Facilitating Seed Iron Uptake through Amine-Epoxide Microgels: A Novel Approach to Enhance Cucumber (Cucumis sativus) Germination.

Enhancing the initial stages of plant growth by using polymeric gels for seed priming presents a significant challenge. This study aimed to investigate a microgel derived from polyetheramine-poly(propylene oxide) (PPO) and a bisepoxide (referred to as micro-PPO) as a promising alternative to optimize the seed germination process. The micro-PPO integrated with an iron micronutrient showed a positive impact on seed germination compared with control (Fe solutions) in which the root length yield improved up to 39%. Therefore, the element map by synchrotron-based X-ray fluorescence shows that the Fe intensities in the seed primers with the micro-PPO-Fe gel are about 3-fold higher than those in the control group, leading to a gradual distribution of Fe species through most internal embryo tissues. The use of micro-PPO for seed priming underscores their potential for industrial applications due to the nontoxicity results in zebrafish assays and environmentally friendly synthesis of the water-dispersible monomers employed.

Plant seedlings of peas, tomatoes, and cucumbers exude compounds that are needed for growth and chemoattraction of Rhizobium leguminosarum bv. viciae 3841 and Azospirillum brasilense Sp7.

This study characterizes seedling exudates of peas, tomatoes, and cucumbers at the level of chemical composition and functionality. A plant experiment confirmed that Rhizobium leguminosarum bv. viciae 3841 enhanced growth of pea shoots, while Azospirillum brasilense Sp7 supported growth of pea, tomato, and cucumber roots. Chemical analysis of exudates after 1 day of seedling incubation in water yielded differences between the exudates of the three plants. Most remarkably, cucumber seedling exudate did not contain detectable sugars. All exudates contained amino acids, nucleobases/nucleosides, and organic acids, among other compounds. Cucumber seedling exudate contained reduced glutathione. Migration on semi solid agar plates containing individual exudate compounds as putative chemoattractants revealed that R. leguminosarum bv. viciae was more selective than A. brasilense, which migrated towards any of the compounds tested. Migration on semi solid agar plates containing 1:1 dilutions of seedling exudate was observed for each of the combinations of bacteria and exudates tested. Likewise, R. leguminosarum bv. viciae and A. brasilense grew on each of the three seedling exudates, though at varying growth rates. We conclude that the seedling exudates of peas, tomatoes, and cucumbers contain everything that is needed for their symbiotic bacteria to migrate and grow on.

N-Phenylnorbornenesuccinimide derivatives, agricultural defensive, and enzymatic target selection.

BACKGROUND: Faced with the need to develop new herbicides with modes of action different to those observed for existing agrochemicals, one of the most promising strategies employed by synthetic chemists involves the structural modification of molecules found in natural products. Molecules containing amides, imides, and epoxides as functional groups are prevalent in nature and find extensive application in synthesizing more intricate compounds due to their biological properties. In this context, this paper delineates the synthesis of N-phenylnorbornenesuccinimide derivatives, conducts biological assays, and carries out in silico investigation of the protein target associated with the most potent compound in plant organisms. The phytotoxic effects of the synthesized compounds (2-29) were evaluated on Allium cepa, Bidens pilosa, Cucumis sativus, Sorghum bicolor, and Solanum lycopersicum. RESULTS: Reaction of endo-bicyclo[2.2.1]hept-5-ene-3a,7a-dicarboxylic anhydride (1) with aromatic amines led to the N-phenylnorbornenesuccinic acids (2-11) with yields ranging from 75% to 90%. Cyclization of compounds (2-11) in the presence of acetic anhydride and sodium acetate afforded N-phenylnorbornenesuccinimides (12-20) with yields varying from 65% to 89%. Those imides were then subjected to epoxidation reaction to afford N-phenylepoxynorbornanesuccimides (21-29) with yields from 60% to 90%. All compounds inhibited the growth of seedlings of the plants evaluated. Substance 23 was the most active against the plants tested, inhibiting 100% the growth of all species in all concentrations. Cyclophilin was found to be the enzymatic target of compound 23. CONCLUSION: These findings suggest that derivatives of N-phenylnorbornenesuccinimide are promising compounds in the quest for more selective and stable agrochemicals. This perspective reinforces the significance of these derivatives as potential innovative herbicides and emphasizes the importance of further exploring their biological activity on weeds. © 2024 Society of Chemical Industry.

