scholarly journals The Effect of Light-dependent Application of Nitrate on the Growth of Aeroponically Grown Lettuce (Lactuca sativa L.)

2004 ◽  
Vol 129 (4) ◽  
pp. 570-575 ◽  
Author(s):  
Jernej Demšar ◽  
Jože Osvald ◽  
Dominik Vodnik
Keyword(s):  
Lactuca Sativa ◽  
Early Spring ◽  
Nitrate Content ◽  
Light Conditions ◽  
Nitrate Accumulation ◽  
Low Light ◽  
Efficient Reduction ◽  
Nitrate Supply ◽  
Lettuce Yield ◽  
Leaf Nitrate

With a high nitrate supply, and most frequently under low-light conditions, lettuce accumulates relatively large amounts of NO3-as a result of an excess of uptake over reduction. Different approaches, which are used to reduce leaf nitrate, often result in a yield loss. A computerized aeroponic system, which supplies different nitrate concentrations in accordance with the changeable light conditions (dynamic light-dependent application of nitrate), was used to reduce nitrate accumulation in lettuce (Lactuca sativa L.) var. Capitata cv. Vanity. Under unfavorable light conditions nitrate was supplied at limited rates (slight, medium, and strong reduction) to the plants. In response to given light conditions the nitrate supply was reduced close to one-half or one-fourth of the full nutrient solution (8 mmol·L-1 NO3-). Controlled nutrition resulted in efficient reduction in leaf nitrate. In the early-spring experiment the average nitrate content in outer leaves was decreased by 9%, 63%, and 92% and in the late-spring experiment the decrease was 23%, 58%, and 76% compared to control. At the same time, the controlled, light-dependent nitrate deprivation did not result in a loss of a lettuce yield (except in the treatment with strong nitrate reduction) and had limited effects on photosynthesis (PN-Ci measurements) and photosynthetic pigments.

scholarly journals EC Sensitivity of Hydroponically-Grown Lettuce (Lactuca sativa L.) Types in Terms of Nitrate Accumulation

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 315
Author(s):  
Noémi Kappel ◽  
Ildikó Fruzsina Boros ◽  
Francia Seconde Ravelombola ◽  
László Sipos
Keyword(s):  
Lactuca Sativa ◽  
Nitrate Content ◽  
Saline Condition ◽  
Fresh Weight ◽  
Nitrate Level ◽  
Nitrate Accumulation ◽  
Strong Negative Correlation ◽  
Lactuca Sativa L ◽  
Hydroponically Grown ◽  
European Markets

The goal of this research was to investigate the effect of electrical conductivity (EC) levels of the nutrient solution on the fresh weight, chlorophyll, and nitrate content of hydroponic-system-grown lettuce. The selected cultivars are the most representative commercial varieties grown for European markets. Seven cultivars (‘Sintia,’ ‘Limeira,’ ‘Corentine,’ ‘Cencibel,’ ‘Kiber,’ ‘Attiraï,’ and ‘Rouxaï’) of three Lactuca sativa L. types’ (butterhead, loose leaf, and oak leaf) were grown in a phytotron in rockwool, meanwhile the EC level of the nutrient solutions were different: normal (<1.3 dS/m) and high (10 dS/m). The plants in the saline condition had a lower yield but elevated chlorophyll content and nitrate level, although the ‘Limeira’ and ‘Cencibel’ cultivars had reduced nitrate levels. The results and the special characteristic of the lollo-type cultivars showed that the nitrate level could be very different due to salinity (‘Limeira’ had the lowest (684 µg/g fresh weight (FW)) and ‘Cencibel’ had the highest (4396 µg/g FW)). There was a moderately strong negative correlation (−0.542) in the reverse ratio among the chlorophyll and nitrate contents in plants treated with a normal EC value, while this relationship was not shown in the saline condition. Under the saline condition, cultivars acted differently, and all examined cultivars stayed under the permitted total nitrate level (5000 µg/g FW).

