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At least 19 recordsLinked to original sources

PubMed2026

PGPR inoculation and growth enhancement of crops cultivated in hydroponic systems.

Plant growth-promoting rhizobacteria (PGPR) are ubiquitous rhizosphere microorganisms that promote plant health through various mechanisms. Although the study of PGPR inoculants in soil has been done for ages, their application in hydroponic systems has received relatively limited attention. This review identifies PGPR inoculants that are commonly used in hydroponics, methods of application, and their effects on plant growth and nutrient use efficiency. Literature shows that PGPR inoculants improve plant performance in controlled hydroponic systems through the production of growth-stimulating substances, nitrogen fixation, and improved nutrient acquisition. However, the plant growth responses are highly variable depending on the composition of nutrient solutions, environmental factors, crop and microbe species, and the type of hydroponic system. The review identifies various challenges of PGPR inoculation in hydroponic systems and future research directions to address the current gaps. Generally, the productivity of hydroponic systems can be enhanced through advanced inoculation strategies and the development of suitable carrier materials to improve inoculant survival, viability, and functions. Emphasis should also be placed on designing system-specific microbial consortia and Synthetic communities that are tailored to the unique ecological conditions of hydroponic systems.

Hydroponics↗

PubMed1988

Uniformity of environmental conditions and plant growth in a hydroponic culture system for use in a growth room with aerial CO2 control.

A portable system of hydroponic culture was developed that maintained temperature, pH, and nutrient concentrations of circulating nutrient solutions. The hydroponic system is used within a controlled-environment room (CER) for control of aerial environment. The CER was equipped with an auto-calibrating system for atmospheric CO2 control. The control systems for the hydroponic chambers were able to maintain acidity within +/- 0.2 pH units and the temperature with +/- 0.5 degree C. Mixing time for the 200-liter volume of solution within a hydroponic chamber was less than 12 min. The CO2 control system was able to maintain aerial concentrations within +/- 10 ppm CO2 during the light period. The only gradient found to occur within the hydroponic chambers or CER was a slight gradient in aerial temperature along the length of hydroponic chambers. Growth of soybeans [Glycine max (L.) Merr.] was characterized during a 3-week period of vegetative development by leaf number and area, plant dry weight, total N content of plants, and N depletion from the nutrient solution. The growth characteristics among populations for three hydroponic chambers within the CER were not significantly different, and the percent standard errors of means of the measurements within populations from each chamber were nearly all less than 10%. Thus, the uniformity of plant growth reflected the uniformity of environmental conditions.

Atmosphere↗

PubMedDate not supplied

Wheat response to differences in water and nutritional status between zeoponic and hydroponic growth systems.

Hydroponic culture has traditionally been used for controlled environment life support systems (CELSS) because the optimal environment for roots supports high growth rates. Recent developments in zeoponic substrate and microporous tube irrigation (ZPT) also offer high control of the root environment. This study compared the effect of differences in water and nutrient status of ZPT or hydroponic culture on growth and yield of wheat (Triticum aestivum L. cv. USU-Apogee). In a side-by-side test in a controlled environment, wheat was grown in ZPT and recirculating hydroponics to maturity. Water use by plants grown in both culture systems peaked at 15 to 20 L m-2 d-1 up to Day 40, after which it declined more rapidly for plants grown in ZPT culture due to earlier senescence of leaves. No consistent differences in water status were noted between plants grown in the two culture systems. Although yield was similar, harvest index was 28% lower for plants grown in ZPT than in hydroponic culture. Sterile green tillers made up 12 and 0% of the biomass of plants grown in ZPT and hydroponic culture, respectively. Differences in biomass partitioning were attributed primarily to NH4-N nutrition of plants grown in ZPT compared with NO3-N in hydroponic nutrient solution. It is probable that NH4-N-induced Ca deficiency produced excess tillering and lower harvest index for plants grown in ZPT culture. These results suggest that further refinements in zeoponic substrate would make ZPT culture a viable alternative for achieving high productivity in a CELSS.

Biomass↗

PubMed2003

Carotenoid composition of hydroponic leafy vegetables.

