Natural elicitors enhanced suberin polyphenolic accumulation in wounded potato tuber tissues.

Introduction: Unintended wounding or bruising during harvest or postharvest handling leads to significant tuber loss and imposes economic burden to potato industry. Therefore, finding effective strategies to mitigate wound-related tuber losses is very important from industry perspectives. Formation of protective barrier through accumulation of suberin polyphenolics (SPP) is a natural and initial response of potato tuber tissues to wounding. Materials and methods: In this study, efficacy of two natural elicitors, such as chitosan oligosaccharide (COS 0.125 g L-1) and cranberry pomace residue (Nutri-Cran 0.125 g L-1) was investigated using a mechanically wounded tuber tissue model and by histological determination of SPP formation in five agronomically relevant and red-skin potato cultivars (Chieftain, Dakota Rose, Dakota Ruby, Red LaSoda, Red Norland). Furthermore, the potential role of stress protective metabolic regulation involving phenolic metabolites, proline, and antioxidant enzymes in tuber WH processes were also investigated during 0-9 days after wounding. Results and discussion: Exogenous treatments of both COS and Nutri-Cran resulted into enhanced SPP formation in wounded surface, but the impact was more rapid with Nutri-Cran treatment in select cultivars. Greater contents of total soluble phenolic, ferulic acid, chlorogenic acid, total antioxidant activity, and superoxide dismutase activity were also observed in elicitor treated tuber tissues at different time points after wounding. Nutri-Cran treatment also reduced the activity of succinate dehydrogenase in Red Norland and Dakota Ruby at 3 d, indicating a suppression in respiration rate. Collectively, these results suggest that Nutri-Cran can be potentially utilized as an effective WH treatment to potato tubers for minimizing wound-related losses.

Transcriptomic and metabolomic changes in postharvest sugarbeet roots reveal widespread metabolic changes in storage and identify genes potentially responsible for respiratory sucrose loss.

Endogenous metabolism is primarily responsible for losses in sucrose content and processing quality in postharvest sugarbeet roots. The genes responsible for this metabolism and the transcriptional changes that regulate it, however, are largely unknown. To identify genes and metabolic pathways that participate in postharvest sugarbeet root metabolism and the transcriptional changes that contribute to their regulation, transcriptomic and metabolomic profiles were generated for sugarbeet roots at harvest and after 12, 40 and 120 d storage at 5 and 12°C and gene expression and metabolite concentration changes related to storage duration or temperature were identified. During storage, 8656 genes, or 34% of all expressed genes, and 225 metabolites, equivalent to 59% of detected metabolites, were altered in expression or concentration, indicating extensive transcriptional and metabolic changes in stored roots. These genes and metabolites contributed to a wide range of cellular and molecular functions, with carbohydrate metabolism being the function to which the greatest number of genes and metabolites classified. Because respiration has a central role in postharvest metabolism and is largely responsible for sucrose loss in sugarbeet roots, genes and metabolites involved in and correlated to respiration were identified. Seventy-five genes participating in respiration were differentially expressed during storage, including two bidirectional sugar transporter SWEET17 genes that highly correlated with respiration rate. Weighted gene co-expression network analysis identified 1896 additional genes that positively correlated with respiration rate and predicted a pyruvate kinase gene to be a central regulator or biomarker for respiration rate. Overall, these results reveal the extensive and diverse physiological and metabolic changes that occur in stored sugarbeet roots and identify genes with potential roles as regulators or biomarkers for respiratory sucrose loss.

Carbohydrate metabolism dynamic in chlorpropham- and 1,4-dimethylnaphthalene-treated potatoes and its effect on the browning of French fries.

The use of a sprout suppressor is crucial for the use of potatoes beyond their natural dormancy period. The main sprout inhibitor used on a commercial scale, chlorpropham (CIPC), is becoming increasingly limited owing to its toxicity. Therefore, we evaluated the effectiveness of 1,4-dimethylnaphthalene (1,4-DMN) compared to CIPC in controlling sprouting and maintaining the quality of potato, Solanum tuberosum 'Asterix', during cold storage. Treatment with 1,4-DMN reduced fresh weight loss and controlled the number and length of sprouts comparable to CIPC. Compared to the control, both sprouting inhibitors led to higher starch and lower reducing sugar contents, and the tubers retained the recommended quality for industrial processing. After frying, less browning was observed in French fries obtained from 1,4-DMN- or CIPC-treated tubers. We ascertain that 1,4-DMN besides being an efficient sprouting inhibitor and alternative to CIPC, it contributes to maintaining the quality of French fries after cold storage.

