Development Of Lettuce Plants Research Articles

Influence of dynamic LED irradiation mode on the content of nitrates, structural and functional characteristics of lettuce plants

One of the promising irradiation modes for plant is dynamic, when parameters change throughout the growing process depending on certain factors. In this work, lettuce plants were illuminated under different LED light sources, including white (2700 K), 30% white (2700 K) + 70% red (660 nm), 15% blue (445 nm) + 85% red (660 nm), 40% blue (445 nm) + 20% red (630 nm) + 40% red (660 nm) and dynamic mode for 35 days to investigate the effects. Photosynthetically active flux density was the same for all lettuce samples during the experiment (210 µmol m−2 s−1). The results showed the effects of photoregulation on the growth and development of lettuce plants. Optimal irradiation regime for lettuce plants was a dynamic regime formed using two colour components: white (2700 K) and red (660 nm) LEDs. Lettuce grown under dynamic conditions had a lower content of nitrates and developed faster than under stationary conditions.

Improvement of Photosynthetic Pigment Characteristics, Mineral Content, and Antioxidant Activity of Lettuce (Lactuca sativa L.) by Arbuscular Mycorrhizal Fungus and Seaweed Extract Foliar Application

Beneficial plant–microbe interaction for enhancing crop yield and quality is a sustainable way to achieve eco-friendly, desirable agricultural productions. The main objective of this experiment was to evaluate the individual and combined effects of an arbuscular mycorrhizal fungus (AMF) strain (Funneliformis mosseae) and a seaweed extract (SWE) derived from Ascophyllum nodosum, on the growth and physiological responses of lettuce (Lactuca sativa L.). Lettuce plants were inoculated with commercial AMF inoculum (5 g kg−1 soil), and SWE foliar application was done at three levels (0.5, 1.5, and 3 g L−1). The findings revealed that AMF along with SWE generated the greatest impact. In fact, co-application of AMF inoculation and 3 g L−1 SWE considerably enhanced root colonization, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, and mineral content in the shoots and roots (N, P, K, Ca, Fe, Zn, and Mn content) of lettuce plants. This combination improved initial fluorescence (F0), photochemical efficiency of PSII (FV/Fm) and Y(NO) and total antioxidant activity (TAA), whereas the maximum fluorescence, (Fm) and Y(II), showed the highest increase in lettuce plants treated with AMF and 1.5 g L−1 SWE. Furthermore, AMF inoculation along with SWE, at concentrations 1.5 and 3 g L−1, considerably enhanced variable fluorescence (FV) and the activity of water decomposition in electron donor photosystem II (FV/F0). As a result of these findings, it can be stated that the co-application of AMF and SWE positively improves the growth and development of lettuce plants.

Effect of γ-radiation of lettuce seeds (Lactuca sativa L.) for the yield and removal of macronutrients by plants

The effect of pre-sowing treatment with different doses of γ-radiation 60Co on the development and yield of lettuce plants has been studied. For this purpose, the seed material was irradiated with ionizing radiation 60Co in doses of 1-6 Gy; vegetation experiment was laid to determine the weight of plants, as well as the accumulation of dry matter, nitrogen, phosphorus, potassium. The values of stimulating and inhibitive doses have been established. It was determined that radiation hormesis was observed for lettuce plants at doses of 1 and 2 Gy: there was an increase in crop yield and maximum accumulation of the main elements of mineral nutrition. A dose of 6 Gy inhibited the growth and development of lettuce plants; at this dose of radiation, not only a decrease in yield occurred, but also a decrease in phosphorus and potassium removal.