Cucumber response to different growing seasons and nitrogen doses / Resposta de pepino a diferentes épocas de cultivo e doses de nitrogênio

The purpose of this study was to verify the effect of growing season and nitrogen doses on the pickling cucumber. This work was carried out in a greenhouse at the Federal Institute of Goiás (IF Goiano) -Campus Urutaí. A randomized block design in a 2 x 5 factorial scheme with four replications was used. Two growing seasons (the first sown in January and second in April) and five nitrogen doses (0, 50, 100, 150, and 200 kg ha-1of N) were evaluated. The seed of pickling cucumber used was the Kybria F1 hybrid. Nitrogen doses were applied at 15, 30, and 45 days after plant emergence. Each plot was composed of 10 plants, and the four central plants of each plot with a spacing of 0.2 m between plants and 0.8 m between rows were evaluated. Leaf nitrogen content, relative chlorophyll index, stem diameter, length and diameter of fruits, fresh and dry matter of fruits, the fresh matter of shoot, number of fruits, and yield per plant were evaluated. The growing seasons and nitrogen doses influenced the productive traits of the cucumber crop. The first growing season of the cucumber crop shows satisfactory results in terms of yield components at a dose of 100 kg ha-1of nitrogen.

Objetivou-se com este estudo verificar o efeito de épocas de plantio e doses de nitrogênio sobre a cultura do pepino para conserva. Este trabalho foi desenvolvido em casa de vegetação no Instituto Federal Goiano (IF Goiano) - Campus Urutaí. O delineamento experimental utilizado foi em blocos casualizados em esquema fatorial 2 x 5, sendo duas épocas de cultivo (primeira época semeada em janeiro e a segunda em abril) e cinco doses de nitrogênio (0, 50, 100, 150 e 200 kg ha-1 de N), com quatro repetições. Utilizou-se a semente de pepino para conserva híbrido Kybria F1.As doses de nitrogênio foram parcelas aos 15, 30 e 45 dias após emergência das plantas. Cada parcela foi constituída 10 plantas, sendo avaliadas as quatro plantas centrais de cada parcela com espaçamento de 0,2 m entre plantas e 0,8 m entre linhas. Avaliou-se o teor de nitrogênio foliar, índice relativo de clorofila, diâmetro do caule, comprimento e diâmetro de frutos, matéria fresca e seca de frutos, matéria fresca de parte aérea, número de frutos e produtividade por planta. As épocas de cultivo e doses de nitrogênio influenciaram nas características produtivas da cultura do pepino. A primeira época de plantio da cultura do pepino apresentou resultados satisfatórios quanto aos componentes de produção na dose de 100 kg ha-1de nitrogênio.

Synthesis and Identification of Epoxy Derivatives of 5-Methylhexahydroisoindole-1,3-dione and Biological Evaluation.

Cyclic imides belong to a well-known class of organic compounds with various biological activities, promoting a great interest in compounds with this functional group. Due to the structural complexity of some molecules and their spectra, it is necessary to use several spectrometric methods associated with auxiliary tools, such as the theoretical calculation for the structural elucidation of complex structures. In this work, the synthesis of epoxy derivatives of 5-methylhexahydroisoindole-1,3-diones was carried out in five steps. Diels-Alder reaction of isoprene and maleic anhydride followed by reaction with m-anisidine afforded the amide (2). Esterification of amide (2) with methanol in the presence of sulfuric acid provided the ester (3) that cyclized in situ to give imides 4 and 4-ent. Epoxidation of 4 and 4-ent with meta-chloroperbenzoic acid (MCPBA) afforded 5a and 5b. The diastereomers were separated by silica gel flash column chromatography, and their structures were determined by analyses of the spectrometric methods. Their structures were confirmed by matching the calculated 1H and 13C NMR chemical shifts of (5a and 5b) with the experimental data of the diastereomers using MAE, CP3, and DP4 statistical analyses. Biological assays were carried out to evaluate the potential herbicide activity of the imides. Compounds 5a and 5b inhibited root growth of the weed Bidens pilosa by more than 70% at all the concentrations evaluated.

Utilization of vitamins in the production of cucumber seedlings under saline stress / Utilização de vitaminas na produção de mudas de pepineiro sob estresse salino

Numerous factors lead to the use of water with saline levels above those suitable for plant development, resulting in negative consequences on crops. Studies have sought techniques that aim to mitigate such consequences and the use of vitamins is promising, since these compounds improve the development conditions of vegetables. Thus, the study aimed to verify the ability of vitamins to mitigate the deleterious effects of using saline water, applied via irrigation during the formation of cucumber seedlings. Cucumber seeds were subjected to imbibition in three vitamin solutions (100 mg L-1thiamine; 100 mg L-1niacin; 50 mg L-1thiamine + 50 mg L-1niacin), in addition to two controls, both with water imbibition . After sowing, irrigation was carried out with saline water (100 mM NaCl), for all treatments, except for one of the controls. It was found that irrigation with saline water affected all variables studied, without, however, having a positive effect from the application of vitamins. Thus, it was concluded that the vitamins were not able to mitigate the deleterious effects caused by the application of saline water under the conditions in which the study was carried out and that future studies should be carried out to evaluate different concentrations and forms of application of the vitamins.

