significant influence on the morpho-anatomy of Aldama grandiflora.

RESUMO Objetivou-se, neste trabalho, verificar o efeito da adição de solução nutritiva em diferentes substratos na produção de mudas de Pochota fendleri, e seu efeito nos teores de macro e micronutrientes e de clorofilas a e b nas folhas. O delineamento experimental utilizado foi inteiramente casualizado em esquema fatorial 3 x 2, com quatro repetições. Os fatores foram três substratos e adição ou não de solução nutritiva, compondo seis tratamentos: (T1) = areia; (T2) = solo; (T3) = solo + areia (1:1); (T4) = areia + solução nutritiva; (T5) = solo + solução nutritiva; (T6) = solo + areia + solução nutritiva. Foram avaliadas características de crescimento (altura, diâmetro do colo e massa seca da parte aérea e radicular, relação raiz/parte aérea e massa seca total), além dos teores de macro e micronutrientes e de clorofilas a e b. A utilização de solução nutritiva reduz o tempo para obtenção de mudas de Pochota fendleri e é importante para o crescimento e qualidade das mudas. A sequência de exigência nutricional das mudas nos três substratos com adição de solução nutritiva segue em ordem decrescente: macronutrientes (N > Ca > K > Mg > P > S ) e micronutrientes (Fe > Mn > B > Zn > Cu).

ABSTRACT This study assessed the effect of different substrates and addition of nutrient solution on the production of Pochota fendleri seedlings, leaf contents of macro and micronutrients and chlorophyll a and b. The experimental design was completely randomized, in a 3 x 2 factorial scheme, with four replicates. The factors were three substrates, with or without addition of nutrient solution, composing six treatments: (T1) = sand; (T2) = soil; (T3) = sand + soil (1:1); (T4) = sand + nutrient solution; (T5) = soil + nutrient solution; (T6) = sand + soil + nutrient solution. Growth characteristics (height, collar diameter, shoot dry matter, root dry matter, root/shoot ratio and total dry matter) and contents of macro- and micronutrients and chlorophyll a and b were evaluated. The use of nutrient solution reduces the time to obtain seedlings of Pochota fendleri, and it is important for proper growth and quality of seedlings. The sequence of nutritional requirement presented by Pochota fendleri seedlings in three substrates with addition of nutrient solution follows the descending order: macronutrients (N > Ca > K > Mg > P > S) and micronutrients (Fe > Mn > B > Zn > Cu).

ABSTRACT For pioneer plants, shaded habitats represent a stressful condition, where sunlight exposure is below the optimum level and so leaves expand in order to intercept a greater amount of light. We investigated changes in both phenotypic variation and stress of Bauhinia brevipes in sunny and shaded microhabitats. Leaf area was used as a measure of phenotypic variation, whereas leaf asymmetry (difference between right and left sides of leaves), was used as a measure of stress. We hypothesized an increase in leaf area and stress in shaded locations, which might indicate that B. brevipes was compensating for low light absorption, and elevated levels of stress, respectively. Plants in the sun fitted a fluctuating asymmetry pattern (normal distribution of right minus left sides), while shaded plants were clearly antisymmetric (bimodal distribution of leaf side differences). Leaf asymmetry and area were 5% and 26.8% higher in plants in the shade compared to plants in the sun, respectively. These results were expected since B. brevipes is found predominantly in open areas; so sunlight exposure is important for its development. The presence of antisymmetry is rare in studies of developmental instability, and here it might indicate higher stress compared to plants with fluctuating asymmetry.

Quercus germana is an endemic species from the cloud forest of Mexico. The selection pressure resulting from fragmentation and environmental changes suggests the presence of phenotypic differentiation. We evaluated the relationship between the environment and the leaf morphology of Q. germana at six sites in the area of Xalapa, Veracruz. Ten leafs of 30 specimens per site were collected. Ten leafs morphometric and seven environmental characteristics were measured and variance analyses were performed with a discriminant analysis. Additionally, UPGMA phylogenetic trees were constructed and the Mahalanobis distances were compared using a Mantel test to estimate the relationship between morphometry and the environment. The morphological variables that best separated the sites were mucrones, ribs and petiole size. Environmentally, the most discriminant variables were light, temperature and loss of humidity. The Mantel test did not show any relationship between the morphometric and the environmental differences (r = 0.090, P = 0.3060), so there is not any association between the two. Because morphological differences were found in sub-populations despite of the short distance between them, these may be affected by fragmentation even without environmental influences.

Quercus germana es una especie endémica del bosque mesófilo de montaña de México. La presión de selección que la fragmentación y los cambios ambientales ejercen, sugieren diferenciación fenotípica. Por lo anterior, la relación de la diferenciación foliar de Q. germana con la fragmentación y las condiciones ambientales se evaluó en seis sitios del bosque mesófilo de Xalapa, Veracruz. Para ello, se colectaron 10 hojas de las ramas nones de 30 individuos por sitio; se midieron 10 características morfométricas foliares y siete ambientales. Los análisis de varianza se realizaron con el modelo linear generalizado; se utilizó un análisis discriminante, se construyeron árboles de ligamiento UPGMA y se proyectaron las poblaciones tridimensionalmente. Las distancias de Mahalanobis se compararon con una prueba de Mantel para estimar la relación morfométrica y ambiental. Las variables morfológicas que mejor separan los sitios son mucrones, nervaduras y tamaño del peciolo. Ambientalmente, las variables más discriminantes son luz, temperatura y pérdida de humedad. La prueba de Mantel no mostró relación entre las diferencias morfométricas y ambientales (r = 0.090, P = 0.306). Las subpoblaciones de Q. germana son morfológicamente diferentes a pesar de la distancia corta que las separa, lo cual indica que posiblemente son afectadas por la fragmentación aún sin influencia ambiental.

Este trabajo examina las diferencias morfológicas entre las mandíbulas de hormigas arrieras que cortan hojas y pastos. Especificamente, se compararon las mediciones morfométricas de mandíbulas de cuatro especies (Atta laevigata, A. bisphaerica, Acromyrmex balzani and Ac. subterraneus). Se encontró que las especies de Attapresentan menos diferencias en la morfología mandibular, siendo la principal diferencia la longitud del diente distal. En contraste, las mandíbulas en Ac. balzani son más robustas y macizas, mientras que en Ac. subterraneus fueron alargadas. Estos resultados permiten afirmar que las diferencias morfológicas dan lugar a una preferencia refinada por pastos u hojas de eudicotiledóneas.

Morphological differences among mandibles of grass and leaf-cutting ant species were examined. Specifically, we compared morphometric measurements from mandibles of four species (Atta laevigata, A. bisphaerica, Acromyrmex balzani, and Ac. subterraneus). It was found that these Atta species had similar mandible morphologies, primarily differing in distal tooth length. In contrast, the two Acromyrmex exhibited considerable variation in morphology: Ac. balzani mandibles are more robust and massive, while Ac. subterraneus mandibles are elongated. These results support that morphological differences in mandible shape and dentition are related to preference for either grasses or eudicot leaves.