Wounding rapidly alters transcription factor expression, hormonal signaling, and phenolic compound metabolism in harvested sugarbeet roots.

Injuries sustained by sugarbeet (Beta vulgaris L.) roots during harvest and postharvest operations seriously reduce the yield of white sugar produced from stored roots. Although wound healing is critically important to reduce losses, knowledge of these processes is limited for this crop as well as for roots in other species. To better understand the metabolic signals and changes that occur in wounded roots, dynamic changes in gene expression were determined by RNA sequencing and the activity of products from key genes identified in this analysis were determined in the 0.25 to 24 h following injury. Nearly five thousand differentially expressed genes that contribute to a wide range of cellular and molecular functions were identified in wounded roots. Highly upregulated genes included transcription factor genes, as well as genes involved in ethylene and jasmonic acid (JA) biosynthesis and signaling and phenolic compound biosynthesis and polymerization. Enzyme activities for key genes in ethylene and phenolic compound biosynthesis and polymerization also increased due to wounding. Results indicate that wounding causes a major reallocation of metabolism in sugarbeet taproots. Although both ethylene and JA are likely involved in triggering wound responses, the greater and more sustained upregulation of ethylene biosynthesis and signaling genes relative to those of JA, suggest a preeminence of ethylene signaling in wounded sugarbeet roots. Changes in gene expression and enzymes involved in phenolic compound metabolism additionally indicate that barriers synthesized to seal off wounds, such as suberin or lignin, are initiated within the first 24 h after injury.

Handmade solar dryer: an environmentally and economically viable alternative for small and medium producers.

The solar dryer can reduce production costs, energy consumption, waste (use fruits outside the quality standard for fresh consumption) and is an alternative for small and medium producers. The solar dryer can reduce costs and is an alternative for small and medium producers worldwide. The consumption of fresh and processed tomatoes is high in the world, but post-harvest losses is also and drying is an alternative to reduce these losses. The temperature maintenance and drying time corresponds 30% of the costs. The objective was evaluated the tomato physicochemical characteristics after drying in handmade solar dryer. 'Carmen' tomato fruits were bleached in water, 2.5% NaCl solution, 2.5% NaCl + 0.5% CaCl2 solution and unbleached. Tomato slices were placed in a handmade solar dryer from 7:00 to 17:00. The solar dryer prototype was wood made, comprising a collector and a drying chamber. The average cost of the camera was US$ 13.08 (1 Brazilian Real = 0.26 United States Dollar). Water loss, drying kinetics, mathematical models and physicochemical characteristics of fresh and dried tomatoes were evaluated. The average length of solar drying for the four treatments was 30 h and the Midilli and Kucuk mathematical model was the most adjusted. The acidity, reducing sugars and soluble solids were concentrated by drying, while ascorbic acid was reduced. The pH did not change. Tomatoes 'Carmen' can be dried in a handmade solar dryer for 30 h while maintaining product quality.

Methyl jasmonate effects on sugarbeet root responses to postharvest dehydration.

BACKGROUND: Sugarbeet (Beta vulgaris L.) roots are stored under conditions that cause roots to dehydrate, which increases postharvest losses. Although exogenous jasmonate applications can reduce drought stress in intact plants, their ability to alleviate the effects of dehydration in postharvest sugarbeet roots or other stored plant products is unknown. Research was conducted to determine whether jasmonate treatment could mitigate physiological responses to dehydration in postharvest sugarbeet roots. METHODS: Freshly harvested sugarbeet roots were treated with 10 µM methyl jasmonate (MeJA) or water and stored under dehydrating and non-dehydrating storage conditions. Changes in fresh weight, respiration rate, wound healing, leaf regrowth, and proline metabolism of treated roots were investigated throughout eight weeks in storage. RESULTS: Dehydrating storage conditions increased root weight loss, respiration rate, and proline accumulation and prevented leaf regrowth from the root crown. Under dehydrating conditions, MeJA treatment reduced root respiration rate, but only in severely dehydrated roots. MeJA treatment also hastened wound-healing, but only in the late stages of barrier formation. MeJA treatment did not impact root weight loss or proline accumulation under dehydrating conditions or leaf regrowth under non-dehydrating conditions. Both dehydration and MeJA treatment affected expression of genes involved in proline metabolism. In dehydrated roots, proline dehydrogenase expression declined 340-fold, suggesting that dehydration-induced proline accumulation was governed by reducing proline degradation. MeJA treatment altered proline biosynthetic and catabolic gene expression, with greatest effect in non-dehydrated roots. Overall, MeJA treatment alleviated physiological manifestations of dehydration stress in stored roots, although the beneficial effects were small. Postharvest jasmonate applications, therefore, are unlikely to significantly reduce dehydration-related storage losses in sugarbeet roots.