Inúmeros fatores levam à utilização de água com teores salinos acima daqueles adequados ao desenvolvimento vegetal, acarretando consequências negativas sobre os cultivos. Estudos têm buscado técnicas que visem amenizar tais consequências e a utilização de vitaminas é promissora, uma vez que esses compostos melhoram as condições de desenvolvimento dos vegetais. Assim, o estudo teve como objetivo verificar a capacidade das vitaminas em mitigar os efeitos deletérios da utilização de água salina, aplicada via irrigação durante a formação de mudas de pepino. Sementes de pepineiro foram submetidas à embebição em três soluções vitamínicas (100 mg L-1tiamina; 100 mg L-1niacina; 50 mg L-1tiamina + 50 mg L-1niacina), além dois controles, ambos com embebição em água. Após a semeadura a irrigação foi realizada comágua salina (100 mM de NaCl), para todos os tratamentos, com exceção de um dos controles. Verificou-se que a irrigação com água salina afetou todas as variáveis estudas, sem que, no entanto, houvesse efeito positivo da aplicação das vitaminas. Dessa maneira, concluiu-se que as vitaminas não foram capazes de mitigar os efeitos deletérios causados pela aplicação de água salina nas condições em que o estudo foi realizado e que estudos futuros devem ser realizados para avaliar diferentes concentrações e formas de aplicação das vitaminas.

Utilization of vitamins in the production of cucumber seedlings under saline stress / Utilização de vitaminas na produção de mudas de pepineiro sob estresse salino

Numerous factors lead to the use of water with saline levels above those suitable for plant development, resulting in negative consequences on crops. Studies have sought techniques that aim to mitigate such consequences and the use of vitamins is promising, since these compounds improve the development conditions of vegetables. Thus, the study aimed to verify the ability of vitamins to mitigate the deleterious effects of using saline water, applied via irrigation during the formation of cucumber seedlings. Cucumber seeds were subjected to imbibition in three vitamin solutions (100 mg L-1thiamine; 100 mg L-1niacin; 50 mg L-1thiamine + 50 mg L-1niacin), in addition to two controls, both with water imbibition . After sowing, irrigation was carried out with saline water (100 mM NaCl), for all treatments, except for one of the controls. It was found that irrigation with saline water affected all variables studied, without, however, having a positive effect from the application of vitamins. Thus, it was concluded that the vitamins were not able to mitigate the deleterious effects caused by the application of saline water under the conditions in which the study was carried out and that future studies should be carried out to evaluate different concentrations and forms of application of the vitamins.(AU)

Inúmeros fatores levam à utilização de água com teores salinos acima daqueles adequados ao desenvolvimento vegetal, acarretando consequências negativas sobre os cultivos. Estudos têm buscado técnicas que visem amenizar tais consequências e a utilização de vitaminas é promissora, uma vez que esses compostos melhoram as condições de desenvolvimento dos vegetais. Assim, o estudo teve como objetivo verificar a capacidade das vitaminas em mitigar os efeitos deletérios da utilização de água salina, aplicada via irrigação durante a formação de mudas de pepino. Sementes de pepineiro foram submetidas à embebição em três soluções vitamínicas (100 mg L-1tiamina; 100 mg L-1niacina; 50 mg L-1tiamina + 50 mg L-1niacina), além dois controles, ambos com embebição em água. Após a semeadura a irrigação foi realizada comágua salina (100 mM de NaCl), para todos os tratamentos, com exceção de um dos controles. Verificou-se que a irrigação com água salina afetou todas as variáveis estudas, sem que, no entanto, houvesse efeito positivo da aplicação das vitaminas. Dessa maneira, concluiu-se que as vitaminas não foram capazes de mitigar os efeitos deletérios causados pela aplicação de água salina nas condições em que o estudo foi realizado e que estudos futuros devem ser realizados para avaliar diferentes concentrações e formas de aplicação das vitaminas.(AU)

Sunlight transmitted by colored shade nets on photosynthesis and yield of cucumber / Luz solar transmitida por malhas coloridas sobre fotossíntese e rendimento de pepino

