Eldo Antônio Monteiro da Silva

Bacterial adherence to different inert surfaces evaluated by epifluorescence microscopy and plate count method

The adherence of Listeria inoccua L6a and Staphylococcus aureus ATCC6538 was evaluated on stainless steel (SS), polycarbonate (PC) and polypropylene (PP) chips. The EP results showed a significant difference (p<0.05) among the microorganism species interactions, the surfaces and the contact time. The number of adhered cells on the chip surfaces increased as contact time increased and the number of L. innocua or S. aureus on the surface of SS, PC and PP chips reached 1.0x105 CFU/cm2 after 12 h of contact, in both methods. The CP method showed a better sensitivity to detect low number of adhered cells. The EP was better when the average number of adhered cells was between 10 and 100 per microscopy field.

Hyperhydricity in in vitro eggplant regenerated plants: structural characteristics and involvement of BiP (Binding Protein)

The hyperhydricity in eggplant (Solanum melongena L.) plants was monitored by the induction of the ER-luminal resident protein BiP. Although tissue culture conditions may induce BiP synthesis, the accumulation of BiP in hyperhydric shoots was consistently higher than in non-hyperhydric shoots. The leaf and stem anatomy in non-hyperhydric and hyperhydric eggplant was investigated aiming to identify structural changes associated with this phenomenon. In non-hyperhydric organs there were smaller and more organized cells, besides a more differentiated vascular system when compared with its hyperhydric counterpart. Scanning electron microscopy of leaves showed that leaf surface and stomata differentiation were also affected in hyperhydric plants.

Flúor em chuva simulada: sintomatologia e efeitos sobre a estrutura foliar e o crescimento de plantas arbóreas

Fluoride in simulated rain: symptomatology and effects on leaf structure and growth of wood plants). The objectives of this study was to characterize the effects of fluoride on seedlings and young plants of native woody species from Parque Estadual do Rio Doce (MG) and on the leaf blade structure of the most sensitive of the studied tree species. This work was carried out to gain information on diagnosing criteria for bioindication and to throw some light on the mechanisms of plant resistance and tolerance in order to assist in the revegetation programs of highly affected areas. The employed species were Gallesia gorazema Moq. (Phytolac- caceae), Genipa americana L. (Rubiaceae), Joannesia princeps Vell. (Euphorbiaceae), Peltophorum dubium (Spreng.) Taub. (Legu- minosae, Caesalpinioideae) and Spondias dulcis Forst. f. (Anarcadiaceae). Seedlings and young plants of those species were submitted to rain with dissolved fluoride (30 mg.L -1 ), during 20 min daily, for 10 consecutive days. Apical and marginal necrosis occurred in the leaf blades of all species just after the first simulated rain. Two days after treatment, S. dulcis, in the young plant stage, showed to be the most sensitive species by exhibiting large necrotic areas, while G. americana was the most resistant species. At the young plant stage, the species that accumulated more fluoride were also the most sensitive ones; such a relation was not observed in plants at the seedling stage. The pollutant at the level employed caused drastic alterations in the leaf blade of S. dulcis and also damaged all of its anatomical structure. The high susceptibility of S. dulcis to fluoride suggests that this species possess potential features to be employed as a bioindicator. However, for a better characterization of the responses of S. dulcis to fluoride and its usage in biomonitoring programs, more studies are required. RESUMO - (Fluor em chuva simulada: sintomatologia e efeitos sobre a estrutura foliar e o crescimento de plantas arboreas). Os objetivos deste trabalho foram: caracterizar os efeitos do fluor em especies arboreas nativas, nos estadios de plântula e muda; identificar injurias provocadas pelo fluor na estrutura da lâmina foliar da especie mais sensivel; fornecer subsidios para selecao de caracteristicas a serem utilizadas na bioindicacao; e contribuir com informacoes sobre a resistencia ou tolerância das plantas, visando ao reflorestamento de areas impactadas pela chuva com fluor. As especies analisadas foram Gallesia gorazema Moq. (Phytolaccaceae), Genipa americana L. (Rubiaceae), Joannesia princeps Vell. (Euphorbiaceae), Peltophorum dubium (Spreng.) Taub. (Leguminosae, Caesalpinioideae) e Spondias dulcis Forst. f. (Anacardiaceae). Plântulas e mudas dessas especies, provenientes do Parque Estadual do Rio Doce (MG), foram submetidas a 20 min diarios de chuva com fluor (30 mg.L -1 ), por 10 dias consecutivos. Necroses apicais e marginais foram observadas em todas as especies analisadas, logo apos a primeira chuva simulada. S. dulcis, no estadio de muda, foi a especie mais sensivel ao fluor, pois apresentou extensas necroses com apenas dois dias de tratamento, enquanto que G. americana foi a especie mais resistente. Nas mudas, as especies que acumularam mais fluor foram tambem as que apresentaram maior sensibilidade a esse poluente; essa relacao nao foi verificada nas plântulas. A concentracao de fluor utilizada promoveu alteracoes drasticas na lâmina foliar de S. dulcis com extensas areas necrosadas, danificando toda a sua estrutura anatomica. A sensibilidade ao fluor observada em S. dulcis indica que essa especie apresenta potencial para ser usada como bioindicadora. Entretanto, estudos detalhados serao necessarios para a melhor caracterizacao das respostas de S. dulcis ao fluor visando a sua utilizacao em programas de biomonitoramento ambiental.

