Germination and vigor of lettuce seeds (Lactuca sativa L.) pelleted with homeopathic preparations Alumina and Calcarea carbonica subjected to toxic levels of aluminum.

Background: aluminum toxicity is the most important factor limiting the growth of plants in acid soils, whereas current treatments are unfeasible. For this reason, alternatives are sought for, among which homeopathic treatment. Aims: this study aimed at evaluating the influence of homeopathic preparations Alumina 6cH, Alumina 12cH, Calcarea carbonica 6cH and Calcarea carbonica 12cH on the germination and vigor of lettuce seeds subjected to toxic levels of aluminum in paper-solution. At the same time, it was sought to develop a new procedure to apply homeopathic preparations in plants (pelleting). Methods: the statistical design was entirely randomized (CRD) with 6 treatments and 4 repetitions. Treatments included: 1) pelleted seeds/talc + Alum 6 cH; 2) pelleted seeds/talc + Alum 12cH; 3) pelleted seed/talc + Calc 6cH; 4) pelleted seeds/talc + Calc 12cH; 5) pelleted seeds/talc + distilled water; 6) non pelleted seeds (control). Variables evaluated were: germination percentage (GP), germination speed index (GSI) and radicle length (RL). Results: there was significant difference in GSI and RL – variables that reflect the vigor of seeds - between the samples treated with homeopathic preparations and the controls Conclusions: homeopathic preparations Alumina 6cH and 12cH and Calcarea carbonica 6cH and 12cH had significant effect on the vigor of lettuce seeds subjected to stress conditions.

The effects of three plasma-activated water generation systems on lettuce seed germination

Irrigation water treatment using plasma technology is a new approach to improve productivity. In this study the generation of plasma-activated water (PAW) as a novel subject in agriculture is investigated. Three water treatment systems were designed and evaluated: 1^st PAW generation from vapor and injection into the water, 2^nd PAW generation using electrical discharge on the water surface and 3^rd PAW generation in the aeration path into the water. The lettuce seeds were irrigated with PAW. The germination rate and mean germination time were measured after 6 days. The seedlings weight and the number of seedlings with a length of more than 3 cm were also recorded after 8 days. The results showed that PAW had a significant effect on the germination rate and length of seedlings. Electrical discharge on the water surface had the best results. Germination rate and the number of seedlings with a length of more than 3 cm increased by 11 and 36% respectively. While injection of plasma-treated air into the water significantly reduced the number of seedlings longer than 3 cm, compared to the control. In conclusion, the PAW application can improve some attributes of lettuce germination depending on the PAW system.

Germination and the Initial Seedling Growth of Lettuce, Celeriac and Wheat Cultivars after Micronutrient and a Biological Application Pre-Sowing Seed Treatment

Seed treatments with zinc, boron, biostimulant Coveron and MIX (zinc + boron + Coveron) were applied to three lettuce and three celeriac cultivars. Seeds of three wheat cultivars were treated under laboratory conditions with Trichoderma harzianum and eight Bacillus spp. Seed germination, seedling growth, and the presence of the following pathogens were determined: Fusarium sp., Alternaria sp., Penicillium sp., and Mucor sp. The Coveron treatment was the most effective on lettuce seeds tested in the germination cabinet. Seed germination was higher by 4% than in the control. Alternatively, germination of seeds treated with boron in the greenhouse was higher by 12% than in the control. The Coveron treatment had the highest effect on the shoot length, which was greater by 0.7 and 2.1 cm in the germination cabinet and the greenhouse, respectively. This treatment was also the most effective on the root length. Zn, B, and MIX treatments increased celeriac seed germination by 14% in the germination cabinet. The Zn treatment was the most efficient on seeds tested in the greenhouse. The germination was higher by 15%. A significant cultivar × treatment interaction was determined in both observed species under both conditions. The maximum effect on wheat seed germination (8%) was achieved with the T. harzianum treatment in the Salazar cultivar. A significant interdependence (p ≤ 0.01 to p ≤ 0.001) was established between seed germination and the seedling growth. The interrelationship between seed germination and pathogens of all cultivars was negative.

The effects of ultra-high diluted gibberellic acid on in vitro lettuce seed germination.