Black shading nets are widely used in the protected cultivation of vegetables as a technique for controlling light and temperature, while the colored shading nets, with special optical properties to improve the use of solar radiation, appeared recently in the agricultural plastics market. Light quality transmitted by gray, aluminized, pearl, blue, red and black (control) nets with 30% shade was evaluated, as well as its effects on photosynthetic properties and fruits production of cucumber plants. Treatments (shade nets) were established under a randomized complete block design with four repetitions. The red net transmitted 23.7 and 40.3% more photosynthetic photon flux density (400 to 700nm) and red light (600 to 700nm) and the blue net transmitted 36% more blue light (400 to 500nm) in comparison with the respective transmissions of black net. All nets increased the photosynthetic responses: transpiration, stomatal conductance and CO2 assimilation, observed in plants grown under black net. Leaf greenness (41.6 SPAD units) and foliar area (90dm2) increased 22.8 and 38.9% with the red net, while the dry weight of leaf (52.5g) increased 21.9% with pearl net. Pearl, red, aluminized and blue nets showed to be viable alternatives because the production of fruit increased in 71, 48, 46 and 46%, respectively, in comparison with the conventional black net (52t ha-1).(AU)

As malhas de sombreamento preto são amplamente utilizadas no cultivo protegido de hortaliças como uma técnica para controlar a luz e a temperatura; enquanto as malhas de sombreamento coloridas, com propriedades ópticas especiais para melhorar o uso da radiação solar, apareceram recentemente no mercado de plásticos agrícolas. A qualidade de luz transmitida por malhas cinza, aluminizada, pérola, azul, vermelha e preta (controle) com 30% de sombreamento foi avaliada, assim como seus efeitos nas propriedades fotossintéticas e na produção de frutos de plantas de pepino. Os tratamentos (malhas de sombreamento) foram estabelecidos sob o desenho de blocos completos casualizados, com quatro repetições. A malha vermelha transmitiu 23,7 e 40,3% mais densidade de fluxo de fótons fotossintéticos (400 a 700nm) e luz vermelha (600 a 700nm) e a malha azul transmitiu 36% mais luz azul (400 a 500nm) em comparação com as respectivas transmissões de malha preta. Todas as malhas aumentaram as respostas fotossintéticas: transpiração, condutância estomática e assimilação de CO2, observadas em plantas cultivadas sob malha preta. O verde da folha (41,6 unidades SPAD) e a área foliar (90dm2) aumentaram 22,8 e 38,9% com a malha vermelha, enquanto o peso seco da folha (52,5g) aumentou 21,9% com a malha pérola. As malhas pérola, vermelha, aluminizada e azul mostraram-se como alternativas viáveis, pois a produção de frutos aumentou em 71, 48, 46 e 46%, respectivamente, em comparação à malha convencional preta (52t ha-1).(AU)

Ecotoxicological assessment of glyphosate-based herbicides: Effects on different organisms.

Glyphosate-based herbicides are the most commonly used worldwide because they are effective and relatively nontoxic to nontarget species. Unlimited and uncontrolled use of such pesticides can have serious consequences for human health and ecological balance. The present study evaluated the acute toxicity and genotoxicity of 2 glyphosate-based formulations, Roundup Original (Roundup) and Glyphosate AKB 480 (AKB), on different organisms: cucumber (Cucumis sativus), lettuce (Lactuca sativa), and tomato (Lycopersicon esculentum) seeds, and microcrustacean Artemia salina and zebrafish (Danio rerio) early life stages. For the germination endpoint, only L. esculentum presented significant sensitivity to AKB and L. sativa to Roundup, whereas both formulations significantly inhibited the root growth of all species tested. Both AKB and Roundup induced significant toxicity to A. salina; both are classified as category 3, which indicates a hazard for the aquatic environment, according to criteria of the Globally Harmonized Classification System. However, Roundup was more toxic than AKB, with 48-h median lethal concentration (LC50) values of 14.19 mg/L and 37.53 mg/L, respectively. For the embryo-larval toxicity test, Roundup proved more toxic than AKB for the mortality endpoint (96-h LC50 values of 10.17 mg/L and 27.13 mg/L, respectively), whereas for the hatching parameter, AKB was more toxic than Roundup. No significant genotoxicity to zebrafish larvae was found. We concluded that AKB and Roundup glyphosate-based formulations are phytotoxic and induce toxic effects in nontarget organisms such as A. salina and zebrafish early life stages. Environ Toxicol Chem 2017;36:1755-1763. © 2016 SETAC.

Amino-substituted para-Benzoquinones as Potential Herbicides.

