ABSTRACT: Seedling production is an important step in the lettuce production system. However, there is a tendency to apply excessive irrigation at this stage. The aim of this study was to test the use of the Simplified Irrigation Controller (SIC) under two conditions: first, with the sensor installed in the substrate (measuring the soil water tension) and second, in the atmosphere (“atmospheric” - responding to vapor demand in the atmosphere) to control the irrigation of lettuce seedlings. The performance of the SIC was evaluated by monitoring plant traits. The lettuce seeds of the Regina cultivar were sown in styrofoam trays with commercial organic substrate. Both experiments were conducted under greenhouse conditions and evaluated under different SIC activation tensions. Shoot fresh weight and dry weight, height, number of leaves, leaf length, leaf area, water use efficiency (WUE) (ratio between the dry mass of plant produced by the volume of water applied), chlorophyll content, stomatal conductance and chlorophyll a fluorescence were assessed. In the experiment with the substrate sensor, the tension of 11.5 kPa caused death in 94 % of the seedlings and was disregarded in the statistical analysis. All biometric and physiological traits evaluated decreased as the SIC tensions increased. Thus, tensions of 4.0 (substrate sensor) and 3.5 kPa (atmospheric sensor) showed greater potential for producing vigorous seedlings, with WUE average values of 1.86 and 1.37 g L−1, respectively. Cultivation of lettuce seedlings proved viable under both conditions when the SIC was used, with the emergence of a number of practical advantages of the atmospheric sensor over the substrate one.

ABSTRACT Anthropogenic activity, such as accidental oil spills, are typical sources of urban mangrove pollution that may affect mangrove bacterial communities as well as their mobile genetic elements. To evaluate remediation strategies, we followed over the time the effects of a petroleum hydrocarbon degrading consortium inoculated on mangrove tree Avicennia schaueriana against artificial petroleum contamination in a phytoremediation greenhouse experiment. Interestingly, despite plant protection due to the inoculation, denaturing gradient gel electrophoresis of the bacterial 16S rRNA gene fragments amplified from the total community DNA indicated that the different treatments did not significantly affect the bacterial community composition. However, while the bacterial community was rather stable, pronounced shifts were observed in the abundance of bacteria carrying plasmids. A PCR-Southern blot hybridization analysis indicated an increase in the abundance of IncP-9 catabolic plasmids. Denaturing gradient gel electrophoresis of naphthalene dioxygenase (ndo) genes amplified from cDNA (RNA) indicated the dominance of a specific ndo gene in the inoculated petroleum amendment treatment. The petroleum hydrocarbon degrading consortium characterization indicated the prevalence of bacteria assigned to Pseudomonas spp., Comamonas spp. and Ochrobactrum spp. IncP-9 plasmids were detected for the first time in Comamonas sp. and Ochrobactrum spp., which is a novelty of this study.

ABSTRACT: Concerns with water crisis involve all sectors of society and irrigated agriculture remains the main water consumer. This study evaluated an agricultural production system for lettuce cultivation in greenhouse, “organic potponics”, to economize water and manure use, using a Simplified Irrigation Controller (SIC), based on soil matric potential monitoring. Five irrigation volumes were evaluated in pots with 4.8 L, fertilized with 200 g of vermicompost. One of the volumes was controlled with the SIC. The other volumes represented 130, 80, 60 and 33 % of that controlled by the SIC and all treatments received water at the same time. Shoot fresh weight, head diameter and stomatal conductance (gs) increased linearly with irrigation volumes. For shoot dry weight, number of leaves and water use efficiency (WUE), the regression was quadratic with maximum values at 126, 114 and 83 %, respectively. Leaf relative water content did not show variation among treatments and changes in some fluorescence parameters (Reo/RC, Sm, N and φR0) were much more remarkable to drought compared with the FV/ FM ratio, one of the most commonly used stress indicators. The data indicated a tradeoff between WUE and plant growth thus the economic values of water and lettuce should be taken into account to indicate the best SIC irrigation volume. Organic potponics is promising and should be further improved to save on water, labor and fertilizer use.