Poređenje parametara kvaliteta nepiliranog i novostvorenog piliranog semena zelene salate

Lettuce is one of the most common types of leafy vegetables in human diet that is grown worldwide. Narrow and very small seeds make its sowing very difficult, requiring a lot of time and labour. Also, plants produced by manual sowing are often characterized by uneven germination. Those problems could be prevented by sowing pelleted seeds which require the development of adequate pelleting technology. Absence of quality lettuce seeds in the Serbian market results in large amounts of imported pelleted seeds every year. The aim of this study was to develop a domestic pelleting procedure and examine its effects on seeds quality parameters, in order to provide seeds to local farmers at a more affordable price compared to imported commercial pelleted seeds. Pelleted and non-pelleted seeds of the Panukia F1 hybrid were compared in several quality characteristics (1000 seed weight, germination energy, germination percentage, seedling length) in laboratory and greenhouse conditions. There was no loss in seed quality with the pelleting process, although the seed weight increased 12-19 times. Pelleted lettuce seeds had very high germination energy and seed germination (97-98%). In greenhouse conditions, non-pelleted seeds sprouted unevenly in relation to pelleted seeds. These results confirm the advantages of sowing pelleted seeds in terms of uniform germination and development of lettuce plants, primarily due to the precision of mechanical sowing. By offering domestic pelleting lettuce seeds to the growers, the production process would be significantly improved and accelerated with the reduction of manual labour, and therefore the overall production cost.

Технічне забезпечення гідропоніки, як прогресивного виду вирощування овочевих культур

The aggravation of the food crisis and the impossibility of exporting agricultural products from the ports against the backdrop of the war in Ukraine only exacerbates the issue of food security. The purpose of writing the article is to substantiate the installation scheme for hydroponic cultivation of vegetable crops in closed soil conditions for obtaining stable harvests of vegetable crops throughout the year. To carry out research, a hydroponic plant that works on the principle of a nutrient layer (NFT) was developed and manufactured at the Department of General Agriculture of the Central Ukrainian National Technical University. The installation is designed for growing green vegetable crops. A coconut-agroperlite soil mixture was used as a substrate. The used installation is compact, provided with a lighting system and works in automatic mode. The useful area of the installation is 0.104 m2, so it is possible to grow from 40 to 112 lettuce plants at the same time. The use of a mineral solution in a hydroponic installation had a significant effect on the growth and development of lettuce plants and caused an increase in the area of leaf plates. In the experiment, the yield of Tudela variety lettuce was obtained - 4.9 kg/m2, which is 10-15% more than in soil conditions, and if the installation is used all year round - 5.0-5.5 times more. The advantage of the method is that there is no need to use fungicides. Since, without the presence of soil, there are no such pests as cabbageworm and sciaridis. And the biggest advantage is saving water and controlling the substances they absorb in the process of development. The latest systems of growing green vegetable crops in the conditions of hydroponic systems make it possible to harvest all year round, and in a much larger volume than under soil conditions. The developed design of the hydroponic system makes it possible to obtain a steady crop of lettuce plants when using a coconut-agroperlite soil mixture as a substrate. The proposed installation of the NFT system using a nutrient solution of mineral-biological preparations made it possible to obtain seedlings with a well-developed root system and an above-ground part with a yield of 4.9 kg/m2.

О влиянии растворов фульвокислот из сапропеля на растения салата при различных видах его обработки

Abstract. The purpose of our research was to assess the influence of treatment with fulvic acid (FA) solutions (obtained from sapropel) on the physiological state, production process, and quality of salad crops under intensive controlled conditions. Research method. Treatment of plants with solutions of FA in various concentrations was carried out under controlled conditions using three different methods: soaking cress seeds (0.03-300mg/l); non-root treatment of vegetative plants (90–150 mg/l), when growing lettuce by a low – volume method with drip fertigation with Knop nutrient solution; adding a nutrient solution to the root medium (0.03-150 mg/l), when growing lettuce under nutrient film technique. Results. The most pronounced stimulating effect on plant growth was obtained after seeds treatment with FA solutions in concentrations of 0.3-150.0 mg/l, during non-root treatment of lettuce in concentrations of 0.3 and 150.0 mg/l, and when FA was introduced into the root medium at a concentration of 90.0 mg/l. It was suggested the lettuce growth under the action of FA was conditioned by enhancing plants metabolism and increased entry of nutrients to the aboveground organs of plants (during non – root processing)- and by nutrient uptake increasingas well as activation of the synthesis of photosynthetic pigments-chlorophylls and carotenoids (when a nutrient solution was add to the root medium. Scientific innovation. Under controlled conditions, a comprehensive assessment of the effect of FA solutions obtained from sapropel on the physiological state, production process, and quality of salad crops was carried out. The concentrations of fulvic acid solutions that had the most pronounced stimulating effect on the growth and development of lettuce plants in various types of treatment were determined. The specificity of the responses of lettuce plants to various types of treatment with FA solutions was revealed.

