Arlete Marchi Tavares de Melo

Fast method for capsaicinoids analysis from Capsicum chinense fruits

Chili peppers are widely utilized in the world as savory food additives due the pungency induced by the capsaicinoids. Also, these compounds have functional properties as antimutagenic, antitumoral, antioxidant and analgesic. These characteristics increase the interest in this compound class, hence the capsaicinoid analysis must be reproducible and accurate. This study aimed to develop and validate a fast, efficient and reproducible method to analyze capsaicinoids in Brazilian Capsicum chinense fruits. The extracts were obtained after an optimization step that indicated the condition 100% of methanol and 10min on ultrasound assisted extraction. The analyses were carried out in an ultra high performance liquid chromatographic system with detection by a photo diode array and mass spectrometer. The analytical method developed permits the separation of 8 capsaicinoids in 4min of time analysis expending only 2mL of solvent as mobile phase. The validation parameters evaluated for the method show the effectiveness and satisfactory performance to answer the analytical needs of this research area, presenting low values to relative standard deviation in repeatability and reproducibility and recoveries ranged from 88 to 112% for capsaicin and 89 to 109% for dihydrocapsaicin. In the extracts from different accessions of C. chinense fruits analyzed, the contents of capsaicin and dihydrocapsaicin were in the range of 156-1442μgg-1 and 26-478μgg-1 of fresh fruit, respectively, showing the large application of this method for quantification of the two major capsaicinoids in fast routine analysis and may be used to determine the concentrations of other minor capsaicinoids once appropriate standards are available.

Interação de bactérias fluorescentes do gênero Pseudomonas e de Bacillus spp. com a rizosfera de diferentes plantas

Despite numerous reports on plant growth-promoting rhizobacteria (PGPR), there are few of them explaining their mode of action. It is possible that some plants promote bacterial colonization in the rhizosphere to facilitate plant-bacterium interaction, as if there were a certain mutual specificity. The objective of this study was to verify if lettuce plants promote root colonization by fluorescent pseudomonads, in comparison with other plants and with Bacillus spp. Roots of lettuce and some other vegetables were sampled in different properties of small commercial producers in Campinas-SP, Brazil. Colony forming units (cfu) of fluorescent pseudomonads and Bacillus spp. were counted by serial dilution and plating. The numbers of fluorescent pseudomonads were significantly higher in lettuce rhizosphere than in other plants, unlike the numbers of Bacillus spp.Embora haja muitos trabalhos na literatura com rizobactérias promotoras do crescimento de plantas (RPCPs), existem poucos que expliquem seu mecanismo de ação. É possível que algumas rizosferas favoreçam a colonização radicular por RPCPs, facilitando o estabelecimento da interação planta-bactéria, como se houvesse certa especificidade entre ambas. O objetivo deste trabalho foi verificar se a rizosfera de alface, em comparação com a de outras espécies vegetais, favorece o estabelecimento de bactérias fluorescentes do gênero Pseudomonas, em comparação com as do gênero Bacillus. Coletaram-se amostras do sistema radicular de alface, rúcula, chicória, salsa e tiririca em oito propriedades de produtores comerciais de hortaliças, na região de Campinas, SP. Foi feita a contagem de Pseudomonas spp. fluorescentes e de Bacillus spp. por diluição em série e plaqueamento. De maneira geral, observou-se maior crescimento de Pseudomonas spp. fluorescentes na rizosfera de alface-crespa em relação à de outras plantas, mas isso não ocorreu com Bacillus spp.

Rizobactérias e alface: colonização rizosférica, promoção de crescimento e controle biológico

SUMMARY : RHIZOBACTERIA AND LETTUCE: ROOT COLONIZATION,PLANT GROWTH PROMOTION AND BIOLOGICAL CONTROL Plant growth-promoting rhizobacteria (PGPR) can increase the productivity of severalcrops, including lettuce. The main objective of this study was to compare the root and/orroot collar colonizing ability on the growth promotion ability. A method of evaluation ofroot colonization was tested with the main objective of speeding up screening trials forgrowth enhancement of lettuce. Additionally, the antagonism in vitro between rhizobacteriaand the pathogen Fusarium sp. was tested to verify if growth promotion ability wasdetermined by biological control. Sixty-four bacterial isolates of fluorescent pseudomonadsfrom the rhizosphere of different lettuce varieties were tested in vitro to verify their capabilityof colonizing lettuce roots. The presence of a turbid, milky and narrow fog around the rootzone indicated bacteria colonization. Only eight isolates colonized the root system, andthirty-eight did in the root collar region, as could be evaluated by visual means. A greenhousetrial was then carried out to verify the growth promotion capacity of the isolates in lettuce.The substrate was a mixture of soil and chicken manure, similar to the one used by producers.Twelve isolates promoted growth of plants. Among those, four increased root dry weight,nine enhanced the number of leaves and eleven colonized the root collar. The antagonismassay was performed in PDA medium and King’s B medium. Although twelve isolatesshowed antagonistic activity against

