Foliar Limb Research Articles

ANATOMICAL ASPECTS OF THE STEM AND LEAF OF MENTHA x PIPERITA L. (LAMIACEAE)

Mentha x piperita (Lamiaceae) has been known since ancient times due to its aromatic and therapeutic properties. The differences in essential oil composition among the members of the genus Mentha offer a diversity of strains with high contents of menthone, menthol, carvone, linalool, or other valued terpenoid components synthesized by the mevalonic acid pathway. The species was analyzed anatomically. As biologic material, stems and leaves have been sampled from crops, during the vegetation period, before blooming. From an anatomical point of view, transverse sections were made through stems and leaves. At the level of the epidermis, both in the stem and in the leaf, the secretory and the tector trichomes were highlighted. The foliar limb is hypostomatic, with stomata in the inferior epidermis, the stomata being of the diacitic type. The mesophilus of the foliar is bifacial, having palisadic tissue with a single layer of cells, located under the superior epidermis and lacunar tissue, located under the inferior epidermis.

Cephaleuros virescens in Brazilian Mahogany: Algae Parasitic Disease Threatening an Important Reforestation Tree

The forest species are frequent targets of diseases. In this context, the plant-parasitic algae comprise a separate group in this process, including the algae genus Cephaleuros, which attacks mahogany cultivars. The objective of this work was to accomplish the molecular and morphological characterization of the causal agent of algae spots occurring in Brazilian mahogany (Swietenia macrophylla). Somatic and reproductive algae structures contained in lesions on the leaves had the DNA extracted and amplified by primers 18SHf and 18SLr of the rRNA nuclear gene 18S. Then, the amplicons were purified and sequenced. The algae structures too were characterized under light microscope. In addition, a total of 12 injured leaves located in the lower third of each attacked tree were randomly extracted for lesion characterization according to its size and number. After algae structures measurements, sporangiophores and sporangia had 260.2 x 12.9 μm and 25 x 18.8 μm. These measurements, combined with the molecular identification, indicated that the algae found in Brazilian mahogany leaves is C. virescens. Attacked leaves showed an average of 33 lesions, 60% of which were smaller than 2 mm in diameter, which shows great capacity of the pathogen to reach different parts of the foliar limb. These measurements, combined with molecular identification, confirmed the algae found in Brazilian mahogany leaves to be C. virescens.

Anatomic Characterization and Photosynthetic Rate in Cotton Genotypes due the Mepiquat Chloride

The FMT 701 and Fibermax 966 genotypes of the herbaceous cotton plants showed distinct morphophysiological characteristics due to their unique genetics. Henceforth, they are likely to have differences both in the foliar anatomic characters and in the photosynthetic apparatus due to the application of the mepiquat chloride (MC) growth regulator. The goal of the present work was to assess two genotypes of cotton plants with unique genetic characteristics through the application of increasing doses of MC by means of anatomic analyses of the foliar limb. The experiment was led in field conditions in the region of Cerrado, and experimental delineation employed was the randomized blocks, in a 5 × 2 factorial scheme totaling 10 treatments, with 4 repetitions making up a total of 40 parcels. MC was applied through foliar route, parceled in three applications performed 50, 60 and 70 days after the emergence, and such treatments consisted of the application of fours doses of MC (500; 1,000; 1,500; 2,500 mL ha-1) and a witness. The results obtained from the FMT 701 and Fibermax 966 genotypes suggest that MC exerted distinct influence upon the thicknesses of the adaxial and abaxial epidermises, palisade and lacuna parenchyma and the total thickness of both the internervural region and the region next to the central nervure. The number of adaxial stomata was reduced due to the doses of MC, exerting influence upon the photosynthetic rate in both genotypes.

Morphological and histological aspects of Solanum tuberosum plants infested by Macrosiphum euphorbiae aphids

Despite the important yield loss caused by Macrosiphum euphorbiae on potato crops, little is known about its direct effect on Solanum tuberosum plant. These phloemophagous insects use their piercing mouthparts (stylets) to follow intercellular pathway till reaching phloem sap. Consequently, host cells are punctured and aphid saliva is injected periodically to seal off the pores. Thus, host tissues are challenged by both mechanical wounding as well as salivary compounds delivered by aphids which might elicit or prevent the early defence responses. Our results display the main symptoms of compatible interaction between M. euphorbiae and its host plant S. tuberosum characterized at macroscopic and microscopic levels. Polyphenol deposits such as lignin and suberin associated with salivary sheath appear within 72 h after infestation resulting in cell wall thickening. Callose deposition was induced earlier in the apoplasm of epidermal and mesophyll cells beneath the feeding site and in the sieves tubes of distal leaves. Continuous aphid feeding led to a remarkable repression of callose in the mesophyll that appears to be co-localized with polyphenols surrounding the aphid stylet track. At high aphid density, localized cell death was observed on the foliar limb resulting in a drastic reduction of aphid’s growth at 4 days. Our results indicate that plant symptoms are tightly dependant on modality and time of aphid infestation which highlights the importance of taking all aspects into consideration when studying plant resistance to herbivores. The use of cytological approach is very promising tool for screening plants for aphid resistance.