Plantas de sol e sombra são frequentemente distinguíveis por diversos aspectos anatômicos. Não obstante, propomos que entre bromélias-tanque, mudanças na arquitetura da roseta satisfazem os requerimentos que permitem habitar extremos de luminosidade. A bromélia-tanque, Neoregelia cruenta naturalmente coloniza microhabitats que variam da exposição direta ao sol, a ambientes sombreados sob o dossel da vegetação de restinga. Quantifi camos aspectos anatômicos e morfológicos das folhas e rosetas de N. cruenta crescida sob sol e sombra. Células com paredes onduladas no parênquima aquífero são pela primeira vez descritas na família. No sol, as folhas são mais largas, menores e amareladas. O diâmetro da roseta é menos que a metade daquele de plantas de sombra. Folhas de sol se sobrepõem pela maior parte do seu comprimento, formando uma roseta cilíndrica que acumula água. Folhas de sombra somente se sobrepõem na base. A maioria dos aspectos anatômicos são similares sob ambas as condições de crescimento. Estômatos são ausentes na base de folhas de sol, provavelmente em função da limitação de trocas gasosas nessa região. Os dados sugerem que a habilidade de N. cruenta em aclimatar a condições de sol e sombra é melhor explicada por mudanças na arquitetura da roseta que por mudanças anatômicas.

Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.

Hypnea musciformis (Wulfen) JV Lamour. is a species of great economic interest as it produces Κ-carrageenan and has shown biological activities against HIV and HSV viruses. This species displays different colour strains in its natural habitat, which may have implications for the biotechnological potential of the species. The aim of this study was to characterize the photosynthetic apparatus and pigment profile of three colour strains of H. musciformis (green, brown and red) in their natural habitat and in culture. Chlorophyll a fluorescence of photosystem II was measured with a pulse-amplitude modulated fluorometer and pigments were quantified by spectrofluorimetry (chlorophyll a) and spectrophotometry (phycobiliproteins). In the natural habitat, we detected significant differences between the colour strains for the following photochemical parameters: the green strain had a higher effective quantum yield (ΦPSII) than the red strain and a higher maximum relative electron transport rate (rETRmax) than the brown and red strains. Saturation irradiances were 1000 µE.m-2.s-1 (green) and 500 µE.m-2.s-1 (brown and red). Concerning in vitro culture, the green strain presented the lowest ΦPSII, rETRmax, and α rETR, while the brown strain presented the highest values for these same parameters. The chlorophyll a content of the cultured green strain was the lowest. The phycoerythrin contents of the three colour strains were unchanged by either natural of in vitro conditions: lower in green, intermediate in brown and higher in the red strain, ensuring the chromatic identity of the strains. Our results suggest that the green strain has a better performance when exposed to high irradiance, but a lower efficiency under low irradiance compared to the brown and red strains.

O desempenho fotossintético de três grupos distintos de macroalgas marinhas, Ulva fasciata Delile (alga verde), Lobophora variegata (J. V. Lamouroux) Womersley ex E. C. Oliveira (alga parda) e Plocamium brasiliensis (Greville) M. A. Howe & W. R. Taylor (alga vermelha), foi comparado com auxílio de um fluorímetro de pulso e amplitude modulada. O potencial fotoquímico máximo do PS II (Fv/Fm) variou de 0,80 a 0,51, sendo que os menores valores foram observados em P. brasiliensis. Sob a irradiância de 400 µmol fótons m-2 s-1, o maior valor de dissipação fotoquímica (qP = 0,92 ± 0,13) foi observado para U. fasciata. A alga vermelha P. brasiliensis dissipou elevada quantidade de energia de excitação (qN = 0,56 ± 0,09), resultando em valores baixos de potencial fotoquímico efetivo do PS II (0,23 ± 0,04), e também de taxa relativa de transporte de elétrons (3,3 ± 0,7). O elevado potencial fotossintético encontrado para U. fasciata explica, parcialmente, a capacidade da espécie de crescimento rápido e de alta produtividade.