Efeitos diretos e indiretos e correlações canônicas para caracteres relacionados com a produção de pimentão

O trabalho foi realizado com os seguintes objetivos: (a) estudar os efeitos diretos e indiretos de oito caracteres de planta e fruto sobre a producao de pimentao (Capsicum annuum L.), utilizando-se de analise de trilha, e (b) obter as correlacoes canonicas entre o grupo dos principais fatores de producao (peso(5) e numero total de frutos) e os grupos: (1) producao precoce-numero de frutos e producao precoce-peso de frutos; (2) comprimento, largura e numero de loculos do fruto, e (3) comprimento e largura do fruto. Empregaram-se seis genotipos de pimentao e os hibridos possiveis entre eles, obtidos mediante esquema dialelico, excluindo-se os reciprocos. Os resultados mostraram que as avaliacoes da producao de pimentao podem ser feitas nas primeiras colheitas, em vista do efeito pronunciado do carater producao precoce-peso de frutos sobre o peso total de frutos, e da significância das correlacoes canonicas entre producao precoce-numero e peso de frutos e peso total de frutos. O numero total de frutos foi o carater que apresentou maior efeito positivo sobre o peso total de frutos. Menor largura e maior numero de loculos por fruto determinaram maior peso total de frutos.

Promoção do crescimento de alface por rizobactérias

Rizobacterias promotoras do crescimento de plantas (RPCPs) podem ser uma alternativa para o aumento da produtividade de varias especies vegetais, inclusive alface. Conduziram-se quatro experimentos com isolados de rizobacterias de diversas origens para verificar sua capacidade de promocao de crescimento de plantas de alface. Ao todo, testaram-se 77 isolados de Pseudomonas do grupo fluorescente, 23 de Bacillus e 11 de outras bacterias rizosfericas em areia esterilizada, em solo esterilizado, em substrato formado por uma mistura de solo e esterco (1:1, em volume), de forma semelhante a usada pelos produtores, e em areia com a solucao nutritiva recomendada para cultivos hidroponicos, em duas concentracoes. Foi marcante o beneficio exercido pelas bacterias do genero Pseudomonas em contraposicao as dos outros generos, revelando algum favorecimento dessas bacterias na rizosfera de alface, de forma a promover melhor crescimento das plantas. Houve diferencas no comportamento dos isolados conforme a fertilidade do substrato.

Analysis of volatile compounds in Capsicum spp. by headspace solid-phase microextraction and GC × GC-TOFMS

A suitable method based on headspace solid-phase microextraction (HS-SPME), comprehensive two-dimensional gas chromatography, with a time-of-flight mass spectrometry detector (GC × GC-TOFMS) and a chemometric approach was used aimed at the investigation of the volatile fraction of Brazilian Capsicum peppers: malagueta (C. frutescens), dedo-de-moca (C. baccatum) and murupi (C. chinense). A total of 184 volatiles compounds were identified in the three pepper samples and 123 of these compounds were described in Brazilian peppers for the first time. In addition, during Brazilian chili pepper maturation, as the maturation time increases, it was noted that the majority of volatile compounds responsible for green odor notes disappeared being replaced by others with fruity notes. Chemometric analysis (PCA) was able to separate samples according to their constituents, where malagueta was characterized by branched esters, murupi by terpenes and dedo-de-moca by the presence of aldehydes and terpenes.

