Seedlings In Greenhouse Research Articles

Effects of dazomet fumigation on growth, biological characteristics of Malus hupehensis seedlings and soil environment

In this study, we examined the effects of dazomet fumigation with different concentrations (0, 0.1, 0.2, 0.4 g·kg-1) on the microbial characteristics of continuous cropping soil and growth of Malus hupehensis seedling in greenhouse and open-field pot. The results showed that all the treatment of dazomet fumigation could promote the growth of M. hupehensis seedlings in continuous cropping soil, with 0.2 g·kg-1 treatment showing the strongest effect. Compared to the control, plant height, stem diameter, dry weight of M. hupehensis seedlings in 0.2 g·kg-1 dazomet fumigation were increased by 192.9% and 91.8%, 72.8% and 60.1%, 196.8% and 195.0%, 138.5% and 130.7%, respectively in greenhouse and open-field. The root related indices (root length, root area, root volume, root respiration rate) were significantly promoted. The activities of SOD, POD, CAT in roots were increased by 114.6% and 118.5%, 123.5% and 107.6%, 164.6% and 175.6% respectively compared with the control, whereas the content of malondialdehyde was significantly lowered. Soil bacterial content, fungal content, copy number of Fusarium oxysporum gene and soil enzyme activity were significantly decreased with the increasing dazomet concentrations. In conclusion, 0.2 g·kg-1 dazomet fumigation could increase the biomass of M. hupehensis seedlings in continuous cropping, improve soil environment, and effectively alleviate the continuous cropping obstacle. Therefore, 0.2 g ·kg-1 dazomet fumigation could be given priority during the reconstruction of old apple orchards.

STUDI PERTUMBUHAN BIBIT BALANGERAN (Shorea balangeran) DI SHADE HOUSE SETELAH MENGALAMI PENYIMPANAN DALAM KARDUS DAN PEMELIHARAAN DALAM SUNGKUP PLASTIK

The research aims to analyze the height anddiameter growth, and survivalpercentage of shorea balangeran seedlingsunder shade house after being kept in the cartons, and tended in the small greenhouse. The method used was a completerandom design. The results showed that the highest high growth of belangeran seedlings under the shadehousewas 3.25 cmthat was reached through the treatmens of keeping the seedlings for 6 days in the carton, and without tending in small green house. The highest diameter growth of belangeran seedlings under the shadehouse was 0.188 cm reached through the treatmens of keeping the seedlings for 9 days in the carton, and tending the seedlings in small green house for 15 days. All belangeran seedlings (141 seedlings) used during the research process were alive under the shade house with the percentage of 100%.

Proanthocyanidin-Aluminum Complexes Improve Aluminum Resistance and Detoxification of Camellia sinensis.

Aluminum (Al) influences crop yield in acidic soil. The tea plant (Camellia sinensis) has high Al tolerance with abundant monomeric catechins in its leaves, especially epigallocatechin gallate (EGCG), and polymeric proanthocyanidins in its roots (rPA). The role of these polyphenols in the Al resistance of tea plants is unclear. In this study, we observed that these polyphenols could form complexes with Al in vitro, and complexation capacity was positively influenced by high solution pH (pH 5.8), polyphenol type (rPA and EGCG), and high Al concentration. In the 27Al nuclear magnetic resonance (NMR) experiment, rPA-Al and EGCG-Al complex signals could be detected both in vitro and in vivo. The rPA-Al and EGCG-Al complexes were detected in roots and old leaves, respectively, of both greenhouse seedlings and tea garden plants. Furthermore, in seedlings, Al accumulated in roots and old leaves and mostly existed in the apoplast in binding form. These results indicate that the formation of complexes with tea polyphenols in vivo plays a vital role in Al resistance in the tea plant.

Identifying Races of Fusarium oxysporum f. sp. niveum in South Carolina Recovered From Watermelon Seedlings, Plants, and Field Soil.