Because hydroponic production of vegetables is becoming more common, the carotenoid composition of hydroponic leafy vegetables commercialized in Campinas, Brazil, was determined. All samples were collected and analyzed in winter. Lactucaxanthin was quantified for the first time and was found to have concentrations similar to that of neoxanthin in the four types of lettuce analyzed. Lutein predominated in cress, chicory, and roquette (75.4 +/- 10.2, 57.0 +/- 10.3, and 52.2 +/- 12.6 microg/g, respectively). In the lactucaxanthin-containing lettuces, beta-carotene and lutein were the principal carotenoids (ranging from 9.9 +/- 1.5 to 24.6 +/- 3.1 microg/g and from 10.2 +/- 1.0 to 22.9 +/- 2.6 microg/g, respectively). Comparison of hydroponic and field-produced curly lettuce, taken from neighboring farms, showed that the hydroponic lettuce had significantly lower lutein, beta-carotene, violaxanthin, and neoxanthin contents than the conventionally produced lettuce. Because the hydroponic farm had a polyethylene covering, less exposure to sunlight and lower temperatures may have decreased carotenogenesis.

Antioxidants↗

PubMedDate not supplied

Identification of QTLs for root characteristics in maize grown in hydroponics and analysis of their overlap with QTLs for grain yield in the field at two water regimes.

We investigated the overlap among quantitative trait loci (QTLs) in maize for seminal root traits measured in hydroponics with QTLs for grain yield under well-watered (GY-WW) and water-stressed (GY-WS) field conditions as well as for a drought tolerance index (DTI) computed as GY-WS/GY-WW. In hydroponics, 11, 7, 9, and 10 QTLs were identified for primary root length (R1L), primary root diameter (R1D), primary root weight (R1W), and for the weight of the adventitious seminal roots (R2W), respectively. In the field, 7, 8, and 9 QTLs were identified for GY-WW, GY-WS, and DTI, respectively. Despite the weak correlation of root traits in hydroponics with GY-WW, GY-WS, and DTI, a noticeable overlap between the corresponding QTLs was observed. QTLs for R2W most frequently and consistently overlapped with QTLs for GY-WW, GY-WS, and/or DTI. At four QTL regions, an increase in R2W was positively associated with GY-WW, GY-WS, and/or DTI. A 10 cM interval on chromosome 1 between PGAMCTA205 and php20644 showed the strongest effect on R1L, R1D, R2W, GY-WW, GY-WS, and DTI. These results indicate the feasibility of using hydroponics in maize to identify QTL regions controlling root traits at an early growth stage and also influencing GY in the field. A comparative analysis of the QTL regions herein identified with those described in previous studies investigating root traits in different maize populations revealed a number of QTLs in common.

Adaptation, Physiological↗

PubMed2003

A novel high efficiency, low maintenance, hydroponic system for synchronous growth and flowering of Arabidopsis thaliana.

BACKGROUND: Arabidopsis thaliana is now the model organism for genetic and molecular plant studies, but growing conditions may still impair the significance and reproducibility of the experimental strategies developed. Besides the use of phytotronic cabinets, controlling plant nutrition may be critical and could be achieved in hydroponics. The availability of such a system would also greatly facilitate studies dealing with root development. However, because of its small size and rosette growth habit, Arabidopsis is hardly grown in standard hydroponic devices and the systems described in the last years are still difficult to transpose at a large scale. Our aim was to design and optimize an up-scalable device that would be adaptable to any experimental conditions. RESULTS: An hydroponic system was designed for Arabidopsis, which is based on two units: a seed-holder and a 1-L tank with its cover. The original agar-containing seed-holder allows the plants to grow from sowing to seed set, without transplanting step and with minimal waste. The optimum nitrate supply was determined for vegetative growth, and the flowering response to photoperiod and vernalization was characterized to show the feasibility and reproducibility of experiments extending over the whole life cycle. How this equipment allowed to overcome experimental problems is illustrated by the analysis of developmental effects of nitrate reductase deficiency in nia1nia2 mutants. CONCLUSION: The hydroponic device described in this paper allows to drive small and large scale cultures of homogeneously growing Arabidopsis plants. Its major advantages are its flexibility, easy handling, fast maintenance and low cost. It should be suitable for many experimental purposes.

Arabidopsis↗

PubMed1996

Excess nutrients in hydroponic solutions alter nutrient content of rice, wheat, and potato.