Photosynthetic performance of distinct marine macroalgae, Ulva fasciata Delile (green alga), Lobophora variegata (J. V. Lamouroux) Womersley ex E. C. Oliveira (brown alga), and Plocamium brasiliensis (Greville) M. A. Howe & W. R. Taylor (red alga), were compared using a pulse amplitude-modulated fluorometer. The maximum quantum yield (Fv/Fm) ranged from 0.80 to 0.51, and the lowest value was found in P. brasiliensis. Under 400 µmol photons m-2 s-1 irradiance, the highest value of photochemical quenching (qP = 0.92 ± 0.13) was observed for U. fasciata. The red alga P. brasiliensis dissipated high amounts of excitation energy (qN = 0.56 ± 0.09), resulting in relatively low values for the effective quantum yield of PS-II (0.23 ± 0.04), as well as for the relative electron transport rate (3.3 ± 0.7). The high photosynthetic potential found for U. fasciata partially explains the species ability for rapid growth and high productivity.

O mamoeiro, Carica papaya L. (Caricaceae) é uma espécie americana, cujos frutos são largamente consumidos em todo mundo. Devido às perdas de produção provocadas por viroses e a dificuldade em controlá-las por métodos convencionais, a espécie tem sido alvo de pesquisas de melhoramento genético envolvendo transgenia para resistência a vírus. O presente trabalho descreve a anatomia foliar de plantas de mamoeiro convencional e transgênico resistente ao vírus da mancha anelar-Papaya ringspot virus (PRSV) com inserção da capa protéica viral. As duas cultivares apresentam pecíolo com endoderme e fibras pericíclicas. As folhas são hipoestomáticas e dorsiventrais, com laticíferos acompanhando os feixes vasculares e grande concentração de idioblastos com drusas de oxalato de cálcio. A epiderme é glabra, possuindo estômatos anomocíticos e anisocíticos, com células de paredes anticlinais retas na face adaxial e levemente sinuosas na face abaxial. O presente trabalho concluiu que o processo de transformação genética não alterou as características anatômicas das folhas de C. papaya, servindo de subsídio para avaliação da conformidade anatômica da cultivar transgênica.

Papaya, Carica papaya L. (Caricaceae), is an American species, consumed worldwide. A major limitation to papaya production is attack by viruses, like the papaya ringspot virus (PRSV). Papaya has been genetically modified to increase its resistance to PRSV. The aim of this research was to compare the leaf anatomy of wild-type and genetically modified (GM) C. papaya plants to evaluate the influence of genetic modification on leaf anatomy. Wild-type and GM plants showed petiole with endodermis and pericycle fibers. The leaves are hypostomatic and dorsiventral, with laticifers along vascular system and abundant druses of calcium oxalate. The epidermis was glabrous and presented anomocytic and anisocytic stomata, straight anticlinal walls on the adaxial face and sinuous on the abaxial face. Anatomical differences between wild-type and GM C. papaya leaves were not observed. These data contribute to risk assessments regarding the anatomical conformity of GM plants.

Investigamos a comunidade e a ocupação de epífitas da floresta seca de Jacarepiá, Rio de Janeiro para entender: i) como epífitas em geral ocupam troncos das árvores; ii) como bromélias epífitas ocupam árvores suporte; iii) distribuição espacial de bromélias CAM. A coleta de dados sobre epífitas, forófitos e árvores foi baseada no método ponto quadrante central. A via fotossintética das bromélias epífitas foi determinada por espectrometria de massa. A presença de Gesneriaceae, Araceae e Cactaceae indicam umidade suficiente para permitir a presença de epífitas supostamente menos especializadas. Não houve correlação entre abundância de epífitas e diâmetro dos forófitos, e forófitos possuíram maior tamanho que árvores sem epífitas. Houve correlação entre diâmetro das árvores e abundância de bromélias e falta de correlação entre diâmetro e riqueza de bromélias. Somente uma espécie foi típica da submata e outra do dossel. Estes resultados diferem do padrão de ocupação de microsítios por epífitas, sugerindo que as copas das árvores são locais super-expostos para bromélias. A única espécie C3 (Vriesea procera (Mart. ex Schult. f.) Wittm.) estava significativamente mais exposta que as demais espécies no dossel. Se a ocorrência de CAM é relacionada à economia de água, o fato desta espécie estar sujeita a condições de maior exposição é notável. Comentários adicionais são apresentados sobre a proporção entre espécies de bromélia CAM e abundância. Em relação às formas de vida, holoepífitas ocorreram em todos os diâmetros dos forófitos ao contrário das hemiepífitas, sugerindo que holoepíftas possuem um estabelecimento melhor sucedido que hemiepífitas.