Português

Galls are structures that show specific associations between the inductor and the host plant, which morphological, anatomical and chemical changes of the plant tissues are highlighted. This paper aimed to describe the morphology and distribution of leaf galls in Anacardium occidentale L. (Anacardiaceae). 294 leafs were collected from the branches apical portion of individuals located in the Federal University of Tocantins - Araguaina Campus, TO. Morphological analyzes were performed using stereoscopic microscope, caliper and specific bibliography. It was determined the number of galls on the foliar limb followed by the number of galls per limb and its length linear regression analysis. Conical type galls were observed crossing the leaf blade, green-colored glabrous when young and orange-red when mature, with isolated/grouped distribution and full adherence; internally it presented a lobe and inducer’s larvae (Cecidomyiidae). The distribution of galls in the limb showed significant differences (p <0.001), in descending order there was a higher number of galls between the veins (57.1%) on the secondary vein (35.7%) on the edge (6.3%) and the central vein (1.2%); Linear regression analysis showed weakly positive (r2 = 0.03; Pearson's correlation coefficient = 0.2025), suggesting that oviposition is associated in part with the foliar limb size and that other variables can be decisive. These are the first records of galls in A. occidentale in the State of Tocantins.

Xanthomyrtus wendaesp. nov. (Myrtaceae), une espèce nouvelle de Papouasie

Xanthomyrtus wendae sp. nov. (Myrtaceae), a new species from Papua.A new species, Xanthomyrtus wendae Danet, sp. nov. recently discovered in the Indonesian province of Papua is described and illustrated. It can be separated from X. grandiflora A.J.Scott by having wider sepals, subglabrous twigs, a shorter petiole, a smaller and glabrous foliar limb.

First Report of Plectosphaerella cucumerina on Greenhouse Cultured Wild Rocket (Diplotaxis tenuifolia) in Italy.

During spring 2012, symptoms of an unusual leaf spot disease were observed in several commercial greenhouses near Salerno (southern Italy) on plants of Diplotaxis tenuifolia (cv Selvatica). The first symptoms on leaves of affected plants consisted of small (1 mm) black-brown spots of irregular shape, later coalescing into larger spots, 1 cm in diameter. Spots were surrounded by a yellow halo, and were mostly located on the foliar limb, rib, and petiole. Affected leaves were often distorted, appearing hook-like. The disease was severe under 75 to 90% RH, at air temperature of 20 to 26°C, and caused severe production losses on about 50 ha. Particularly, affected tissues rotted quickly after packaging and during transit and commercialization of processed rocket. Diseased tissue was excised, immersed in a solution containing 1% sodium hypochlorite for 60 s, rinsed in water, then placed on potato dextrose agar (PDA) medium, containing 25 mg/l of streptomycin sulphate. After 5 days, a fungus developed producing a whitish-orange mycelium when incubated under 12 h/day of fluorescent light at 22°C. The isolates obtained were purified on PDA. On this medium, they produced hyaline elliptical and ovoid conidia, sometimes one-septate, measuring 4.5 to 9.2 × 1.7 to 3.5 (average 6.8 × 2.6) μm. Conidia were born on phialides, measuring 6.8 to 20.2 × 1.3 to 3.1 (average 16.5 × 2.1) μm. Such characteristics are typical of Plectosphaerella sp. (2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 (3) and sequenced. BLAST analysis of the 519-bp segment showed a 98% similarity with the sequence of Plectosphaerella cucumerina (GenBank Accession No. AB469880). The nucleotide sequence has been assigned the GenBank Accession JX185769. To confirm pathogenicity, tests were conducted on 45-day-old D. tenuifolia plants. Plants (21/treatment), grown in 15 liter pots (7 plants/pot) were inoculated by spraying a 1 × 106 CFU/ml conidial suspension of one isolate of P. cucumerina, prepared from 10-day-old cultures, grown on PDA. Inoculated plants were maintained in a growth chamber at 23 ± 1°C, at 90% RH for 4 days. Non-inoculated plants served as control. Inoculated plants showed the typical first leaf spots 6 days after the artificial inoculation. Four days later, spots enlarged and leaves became distorted, showing chlorosis. Non-inoculated plants remained healthy. P. cucumerina was reisolated from inoculated plants. The pathogenicity test was conducted twice with identical results. This is, to our knowledge, the first report of P. cucumerina on D. tenuifolia in Italy as well as worldwide. P. cucumerina has been described as associated with root and collar rots of other horticultural crops in southern Italy (1). Due to the importance of the crop in Italy, this disease can cause serious economic losses.

