Total wax and n-alkane profiles from fruit and leaf waxes of Malpighia glabra L.

Malpighia glabra L., conhecida popularmente como acerola, é uma espécie economicamente importante devido ao elevado nível de ácido ascórbico (vitamina C) em seus frutos. A cera cuticular afeta o armazenamento do fruto pós-colheita. No entanto, não há dados disponíveis sobre a composição das ceras nessa espécie. Teor de cera total e perfil de n-alcanos foram estudados em três genótipos diferentes de acerola. A quantidade de cera total variou de 11 µg.cm-2 a 24 µg.cm-2 nas folhas e nos frutos de 10 µg.cm-2 a 30 µg.cm-2. Dois dos três genótipos apresentaram diferenças significativas entre os teores de cera dos frutos e das folhas. O tipo A (epicarpo amarelo) apresentou a maior quantidade de cera tanto nas folhas como nos frutos. O perfil de n-alcanos nos frutos variou de C18-C34, sendo n-pentacosano (C25) o homólogo principal na maioria dos indivíduos. A cera cuticular foliar apresentou um perfil de n-alcanos com distribuição mais restrita, com os homólogos C22-C33 como componentes majoritários. Os homólogos de cadeia curta foram detectados sempre em quantidades menores do que 1%. O n-hentriacontano (C31) foi o n-alcano principal na cera foliar. Implicações econômicas e ecológicas relacionadas à quantidade das ceras cuticulares e ao perfil de n-alcanos são discutidas.Malpighia glabra L., popularly known as "acerola" or Barbados cherry, is an economically important species due the high levels of ascorbic acid (vitamin C) in its fruits. Cuticular wax affects post-harvest storage. Nevertheless, no data are available for wax composition on this species. Crude wax amount and n-alkane profiles have been evaluated for three distinct genotypes of acerola. The total amount of wax ranged from 11 µg.cm-2 to 24 µg.cm-2 on leaves and 10 µg.cm-2 to 30 µg.cm-2 on fruits. Two of the three genotypes presented statistically distinct totals for leaf and fruit-wax. Type A (yellow epicarp) presented the highest amounts of crude wax on both leaves and fruits. n-Alkanes ranged from C18 to C34 in fruits, with n-pentacosane (C25) as the main homologue of most individuals. Narrower n-alkane distribution was found in cuticular foliar wax, with C22-C33, with n-hentriacontane (C31) as the major component of most individuals. The environmental and economical aspects related to total wax amounts and n-alkane profiles are discussed herein

Efeito do Cowpea aphid-borne mosaic virus sobre crescimento e variação quantitativa de fenois totais e flavonoides de Passiflora edulis Sims

Cowpea aphid-borne mosaic virus induz o endurecimento do pericarpo do fruto, nanismo, mosaico foliar e bolhas em plantas de maracujá. Os teores totais de fenois e flavonoides de folhas sadias e artificialmente infectadas foram quantificados pelo método de Folin-Ciocalteu e reação com cloreto de alumínio. Alturas de todas as plantas foram medidas no início e no final do experimento. As plantas infectadas apresentaram alturas 80% menores do que as plantas sadias. Não houve diferença estatística nos teores de fenois totais e de flavonoides entre tratamentos

Cuticle structure and chemical composition of waxes in Phaeoceros laevis (L.) Prosk (Notothyladaceae, Anthocerotophyta)

The development of a hydrophobic cuticle covering the epidermis was a crucial evolutionary novelty ensuring the establishment of land plants. However, there is little information about its structure and chemical composition, as well as its functional implications in avascular lineages such as Anthocerotophyta. The main goal of the present study was to compare the gametophyte and sporophyte cuticles of Phaeoceros laevis. Semithin sections were analyzed through light microscopy (LM), cuticle structure was evaluated by transmission electron microscopy (TEM) and epicuticular wax morphology was analyzed by scanning electron microscopy (SEM). Total waxes were analyzed by CG/MS, and the components were identified based on the mass spectra. A thin lipophilic layer was detected on the sporophyte surface, structured as a stratified cuticular layer, similar to the well-known structure described for vascular plants. On the other hand, the gametophyte cuticle was observed only with TEM as a thin osmiophilic layer. SEM analyses showed a film-type wax on the surface of both life phases. The wax layer was eight-fold thicker on the sporophyte (0.8 µg cm(-2)) than on gametophyte (0.1 µg cm(-2)). Possible mechanical and/or drought protection are discussed. Fatty acids, primary alcohols, and steroids were identified in both life phases, while the kauren-16-ene diterpene (3%) was detected only on the sporophyte. Although no alkanes were detected in P. laevis, our findings unveil great similarity of the sporophyte cuticle of this hornwort species with the general data described for vascular plants, reinforcing the conservative condition of this character and supporting the previous idea that the biosynthetic machinery involved in the synthesis of wax compounds is conserved since the ancestor of land plants

Ceras foliares epicuticulares de espécies congêneres da mata e do cerrado

Espécies de cerrado e mata foram analisadas quanto à sua composição em ceras foliares epicuticulares e de seus componentes hidrocarbonetos. Observou-se nas espécies de cerrado uma tendência a teores de ceras pouco maiores que os de espécies de mata estacionai semidecídua. A porcentagem de hidrocarbonetos nas ceras foi maior na maioria das espécies de mata que nas espécies congêneres de cerrado. Pela análise em CG, os hidrocarbonetos mostraram predominância de C29 e C31 apresentando um comprimento médio da cadeia de carbono dos homólogos menos variável em espécies de mata, em torno de 30,5, que de cerrado nas quais este valor variou de 28,5 a 31,3. Os resultados são discutidos em relação ao provável papel ecológico das ceras e sua aplicação como marcadores taxônomicos

Determination of sulfate in algal polysaccharide samples: a step-by-step protocol using microplate reader

Algal polysaccharides exhibit a wide range of biological activities and potential applications. Many of these bioactivitiescorrelate positively with the presence of sulfate groups on the polysaccharides. The most common method used forsulfate quantification in algal samples is the turbidimetric method using the barium chloride-gelatin reagent. However,the original procedure is difficult to adapt for routine analysis since it is laborious and time-consuming. An optimizedmethod was established using 96-well microplates, with the advantage of reducing waste and discrimination betweenorganic and inorganic sulfates. This proposed method produced the same accuracy as the original