Fusarium wilt of watermelon (Citrullus lanatus), caused by the soilborne fungus Fusarium oxysporum f. sp. niveum, is the most serious disease of watermelon in South Carolina and other southeastern U.S. states. Isolates of F. oxysporum collected from field-grown plants, greenhouse-grown seedlings, and field soil between 1999 and 2018 were inoculated onto three differential watermelon cultivars to identify races. Of 197 isolates obtained from plants, 12% were nonpathogenic, 2% were race 0, 23% were race 1, and 63% were race 2. One collection of isolates from greenhouse seedlings was exclusively race 1 and the other was exclusively race 2. Seventeen of 81 soil isolates were pathogenic: five were race 1 and 12 were race 2. Reactions of C. amarus PI 296341-FR, Carolina Strongback, and SP-6, cultigens with resistance to race 2, did not differ significantly among five highly virulent race 2 isolates and a standard race 2 isolate, indicating a lack of a race 3 phenotype. Forma specialis-specific primers matched phenotypic race identification for 74% of the isolates. Race-specific primers based on a secreted-in-xylem elicitor present in race 0 and 1 isolates matched phenotypic race identification for 66% of the isolates. Because a majority of the F. oxysporum f. sp. niveum isolates from South Carolina were race 2, integrated management practices should be used until commercial cultivars with resistance to race 2 are available.

Small gradients in salinity have large effects on stand water use in freshwater wetland forests

Salinity intrusion is responsible for changes to freshwater wetland watersheds globally, but little is known about how wetland water budgets might be influenced by small increments in salinity. We studied a forested wetland in South Carolina, USA, and installed sap flow probes on 72 trees/shrubs along a salinity gradient. Species investigated included the trees baldcypress (Taxodium distichum [L.] Rich.), water tupelo (Nyssa aquatica L.), swamp tupelo (Nyssa biflora Walt.), and the shrub waxmyrtle (Morella cerifera (L.) Small). This study improves upon past reliance on greenhouse seedling studies by adding measurements of trees/shrubs along a salinity gradient, and better describes the role of low salinity on water use in freshwater wetland forests. We measured patterns of water use related to salinity, atmospheric conditions and season, and hypothesized that salinity would influence wetland forest water use through two mechanisms: salinity disturbances would yield stands with species and size classes that transpire less and individual trees with less conductive xylem tissue (i.e., sapwood). Both hypotheses held. At salinity concentrations ranging from fresh to 3 psu, forest structural changes alone resulted in stand water use reductions from 494 mm year-1 in freshwater stands to 316 mm year-1 in stands of slightly higher salinity. Tree sapwood function (inferred from radial sap flux profiles) also changed along this gradient and reduced sap flow rates by an additional 13.3% per unit increase in salinity (psu). Thus, stand water use was further reduced to 190 mm year-1 on saline sites. We found that forest structure is not the only change that affects water use in salinized watersheds; individual tree eco-physiological responses to salinity, manifesting in different radial sap flow profiles, are important as well.

Management of Heat Stress in Tomato Seedlings under Arid and Semi-Arid Regions: A Review

The production of protected cultivation of vegetables could be considered a sustainable solution in arid and semi-arid regions. These regions already suffer from the raising temperature due to the global warming, which represents a great challenge facing our universe nowadays. Hence, the production of vegetables under greenhouse system during the high temperatures may be considered a serious problem in these arid zones due to heat stress. In greenhouses, the production of tomato seedlings should avoid the high temperature stress in particular in arid and semi-arid in summer. The heat stress may cause a lot of troubles for the tomato seedlings in greenhouses in summer starting with the photosynthetic rate, and the metabolism processes in seedlings and in turn the growth and development of these seedlings. Although studies have recognized heat stress on tomato seedlings, research has yet to systematically investigate the effect of heat stress on tomato seedlings in greenhouse in summer under arid and semi-arid regions particularly in developed countries, which their greenhouses have not any climate controllers. Therefore, the management of tomato seedlings may need to address the production problems caused by heat stress in greenhouse conditions particularly in arid and semi-arid zones

Morphological Characterization and Pathogenicity of pythium sp. Infecting Cucumber Seedlings in Greenhouses