Although quinones present a large array of biological activities, a few studies on the herbicidal potential of 2,5-bis(alkyl/arylamino)-1,4-benzoquinones have been reported to date. In this work, starting from benzoquinone, 13 2,5-bis(alkyl/arylamino)-1,4-benzoquinones were prepared in 46 - 93% yield. The products were fully characterized by spectroscopic analyses and their phytotoxicity against Cucumis sativus and Sorghum bicolor seedlings was investigated. At 100 ppm, compounds caused 10 - 88% growth inhibition of the dicotyledonous species, whereas the monocotyledon was less affected. Most compounds exerted little inhibitory effect on a cyanobacterial model strain. However, at 100 µm, compounds 8 - 10 caused about 50% inhibition of algal growth, and compounds 1 and 2 reduced cell viability in the 1 - 10 µm range. The ability of benzoquinone derivatives to interfere with the light-driven ferricyanide reduction by isolated spinach chloroplasts was evaluated. Some substances showed a moderate effect as uncouplers, but no relationship was found between this property and their biological activity, indicating that the herbicidal effect is not associated with the inhibition of the photosynthetic electron transport chain. Phytotoxic compounds were not toxic to insects, strengthening the possibility that they may serve as lead for the development of eco-friendly herbicides.

Phytotoxicity as an indicator of stability of broiler production residues.

Beddings used for successive broiler lots act as substrate to absorb water and feed from the excreta and may be subsequently used as agricultural fertilizers. This study evaluated the physicochemical characteristics and the phytotoxicity of beddings used to raise five consecutive broiler lots in five aviaries. Samples were collected for beddings not used yet and for beddings used at each of the five broiler lots. Lettuce and cucumber seeds were considered as phytotoxicity bioindicators. As beddings were used for greater number of lots, N, Ca, K, Mg and P contents generally increased, but the C content decreased, the pH alkalinized and humidity was reduced (P < 0.05). The germination index for lettuce and cucumber seeds was reduced with increased bedding (P < 0.05). Beddings used for at least five broiler lots presented decreased C:N ratio and would not recommended for agricultural use due to its toxicity for both tested seeds.

Efeito da solução nutritiva sob o crescimento e composição mineral em pepino cultivado em substrato de fibra de coco / Nutrient solution effect on development and mineral composition of cucumber grown in coconut fiber substrate

O pepino é uma importante hortaliça amplamente cultivada por pequenos e médios produtores no semiárido do Brasil. O experimento foi desenvolvido com o objetivo de avaliar os efeitos de diferentes soluções nutritivas do pepino cultivados em substrato de fibra de coco sob o crescimento e composição mineral de folhas. O delineamento experimental foi o de blocos casualizados com quatro repetições. A solução nutritiva padrão foi preparada seguindo a recomendação de 100% sugerida por Furlani para a cultura do pepino. A partir dessa recomendação, foram testadas novas concentrações de nutrientes: 12,5; 17; 25; 50 e 100%, que após a diluição dos nutrientes apresentou condutividades de 1,0; 1,2; 1,5; 2,3 e 3,8 dS m-¹, respectivamente. A partir dos sete dias após o transplantio foram medidas as variáveis altura de plantas, diâmetro caulinar e número de folhas. No início da floração (30 dias após o transplantio) foram coletadas de cada parcela duas folhas por planta, a partir do broto terminal, para determinação dos teores de macro e micronutrientes na biomassa seca das folhas. As variáveis de crescimento altura de plantas, diâmetro do caule e número de folhas foram influenciadas pela interação proporção de nutrientes na solução nutritiva × idade das plantas. As plantas de pepineiro estavam adequadamente nutridas em nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg), cobre (Cu), manganês (Mn), ferro (Fe) e zinco (Zn).(AU)

Cucumber is an important horticultural crop widely cultivated for small and medium growers in semiarid regions of the Brazil. In order to evaluate the nutrient solution effect on development and mineral composition of cucumber grown in coconut fiber substrate, an experimental was carried out using completely randomized design with four replications. A standard nutrient solution was prepared following the recommendation of 100% suggested by Furlani for cucumber crop. Concentrations of nutrient solution were to simulate by standard nutrient solution: 12.5, 17, 25; 50 and 100% (control) and, after the nutrients dilution showed conductivities following: 1.0, 1.2, 1.5, 2.3 and 3.8 dS m-¹, respectively. Seven days after transplanting the variables plant height, stem diameter and number of leaves were recording. For each plot two leaves of cucumber terminal shoot was collected at beginning of flowering (30 days after transplanting) and, macro and micronutrients was analyzed in dry biomass. Growth variables plant height, stem diameter and number of leaves were influenced by the interaction ratio of nutrients in the nutrients solution age of the plants. The cucumber plants were adequately nourished in nitrogen, phosphorus, potassium, calcium, magnesium, copper, manganese, iron and zinc.(AU)

Inheritance and quantitative trait locus analysis of low-light tolerance in cucumber (Cucumis sativus L.).