Environment has significant effects on the nutrient content of field-grown crop plants. Little is known, however, about compositional changes caused by controlled environments in which plants receive only artificial radiation and soilless, hydroponic culture. This knowledge is essential for developing a safe, nutritious diet in a Controlled Ecological Life-Support System (CELSS). Three crops that are candidates for inclusion in a CELSS (rice, wheat, and white potato) were grown both in the field and in controlled environments where the hydroponic nutrient solution, photosynthetic photon flux (PPF), and CO2 level were manipulated to achieve rapid growth rates. Plants were harvested at maturity, separated into discrete parts, and dried prior to analysis. Plant materials were analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate, minerals, and amino-acid composition. The effect of environment on nutrient content varied by crop and plant part. Total N and nonprotein N (NPN) contents of plant biomass generally increased under controlled-environment conditions compared to field conditions, especially for leafy plant parts and roots. Nitrate levels were increased in hydroponically-grown vegetative tissues, but nitrate was excluded from grains and tubers. Mineral content changes in plant tissue included increased phosphorus and decreased levels of certain micronutrient elements under controlled-environment conditions. These findings suggest that cultivar selection, genetic manipulation, and environmental control could be important to obtain highly nutritious biomass in a CELSS.

Amino Acids↗

PubMed2003

Screening of willow species for resistance to heavy metals: comparison of performance in a hydroponics system and field trials.

The aim of this study was to ascertain whether metal resistance in willow (Salix) clones grown in a hydroponics screening test correlated with data from the same clones grown independently in a field trial. If so, results from a short-term, glasshouse-based system could be extrapolated to the field, allowing rapid identification of willows suitable for planting in metal-contaminated substrates without necessitating longterm field trials. Principal Components Analysis was used to show groups of clones and to assess the relative importance of the parameters measured in both the hydroponics system and the field; including plant response factors such as increase in stem height, as well as metal concentrations in plant tissues. The clones tested fell into two distinct groups. Salix viminalis clones and the basket willow Black Maul (S. triandra) were less resistant to elevated concentrations of heavy metals than a group of hardier clones, including S. burjatica 'Germany,' S.x dasyclados, S. candida and S. spaethii. The more resistant clones produced more biomass in the glasshouse and field, and had higher metal concentrations in the wood. The less resistant clones had greater concentrations of Cu and Ni in the bark, and produced less biomass in the glasshouse and field. Significant relationships were found between the response of the same clones grown the in short-term glasshouse hydroponics system and in the field.

Biomass↗

PubMed2001

[Feasibility of the use of degraded inedible biomass of plants as a nutrient liquid for hydroponic cultivation].

Objective. To demonstrate that the recycled liquid, which originated from lettuce inedible biomass degraded by fixed microorganism (correction of microorgannism) and enzyme, can be used as a nutrient solution for lettuce hydroponic cultivation. Method. After biologically degrading the weighted, oven-dried and milled leaves and roots of lettuce in a biological reactor under aerobic condition, the original effluent and its supplemented effluent were used as nutrients for lettuce hydroponic cultivation. Result. The average dried weight (ADW) of lettuce from the original effluent group was approximately half of that from the control group, and the ADW from supplemented effluent group was about equal to that from the control group; some qualities of the lettuce such as a relatively lower content of NO3- from both the original effluent group and the supplemented effluent one improved, and some of those such as a relatively higher content of NO2- dropped. Conclusion. The biologically-degraded effluent was able to be used as nutrient solution for lettuce hydroponic cultivation, although the effects of the inorganic ion-supplemented effluent were much better; the plants of lettuce from the biologically-degraded effluent were safely edible.

Biodegradation, Environmental↗

PubMed1984

The effect of aldicarb on nematode population and its persistence in carrots, soil and hydroponic solution.

Aldicarb, Temik 15 G, was incorporated in furrows at 3.37 and 6.73 kg ai (active ingredient)/ha and carrots (Daucus carota L.) were directly seeded on the same day. The numbers of nematode larvae were significantly suppressed in the treated plots; averages were 249, 74, and 51/50 cc soil samples for control (0), 3.37 and 6.73 kg ai/ha, respectively. Aldicarb treatment resulted in a 28% yield increase as compared to the untreated. Aldicarb residue in carrots was 28 ppb for the low treatment and 46 ppb for the high. Residual levels in soil of high treatment declined from 61 to 31 ppb during two weeks prior to harvest, meanwhile, those in the low decreased slightly from 13 to 12 ppb. Carrots placed in hydroponic solution containing aldicarb 14.5 ppm for 6 days, had an aldicarb residue of 10.26 ppb and the hydroponic solution, 2.7 ppb. Persistence of aldicarb residue was in carrot greater than in soil greater than in hydroponic solution.