Greenhouse-grown cucumber seedlings exhibiting typical symptoms of Pythium damping-off and root rot were collected. The causal agents were isolate on Pythium selective medium; nystatin, ampicillin, rifampicin, and miconazole (NARM) in potato dextrose agar (PDA). Four different isolates was isolated and their pathogenicity was tested using cotyledon and young seedlings assays. Results of these isolates showed variation in their ability to infect cucumber seedling. Isolate GZ-11 was highly pathogenic, caused 100 % pre- and post-emergence damping-off. The isolate was identified to the species level based on morphological characters along with sequences of the internal transcribed spacer (ITS) of the ribosomal DNA and showed 99% similarity to Pythium spinosum (Synonym of Globisporangium spinosum). Aggressiveness of P. spinosum was investigated at two levels of inoculum concentrations (10 and 20 g/kg soil). Results reported that P. spinosum was highly aggressive and significantly reduced cucumber seed germination compared to the control.

Effect of Supplementary Lighting Duration on Growth and Activity of Antioxidant Enzymes in Grafted Watermelon Seedlings

Insufficient exposure to light in the winter may result in a longer production periods and lower quality of seedlings in greenhouses for plug growers. Supplementary artificial lighting to plug seedlings may be one solution to this problem. The objective of this study was to assess the effects of the duration of the supplementary light on the growth and development of two watermelon cultivars, ‘Speed’ and ‘Sambok Honey’ grafted onto ‘RS-Dongjanggun’ bottle gourd rootstocks (Lagenaria siceraria Stanld). Seedlings were grown for 10 days in a glasshouse with an average daily natural light intensity of 340 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and daily supplementary lighting of 8, 12 or 16 h from mixed LEDs (W1R2B1, chip ratio of white:red:blue = 1:2:1) at a light intensity of 100 μmol·m−2·s−1 PPFD, a group without supplementary light was set as the control (CK). The culture environment in a glasshouse had 25/15 °C day/night temperatures, an 85 ± 5% relative humidity, and a natural photoperiod of 8 h. The results showed that all the growth and development parameters of seedlings grown with supplementary light were significantly greater than those without supplementary light (CK). The 12 and 16 h supplementary light resulted in greater growth and development parameters than the 8 h supplementary light did. The same trend was also found with the indexes that reflect the quality of the seedlings, such as the dry weight ratio of the shoot and root, total biomass, dry weight to height ratio of scions, and specific leaf weight. The 12 h and 16 h light supplements resulted in greater Dickson’s quality indexes compared to the 8 h supplementary light, and the 12 h supplementary light showed the greatest use efficiency of the supplementary light. 16 h of daily supplementary light significantly increased the H2O2 content and the antioxidant enzyme activities in seedlings compared to the other treatments. This indicated that 16 h of supplementary light led to certain stresses in watermelon seedlings. In conclusion, considering the energy consumption, 12 h of supplementary light was the most efficient in improving the quality of the two cultivars of grafted watermelon plug seedlings.

From field sampling to pneumatic bioreactor mycelia production of the ectomycorrhizal mushroom Laccaria trichodermophora

In order to increase survival rates of greenhouse seedlings destined for restoration and conservation programs, successful mycorrhization of the seedlings is necessary. To reforest forest ecosystems, host trees must be inoculated with ectomycorrhizal fungi and, in order to guarantee a sufficient supply of ectomycorrhizal inoculum, it is necessary to develop technologies for the mass production of ectomycorrhizal fungi mycelia. We selected the ectomycorrhizal fungus Laccaria trichodermophora, due to its ecological traits and feasible mycelia production in asymbiotic conditions. Here, we report the field sampling of genetic resources, as well as the highly productive nutritional media and cultivation parameters in solid cultures. Furthermore, in order to achieve high mycelial production, we used strain screening and evaluated pH, carbon source concentration, and culture conditions of submerged cultures in normal and baffled shake flasks. The higher productivity culture conditions in shake flasks were selected for evaluation in a pneumatic bioreactor, using modified BAF media with a 10 g/L glucose, pH 5.5, 25 °C, and a volumetric oxygen transfer coefficient (KLa) of 36 h−1. Under those conditions less biomass (12–37 %) was produced in the pneumatic bioreactor compared with the baffled shake flasks. This approach shows that L. trichodermophora can generate a large biomass concentration and constitute the biotechnological foundation of its mycelia mass production.