Somatic embryogenesis from immature zygotic embryos of annatto (Bixa orellana L.)

SummaryIn order to establish a protocol for somatic embryogenesis of annatto, Bixa orellana L., seeds (70 d after anthesis) from field-grown orchards had their coats dissected off, and immature zygotic embryos were excised aseptically from immature seeds collected from field-grown trees and used as explants. Embryos were cultured onto MS medium supplemented with or without different combinations of plant growth regulators and activated charcoal. Direct somatic embryogenesis was induced on explants incubated either in Murashige and Skoog (MS), 2,4-dichlorophenoxyacetic acid (2,4-D), and/or kinetin-supplemented media after 25 d of culture. The highest frequencies of embryogenesis and embryos per explant were obtained on medium containing 2.26 μM 2.4-D, 4.52μM kinetin, and 1.0 gl−1 activated charcoal. The presence of charcoal was critical in increasing embryos per explant, to reduce the time to obtain somatic embryos, and mainly to prevent callus proliferation and subsequent indirect somatic embryogenesis. No embryogenic response was achieved when mature embryos were used. It was also observed that embryogenic response was significantly affected by genotype. Histological investigations revealed that primary direct somatic embryos differentiated exclusively from the protodermis or together with the outer ground meristem cell layers of the zygotic embryo axis, and from the protodermis of zygotic cotyledons. Diverse morphological differences, including malformed embryos, were observed among somatic embryos. In spite of the high frequencies of histodifferentiation of all embryo stages, a very low conversion frequency to normal plants from somatic embryos was observed.

Composição química e digestibilidade in vitro de lâminas foliares e colmos de gramíneas forrageiras, em função do nível de inserção no perfilho, da idade e da estação de crescimento

Chemical composition and the in vitro dry matter digestibility were evaluated in blades and stems at two stages of development and two insertion levels on tillers of signalgrass (Brachiaria decumbens), molassesgrass (Melinis minutiflora) and tifton 85 bermudagrass (Cynodon sp), in two seasons of the year (summer and autumn). Lower and upper leaf blades were sampled from the tillers, on the day of ligule exposure and 20 days thereafter, and stems segments located below of the upper leaf blade. The crude protein contents of leaf blades showed little differences among the species, but decreased with development from 18.8 to 14.6% and level of insertion from 18.9 to 14.5% from lower to upper position. Leaf blades of higher insertion level had a greater neutral detergent fiber and lignin concentrations. The IVDMD decreased as leaf aged and exhibited greater values when situated at lower insertion level and sampled in the autumn. The IVDMD of old leaf blades were higher to tifton 85 bermudagrass and lower to signalgrass. The average values of IVDMD of stems varied from 56.7 to 62.7%, according to stage of development and season of growth. The values were 56.9, 59.6 and 60.5% for the signalgrass, bermudagrass and molassesgrass, respectively.

Ação do flúor dissolvido em chuva simulada sobre a estrutura foliar de Panicum maximum Jacq. (Colonião) e Chloris gayana Kunth. (Capim-Rhodes): Poaceae

Panicum maximum e Chloris gayana foram submetidas a chuvas simuladas com solucoes de fluoreto de potassio (15mg ml-1) com objetivo de identificar as injurias causadas pelo fluor (F-), como poluente atmosferico, na estrutura da lâmina foliar e fornecer subsidios para a selecao de caracteristicas diagnosticas a serem utilizadas na bioindicacao. Os principais sintomas foram clorose e necrose, principalmente no apice e margens das lâminas. Nos cortes transversais, quatro tipos de alteracoes causadas pelo fluor sao relacionadas: reducao do numero, tamanho e arranjo dos cloroplastos; necrose dos tecidos principalmente nas margens das folhas; erosoes na superficie da folha e hipertrofia das celulas. Em C. gayana, no entanto, nao foram observadas as alteracoes nos cloroplastos e os outros sintomas foram bem mais discretos que em P. maximum. A ocorrencia de compostos fenolicos foi registrada pela coloracao com fucsina em todas as regioes da lâmina onde foram observadas lesoes. Ao microscopio eletronico de varredura foi observado o achatamento e formacao de concavidades nas paredes externas das celulas. Este experimento confirma a maior sensibilidade de P. maximum ao fluor e revela algumas caracteristicas anatomicas de C. gayana que, entre outros fatores, podem estar contribuindo para a maior resistencia desta especie a este poluente.