Aldicarb↗

PubMed1980

Suspected foodborne carbamate pesticide intoxications associated with ingestion of hydroponic cucumbers.

In the period April 1--15, 1977, nine residents of one Nebraska town experienced violent illnesses with short duration following ingestion of locally grown hydroponic cucumbers. Despite a thorough investigation, the etiologic agent of illness was not determined. From July 16--25, 1978, a second similar outbreak occurred in an adjacent city. Five individuals experienced illness similar to that which occurred in 1977, also following ingestion of hydroponic cucumbers grown at the same greenhouse involved in the 1977 outbreak. The carbamate insecticide, aldicarb, was detected in some cucumbers grown at the hydroponic greenhouse. The source of this chemical in the greenhouse could not be determined.

Acute Disease↗

PubMed1992

Influence of hydroponic culture method on morphology and hydraulic conductivity of roots of honey locust.

The morphology and hydraulic conductivity of root systems of Gleditsia triacanthos L. var. inermis Willd. (honey locust) grown hydroponically in sand and solution cultures were compared. Total root system length was similar in the two cultures. However, root systems grown in solution had longer primary roots, fewer lateral roots and root hairs, and a greater distance between the tip of the primary root and the junction of the youngest secondary root and the primary root than root systems grown in sand. Hydraulic conductivities of root systems grown hydroponically for 21 or 35 days in sand or solution culture were similar. These findings show that different methods of hydroponic culture can affect root morphology without altering root resistance to water transport.

Journal Article↗

PubMed1987

The concurrent growth of plants and chemical purification of wastewater used as a hydroponic unit.

In this study the seedling of a variety of plants were successfully grown hydroponically on raw wastewater obtained from one of the main sewer outfalls in Beirut. In the first phase, a series of experiments was run on a batch system in glass or plastic containers provided with aeration facilities. A continuous-flow system with recirculation was adopted in the second phase. Iron supplementation was applied in all cases to compensate for its deficiency in the raw wastewater used. The immediate and ultimate objectives of the project were threefold: (a) to demonstrate the feasibility of utilizing as a hydroponic medium untreated municipal wastewater having relatively high mean values for BOD and mineral content; (b) to achieve the growth of useful plants on such readily available hydroponic media, thereby saving on fertilizers and scarce water resources; and (c) reclamation of the wastewater through biological purification leading to the gradual depletion of the nutritive constituents. Experimental conditions are described, and the data presented leads to the conclusion that the system is practicable on a laboratory scale. It has great potential for trial on a pilot scale prior to field applications in developing countries suffering from water shortage and hard currency expended on imported fertilizers and wastewater purification facilities.

Plant Development↗

PubMed1996

Survival of potentially pathogenic human-associated bacteria in the rhizosphere of hydroponically grown wheat.

Plants may serve as reservoirs for human-associated bacteria (H-AB) in long-term space missions containing bioregenerative life support systems. The current study examined the abilities of five human-associated potential pathogens, Pseudomonas aeruginosa, Pseudomonas cepacia, Staphylococcus aureus, Streptococcus pyogenes and Escherichia coli, to colonize and grow in the rhizosphere of hydroponically grown wheat, a candidate crop for life support. All of these bacteria have been recovered from past NASA missions and present potential problems for future missions. The abilities of these organisms to adhere to the roots of axenic five-day-old wheat (Triticum aestivum L. cv. Yecora rojo) were evaluated by enumeration of the attached organisms after a one hour incubation of roots in a suspension (approximately 10(8) cfu ml-1) of the H-AB. Results showed that a greater percentage of P. aeruginosa cells adhered to the wheat roots than the other four H-AB. Similarly incubated seedlings were also grown under attempted axenic conditions for seven days to examine the potential of each organism to proliferate in the rhizosphere (root colonization capacity). P. cepacia and P. aerogiunosa showed considerable growth, E. coli and S. aureus showed no significant growth, and S. pyogenes died off in the wheat rhizosphere. Studies examining the effects of competition on the survival of these microorganisms indicated that P. aeruginosa was the only organism that survived in the rhizosphere of hydroponically grown wheat in the presence of different levels of microbial competition.

Antibiosis↗

PubMed1992

Growing root, tuber and nut crops hydroponically for CELSS.