Naturally based ionic liquids with indole-3-acetate anions and cations derived from cinchona alkaloids.

The use of highly efficient methods and natural raw materials in syntheses of new biologically active substances addresses the current challenges in this area: ensuring the highest possible efficacy at low concentrations and reducing negative environmental impact. In the present study, we applied this strategy to obtain a new group of ionic liquids containing the indole-3-acetate anion, which is a well-known plant growth hormone, and a cation derived from a cinchona alkaloid – quinine or quinidine. A comparison of the derivatization kinetics of both alkaloids was also carried out, and the use of a quaternary quinidine derivative as a source of biologically active ionic liquids is described here for the first time. The structures of the obtained compounds were fully confirmed based on spectral methods. According to analyses of the effects of the obtained compounds on the growth and development of lettuce plants (Lactuca sativa L.), the ionic liquids obtained with indole-3-acetate anions exhibited activity at a concentration of 0.5 mg dm−3, and the length of the alkyl substituent in the alkaloid-derived cation or the chirality of this cation is crucial in determining the biological activity of the compound. In the cases of several salts containing the 1-alkylquininium cation, we recorded significant, beneficial changes in micronutrient content, which directly translated into plant nutritional value, while no signs of phytotoxicity were observed. Analyses of relevant physicochemical properties (e.g., with differential scanning calorimetry, thermogravimetric analysis and solubility analysis) as well as microbial toxicity tests were also performed to evaluate the environmental impacts of the products. The promising results of our study indicate significant potential for application of these new ionic liquids derived from cinchona alkaloids.

GROWTH, YIELD AND POST-HARVEST EVALUATION OF LETTUCE PLANTS SUBJECTED TO DIFFERENT LEAF SILICON CONCENTRATIONS

Lettuce is considered the most produced and consumed leafy vegetable; however, it has short post-harvest life, which generates significant losses for both producers and consumers. Studies have proven the beneficial effect of silicon on fruits and vegetables. Therefore, the aim of the current study is to evaluate the influence of leaf calcium silicate application on the growth, biomass production and postharvest conservation of curly lettuce. The experiment was carried out in greenhouse at Federal Rural University of Amazonia, Parauapebas Campus / PA. It followed a completely randomized design (CRD) with five Si concentrations (0.0, 2.0, 4.0, 6.0 and 8.0 mg L-1) and eight repetitions, which totaled 40 plants. Plants were grown in plastic pots (capacity = 3 dm3) filled with soil classified as Red-Yellow Argisol. Different Si concentrations were applied to plant leaves, at the 20th and 27th days after transplantation (DAT). Silicon has favored the growth and development of lettuce plants, as well as reduced their post-harvest weight loss. It was possible concluding that the herein tested Si concentrations, which were applied to leaves - in the form of calcium silicate - had beneficial effect on lettuce plants.