Eco-physiological evaluation of Stele Transversal Area 1 for rice root anatomy and shoot growth

ABSTRACTLarger stele size with greater xylem area or endodermis thickness in rice roots may lead to higher plant water status and maintain yield. Sta1-NIL, a near-isogenic line of IR64 introgressed with Stele Transversal Area 1 (Sta1), a quantitative trait locus controlling stele transversal area (STA) was investigated together with IR64 for their root anatomy and physiological parameters, at seedling, heading and maturity stages in greenhouse and fields of water deficit and well-watered conditions in 2017 and 2018. Combined analysis of STA from nine observations of overall four experiments showed that STA was increased by 7% (35,400 to 37,800 μm2) by the introduction of Sta1 into IR64. Total late metaxylem area also increased by 6% (5,840 to 6,180 μm2), which came mainly from its single area rather than its number, whereas small increase in endodermis thickness was also noted. Genotype x observation for STA was marginal, but Sta1-NIL had larger STA under water deficit environments. Sta1-NIL also maintained higher mid-day leaf water potential (−2.34 ± 0.3 MPa) than IR64 (−2.57 ± 0.3 MPa). Meta-analysis of seven experiments under 14 environments showed tendency of the positive effect of Sta1 on grain yield increment (579 to 604 g m−2), which came from the increment of harvest index. This study indicated the importance of wider stele size for maintenance of higher plant water status and yield across different water regimes.

Phytophthora Antagonism of Endophytic Bacteria Isolated from Roots of Black Pepper (Piper nigrum L.)

In this study, 90 root samples were collected from 30 black pepper farms in three provinces in the Central Highlands of Vietnam. A total of 352 endophytic bacteria were isolated and their morphology described. An in vitro assay on the antifungal activity of these isolates was then conducted and 47 isolates were found to have antagonistic activity on Phytophthora fungi. The antifungal activity of the 47 isolates was evaluated in vivo by shoot assay. Among these 47 isolates, 6 were selected for further investigation. The six isolates were classified and identified by sequencing the 16S RNA gene and phylogeny. The results showed that all six endophytic bacteria belong to the following species of Bacillus genus: B. siamensis, B. amyloliquefaciens, B. velezenis, and B. methylotrophiycus. Enzymatic activity related to the antifungal activity of the six potent isolates was determined; it showed that they possessed high chitinase and protease activities. These isolates were applied for black pepper seedlings in greenhouse. The results showed three promising isolates: B. siamensis EB.CP6, B. velezensis EB.KN12, and B. methylotrophycus EB.KN13. Black pepper seedlings treated with the promising bacteria had the lowest rate of root disease (8.45–11.21%) and lower fatal rate (11.11–15.55%) compared to the control group (24.81% and 24.44%). In addition, the three promising isolates strongly affected the growth of the black pepper seedlings in greenhouse. The plant height, length of roots, and fresh biomass of the seedlings in the treated plots were higher than those in the control plots. Thus, the endophytic bacterial isolates have the potential to act as biocontrol agent for the sustainable production of black pepper.