Ideal temperature and storage period for commercial potato cultivars selected for frying / Temperatura e período de armazenamento ideais para cultivares comerciais de batata selecionadas para fritura

ABSTRACT: Potatoes for industrial processing must have high dry matter, low sugar and free from damage or disease. The objective was to determine the ideal temperature and storage period of commercial cultivars for frying. Tubers of Asterix and Cronos cultivars were stored in a cold chamber (Gallant CMC4 Premium) inside plastic boxes at 6 and 8 °C with 85 to 95% humidity for 180 days. Accumulated mass loss (PMA), alcohol insoluble solids (SIA), total soluble sugars (AST), non-reducing sugars (ANR), reducing sugars (AR), polyphenoloxidase activity (PPO) and enzymatic and non-enzymatic browning were analyzed. The PMA of Asterix at 6 and 8 ºC and Cronos at 6 °C was higher. The SIA of both cultivars stored at 6 ºC were lower and AST, AR and ANR higher. Those parameters of Cronos and Asterix did not differ between temperature or storage period. The browning was greater in the fried sticks of Asterix and Cronos stored at 6 ºC (4 to 5) for 60 and 90 days and at 8 °C (2 to 3) for 180 days, respectively. The ideal temperature and storage period for Asterix and Cronos cultivars is 8 ºC for a maximum of 120 days due to non-enzymatic browning.

RESUMO: As batatas destinadas ao processamento industrial devem ter alto teor de matéria seca, baixo teor de açúcar e estar livre de danos ou doenças. O objetivo foi determinar a temperatura e o período de armazenamento ideais para cultivares comerciais para fritura. Os tubérculos das cultivares Asterix e Cronos foram armazenados em caixas de plástico a 6 e 8 °C com umidade de 85 a 95% por 180 dias. As perdas de massa acumulada (PMA), sólidos insolúveis em álcool (SIA), açúcares solúveis totais (AST), açúcares não redutores (ANR), açúcares redutores (AR), atividade de polifenoloxidase (PPO) e escurecimento enzimático e não enzimático foram analisadas. A PMA de tubérculos da cultivar Asterix a 6 e 8 ºC e a da cultivar Cronos, armazenadas a 6 °C foram maiores. Os teores de SIA foram menores e os de AST, AR e ANR maiores nos tubérculos de ambas as cultivares armazenadas a 6 ºC. A temperatura e o período de armazenamento não afetaram as cultivares Cronos e Asterix. O escurecimento foi maior nos palitos fritos das cultivares Asterix e Cronos armazenados a 6 ºC (4 a 5) por 60 e 90 dias e a 8 °C (2 a 3) por 180 dias, respectivamente. O período ideal de temperatura e armazenamento para as cultivares Asterix e Cronos é de 8 ºC por, no máximo, 120 dias devido ao escurecimento não enzimático.

Sucrose degradation pathways in cold-induced sweetening and its impact on the non-enzymatic darkening in sweet potato root.

This study investigated sucrose catabolism during cold-induced sweetening (CIS) and its impact on the quality of sweet potato chips of cultivars with varied levels of tolerance to cold during storage at 6 and 13 °C. In contrast to cultivar Beauregard, cultivar BRS Rubissol and BRS Cuia were cold-sensitive exhibiting intense symptoms of chilling injury at 6 °C. CIS in the sensitive cultivars BRS Rubissol and BRS Cuia was characterized by low accumulation of reducing sugar (RS), high non-reducing sugars content, low invertase activity and high sucrose synthase (SuSy) activity. In the tolerant cultivar Beauregard, the high content of RS was due to high invertases activity. In the three cultivars, the darkening of chips was more influenced by the non-reducing sugars, instead of RS. Our results suggest that SuSy was induced by cold stress in cold-sensitive cultivar, but did not contribute to the CIS in sweet potato.