Among the crops selected by the National Aeronautics and Space Administration for growth in controlled ecological life support systems are four that have subsurface edible parts -- potatoes, sweet potatoes, sugar beets and peanuts. These crops have been produced in open and closed (recirculating), solid media and liquid, hydroponic systems. Fluorescent , fluorescent plus incandescent and high pressure sodium plus metal halide lamps have proven to be effective light sources. Continuous light with 16 degrees C and 28/22 degrees C (day/night) temperatures have produced highest yields for potato and sweet potato, respectively. Dry weight yields of up to 4685, 2541, 1151 and 207 g m-2 for for potatoes, sweet potatoes, sugar beets and peanuts, respectively, have been produced in controlled environment hydroponic systems.

Arachis↗

PubMed1996

Comparison of aerobically-treated and untreated crop residue as a source of recycled nutrients in a recirculating hydroponic system.

This study compared the growth of potato plants on nutrients recycled from inedible potato biomass. Plants were grown for 105 days in recirculating, thin-film hydroponic systems containing four separate nutrient solution treatments: (1) modified half-strength Hoagland's (control), 2) liquid effluent from a bioreactor containing inedible potato biomass, 3) filtered (0.2 micrometer) effluent, and 4) the water soluble fraction of inedible potato biomass (leachate). Approximately 50% of the total nutrient requirement in treatments 2-4 were provided (recycled) from the potato biomass. Leachate had an inhibitory effect on leaf conductance, photosynthetic rate, and growth (50% reduction in plant height and 60% reduction in tuber yield). Plants grown on bioreactor effluent (filtered or unfiltered) were similar to the control plants. These results indicated that rapidly degraded, water soluble organic material contained in the inedible biomass, i.e., material in leachate, brought about phytotoxicity in the hydroponic culture of potato. Recalcitrant, water soluble organic material accumulated in all nutrient recycling treatments (650% increase after 105 days), but no increase in rhizosphere microbial numbers was observed.

Aerobiosis↗

PubMed1997

Integrating biological treatment of crop residue into a hydroponic sweetpotato culture.

Residual biomass from hydroponic culture of sweetpotato [Ipomoea batatas (L.) Lam.] was degraded using natural bacterial soil isolates. Sweetpotato was grown for 120 days in hydroponic culture with a nutrient solution comprised of a ratio of 80% modified half Hoagland solution to 20% filtered effluent from an aerobic starch hydrolysis bioreactor. The phytotoxicity of the effluent was assayed with Waldmann's Green' lettuce (Lactuca sativa L.) and the ratio selected after a 60-day bioassay using sweetpotato plants propagated vegetatively from cuttings. Controlled environment chamber experiments were conducted to investigate the impact of filtrate from biological treatment of crop residue on growth and storage root production with plants grown in a modified half Hoagland solution. Incorporation of bioreactor effluent, reduced storage root yield of 'Georgia Jet' sweetpotato but the decrease was not statistically significant when compared with yield for plants cultured in a modified half Hoagland solution without filtrate. However, yield of 'TU-82-155' sweetpotato was significantly reduced when grown in a modified half Hoagland solution into which filtered effluent had been incorporated. Total biomass was significantly reduced for both sweetpotato cultivars when grown in bioreactor effluent. The leaf area and dry matter accumulation were significantly (P < 0.05) reduced for both cultivars when grown in solution culture containing 20% filtered effluent.

Biodegradation, Environmental↗

PubMed2002

An in vitro and hydroponic growing system for hypericin, pseudohypericin, and hyperforin production of St. John's wort (Hypericum perforatum CV new stem).

While the interest in medicinal plants continues to grow, there is a lack of basic information with respect to efficient protocols for plant production. Recently, in vitro regeneration protocols have been developed to provide masses of sterile, consistent St. John's wort. The current study assessed the potential for acclimatization of in vitro grown St. John's wort plantlets to a nutrient film technique (NFT) hydroponic system in a controlled environment greenhouse. Quantitative analyses of hypericin, hyperforin and pseudohypericin in flower tissues were used as the parameters to assess the quality of the greenhouse-grown plants. The three bioactive compounds were found to be present in similar or higher amounts than previously reported values for field-grown plants. These data provide evidence that greenhouse hydroponic systems can be effectively used for the efficient production of St. John's wort and other medicinal plants.

Anthracenes↗