The low-light tolerance index was investigated in a set of 123 F2:3 lines during the seedling stage across 2 seasons, and the heredity of low-light tolerance was assessed via different ge-netic analysis methods. The results of the classical analysis showed that low-light tolerance is controlled by an additive-dominant poly-gene, and the polygenic inheritance rate of separate generations was >30%. In addition, 5 quantitative trait loci (QTLs) exhibited a low-light tolerance index across both seasons, including 2 QTLs (Llti1.1 and Llti1.2) on the 1st linkage group (variances of 6.0 and 9.5%) and 3 QTLs (Llti2.1, Llti2.1, and Llti2.1) on the 2nd linkage group (variances of 10.1-14.0%). The classical analysis method and QTL information on the heredity of low-light tolerance showed that it is controlled by several major genes and a mini-polygene. The results will facilitate the breeding of resistance to low-light stress in cucumber.

Rubrolides as model for the development of new lactones and their aza analogs as potential photosynthesis inhibitors.

Natural phytotoxins and their synthetic analogs are a potential source of new bioactive compounds for agriculture. Analogs of rubrolides, a class of γ-alkylidene-γ-lactones isolated from different ascidians, have been shown to interfere with the photosynthetic electron-transport chain, yet their activity needs to be improved. With this aim, ten 5-aryl-6-benzyl-4-bromopyridazin-3(2H)-ones were prepared in yields ranging from 44 to 88% by reaction of their correspondent γ-alkylidene-γ-lactones with NH2 NH2 . The structures of these rubrolide analogs were determined by (1) H- and (13) C-NMR, 2D-NMR (COSY and HETCOR), NOE difference, and MS techniques. These compounds were evaluated for their abilities of interfering with the light-driven reduction of ferricyanide by isolated spinach chloroplasts. Lactones with electron-withdrawing substituents in the para-position of the benzylidene ring were the most effective inhibitors. Characterization of the activity of 11b/11b' suggested a mechanism based on the interaction with the plastoquinone binding site of photosystem II. Addition of several compounds to the culture medium of a cyanobacterial model strain was found to inhibit algal growth. However, the relative effectiveness was not consistent with their activity in vitro, suggesting the occurrence of multiple targets and/or detoxyfication mechanisms. Indeed, the compounds showed differential effects on the heterotrophic growth of some crop species, Cucumis sativus and Sorghum bicolor. Pyridazin-3(2H)-ones 12e, 12i, and 12j, which have been found poorly active against the photosynthetic electron transport, were the most effective in inhibiting the growth of some weeds, Ipomoea grandifolia and Brachiaria decumbens, under greenhouse conditions.

Assessment of genetic diversity of cucumber cultivars in China based on simple sequence repeats and fruit traits.

The cucumber (Cucumis sativus L.) is an important crop grown worldwide. In this study, the genetic diversity of 42 cucumber cultivars in China was analyzed using 51 pairs of simple sequence repeat (SSR) primers. These primers identified 129 polymorphic loci, 95.6% of which were polymorphic. The mean effective number of alleles, mean Nei's gene diversity, and mean Shannon's information index were 0.36, 0.16, and 0.21, respectively. A cluster analysis demonstrated that the 42 cultivars could be divided into three groups, a result that was largely consistent with those of a principal component analysis (PCA). The PCA indicated that the three groups displayed significant variation in fruit traits. The cultivars of group 1 tended to have longer fruits (>30 cm), longer fruit ends (>4 cm), larger fruit diameters (>5 cm), a sharp strigose fruit spine, and the same fruit end shape. The basal color of the fruit in group 2 was dark green. Group 3 cultivars have no wax or mottling on the fruit surface. Our study demonstrates the value of our SSR primers for assessing genetic diversity in cucumber.

Efeito da solução nutritiva sob o crescimento e composição mineral em pepino cultivado em substrato de fibra de coco / Nutrient solution effect on development and mineral composition of cucumber grown in coconut fiber substrate

O pepino é uma importante hortaliça amplamente cultivada por pequenos e médios produtores no semiárido do Brasil. O experimento foi desenvolvido com o objetivo de avaliar os efeitos de diferentes soluções nutritivas do pepino cultivados em substrato de fibra de coco sob o crescimento e composição mineral de folhas. O delineamento experimental foi o de blocos casualizados com quatro repetições. A solução nutritiva padrão foi preparada seguindo a recomendação de 100% sugerida por Furlani para a cultura do pepino. A partir dessa recomendação, foram testadas novas concentrações de nutrientes: 12,5; 17; 25; 50 e 100%, que após a diluição dos nutrientes apresentou condutividades de 1,0; 1,2; 1,5; 2,3 e 3,8 dS m-¹, respectivamente. A partir dos sete dias após o transplantio foram medidas as variáveis altura de plantas, diâmetro caulinar e número de folhas. No início da floração (30 dias após o transplantio) foram coletadas de cada parcela duas folhas por planta, a partir do broto terminal, para determinação dos teores de macro e micronutrientes na biomassa seca das folhas. As variáveis de crescimento altura de plantas, diâmetro do caule e número de folhas foram influenciadas pela interação proporção de nutrientes na solução nutritiva × idade das plantas. As plantas de pepineiro estavam adequadamente nutridas em nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg), cobre (Cu), manganês (Mn), ferro (Fe) e zinco (Zn).