Effect of salt stress on nutrient concentration, photosynthetic pigments, proline and foliar morphology of Salvinia auriculata Aubl.

AIM: This study aimed to investigate the effects of NaCI and Na2So4 salts on Ca, CI, K, Mg N, P, S and Na content as well as on the content of photosynthetic pigments (chlorophyll-a, chlorophyll-b and carotenoids), proline content and on the foliar morphology of Salvinia auriculata Aubl. METHODS: The plants were collected in Jacu lagoon, located in the North of Rio de Janeiro State, and after a five-day-acclimation period, experiments were performed in the greenhouse with 0, 100, 200 mM concentrations of NaCI and Na2SO4 salts and the usual techniques for light and electron microscopy. RESULTS: After seven days of experiment, a decrease in the content of Ca2+, K+, Mg2+, P, N ions as well as in the content of photosynthetic pigments (chlorophyll-a,b and carotenoids) in Salvinia auriculata under saline treatments was observed. The proline content showed an upward tendency as compared to the control. Under transmission electron microscopy, it was observed that, on the foliar limb, there was a membrane system disorder, mainly of chloroplasts, with higher presence of starch grains of plant cells subjected to salinity. Under scanning electron microscope, the integrity of trichomes and foliar limb cells of Salvinia auriculata subjected to the control treatment as well as the changes caused by salinization on the surface of cells were observed. CONCLUSION: As for all the salinization effects evaluated, it was noticed that the increase in Na2SO4 salt concentration resulted in higher morphological and nutritional alterations in the floating aquatic macrophyte, Salvinia auriculata.

Características morfofisiológicas de abacaxizeiro 'gomo de mel' enraizado in vitro sob luz natural e substrato vermiculita

Objetivou-se avaliar o efeito da vermiculita, ágar, da luz artificial e a da natural no enraizamento in vitro de brotos de abacaxizeiro 'Gomo de Mel', bem como caracterizar anatomicamente essas plantas. O trabalho foi realizado no laboratório de Cultura de Tecidos Vegetais, do Departamento de Agricultura - UFLA, Lavras-MG. Foram utilizados brotos com 2 cm de comprimento, cultivados em meio MS acrescido de 30g.L-1 de sacarose. Testaram-se dois suportes físicos: 6g.L-1 de ágar e 15 g.L-1 de vermiculita para o enraizamento dos brotos em dois ambientes: sala de crescimento a 25±1 ºC, 45 W.m-2.s-1 durante 16 horas e casa de vegetação com radiação de 115,08 W.m-2.s-1 e 33 ºC (luz natural). Após 60 dias, avaliaram-se comprimento de parte aérea, massa fresca e seca de parte aérea e raízes, espessuras dos tecidos do limbo foliar, além de número, diâmetro polar e equatorial dos estômatos. O experimento foi instalado em delineamento inteiramente casualizado. Os resultados mostraram-se significativos para interação entre suportes físicos e ambientes para todas as variáveis analisadas. O uso do substrato vermiculita em luz artificial apresentou melhores resultados para todas as variáveis, exceto para número de estômatos. Para as características anatômicas, maiores espessuras dos tecidos do limbo foliar foram verificadas quando se utilizaram vermiculita e luz natural, sendo que, para o uso de ágar, também houve aumento das espessuras somente quando se utilizou o ambiente de luz natural. Quanto ao número de estômatos/mm², não houve diferença significativa para os tratamentos. Maior diâmetro polar e equatorial foi observado em estômatos de folhas cultivadas em luz artificial e vermiculita, e luz natural e vermiculita, respectivamente.