Selenium-Ethylene Interplay in Postharvest Life of Cut Flowers.

Selenium (Se) is considered a beneficial element in higher plants when provided at low concentrations. Recently, studies have unveiled the interactions between Se and ethylene metabolism throughout plant growth and development. However, despite the evidence that Se may provide longer shelf life in ethylene-sensitive flowers, its primary action on ethylene biosynthesis and cause-effect responses are still understated. In the present review, we discuss the likely action of Se on ethylene biosynthesis and its consequence on postharvest physiology of cut flowers. By combining Se chemical properties with a dissection of ethylene metabolism, we further highlighted both the potential use of Se solutions and their downstream responses. We believe that this report will provide the foundation for the hypothesis that Se plays a key role in the postharvest longevity of ethylene-sensitive flowers.

Colocalization of sucrose synthase expression and sucrose storage in the sugarbeet taproot indicates a potential role for sucrose catabolism in sucrose accumulation.

Sucrose metabolism is believed to have a central role in promoting sink strength and sucrose storage in the sugarbeet taproot. How sucrose accumulation is increased by sucrose-degrading enzymes, however, is a paradox. To elucidate roles for sucrose-degrading activities in sucrose accumulation, relationships between the intercellular location of sucrose-catabolizing enzymes and sites of sucrose accumulation were determined in the sugarbeet taproot. Sucrose storage was evident in parenchyma cells of the outer cortex, rays, and rings of parenchyma tissue, but was absent in phloem, the vascular cambium, cells surrounding these tissues, or cells surrounding xylem. Sucrose synthase, which was primarily responsible for sucrose catabolism throughout the taproot, was expressed in similar cell and tissue types to those accumulating sucrose. Colocalization of sucrose synthase with sucrose accumulation, as well as sucrose synthase localization near the tonoplast, suggests a role for the enzyme in generating metabolic energy to fuel sucrose sequestration in the vacuole. Localization near the plasma membrane also suggests a role for sucrose synthase in supplying substrates for cell wall biosynthesis. By utilizing sucrose for ATP or cell wall biosynthesis, sucrose synthase likely maintains the source-to-sink sucrose gradient that drives sucrose transport into the root, thereby promoting sugarbeet root sink strength.

Healing of Gladioulus grandiflora corms and Fusarium oxysporum infection.

Gladiolus grandiflorus L. is highly susceptible to Fusarium and losses caused by this disease varies from 60% to 100%. Injuries caused during harvest, transport and inadequate storage, facilitate infection. The dynamics of wound healing can reduce infection by Fusarium. The objective was to characterize the wound healing in corms of G. grandiflora stored under refrigeration and how it affects the entry and establishment of F. oxysporum f. sp. gladioli infection. Corms were wounded and stored at 12 ± 4°C and relative humidity of 90 ± 5%. Cell damage, fresh weight loss, respiration, phenolic compounds, tissue darkening, suberization, lignification and resistance to infection were evaluated. Wounds on corms caused transepidermal damage with collapse and cell death. Physiological (increased loss of mass and respiration) and biochemical changes (deposition of lignin and suberin, enzymatic activity) occurred in the cells neighboring those death by the injury. The injury caused gradual darkening of the tissue, injured and neighbor. Fusarium oxysporum infection decreased with wound healing. The healing of injured G. grandiflora corms stored at 12ºC occurs from the 3rd day after injury by the accumulation of suberin, lignin, and melanin, inhibiting F. oxysporum f. sp. gladioli infection.

Ripening of bananas using Bowdichia virgilioides Kunth leaves.

Bananas are usually ripened with calcium carbide (CaC2), a dangerous substance that can cause food poisoning. The objective was to test the empirical ripening banana method using Bowdichia virgilioides leaves compared to carbide. Ripening tests were carried out using 'Pacovan' banana fruits with B. virgilioides leaves and carbide following the empirical method used by Borborema farmers, Paraíba, Brazil. Bowdichia virgilioides leaves induced increased respiration and ascorbic acid production and reduced acidity, chlorophyll and pH in banana fruits like CaC2. Leaves of B. virgilioides induce ripening of 'Pacovan' banana with safer and same results than with CaC2.