Cucumber is an important horticultural crop widely cultivated for small and medium growers in semiarid regions of the Brazil. In order to evaluate the nutrient solution effect on development and mineral composition of cucumber grown in coconut fiber substrate, an experimental was carried out using completely randomized design with four replications. A standard nutrient solution was prepared following the recommendation of 100% suggested by Furlani for cucumber crop. Concentrations of nutrient solution were to simulate by standard nutrient solution: 12.5, 17, 25; 50 and 100% (control) and, after the nutrients dilution showed conductivities following: 1.0, 1.2, 1.5, 2.3 and 3.8 dS m-¹, respectively. Seven days after transplanting the variables plant height, stem diameter and number of leaves were recording. For each plot two leaves of cucumber terminal shoot was collected at beginning of flowering (30 days after transplanting) and, macro and micronutrients was analyzed in dry biomass. Growth variables plant height, stem diameter and number of leaves were influenced by the interaction ratio of nutrients in the nutrients solution age of the plants. The cucumber plants were adequately nourished in nitrogen, phosphorus, potassium, calcium, magnesium, copper, manganese, iron and zinc.

Effects of exogenous 5-aminolevulinic acid on PIP1 and NIP aquaporin gene expression in seedlings of cucumber cultivars subjected to salinity stress.

Aquaporins play a direct role in plant water relation under salt stress, but the effects of 5-aminolevulinic acid (ALA) on aquaporin gene expression in salt-treated plants remain unknown. This study investigated the potential effects of exogenous ALA (50 mg/dm3) on aquaporin expression levels under salt stress (75 mM NaCl) in the salt-sensitive (Jinchun No.4) and the relatively salt-tolerant cucumber (Jinyou No.1) seedlings. The expressions of cucumber PIP aquaporin gene (CsPIP1:1) and cucumber NIP aquaporin gene (CsNIP) were analyzed in 20-day-old seedling leaves at 2, 4, 8, 16, and 24 h after ALA treatment. After treatment with saline alone and ALA alone, CsPIP1:1 and CsNIP gene expression levels in the 2 cucumber cultivars increased to maximum at 2 h. The aquaporin gene expression in salt-treated cucumber seedling leaves was considerably higher than that in leaves subjected to exogenous ALA. Further, the aquaporin expression levels in Jinchun No.4 were higher than those in Jinyou No.1, reaching 5.20- and 2-fold induction levels, respectively. After treatment with both ALA and NaCl, the CsNIP gene expression was downregulated in both the cucumber cultivars, while that of CsPIP1:1 decreased at 2 h and then increased to 3.8-fold in Jinchun No.4. In Jinyou No.1, CsPIP1:1 gene expression gradually increased to 2.3-fold at 4 h, followed by a decline in expression. The results indicated that ALA might delay and counteract the upregulated expression of CsPIP1:1 and CsNIP genes in cucumber seedlings under NaCl stress. Thus, salt tolerance of cucumber seedlings might be enhanced by ALA application.

Roots of the invasive species Carduus nutans L. and C. acanthoides L. produce large amounts of aplotaxene, a possible allelochemical.

The invasive thistle Carduus nutans has been reported to be allelopathic, yet no allelochemicals have been identified from the species. In a search for allelochemicals from C. nutans and the closely related invasive species C. acanthoides, bioassay-guided fractionation of roots and leaves of each species were conducted. Only dichloromethane extracts of the roots of both species contained a phytotoxin (aplotaxene, (Z,Z,Z)-heptadeca-1,8,11,14-tetraene) with sufficient total activity to potentially act as an allelochemical. Aplotaxene made up 0.44 % of the weight of greenhouse-grown C. acanthoides roots (ca. 20 mM in the plant) and was not found in leaves of either species. It inhibited growth of lettuce 50 % (I 50) in soil at a concentration of ca. 0.5 mg g(-1) of dry soil (ca. 6.5 mM in soil moisture). These values gave a total activity in soil value (molar concentration in the plant divided by the molarity required for 50 % growth inhibition in soil = 3.08) similar to those of some established allelochemicals. The aplotaxene I 50 for duckweed (Lemna paucicostata) in nutrient solution was less than 0.333 mM, and the compound caused cellular leakage of cucumber cotyledon discs in darkness and light at similar concentrations. Soil in which C. acanthoides had grown contained aplotaxene at a lower concentration than necessary for biological activity in our short-term soil bioassays, but these levels might have activity over longer periods of time and might be an underestimate of concentrations in undisturbed and/or rhizosphere soil.