RESEARCH CONCERNING THE ADULT HARMING WAY OF DIABROTICA VIRGIFERA VIRGIFERA LE CONTE

In Romania, Diabrotica virgifera virgifera Le Conte, it has a generation a year. The activity of the adults being present in corn crops in our country since the first decade of June up to the first decade of October. The first adults appeared feed with corn leaves. The foliar attack consists in chewing the leaves as longitudinal lines, along the veins. Round the chewing places, the leaves turn yellow and dry. The foliar limb can be harmed both on the superior and the inferior side, without ant preferences for one of the leaf tissue. In the period of flowering, the adults feed with silk and pollen. They can consume the silk of a corn partially or totality. After the partial consumption of the silk the corn presents only a little lock as if it has been cut with the scissors the lack of the silk leads to a corn formation with few seeds. After flowering the adults feed with leaves, seeds in the milk phase – situated in the superior part of the corn and sometimes with brown silk. The damage is higher on basal leafs, and decrease as the leafs have a higher position on corn plant.

Anatomia dos órgãos vegetativos e histolocalização de compostos fenólicos e lipídicos em Porophyllum ruderale (Asteraceae)

Porophyllum ruderale (Asteraceae) é uma erva ruderal e aromática conhecida popularmente como couve-cravinho. Na medicina popular, é utilizada como cicatrizante e antiinflamatória, antifúngica, antibacteriana, calmante, no combate à hipertensão arterial, no tratamento de leishmaniose, no tratamento de edemas e traumatismos, no tratamento de picada de cobra, doenças reumáticas e dores em geral. A atividade cicatrizante tem sido relacionada à presença de teores variáveis de compostos fenólicos do tipo taninos. Os objetivos do trabalho foram caracterizar as estruturas secretoras quanto à histolocalização dos compostos fenólicos e lipídicos e descrever a anatomia da raiz, do caule e da folha de couve-cravinho. De cinco plantas cultivadas, em fase de prefloração, foram coletadas a raiz, o caule e a folha, os quais foram fixados em FAA 50 ou em sulfato ferroso em formalina neutra tamponada (para observação de compostos fenólicos) e submetidos ao teste com Sudan III, visando a observação de compostos lipídicos. O laminário foi obtido utilizando-se metodologia tradicional. As raízes são tetrarcas, desenvolvem estrutura secundária e apresentam ductos secretores, os quais estavam presentes no córtex. O caule possui epiderme unisseriada recoberta por cutícula relativamente espessa; o parênquima cortical é intercalado com o colênquima subepidérmico; a medula é parenquimática; e os feixes são colaterais. Nos caules, os ductos também estavam presentes, porém somente nos jovens a reação para compostos fenólicos foi positiva. Nas folhas, o contorno das células epidérmicas é sinuoso e a epiderme é unisseriada e recoberta por cutícula delgada. São evidentes duas a três camadas de colênquima subepidérmico, e imerso no parênquima fundamental está o feixe colateral. No limbo foliar, foram observados ductos delimitados por várias camadas de células epiteliais, cujo conteúdo reagiu positivamente, indicando a presença de compostos lipídicos e fenólicos. Conclui-se que os ductos do caule e do limbo foliar são provavelmente as estruturas responsáveis pela secreção de tanino e que apenas os ductos do limbo foliar são responsáveis pela secreção de compostos lipídicos.

CONTRIBUTION TO THE STUDY OF THE ANATOMICAL STRUCTURE OF ERICACEOUS LEAVES SPECIES

The anatomical structures of the leaves of two species belonging to the Romanian Ericaceous species were studied. For the Loiseleuria procumbens Desv. leaves the structure is of ericoid type, the foliar limb having the shape of T letter with thick cuticle and cuticular hairs (papilla), the palisade parenchyma with 4-5 cellular layers. In Rhododendron myrtifolium the cuticle is well developed at upper side and with a great number of secretory glands of peltate types in the lower side, the palisade parenchyma being well developed. The shape of transversal section of the leaf, the presence of secretor tissues and leaves structure may be criteria for species identity or for establishing the adulteration for Ericaceous medicinal plants.

Morpho-anatomical aspects of the epiderm in two species of Lathyrus

The paper deals with the microscopic study of the leaves epiderm in Lathyrus latifolius L. and Lathyrus odoratus L. The transversal section through the foliar limb shows slight differences between the two faces of the limb and a weak development and differentiation of the mesophyll. The epidermic cells have rectangular or polygonal shapes, with undulated walls with great and medium amplitudes in Lathyrus latifolius and medium and small ones in Lathyrus odoratus. Stomata apparatus consists of two reniform cells, with two, three, seldom four epidermic cells. Lathyrus odoratus has the ranunculaceous anomocytic type of stomata and Lathirus latifolius presents both this type and the ranunculaceous hemiparacytic type.