Características químicas de um latossolo adubado com uréia e cloreto de potássio em ambiente protegido

The production of healthy, high quality vegetables and the development of technologies for continuous supply to the market are important factors determining the adaption of protected cultivation systems by an increasing number of growers. Due to the little knowledge on soil management practices under these conditions, high fertilizer rates are normally applied, causing salinity problems and nutricional unbalances. The objective of this paper was to evaluate the effects of urea and potassium chloride applications on the chemical characteristics of an Eutrorthox, mainly on its acidity and potassium saturation. The N was applied in rates of 13.3 and 39.9g m-2 and the K in rates 5.5 and 16.6 g m-2, in a fatorial (2X2+1) design, including a control. Pepper plants (Capsicum annuum, Mayata cultivar) were grown under protected condition, during 34 weeks. After seedling rooting, the nutrients were applied at the rate of one sixth of the total at ten day intervals, up to 60 days. It was observed that urea did not acidify the soil probabily due to its high buffering capacity. The nitric and ammoniacal forms of N were directly effeted by the N rates applied in relation to the soil. In the treatment with N, the roots showed better development compared to the control. However, the highest K rate, applied as KCl, decreased root growth, probably due to the high soil K concentration and possible salinity effects, resulting in more than 5.0 mmolc dm-3 of K and more than 5.3% of K saturation in the exchange complex.

Caracterização de híbridos de pimentão em cultivo protegido

This research was carried out to study agronomic and morphological fruit characteristics of eleven sweet pepper hybrids obtained under protected cultivation conditions. The trial was conducted from November/95 to July/96 in Campinas, Sao Paulo state, Brazil. The treatments consisted of eleven hybrids which were grouped according to fruit colour, as red (Luis, Fresco, Juncal and XPH-14187), yellow (Indalo and Rupia), orange (Mandarin and Orange Wonder), purple (Cardinal and Lilac) and ivory hybrid (Ivory) groups. The following characteristics were evaluated: plant yield during one hundred days of harvest, and weight, length, width and pulp thickness of the first five marketable fruits per plant. Fresco and Luis hybrids produced the greatest yield whereas Lilac and Orange Wonder hybrids produced the lowest yield. All other hybrids displayed an intermediate performance. The greatest pulp thickness was observed in Ivory, Orange Wonder and Rupia hybrids, which differed significantly from Juncal, Luis and Cardinal hybrids. Fresco and Rupia hybrids showed the best performance in the red and yellow fruit groups, respectively.

SELEÇÃO DE TOMATEIROS RESISTENTES A TOSPOVÍRUS

Advanced progenies and cultivars of tomato have been evaluated through seven years as to local tospovirus infection at Instituto Agronomico de Campinas, in the State of Sao Paulo, Brazil. Among the germplasm considered resistant, LA 444-1 (Lycopersicon peruvianum), PI 134417 (L. hirsutum) and TSW-10 (L. esculentum x L. peruvianum) have confirmed their resistance while L. esculentum cultivars Platense, Rey de los Tempranos, Leopardo and HE-233 were susceptible. Although parentals LA 444-1 and PI 134417 presented high resistance levels, the lowest infection rates have been observed in progenies of L. peruvianum. The cultivar Stevens, developed in South Africa from L. peruvianum, has shown stable resistance to the tospovirus; some of the progenies of the cross cv. Stevens x IPA-6 have revealed resistance levels as high or even higher than that of the resistant parental (cv. Stevens) as well as desirable agronomic traits.

Resistência de linhagens avançadas de tomateiro a tospovírus

Tomato advanced lines, obtained in the IAC breeding program, were recently evaluated, under different Brazilian states producing areas to tospovirus reaction, fruit yield and soluble solid contents. In the growing season 95/96, IAC S4-3, IAC S4-4, IAC S4-13 and IAC S4-17, behaved as tospovirus resistant in Campinas, State of Sao Paulo, and Petrolina, State of Pernambuco; IAC S4-17, in the last site, showed productivity levels similar to that of AG-45, which is highly productive but susceptible to the disease. During the growing season 96/97, evaluation carried out under greenhouse conditions, in Campinas, showed that the ten selections above mentioned lines presented higher levels of Tospovirus resistance as compared to other tomato lines derived from different resistance sources. Nine new lines selected within the IAC S4-group were tested under field trials (Campinas), during the growing season 97/98, and compared to cultivars Colosso (SVS), Stevens and IPA-6 and four SVS lines. Tospovirus infection levels varied from 8.6% (IAC S4-4-16G) to 100% (IPA-6), with cultivars Stevens and Colosso reaching 31.7% and 70.3%, respectively. Also in 97, under field conditions in Patos de Minas, State of Minas Gerais, tomato lines IAC S4-3-10 and IAC S4-3-18H presented soluble solid contents similar to that of AG-45, considered outstanding for the character. They also showed higher fruit yields than cultivars AG-45 and IPA-5, although showing excessively late flowering and fruit maturing cycles.