Action of Essential Oils on Sprouting of Non-Dormant Potato Tubers

ABSTRACT The breakdown of dormancy and early sprouting is one of the main causes of losses of stored potatoes. Sprouting control becomes important especially when tubers are submitted to long-term storage for further processing by the potato industry. The objective of this work is to evaluate the effect of organic sprout inhibitors, eugenol and menthol essential oils, on the suppression of growth on non-dormant 'Asterix' tubers stored at 8 °C. Administration of eugenol and menthol essential oils reduced the number and the length of sprouts during cold storage up to fifty days. Nevertheless, the essential oils stimulated the break of bud apical dominance, stimulating auxiliary buds growth. The effect of the oils was restricted to inducing necrosis of superficial sprout cells without any apparent effect on the skin periderm structure. Repeated applications of oils are necessary to prolong the inhibitory effects of the essential oils on sprouts growth.

Glycolysis Is Dynamic and Relates Closely to Respiration Rate in Stored Sugarbeet Roots.

Although respiration is the principal cause of the loss of sucrose in postharvest sugarbeet (Beta vulgaris L.), the internal mechanisms that control root respiration rate are unknown. Available evidence, however, indicates that respiration rate is likely to be controlled by the availability of respiratory substrates, and glycolysis has a central role in generating these substrates. To determine glycolytic changes that occur in sugarbeet roots after harvest and to elucidate relationships between glycolysis and respiration, sugarbeet roots were stored for up to 60 days, during which activities of glycolytic enzymes and concentrations of glycolytic substrates, intermediates, cofactors, and products were determined. Respiration rate was also determined, and relationships between respiration rate and glycolytic enzymes and metabolites were evaluated. Glycolysis was highly variable during storage, with 10 of 14 glycolytic activities and 14 of 17 glycolytic metabolites significantly altered during storage. Changes in glycolytic enzyme activities and metabolites occurred throughout the 60 day storage period, but were greatest in the first 4 days after harvest. Positive relationships between changes in glycolytic enzyme activities and root respiration rate were abundant, with 10 of 14 enzyme activities elevated when root respiration was elevated and 9 glycolytic activities static during periods of unchanging respiration rate. Major roles for pyruvate kinase and phosphofructokinase in the regulation of postharvest sugarbeet root glycolysis were indicated based on changes in enzymatic activities and concentrations of their substrates and products. Additionally, a strong positive relationship between respiration rate and pyruvate kinase activity was found indicating that downstream TCA cycle enzymes were unlikely to regulate or restrict root respiration in a major way. Overall, these results establish that glycolysis is not static during sugarbeet root storage and that changes in glycolysis are closely related to changes in sugarbeet root respiration.

Short- and long-term changes in sugarbeet (Beta vulgaris L.) gene expression due to postharvest jasmonic acid treatment - Data.

Jasmonic acid is a natural plant hormone that induces native defense responses in plants. Sugarbeet (Beta vulgaris L.) root unigenes that were differentially expressed 2 and 60 days after a postharvest jasmonic acid treatment are presented. Data include changes in unigene expression relative to water-treated controls, unigene annotations against nonredundant (Nr), Swiss-Prot, Clusters of Orthologous Groups (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) protein databases, and unigene annotations with Gene Ontology (GO) terms. Putative defense unigenes are compiled and annotated against the sugarbeet genome. Differential gene expression data were generated by RNA sequencing. Interpretation of the data is available in the research article, "Jasmonic acid causes short- and long-term alterations to the transcriptome and the expression of defense genes in sugarbeet roots" (K.K. Fugate, L.S. Oliveira, J.P. Ferrareze, M.D. Bolton, E.L. Deckard, F.L. Finger, 2017) [1]. Public dissemination of this dataset will allow further analyses of the data.