We studied the community and habitat occupation of epiphytes to understand how these plants cope with a supposedly stressful habitat: i) how general epiphytes occupy tree trunks, ii) how epiphytic bromeliads, occupy their supportive trees, iii) how CAM bromeliads are spatially distributed. The study was done in the dry forest of Jacarepiá, State of Rio de Janeiro. Data collection on epiphytes, phorophytes, and trees was based on the point-center quarter method. The photosynthetic pathway of the bromeliad species was determined using isotope ratio mass spectrometry. The presence of Gesneriaceae, Araceae, and Cactaceae indicates that some humidity is present in the area allowing the presence of supposedly less-specialized epiphytes. There was no correlation between epiphyte abundance and phorophyte diameter, and phorophytes had larger sizes than trees that do not host epiphytes. There was correlation between tree diameter and bromeliad abundance, and lack of correlation between diameter and bromeliad richness. Only one species was typical of the understorey and one was typical of the canopy, while intermediate heights were occupied by different species. The only C3 bromeliad species (Vriesea procera (Mart. ex Schult.f.) Wittm.) was significantly more exposed than the other species. If CAM occurrence is related to water economy, the fact that a C3 species is subjected to more exposed conditions is remarkable. Further comments are presented on the proportion between CAM bromeliad species and abundance in dry forest. Regarding life forms, holoepiphytes, as opposed to hemiepiphytes, showed not to be restricted by the phorophyte's diameter suggesting a more successful establishment of this life form.

RESUMO Investigamos a vegetação arbórea e a comunidade epífita da floresta seca para responder às seguintes perguntas: i) como a abundância e riqueza de epífitas ocorrem sobre os indivíduos das espécies arbóreas? ii) a abundância de forófitos depende do número de indivíduos das espécies arbóreas? iii) a abundância e riqueza de epífitas dependem do número e tamanho dos forófitos? iv) espécies arbóreas são selecionadas por espécies epifíticas? Nesta floresta, as espécies arbóreas mais abundantes é que hospedam a maioria das epífitas. Quatorze espécies arbóreas foram especialmente propensas a apresentar muitos grupos epifíticos e nove propícias a possuir várias espécies de epífitas mas não em alta abundância. O número de indivíduos arbóreos foi um bom parâmetro para estimar a abundância de forófitos e seu número foi considerado um bom parâmetro para estimar a riqueza de epífitas a ocorrerem nesta floresta seca. Quatro espécies arbóreas foram especialmente preferidas pelas duas espécies epífitas de maior abundância e freqüência na área, onde ocorreram com alta abundância. Entretanto, não houve seletividade de nenhuma espécie arbórea por epífitas raras que ocorreram na área.

ABSTRACT We investigated the arboreal vegetation and epiphytic community of a 'restinga' dry forest to answer the following questions: i) how does epiphyte abundance and richness occur on arboreal species? ii) does phorophyte abundance depend on the abundance of tree species? iii) does epiphyte abundance and richness depend on the size and abundance of phorophytes? iv) are arboreal species selected by epiphyte species? The most abundant arboreal species host most of the epiphytes. Fourteen arboreal species were especially prone to hosting many epiphyte groups and nine arboreal species were especially prone to hosting only high epiphyte richness. The abundance of arboreal species was a good surrogate to predict the number of phorophytes, and the number of phorophytes was a good surrogate to predict epiphyte abundance and epiphyte richness. Four arboreal species were especially preferred by the most abundant epiphyte species. Nevertheless, no rare epiphyte species had high abundance on any tree species.