Lettuce seeds bioassays have been used in many different tests such as: alellopathyc models; developing of new drugs; ecotoxicity tests. In most cases, lettuce (Lactuca sativa L., Asteraceae) has been used because of its sensitivity, simultaneous and rapid germination, reliability of germination percentage and homogeneity of seeds. The main goal was to evaluate the effects of ultra-high diluted gibberellic acid (GA3) on lettuce seeds germination and seedling growth. Experiment was performed using Petri dishes containing one disk of Whatman nº01 paper watered with 1ml of water. In each Petri dish 10 lettuce seeds(Lactuca sativa L.) cv Regina 500 were placed and 2ml of the different treatment solutions were add: GA33µmol, GA3 3CH (10-6), GA3 12CH (10-24), water 12CH and water (no dilution and succussion). One milliliter solutions were added every 2 days of experiment. The experiment was repeated twice and each one consisted in 5 Petri dishes per treatment (n=100). All seeds were maintained in germination incubator under controlled temperature (25°C) and photoperiod (16L/8D). The tested substances were prepared according to Brazilian Homeopathic Pharmacopoeia (Brazil, 2011). The experiment was blinded all the time. All seeds germinated at same time (2 days) and after 7 days the germination rate was the same in all treatments. Root was affected just by Water 12 CH, in which shown the longest length (4.59 cm) when compared with others treatments. Shoot length was higher where gibberellin was added in concentration upper then Avogrado’s number.

Antimicrobial and allelopathic effects of leaves extracts of Myrcia hatschbachii

Plants have been seen as alternatives for researching natural antimicrobials and herbicides. The aim of this work was to evaluate the antibacterial, antifungal, and allelopathic properties of leaves extracts of Myrcia hatschbachii. The crude extract and fractions were obtained by Soxhlet apparatus. Antimicrobial activity was determined by the minimum inhibitory concentration (MIC) using the broth microdilution method. The ethyl acetate fraction showed activity against Candida albicans (MIC: 62.5 µg/mL), Staphylococcus aureus (MIC: 500 µg/mL), and Pseudomonas aeruginosa (MIC: 1000 µg/mL). Allelopathic activity evaluated the influence of crude extract and fractions on the germination and growth of Lactuca sativa. The crude extract and the chloroform fraction inhibited the growth of the radicle, while the hexane fraction inhibited the growth of the hypocotyl and radicle of lettuce seeds in all concentrations (100-1000 μg/mL). The biological potential of the species motivates further study of new antimicrobial and bioherbicidal agents.

Omphaloprenol A: A new bioactive polyisoprenepolyol isolated from the mycelium of poisonous mushroom Omphalotus japonicus

Mushrooms of the Omphalotus genus are known to be rich in secondary metabolites. In the quest for new bioactive compounds, we analyzed the compounds isolated from the mycelium of the poisonous mushroom Omphalotus japonicus. As a result, a new polyisoprenepolyol, which was named omphaloprenol A, was identified, along with known substances such as hypsiziprenol A10 and A11, illudin S, and ergosterol. The chemical structure of omphaloprenol A was elucidated by nuclear magnetic resonance and infrared spectroscopies and mass spectrometry, and its bioactivity was investigated. Omphaloprenol A showed growth promoting activity against the root of lettuce seeds and cytotoxicity against HL60 cells. To the best of our knowledge, this is the first report on the isolation of a polyisoprenepolyol compound from Omphalotaceae mushrooms.

Fitoquímica e Alelopatia da Aroeira -Vermelha (Schinus terebinthifolius Raddi) na Germinação de Sementes