Investigation of a root zone heating system for greenhouse seedling and its effects on micro-environment

Under the extremely cold climatic condition, crops have to survive severe heat stress conditions, even if they are being kept in greenhouses. In the winter and spring of North China, the air and soil temperature is low inside the greenhouse, and when using a traditional heating system, the energy consumption is high. This paper reports on a study of different design solutions for a root zone heating system based on a kind of low temperature radiation material. Root zone heating systems offer increasing crop quality and productivity. A novel type of heat preservation and root zone heating system was applied in greenhouse seedling. And through multiple experiments, the effect of the root zone heating system on the ambient environment and seedbed surface was studied, and the heat preservation effect and heating uniformity were discussed. Results show that single-layer film covering on the root zone heating system can make the average temperature at night increase 1°C. And the average seedbed surface and substrate temperature can increase 11.3°C and 5.2°C, respectively. In conclusion, the root zone heating system can effectively improve the environmental temperature of seedling and the uniformity of heating is high, which provides a strong guarantee for high-quality seedling cultivation. Keywords: greenhouse, root zone heating system, micro-environment, seedling, substrate temperature, air temperature DOI: 10.25165/j.ijabe.20201306.5905 Citation: He F, Hou Y, Li K, Wei X M, Liu Y Q. Investigation of a root zone heating system for greenhouse seedling and its effects on the micro-environment. Int J Agric & Biol Eng, 2020; 13(6): 47–52.

Genome‐wide mapping of resistance to stripe rust caused by Puccinia striiformis f. sp. tritici in hexaploid winter wheat

AbstractStripe rust, caused by the fungus Puccinia striiformis f. sp. tritici (Pst), is a widespread disease and major limit to wheat (Triticum aestivum L.) production worldwide. The USDA‐ARS National Small Grains Germplasm Collection has proven to be a rich source of genetic diversity to improve stripe rust resistance in wheat breeding programs. The objective of the present study was to investigate the genetic diversity and sources of resistance to stripe rust in 441 accessions from the collection representing globally sourced winter wheat germplasm, as a complement to a previous study. A genome‐wide association study was conducted to identify loci conferring resistance to Pst based on phenotypic data from four field experiments and greenhouse seedling resistance screening against three races of the pathogen. A total of 5831 single nucleotide polymorphism markers were used to investigate population structure, linkage disequilibrium, and marker–trait associations. Our results showed 12 and 7 genomic regions significantly associated with Pst resistance based on field adult‐plant and greenhouse seedling responses, respectively, at a false discovery rate adjusted P value of <0.1. Four of the significantly associated genomic regions were mapped far from previously identified Pst resistance genes and quantitative trait loci, indicating that they represent potentially new Pst resistance loci. The present study provides additional insight into the usefulness of wheat germplasm collections as an important resistance source that can be used to incorporate diverse resistance genes into adapted wheat cultivars. Further work should aim to validate the identified genomic regions and the associated molecular markers to enhance their utility in marker‐assisted breeding.

Ideal harvesting point of ‘Limeira-IAC382’ trifoliate orange fruits for seed extraction

Abstract Trifoliate orange is one of the rootstocks most used worldwide mainly because it provides excellent quality fruit production. Harvest at the correct time is among factors that determine the physiological quality of seeds. The aim of this study was to identify physicochemical changes in ‘Limeira-IAC382’ trifoliate orange fruits, searching for the ideal harvest moment to obtain high quality seeds. Fruits were harvested at 180, 210 and 240 days after anthesis, stored in cold chamber and evaluated at 0, 15, 30 and 45 days of storage. The following variables were determined: mass loss, fruit color index, soluble solids, total titratable acidity and fruit juice ratio. Seeds were manually extracted and dried until reaching 30% water content. Seeds were used for the performance of germination, electrical conductivity and greenhouse seedling emergence tests. Seeds from fruits harvested at 240 DAA showed higher germination and greenhouse seedling emergence percentage compared to the other treatments until 30 and 45 days of storage in cold chamber, respectively. Storage for 45 days in cold chamber of fruits harvested at 210 DAA increases seed germination rate and the percentage of seedlings from seeds harvested at 180 DAA. It could be concluded that the harvesting of ‘Limeira-IAC382’ trifoliate orange fruits should be performed when fruits reached yellowish peel and low juice ratio, aiming at obtaining seeds with physiological quality.