Uso de Rejeito de Mineração de Calcário Ornamental para a Correção de Acidez do Solo e Desenvolvimento de Plantas

In the municipality of Nova Olinda - CE, the extraction of limestone for ornamental purposes, denominated Pedra Cariri, has been causing a series of environmental impacts due to the high generation and stock of tailings in the locality. The objective of this research was to verify the efficiency of this residue as a soil acidity broker and in the development of lettuce plants. The experiment was carried out in two stages: the first consisted of the incubation of 5 dm3 of soil in pots during three months, with doses of the powder from the Pedra Cariri tailing equivalent to 0%, 50%, 100% and 200% of the recommended dose for the elevation of soil base saturation to 60%, and a dose equivalent to 100% of the recommended dose, but using commercial calcitic limestone. The second stage of the experiment consisted in the cultivation of cv Lucy Brown lettuce in pots with soil previously corrected by liming. The powder from the Pedra Cariri tailing has potential to be commercialized as an agricultural input, because it caused elevation of the pH and Ca soil contents, reduction of exchangeable acidity, potential acidity and, consequently, decrease of aluminum saturation and increase of base saturation, not differing from the action of commercial calcitic limestone. The results of analyzes of lettuce development were not significant, where lettuce did not reach its productive potential. Nevertheless, the tailings powder had no toxic effects that would impair the development of the plant.

Enrichment of lithium in lettuce plants through agronomic biofortification

Biofortification of crops with lithium (Li) is a new trend in agriculture and researches on this subject still scarce, therefore, this work aims to evaluate the accumulation potential and the effects in agronomic characteristics of lettuce (Lactuca sativa L.) submitted to foliar application of two Li chemical sources and different concentrations. The experiment was conducted in a greenhouse and the applications of lithium hydroxide (LiOH) and lithium sulfate (Li2SO4) were done via foliar spray at concentrations ranging from 0 to 40 mg dm−3. The applications were divided into three applications distributed at 15, 25, and 35 days after transplanting. Positive and promising results were observed in agronomic characteristics and Li in accumulation. High concentrations of Li (40 mg dm−3) may compromise the development of lettuce plants, however, lower concentrations applied (16 to 26 mg dm−3 of Li) promoted an increase in dry weight of roots and shoot/root ratio, both chemical forms, and stem diameter and specific leaf area, Li2SO4, suggesting beneficial effect of this element. Li accumulation in shoots depend on the concentrations of this element in the applied solution of Li but not on its chemical form.

Vermicomposto bioenriquecido com Trichoderma spp.

The intensification of agropastoral activity leads to a high production of waste. The composting of these residues produces an agricultural input with high potential in the production of vegetables and with the possibility of association with organisms of biological control, allowing the production of an ecologically correct substrate, rich in nutrients and protector of the health of the plants. In this sense, the objective of this work was to evaluate the survival of the fungus Trichoderma spp. During the vermicompost process, as the physical / chemical development caused not substrate and the growth and development of lettuce plants grown in the different treatments used. Basal substrates were obtained from the creation of three different animals: sheep, Horses and rabbits, whether or not containing added Trichoderma spp. In all treatments, worms of Eisenia foetida were added. Evaluations of fungus survival, physical and chemical analyzes of the substrate produced and evaluation without growth and development of lettuce plants were carried out. The treatments were arranged in a 3x2 factorial scheme and the experimental design was completely randomized, with 4 replicates. Data were analyzed using Sisvar® software, and as means averages compared by Scott Knott's test at 5% error probability. Trichoderma spp. It survives the vermicompost process by improving the development of lettuce plants when associated with farms residue. The use of Trichoderma spp. It reduced the calcium values of all substrates, raised a dry density of the base substrate of rabbit residues, and reduced the base substrate of farmyard residues. The substrate that provided the best growth and development of lettuce plants was the residues of rearing of horses, being favored by the presence of Trichoderma spp. in the second year.