Ethylene, 1-methylcyclopropene and silver thiosulfate on the post-production of ornamental pepper / Etileno, 1-metilciclopropeno e tiossulfato de prata na pós-produção de pimenteiras ornamentais

ABSTRACT: Species from Capsicum genus are used for different purposes and in more recent years as ornamental potted plant. Despite the increased commercial importance, there are only a few studies on the environmental factors affecting the post-production shelf life of these ornamental plants. The presence of ethylene induces various responses on potted peppers, reducing the shelf life of sensitive cultivars. This study aimed to evaluate the effects of ethylene and the inhibitors of ethylene action, 1-methylcyclopropene (1-MCP) and silver thiosulfate (STS) on the shelf life of potted 'Calypso' and 'MG 302' peppers. Cultivar 'MG 302' showed intermediate sensitivity to ethylene action, while the cultivar 'Calypso' showed complete abscission of leaves when exposed to ethylene. In both cultivars, treatment with STS + Ethylene presented symptoms of phytotoxicity in plants, while treatment with 1-MCP + Ethylene was effective in delaying senescence and abscission for the cultivar 'MG 302', while cultivar 'Calypso' showed abscission similar to control plants. Plants treated with STS showed the longest durability when compared to the other treatments, about six days for 'Calypso' and 18 days for 'MG 302'. Nevertheless, plants treated with 1-MCP also exhibited good shelf life, about six days for 'Calypso' and nine days for the 'MG 302'. Although the treatment with STS was more efficient on the plants shelf life, did not completely block the action of ethylene and exhibited some phytotoxicity, while the treatment with 1-MCP had good efficiency without inducing any toxicity.

RESUMO: Espécies do gênero Capsicum estão sendo usados para diversas finalidades e nos últimos anos como planta ornamental de vaso. Apesar da crescente importância comercial, há poucos estudos sobre os fatores ambientais que afetam a sua vida útil de pós-produção destas plantas ornamentais. A presença de etileno induz várias respostas em pimenteiras em vasos, reduzindo a vida útil de prateleira de cultivares sensíveis. Este estudo teve como objetivo avaliar os efeitos do etileno e inibidores da ação do etileno, 1-metilciclopropeno (1-MCP) e tiossulfato de prata (STS) sobre a vida útil de vaso de pimenteiras das cultivares 'Calypso' e 'MG 302'. A cultivar 'MG 302' apresentou sensibilidade intermediária a ação do etileno, enquanto a cultivar 'Calypso' apresentou abscisão completa das folhas quando exposta ao etileno. Em ambas as cultivares, o tratamento STS + Etileno mostrou sintomas de fitotoxicidade nas plantas. O tratamento com 1-MCP + Etileno foi eficaz em retardar a senescência e abscisão apenas para a cultivar 'MG 302', enquanto a cultivar 'Calypso' mostrou abscisão foliar semelhante as plantas controle. Plantas tratadas com STS mostraram maior durabilidade quando comparadas aos outros tratamentos, cerca de seis dias para 'Calypso' e dezoito dias para 'MG 302'. No entanto, as plantas tratadas com 1-MCP também exibiram boa vida útil de prateleira, cerca de seis dias para 'Calypso' e nove dias para a 'MG 302'. Embora o tratamento com STS tenha sido mais eficiente na vida de prateleira das plantas, não bloqueou completamente a ação do etileno e apresentaram algum fitotoxicidade, enquanto o tratamento com 1-MCP teve boa eficiência sem induzir qualquer toxicidade.

Vase life and rehydration capacity of dry-stored gladiolus flowers at low temperature / Vida de vaso e capacidade de reidratação de flores de gladíolo armazenadas a seco em baixa temperatura

ABSTRACT: Normally, it is not recommended the conditioning of gladiolus stems in water during storage or transport. Hydration of petals may accelerate flower opening, even at a low temperature, which compromises quality at marketing moment. However, for this species, neither the effect of prolonged dry cold storage nor its behavior when transferred to water at room temperature has been evaluated. The present study aimed to evaluate the vase life and the rehydration capacity of gladiolus flowers ( Gladiolus grandiflora Hort.) after dry storage at low temperature. Flower stems of cultivars Blue Frost, Gold Field, Traderhorn, and Jester were dry-stored at a temperature of 5 ± 1 ºC and relative humidity of 85% for 12, 24, 36, and 48h. Control stems remained always in deionized water. After storage, they were returned to the water at room temperature and evaluated for vase life (adopting the discard criterion when 50% of the basal flowers displayed loss of color and wilting), fresh weight change (%), water uptake rate and transpiration rate, as well as relative water content of the petals (%). In dry cold storage conditions, for up to 36h, the vase life was not affected although incomplete rehydration of the flowers. Rehydration capacity of the stem is linked to the staggered opening of flowers along the inflorescence.