Cassava-based biocomposites as fertilizer controlled-release systems for plant growth improvement

One of the main problems caused by intensive agriculture, is the consequent water pollution resulting from fertilizer leaching, especially as a result of fertilizers overuse. Therefore, in the present study an evaluation of the efficiency of different urea controlled-release systems, based on cassava starch and bagasse, over tomato plants growth was carried out. All fertilized systems showed a tendency towards a greater general development, photosynthetic pigments content and nitrogen status of the plant. However, significant differences were observed regarding macronutrient dosage, being unsupported biocomposite films with 25 wt.% urea content the systems with a better performance. Thus, an ecofriendly, efficient and easy to implement urea dosage alternative system for greenhouse seedling has been developed.

Utility of ion-exchange substrates to grow potato seedlings under pot conditions

Present study reports the cultivation of potato seedlings on ionite substrates in pot culture. The possibility of using these substrates to preserve the qualitative characteristics of the potato genotype was studied. The research was conducted on hybrid seed potatoes produced in VNIIKH named after A. G. Lorch. During the growing season, the intensity of seedlings development in terms of stem height (every 2 weeks) was taken into account. At the end of the growing season, the number of leaves was analyzed, and after harvesting, the yield and its contributing components were taken into account. Dispersion analysis was performed to study the quantitative assessment of phenotypic factors. In peat soil, depending on their origin and year of cultivation, the percentage of seedling death varied from 26.0 to 41.6%. On ionite substrates, the survival rate of seedlings significantly increased - only 4.0-14.4% died when grown in cuvettes. After picking in pots, the full survival of seedlings was observed both in the control and in the experimental variants. The best of the experimental options for growing seedlings in pot culture was the substrate IS-2E, prepared on the basis of IS-2V and clinoptilolite in a volume ratio of 3:1. Growth and survival rate of seedlings on ionite substrates significantly increased by 19.3-30.2% over control and thus reduces percentage of seedlings elimination. Growing seedlings is one of the first and most important stages in the general scheme of potato breeding [1,2]. The pot culture of seedlings in greenhouses, which provides separate cultivation of genotypes, high planting density and the ability to eliminate the seasonality of this process, has acquired great importance [3]. However, the mixtures used as a substrate for growing plants do not provide optimal conditions for the growth and development of seedlings and the preservation of all genotypes [4,5]. Identifying optimal substrates and methods for obtaining hybrid seedlings of potatoes and improving the efficiency of selecting high-yielding genotypes at an early stage of selection is considered as an important researchable issue to increase the effectiveness of the entire selection process [6,7]. All this leads to strengthen the research in this direction, which has not yet developed and reported [8].

Produção de mudas de maracujazeiro-azedo em ambiente protegido: dimensionamento e manejo do ambiente de produção

A produção de mudas de maracujazeiro-azedo em ambiente protegido é uma tecnologia diferenciada, que qualifica o setor produtivo a reduzir ou até eliminar o risco de disseminação de doenças e pragas através das mudas. Também proporciona a obtenção de mudas avançadas (maiores que 80cm de altura), que possibilitam antecipação de colheita e maior produtividade em áreas de ocorrência endêmica da virose do endurecimento dos frutos do maracujazeiro, principal doença dessa cultura. Termos para indexação: Passiflora edulis; virose do endurecimento dos frutos; mudas sadias.

Developing Trees Tolerant to Degraded Mine Soils in an Underground Greenhouse

This project is exploring the potential for developing trees tolerable to degraded un-reclaimed mine site soils and tailings as a solution to re-establishing long-term tree growth on those sites. The project incorporates growing tree seedlings in an underground greenhouse grown from seeds planted in the degraded mine soils in which they will eventually be planted. The outcome of the project is expected to lead to a successful solution for re-establishing tree growth in soils and tailings containing high metal concentrations with minimal post-planting human intervention. The research is being conducted in an underground greenhouse located 100 ft below the surface in the old Orphan Boy Mine Underground Mine Education Center (UMEC) located on Montana Tech’s campus in Butte, Montana.