Os compostos alelopáticos podem afetar o crescimento e inibir a germinação das espécies. O objetivo deste trabalho foi analisar a fitoquímica e o efeito alelopático do extrato das folhas de Schinus terebinthifolius Raddi na germinação e crescimento de plântulas de Lactuca sativa L. e, posteriormente, aplicar a metodologia em eucalipto vermelho (Eucalyptus camaldulensis). Os compostos químicos foram determinados em extrato alcoólico das folhas, comparados e contrastados observando a alteração de cor. As sementes de alface e eucalipto vermelho foram distribuídas em gerbox contendo papel filtro como substrato, umedecido com 7 mL do extrato aquoso das folhas frescas, nas seguintes concen trações: (0; 12,5; 25; 50; 75 e 100%). Para todas as análises e experimentos foram utilizados três repetições. Os gerbox foram distribuídos em um delineamento inteiramente casualizado, mantidos em câmara de germinação com temperatura de 20 °C para alface e 28°C para eucalipto e fotoperíodo de 12 horas. Durante o segundo e quinto dia foram realizadas contagens das sementes germinadas de alface. O período de avaliação do experimento foi de cinco dias para alface e 12 dias para eucalipto. Ao final, foram determinadas as porcentagens de germinação, comprimento da raiz e de parte aérea das plântulas. Os resultados demonstraram interferência negativa na germinação e crescimento de alface e eucalipto em função do aumento da concentração do extrato. Entre os aleloquímicos predominantes estão os compostos fenólicos e derivados, com destaque aos flavonoides, terpenos e heterosídeos cardioativos o que pode estar relacionados ao efeito alelopático negativo da aroeira. O uso da aroeira associado ao eucalipto deve ser feito com um manejo adequado. Palavras-chave: Alface. Aleloquímicos. Anacardiaceae. Eucalipto. Efeito Alelopático. Abstract Allelopathic compounds can affect growth and inhibit species germination. The objective of this work was to analyze the phytochemistry and the allelopathic effect of extract of Schinus terebinthifolius Raddi leaves on the Lactuca sativa L. seedlings germination and growth and later apply the methodology in red eucalyptus (Eucalyptus camaldulensis). The chemical compounds were determined in the leaves alcoholic extract, compared and contrasted observing the color change. The lettuce and red eucalyptus seeds were distributed in a gearbox containing filter paper as a substrate, moistened with 7 mL of the fresh leaves aqueous extract in the following concentrations: (0; 12.5; 25; 50; 75 and 100%). For all analyzes and experiments, three repetitions were used. The gearbox was distributed in a completely randomized design, maintained in a germination chamber with a temperature of 20 °C for lettuce and 28 °C for eucalyptus and a photoperiod of 12 hours. Germinated lettuce seeds were counted during the second and fifth days. The experiment evaluation period was five days for lettuce and 12 days for eucalyptus. At the end, the germination percentages, root length and the seedlings aerial part were determined. The results showed negative interference in the germination and growth of lettuce and eucalyptus due to the extract increased concentration. The most frequent allelochemicals were flavonoids, terpenes, tannins, anthocyanins and heterosides, which are probably related to the negative allelopathic effect. The use of aroeira associated with eucalyptus must be done with proper management. Keywords: Lettuce, Allelochemicals Anacardiaceae. Eucalyptus. Allelopathic Effect.

Inductively Coupled Electrical Stimulation - Part 4: Effect of PEMF on seed germination; evidence of triphasic inverse hormesis

Our objectives were to study the effects of PEMF on a non-animal living system with a simple and unambiguous biomarker: seed germination rate. We selected seeds representing three groups: high- intermediate- and low-germination-rate seeds (lettuce, bell pepper, and strawberry, respectively). PEMF was applied at 15 pulses per second (pps or Hz) to strawberry and lettuce seeds, and 3 or 15 pps to bell pepper seeds, using only one well-defined PEMF pulse waveform shape and intensity. The only PEMF variables between groups were therefore PEMF pulse rate and total number of pulses, which was taken to be the PEMF dose, equivalent to the duration of exposure at a known pulse rate. In the case of lettuce, we studied the effects of germination using only one PEMF dose compared to no-dose (PEMF -) controls, and no interactions with other pre-planting procedures. In the case of strawberry seeds, we studied possible interactions between PEMF, pre-freezing and pre-soaking of seeds immediately before planting. For bell peppers, extensive dose-response curves are reported. Total dose was calculated as D = R * t, where R = pulse rate (pulses per second) and t = treatment duration (seconds), the product yielding D (dose, i.e. total number of pulses in the PEMF treatment). Bell pepper seeds have an intermediate germination rate that allows the possibility for large and commercially important swings in germination rate both up and down, so we attempted to construct a full spectrum dose-response curve, beginning with PEMF dosing thought to be below threshold then extending into what was thought to potentially be the excessive and toxic range. We also attempted to identify which PEMF parameters are most relevant for dosing: total number of pulses versus “frequency” (pulse rate) and duration of exposure. Results: Lettuce seeds showed evidence of a positive effect of PEMF on germination rate (79% unstimulated, 92% stimulated), with no effect on average time to germination. Strawberry seeds showed little effect of PEMF on germination, if any, and no apparent interaction with pre-freezing or pre-soaking of seeds. Bell Pepper seeds showed a clear inverse hormesis response within the dose range studied, and suggested a tri-phasic response to PEMF exposure for doses in excess of those applied. Specifically, extremely low PEMF doses had a negative effect on bell pepper seed germination rate, whereas intermediate doses had significant positive effects on germination rate, and germination rate began trending down again for the highest PEMF doses, suggesting a third phase of inhibited germination for extreme PEMF dosages. This latter trend was not fully elucidated by the present data set, but is only suggested by data points at the most extreme upper dosages included in this study. Overall, these results were entirely unexpected and may be of importance, therefore independent replication of these results is advised. To explain the unexpected results, a detailed discussion of various multi-phasic dose-response curves is also included. All negative findings were included in this report, specifically to counteract the dominant practice of publication bias in the life sciences.