RESUMO: Normalmente, não é recomendado o condicionamento de hastes de gladíolo em água durante o armazenamento ou transporte. A hidratação das pétalas acelera a abertura das flores, mesmo em baixa temperatura, o que compromete a qualidade no momento da comercialização. No entanto, para essa espécie, ainda não foi estudado o efeito do armazenamento refrigerado prolongado a seco e nem o seu comportamento quando transferida para a água em temperatura ambiente. O presente estudo teve como objetivo avaliar a vida de vaso e a capacidade de reidratação de hastes florais de gladíolo após armazenamento a seco em baixa temperatura ( Gladiolus grandiflora Hort.). As hastes das cultivares Blue Frost, Gold Field, Traderhorn e Jester foram armazenadas a seco em temperatura de 5 ± 1 ºC e umidade relativa de 85% por 12, 24, 36 e 48 horas. As hastes controle permaneceram sempre em água deionizada. Após armazenamento, retornaram a água sob condição de temperatura ambiente (22 ± 1 ºC) e foram avaliadas quanto à vida de vaso (adotando o critério de descarte quando 50% das flores basais apresentaram perda de coloração e murcha), variação da massa de matéria fresca (%), taxa de absorção de água e taxa transpiratória, bem como o teor relativo de água das pétalas (%). Em condições de armazenamento a seco em baixa temperatura, por até 36 horas, a vida de vaso não foi afetada, embora tenha ocorrido reidratação incompleta das flores. A capacidade de reidratação da haste está relacionada com a abertura escalonada das flores ao longo da inflorescência.

Cold Temperature Delays Wound Healing in Postharvest Sugarbeet Roots.

Storage temperature affects the rate and extent of wound-healing in a number of root and tuber crops. The effect of storage temperature on wound-healing in sugarbeet (Beta vulgaris L.) roots, however, is largely unknown. Wound-healing of sugarbeet roots was investigated using surface-abraded roots stored at 6 and 12°C for 28 days. Surface abrasions are common injuries of stored roots, and the storage temperatures used are typical of freshly harvested or rapidly cooled roots. Transpiration rate from the wounded surface and root weight loss were used to quantify wound healing. At 12°C, transpiration rate from the wounded surface declined within 14 days and wounded roots lost weight at a rate similar to unwounded controls. At 6°C, transpiration rate from the wounded surface did not decline in the 28 days after injury, and wounded roots lost 44% more weight than controls after 28 days storage. Melanin formation, lignification, and suberization occurred more rapidly at 12°C than at 6°C, and a continuous layer of lignified and suberized cells developed at 12°C, but not at 6°C. Examination of enzyme activities involved in melanin, lignin, and suberin formation indicated that differences in melanin formation at 6 and 12°C were related to differences in polyphenol oxidase activity, although no relationships between suberin or lignin formation and phenylalanine ammonia lyase or peroxidase activity were evident. Wound-induced respiration was initially greater at 12°C than at 6°C. However, with continued storage, respiration rate of wounded roots declined more rapidly at 12°C, and over 28 days, the increase in respiration due to injury was 52% greater in roots stored at 6°C than in roots stored at 12°C. The data indicate that storage at 6°C severely slowed and impaired wound-healing of surface-abraded sugarbeet roots relative to roots stored at 12°C and suggest that postharvest losses may be accelerated if freshly harvested roots are cooled too quickly.