The Effect of Cadmium Toxicity on the Development of Lettuce Plants on Contaminated Sod-Podzolic Soil

The influence of cadmium on the morphometric and biochemical indicators of the development of lettuce of the Moscow greenhouse variety, on productivity and also on metal accumulation in plant biomass during cultivation on sod-podzolic soil polluted with this toxicant in the doses range from 2 to 100 mg/kg was studied. It was shown that cadmium has a toxic effect on the development of lettuce: the plant height was reduced by 29.7–77.5%, the number of leaves was reduced by 16.4–61.3%, and the leaf surface area decreased by 34.5–99% depending on the level of contamination. The presence of metal in the soil in concentrations 5–100 mg/kg caused a decrease of the content of chlorophyll a by 15.6–38.1% in plants; chlorophyll b content decreased by 18–20% at cadmium concentration 10–100 mg/kg; carotenoids decreased by 40% at concentrations 20–50 mg/kg. Cadmium contributed to a decrease in free proline content by 20–26% with Cd concentrations at 5–100 mg/kg of soil; at a concentration of 2 mg/kg, on the contrary, Cd caused an increase of proline content of 66.2% and malondialdehyde content of 59.9% in comparison with the control. Productivity of plants decreased by 49.6–99.6% at all studied concentrations, and the level of metal accumulation in plants was significantly higher than the permissible level of cadmium (0.03 mg/kg) for lettuce.

Effects of different growth media and planting densities on growth of lettuce grown in a closed soilless system

This study aimed at determining the effects of growth medium and planting density on lettuce (Lactuca sativa L.) production under a closed soilless system. Soilless lettuces were produced during autumn season of 2012–13, that were tested under three different growth media and two planting densities (16 and 33 plants/m2). The highest head mass and marketable head mass (0.640 and 609 kg) were obtained at planting density (16 plants/m2). When analyzed for interaction between the growth medium and planting density, the higher head mass (691 and 697 g) was obtained between the interactions Tuff br: peatmoss and Tuff br with planting density of 16 plants/m2. The results showed that planting density and growth medium exhibited significant effects on stem weight (g), weight of leaves (outer+inner) (g), number of non-consumable leaves, number of outer leaves, number of inner leaves, total number of leaves, marketable head mass (g), head mass (g) and plant height (cm). In conclusion, the substrates interference with the development of lettuce plants, it was Tuffbr: Peatmoss and Tuff brown which provided the best plant growth.

Vermicomposto bioenriquecido com Trichoderma spp.

A ciclagem de resíduos de origem animal pelo processo de compostagem e sua transformação em insumos para produção vegetal além de minimizarem os impactos ambientais, podem ser uma importante fonte de renda ao produtor. Além disso, a compostagem desses resíduos produz um insumo agrícola com elevado potencial na produção de hortaliças e com possibilidade de associação com organismos de controle biológico, possibilitando a produção de um substrato ecologicamente correto, rico em nutrientes e protetor da saúde das plantas. Nesse sentido, o objetivo deste trabalho foi avaliar a sobrevivência do fungo Trichoderma spp. durante o processo de vermicompostagem, as alterações físico/químicas ocasionadas no substrato e o crescimento e desenvolvimento de plantas de alface cultivadas. Foram avaliados, como substratos base, resíduos da criação de ovinos; cavalos e coelhos, com ou sem a adição de Trichoderma spp. Em todos os tratamentos foram adicionadas minhocas da espécie Eisenia fetida. Os tratamentos foram arranjados em esquema fatorial 3x2 e o delineamento experimental foi o inteiramente casualizado, com 4 repetições O fungo Trichoderma spp. sobrevive durante o processo de vermicompostagem dos diferentes resíduos. A utilização de Trichoderma spp. não teve efeito nos teores de fósforo, magnésio e matéria orgânica, reduziu os valores de cálcio, elevou os teores de potássio para o substrato a base de coelho, aumentou a densidade seca do substrato base de resíduos de coelho e reduziu do substrato base de resíduos de cavalos. O substrato que proporcionou o melhor crescimento e desenvolvimento de plantas de alface foi o de resíduos de criação de cavalos, sendo favorecido pela presença de Trichoderma spp. no segundo ano de cultivo.