Beyond the two compartments Petri-dish: optimising growth promotion and induced resistance in cucumber exposed to gaseous bacterial volatiles in a miniature greenhouse system

BackgroundBacterial volatiles promote plant growth and elicit immunity responses in plants grown in two-compartment Petri dishes. Due to the limitations of bacterial volatile compound (BVC) treatments such as their high evaporation rates, it is convenient to apply BVCs in closed systems such as greenhouses. However, the concentrations of BVCs must be optimised. We therefore attempted to optimise BVC emissions from bacteria grown on solid medium and synthetic BVC treatment in order to maximise plant growth and induced resistance in a miniature greenhouse system.ResultsWe cultivated the model BVC emitter Bacillus subtilis GB03 on complex medium for continuous treatment, which we placed near 1-week-old cucumber seedlings in a miniature greenhouse. Aboveground and belowground plant growth parameters were significantly increased at 1 and 2 weeks after treatment with BVCs released by B. subtilis GB03. Moreover, this treatment protected cucumber seedlings against the angular leaf spot pathogen Pseudomonas syringae pv. lachrymans. In addition, cucumber shoot growth was promoted in response to the slow release of BVCs from filter paper that had absorbed 1000 and 10 µM synthetic 2,3-butanediol, a key BVC from B. subtilis strain GB03. However, induced resistance was only elicited when 10 plates containing 10 µM 2,3-butanediol were utilised in the miniature greenhouse. The mechanism of induced resistance appears to involve the activation of the jasmonic acid signalling pathway.ConclusionsTo overcome the difficulties associated with treatment using a single application of BVC in the greenhouse, we optimised conditions for BVC application via consistent exposure in a slow-release system.

ВПЛИВ ДОДАТКОВОГО ШТУЧНОГО ОСВІТЛЕННЯ НА ПОЧАТКОВІ ЕТАПИ РОСТУ ТА РОЗВИТКУ РОЗСАДИ ПОМІДОРА І ОГІРКА

Мета. Вивчення впливу додаткового штучного освітлення на початкові етапи росту та розвитку розсади огірка і помідора в умовах закритого ґрунту. Методи. Фенологічні спостереження, біометричні вимірювання, статистичні методи дослідження. Результати. Встановлено, що відмінності у швидкості росту гібридів помідора й огірка проявилися вже на ранніх етапах. Найбільш різкі відмінності спостерігали у помідора. У варіанті з досвічуванням вже на п’ятий день відмічали добре розвинені сім’ядольні листки, висота гіпокотиля при цьому становила в середньому 3,6 см, площа листкової поверхні першого справжнього листка – 3,08 см2. У той самий час у контролі рослини перебували на стадії розгортання сім’ядольних листків. У фазі двох – чотирьох справжніх листків як за висотою стебла, так і за площею листкової поверхні виділялася розсада варіанту з досвічуванням. Встановлено, що рослини при досвічуванні були більш вирівняні за висотою, мали міцне, сильно опушене, більшого діаметру стебло, сира маса рослин у середньому на 19% перевищувала варіант із природним освітленням. За фенологічними спостереженнями рослини огірка розвивалися майже однаково, за морфометричними даними рослини, які додатково досвічували, перевищували контроль. У фазі розгорнених сім’ядольних листків висота гіпокотиля в середньому на 23% перевищувала контроль. На цей період рослини обох варіантів досліду перебували на початковій стадії формування першого справжнього листка. У подальшому спостерігали значне прискорення росту в рослин, які додатково досвічували. У фазі двох справжніх листків висота рослин у досліді на 45% перевищувала контроль, а площа листкової поверхні – на 30%, товщина стебла при цьому у контролі на 7,9% була меншою. Висновки. Проведені дослідження свідчать про ефективність застосування світлодіодних фотоламп 30 Вт у весняний період для вирощування розсади в умовах закритого ґрунту. Протягом усього досліду у варіанті з додатковим досвічуванням у рослин помідора й огірка спостерігали прискорений ріст, більші висоту, площу поверхні листків та масу надземної частини. Крім того, при досвічуванні у рослин помідора одного віку спостерігали суттєві відмінності за темпами розвитку справжніх листків.