Molecular cloning and expression analysis of the ethylene insensitive3 (EIN3) gene in cucumber (Cucumis sativus).

The plant gaseous hormone ethylene regulates many aspects of plant growth, development, and responses to the environment. Ethylene insensitive3 (EIN3) is a key transcription factor involved in the ethylene signal transduction pathway. To gain a better understanding of this particular pathway in cucumber, the full-length cDNA encoding EIN3 (designated as CsEIN3) was cloned from cucumber for the first time by rapid amplification of cDNA ends. The full length of CsEIN3 was 2560 bp, with an open reading frame of 1908 bp encoding 635 amino acids. Sequence alignment and phylogenetic analyses revealed that CsEIN3 has high homology with other plant EIN3/EIL proteins that were derived from a common ancestor during evolution, and CsEIN3 was grouped into a cluster along with melon. Homology modeling demonstrated that CsEIN3 has a highly similar structure to the specific DNA-binding domain contained in EIN3/EIL proteins. Based on quantitative reverse transcription-polymerase chain reaction analysis, we found that CsEIN3 was constitutively expressed in all organs examined, and was increased during flower development and maturation in both male and female flowers. Our results suggest that CsEIN3 is involved in processes of flower development. In conclusion, this study will provide the basis for further study on the role of EIN3 in relevant biological processes of cucumber and on the molecular mechanism of the cucumber ethylene signaling pathway.

Produção e curva de crescimento de pepineiros para conserva em manejo convencional e com controle alternativo de pragas / Production and growth curve of pickling cucumber plants in conventional and alternative pest control

Com o objetivo de avaliar a produção e a dinâmica do incremento produtivo de pepineiros para conserva, instalou-se um experimento no período de janeiro a março de 2011, na Epagri - Estação Experimental de Ituporanga , SC. O delineamento experimental utilizado foi o de blocos ao acaso com parcelas subdividas com quatro repetições. Os fatores empregados foram dois sistemas de produção (convencional e diferenciado), nas parcelas, e três cultivares de pepino (Marinda, Prêmio e Zapata), nas subparcelas. As parcelas foram constituídas de quatro linhas de 3 m, espaçadas em 1,0 x 0,30 m, com uma planta por cova e área útil constituída pelas linhas centrais. Avaliou-se a produção de massa fresca de frutos por planta (g planta-1), produtividade (t ha-1), peso médio de frutos (g), número de frutos por planta, porcentagem de frutos comerciais e porcentagem de frutos brocados. Aos dados acumulados do número de frutos por planta e produção de massa fresca de frutos por planta, em função de dias de colheita, ajustou-se o modelo logístico para determinar os máximos acumulados para cada uma dessas variáveis. A produção de massa fresca de frutos por planta e a produtividade não foram afetadas pelos sistemas de cultivo, cujos valores médios foram 538,9 g e 17,9 t ha-1, respectivamente. A perda por frutos brocados foi superior no sistema diferenciado, porém ainda com alto índice de frutos comercializáveis, 78,6 a 87,2%. A indústria deve avaliar se a venda de um produto mais saudável pode atrair mais consumidores e compensar as perdas observadas.(AU)

Aiming to evaluate the production and the dynamics of productive increment of pickling cucumber plants, an experiment was carried out at the Epagri, Ituporanga Experimental Station, Santa Catarina State, Brazil, from January to March 2011. The test was conducted in splitplots in time in in a randomized block design, with four replications. The factors used were two production systems (conventional and differentiated) in the plots and three cultivars of cucumber (Marinda, Premium and Zapata) in the subplots. The plots were composed of four lines of 3 m in length, spaced 1.0 x 0.30 m apart with one plant per hill and the fl oor area consisting of central lines. We evaluated the production of fresh fruit per plant (g plant-1), productivity (t ha-1), fruit weight (g), number of fruits per plant, percentage of commercial fruit and percentage of infested fruit. For the accumulated data on the number of fruits per plant and yield of fresh fruit, depending on harvest days, we adjusted the logistic model to determine the maximum accumulated for each variable. The production of fresh fruit per plant and productivity were not affected by cropping systems, whose values were 538.9 g and 17.9 t ha-1, respectively. The loss per infested fruit was higher in the differentiated system, but was still with high percentage of commercial fruit, from 78.6 to 87.2%. The industry should evaluate whether the sale of a healthier product can attract more consumers and offset the losses observed.(AU)