Resíduo da produção de Pochonia chlamydosporia no desenvolvimento de mudas e plantas de alface

O objetivo deste trabalho foi avaliar o efeito de subproduto do processo de produção de Pochonia chlamydosporia var. chlamydosporia no desenvolvimento de mudas e plantas de alface. Esse subproduto, um resíduo constituído de arroz que continha propágulos do fungo, foi adicionado em diferentes concentrações (0, 2 e 4% volume de resíduo:volume de substrato) a três tipos de substratos para mudas (formulado, comercial e fibra de coco). Sementes de alface foram semeadas em bandejas de isopor que continham os diferentes substratos enriquecidos com o resíduo. As mudas de alface foram transplantadas para vasos com o substrato solo e areia na proporção 1:1 (v:v), 28 dias após a semeadura. Todos os tipos de substratos e doses do resíduo apresentaram interação significativa para todas as variáveis relacionadas ao desenvolvimento das mudas e das plantas de alface. O maior desenvolvimento das mudas ocorreu na testemunha (sem o resíduo) dos substratos. Entretanto, após o transplantio das mudas para os vasos, as doses de resíduo até 4 e 2% v:v - nos substratos formulado e comercial, respectivamente - foram as que promoveram o maior desenvolvimento das plantas. A utilização de até 2% v:v do resíduo nos substratos formulado e comercial é viável e não prejudica o desenvolvimento de plantas de alface.

FERTILIZAÇÃO E QUALIDADE DA ÁGUA DE IRRIGAÇÃO NO CRESCIMENTO E DESENVOLVIMENTO DA ALFACE

O presente trabalho foi desenvolvido no CEA/UNESP, com o objetivo de avaliar os efeitos das diferentes fontes de adubação e da qualidade da água de irrigação no crescimento e desenvolvimento da cultura da alface. Adotou-se delineamento em blocos casualizados, com tratamentos distribuídos em esquema fatorial 5 x 2, correspondentes aos tipos de fertilização (não adubado, efluente de biodigestor, esterco bovino, cama-de-frango, adubação mineral) e qualidades de água de irrigação (tratada e residuária), com três repetições. Foram avaliados os parâmetros altura de planta, diâmetro do caule, produção de matéria seca e fresca e índice de área foliar. Apenas houve influência estatística dos tratamentos na produção de matéria seca e fresca, com inferioridade dos tratamentos não adubados. Não houve diferença no crescimento da alface quando submetido às  diferentes fontes de fertilizantes. A qualidade da água não exerceu influência sobre o crescimento e desenvolvimento da alface.

Growth and development of lettuce plants at high NH4+:NO3- ratios in the nutrient solution

Lettuce plants, cv. Vera, were grown at five NH4+:NO3- ratios in the nutrient solution in a 0.15 m deep sand growing bed. A standard nutrient solution was used, with the composition of, in mmol L-1, 11.0 NO3-; 1.5 H2PO4-; 6.5 SO4--; 7.5 Ca++; 10.0 K+ and 1.5 Mg++, and, in mg L-1, 0.42 Mn; 0.26 Zn; 0.05 Cu; 0.50 B; 0.04 Mo, and 4.82 chelate Fe. Ammonium nitrate was used to supply NH4+ concentrations of 2.5; 5; 7.5 and 10 mmol L-1, reaching NH4+:NO3- ratios of 0:11 (T1); 2.5:13.5 (T2); 5:16 (T3); 7.5:18.5 (T4) and 10:21 mmol L-1 (T5) as treatments. A completely randomized experimental design was used, with four replications and 20 plants per plot. Four plants of each plot were harvested at 25 days after planting, to determine shoot and root dry mass, shoot fresh weight and number of leaves per plant. Number of leaves, shoot fresh and shoot and root dry mass decreased 25.5%; 52.5% and 68.5% from T1 to T5, respectively, following polynomial models. Root dry mass was 1.7 g/plant for T1 and T2, and 0.82 g/plant for T3, T4 and T5, decreasing in a proportion of 51.8%. For lettuce crop production in hydroponical facilities, the NH4+ threshold limit of about 9-12% of the total N should be retained.