Anatomia foliar como subsídio à taxonomia de Hippocrateoideae (Celastraceae) no Sudeste do Brasil

Leaf anatomy of thirteen species belonging to nine genera of the subfamily Hippocrateoideae (Celastraceae) was studied, in order to select anatomical characters to help the taxonomy at genera and species levels. The species studied were: Anthodon decussatum Ruiz & Pav., Cheiloclinium cognatum (Miers) A.C. Sm., Cheiloclinium serratum (Cambess.) A.C. Sm., Cuervea crenulata Mennega, Elachyptera micrantha (Cambess.) A.C. Sm., Hippocratea volubilis L., Peritassa flaviflora A.C. Sm., Peritassa mexiae A.C. Sm., Pristimera nervosa (Miers) A.C. Sm., Salacia crassifolia (Mart. ex Schult.) G. Don, Tontelea fluminensis (Peyr.) A.C. Sm., Tontelea leptophylla A.C. Sm. and Tontelea miersii (Peyr.) A.C. Sm. The selected anatomical characters that can be used as diagnostic for the taxonomy of the distinct genera and species are: the type of sclereids in petiole or leaf blade, stomata type, the conformation of the petiole vascular system, shape of epidermal cell walls, presence of hypodermis, occurrence of laticifers, among others.

Effects of simulated acid rain on the growth of five Brazilian tree species and anatomy of the most sensitive species (Joannesia princeps)

Seedlings and young saplings of some woody species were exposed to simulated low-pH acid rain, in order to develop a response screening for tropical tree species by determination of the symptoms of foliar injury and growth responses, as well as to identify anatomical alterations in the leaf blade of the most sensitive species. Gallesia integrifolia (Spreng.) Harms, Genipa americana L., Joannesia princeps Vell., Mimosa artemisiana Heringer & Paula and Spondias dulcis Forst.f. were exposed daily to 20 min of acid rain, pH 3.0, for 10 consecutive days. The degree of leaf damage and the anatomical alterations observed were efficient parameters to determine the sensitivity to acid rain. At the end of the experiment J. princeps was the most sensitive species as determined by foliar injury and seedling growth. The degree of leaf damage was similar among the seedlings, except in S. dulcis, which showed reduced percentage of foliar injury. Necrotic and chlorotic spots on the leaf blade occurred. In the most sensitive species, J. princeps, necrotic blade tissues showed accumulation of phenolic compounds, hypertrophy and collapsed cells. Most of the structural alterations were observed in the adaxial epidermis, the palisade parenchyma and spongy parenchyma and the abaxial epidermis. Long-term experiments with seedlings of S. dulcis and saplings of G. integrifolia are suggested, to characterise the response of these species that presented fewer symptoms but whose growth was affected under acid rain.

Características anatômicas da lâmina foliar e do colmo de gramíneas forrageiras tropicais, em função do nível de inserção no perfilho, da idade e da estação de crescimento

An experiment was carried out to evaluate the effect of leaf age and insertion level and season of growth on the tissue proportion and the cell wall thickness of leaf blade and stem segment of signalgrass (Brachiaria decumbens), molassesgrass (Melinis minutiflora) and Tifton 85 bermudagrass (Cynodon sp). Leaf blades from bottom and top layers were sampled on the day of ligule exposure and 20 days later. The relative proportion of epidermis, xylem, phloem, parenchyma bundle sheath, sclerenchyma, stem parenchyma and leaf blade mesophyll were estimated. The thickness of cell wall of metaxylem vessels and sclerenchyma were evaluated. Leaf tissue proportion changed neither with age nor season of growth; thickness of leaf sclerenchyma cell wall was the only trait to change with age. Leaf from the top layer showed higher proportion of sclerenchyma, parenchyma bundle sheath and xylem as well as thicker cell wall in sclerenchyma and metaxylem; while leaves from the bottom layer had higher proportion of mesophyll and thinner sclerenchyma and metaxylem cell walls. While the parenchyma proportion of the stem decreased, the relative area of the sclerenchyma and the cell wall thickness increased as the plant aged. These traits showed greater values in summer samples.

Aspectos morfofisiológicos das cultivares de cafeeiro Catuaí-Vermelho e Conilon

n The objective of this work was to compare plants of the Coffea arabica†L. cv.†CatuaI- Vermelho and C.†canephora Pierre cv.†Conilon species in relation to the net photosynthesis rate and aspects of leaf anatomy. Coffea canephora plants presented higher net photosynthetic rate, transpiratory rate and leaf conductance rate than C.†arabica plants, which presented smaller photochemical capacity of photosystem†I, and shorter and thicker leaves than C.†canephora. Both species differed also in rela- tionship to the type, number and dimensions of stomata in the leaf epiderm: they are paracytics in C.†arabica and actinocytics in C.†canephora, and they are larger, but in smaller number in C.†arabica.