Inhibition of ethylene response by 1-methylcyclopropene in potted ornamental pepper / Inibição das respostas ao etileno por 1-methylcyclopropeno em pimenta ornamental de vaso

In the face of great potential of 1-MCP in blocking ethylene action, this study aimed to evaluate the efficacy of 1-MCP on ethylene action and extend the post-production of ornamental peppers Capsicum annuum potted plants. Ornamental pepper cultivar Calypso shows complete abscission of leaves when exposed to 10µL L-1 ethylene. By exposing plants to ethylene, significant drops on a, b and total chlorophyll were found at the end of the treatment. Nevertheless, no changes on leaf total carotenoid were observed after the treatment with ethylene. When the plants were treated with 1-methylcyclopropene (1-MCP), followed or not by treatment with ethylene, contents of a, b, total chlorophyll and carotenoid remained unchanged. Control plants showed no changes in chlorophylls or carotenoid contents after 48 hours from moving the pots from greenhouse to indoor conditions illuminated with white fluorescent light. The 1-MCP was able to prolong the post production shelf life, by inhibiting the abscission of leaves. Plants treated with 1-MCP, followed by ethylene had 38% accumulated leaf abscission, after 18 days of post production life, similar to control plants. After the same period, plants treated only with 1-MCP had 22% leaf abscission. The 1-MCP partially blocked ethylene and induced leaf abscission. Regardless which treatment was applied during post production life, there was a continuous decrease on leaf chlorophyll content beyond 18th day. Thus, 1-MCP was effective in preventing leaf abscission even in the presence of ethylene, avoiding deleterious effects of ethylene by blocking its receptor sites.

Em face do grande potencial de utilização do 1-MCP no bloqueio da ação do etileno, este trabalho teve como objetivo avaliar a eficiência do 1-MCP em bloquear a ação do etileno e estender a vida pós-produção de plantas de pimenta ornamental da espécie Capsicum annuum. A pimenta ornamental, cultivar Calypso, apresenta abscisão completa das folhas quando exposta a 10µL L-1 de etileno. Nas plantas expostas ao etileno, houve reduções significativas dos teores de clorofila a, b e total ao final do tratamento. Nenhuma alteração no conteúdo de carotenoides total das folhas foi observada após o tratamento com etileno. Quando as plantas foram tratadas com 1-metilciclopropeno (1-MCP), seguido ou não pelo tratamento com etileno, os teores de clorofila a, b, total e carotenoides permaneceram inalterados. As plantas controle não apresentaram alterações nas clorofilas ou carotenoides, após 48 horas da remoção dos vasos da estufa para recinto fechado iluminado com luz branca fluorescente. O 1-MCP foi capaz de prolongar a vida de prateleira semelhante às plantas controle. No mesmo período, plantas tratadas somente com 1-MCP tiveram 22% de abscisão foliar. O tratamento com 1-MCP bloqueou parcialmente a queda das folhas induzida por etileno. Independentemente do tratamento aplicado, houve diminuição contínua do teor de clorofila das folhas após o 18º dia. A fumigação com 1-MCP foi eficaz na pós-produção, inibindo a abscisão das folhas. Plantas tratadas com 1-MCP, seguido por etileno, tiveram 38% de abscisão foliar acumulada, após 18 dias de vida em pós-produção, prevenção da queda de folhas, mesmo na presença de etileno, evitando os efeitos deletérios de etileno, através do bloqueio dos sítios receptores de etileno.

Exploring natural variation of photosynthetic, primary metabolism and growth parameters in a large panel of Capsicum chinense accessions.

MAIN CONCLUSION: Collectively, the results presented improve upon the utility of an important genetic resource and attest to a complex genetic basis for differences in both leaf metabolism and fruit morphology between natural populations. Diversity of accessions within the same species provides an alternative method to identify physiological and metabolic traits that have large effects on growth regulation, biomass and fruit production. Here, we investigated physiological and metabolic traits as well as parameters related to plant growth and fruit production of 49 phenotypically diverse pepper accessions of Capsicum chinense grown ex situ under controlled conditions. Although single-trait analysis identified up to seven distinct groups of accessions, working with the whole data set by multivariate analyses allowed the separation of the 49 accessions in three clusters. Using all 23 measured parameters and data from the geographic origin for these accessions, positive correlations between the combined phenotypes and geographic origin were observed, supporting a robust pattern of isolation-by-distance. In addition, we found that fruit set was positively correlated with photosynthesis-related parameters, which, however, do not explain alone the differences in accession susceptibility to fruit abortion. Our results demonstrated that, although the accessions belong to the same species, they exhibit considerable natural intraspecific variation with respect to physiological and metabolic parameters, presenting diverse adaptation mechanisms and being a highly interesting source of information for plant breeders. This study also represents the first study combining photosynthetic, primary metabolism and growth parameters for Capsicum to date.