O principal objetivo desse trabalho foi estudar as plantas úteis comercializadas em feiras livres em Petrópolis e Nova Friburgo, Rio de Janeiro, Brasil. Os dados foram coletados utilizando as técnicas de observação participante, entrevistas semi-estruturadas e listagem livre com quatro comerciantes de plantas medicinais. A partir dessas entrevistas, 115 espécies (pertencentes a 49 famílias) foram relacionadas: 94 com uso medicinal, 12 com uso religioso e 9 com uso ornamental. Trinta por cento das espécies são nativas e 72% possuem hábito herbáceo. As famílias mais representativas foram Asteraceae (26 espécies) e Lamiaceae (10 espécies). As espécies medicinais indicadas para o tratamento de doenças do sistema respiratório foram mais freqüentes durante o outono e inverno. A espécie denominada como Espinheira-santa (Clarisia cf. ilicifolia) obteve o valor mais alto de Importância Relativa (1,8) e a mais alta colocação em todas as estações do ano utilizando o cálculo Preference Ranking, embora seus níveis de eficiência e toxidez não tenham sido ainda estabelecidos. O estudo se mostrou relevante, pois visa reunir o conhecimento dos informantes sobre as espécies que comercializam em feiras livres e mercados populares no estado do Rio de Janeiro, que representa uma valiosa fonte para a bioprospecção.

The main goal of this paper was the study of the useful plants sold in the open-air fairs of Petrópolis and Nova Friburgo, Rio de Janeiro, Brazil. Data collection was obtained through participant observation, semi structured interviews and free listing with four herbalist informants. From the interviews, 115 species (belonging to 49 families) were recorded: 94 for medicinal purposes, 12 with religious application, and 9 for ornamental purposes. Thirty percent of the species were native, and 72% herbaceous. The most representative families were Asteraceae (26 species) and Lamiaceae (10 species). The medicinal species related to diseases of the respiratory system were more common during the winter and autumn. "Espinheira-santa" (Clarisia cf. ilicifolia) had the highest Relative Importance (1.8) and collocation in all seasons using the Preference Ranking, although its effectiveness or toxicity levels have not been established. The importance of the study is to gather knowledge from local herbalists about commercialized species in open-air fairs and popular markets in the Rio de Janeiro State, which represent valuable resources for bioprospection.

A viabilidade polínica do mamoeiro cultivar 'Sunrise Solo' (Carica papaya L.) foi estudada utilizando germinação in vitro e testes colorimétricos, assim como a validade dos testes colorimétricos como estimativa de viabilidade comparada àquela do teste germinativo. Os dois meios de cultura, descritos na literatura como meios eficientes para germinação da espécie, diferem basicamente pela presença de nutrientes essenciais e concentração de ágar. O meio de cultura sem elementos essenciais e com maior concentração de ágar forneceu o melhor índice de germinação polínica (65%). Os cinco corantes testados foram: 2,3,5-cloreto de trifeniltetrazólio (TTC), Alexander, carmim acético, lugol e Sudan IV. O teste de coloração com TTC forneceu estimativa de viabilidade (67,5%) equivalente ao teste de germinação in vitro e, portanto, confiável de viabilidade polínica. Os demais corantes testados superestimaram a viabilidade polínica (> 90%), porém são eficientes na determinação de constituintes celulares e da integridade do grão de pólen.

Pollen viability of Carica papaya L. 'Sunrise Solo' cultivar was estimated using in vitro germination and pollen stain tests. Two culture media described in the literature as efficient for pollen in vitro germination of C. papaya were used. Germination was higher in the media without essential elements but with a higher concentration of agar (65% compared with 51.5%). These results were compared with viability estimates based on staining pollen. The five stains used to test for pollen viability were: 2,3,5-triphenyl tetrazolium chloride - TTC, Alexander's stain, acetocarmine, iodine-potassium iodide and Sudan IV. Pollen viability estimated with TTC was 67.5% and similar to germination results providing a reliable estimate of in vitro germination. The four other stains overestimated pollen viability (> 90%), and their use should be restricted to determining cell constituents, and pollen grain integrity.