scholarly journals Development of Lettuce Plant in Spring and Autumn Period, Effects of Led Lightening on the Quantity of Mineral Substrates and Leaf Nitrate

2019 ◽  
pp. 1-9
Author(s):  
Seda Bice Ataklı ◽  
Sezer Şahin
Keyword(s):  
Blue Light ◽  
Red Light ◽  
Early Spring ◽  
Nutrient Concentrations ◽  
Nitrate Content ◽  
Winter Period ◽  
Significant Difference ◽  
Spring And Autumn Period ◽  
Leaf Nitrate ◽  
Curly Leaf

Aims: This study was performed during early spring and winter period of 2015-2016 by utilizing soilles technique in a non-heated glasshouse that belongs to Gaziosmanpaşa University Faculty of Agriculture. Study Design: Whereas Funly F1 lettuce species was used as vegetal materials, 2:1 ratio cocopeat and perlite mixture was used as cultivation environment. According to the experiment design, experiment coincidence parcels were performed as 3-recurrences. In the experiment, the effects of different colored LED lights (blue, yellow, red, blue + yellow, blue + red, yellow + red, blue + yellow + red) additional to sunlight were examined. Results: SMD strip LEDs with different colors were used as light source. The light practice does not affect on the plant diameter, plant lenght, SÇKM, pH, titered acid, vitamin C and plant nutrient concentrations. Statistically significant difference occured in the yield of spring and winter curly leaf head salad. There was also an increase at 1% importance level in the light practices compared to the control. In the experiment, red and red blue light combinations had an increase of 1% in the curly leaf head salads in the yield rate when it was compared to the control. Whereas the highest total plant head weight was 840 gr/piece in spring practice, and it was 732 gr/piece for the red light practices in winter practice. Compared to the control, the amount of plant leaf nitrate for the light practices resulted in a decrease at 1% importance level in the curly leaf head salad. When the results were compared with the control conditions, the lowest nitrate contents were obtained as 1764.5 mg NO3-kg- in spring practices, 1898.6 NO3-kg- in winter practices. Coclusion: More amount of nitrate was observed on the leaves of curly leaf head salad in winter practice compared to the one in spring. The amount of leaf nitrate decreased in the light practices compared to the control. As a result, the red and blue light practices and their combinations improved the amount of yield and plant growth by reducing nitrate content.

The effect of plant mulching and covering on the lettuce yield and nitrate content (Lactuca sativa L.)

2014 ◽  
Vol 9 (23) ◽  
pp. 1774-1777 ◽  
Author(s):  
Toić Ivana ◽  
Ilin Žarko ◽  
Maksimović Ivana ◽  
Pavlović Slobodanka
Keyword(s):  
Lactuca Sativa ◽  
Nitrate Content ◽  
Lactuca Sativa L ◽  
Lettuce Yield

Changes in the Stoichiometry of Photosystem II Components as an Adaptive Response to High-Light and Low-Light Conditions during Growth

1986 ◽  
Vol 41 (5-6) ◽  
pp. 597-603 ◽  
Author(s):  
Aloysius Wild ◽  
Matthias Höpfner ◽  
Wolfgang Rühle ◽  
Michael Richter
Keyword(s):  
Photosystem Ii ◽  
Functional Organization ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Molar Ratio ◽  
Light Conditions ◽  
Low Light ◽  
Pigment System ◽  
Transport Chain ◽  
The One

The effect of different growth light intensities (60 W·m-2, 6 W·m-2) on the performance of the photosynthetic apparatus of mustard plants (Sinapis alba L.) was studied. A distinct decrease in photosystem II content per chlorophyll under low-light conditions compared to high-light conditions was found. For P-680 as well as for Oᴀ and Oв protein the molar ratio between high-light and low-light plants was 1.4 whereas the respective concentrations per chlorophyll showed some variations for P-680 and Oᴀ on the one and Oв protein on the other hand.In addition to the study of photosystem II components, the concentrations of PQ, Cyt f, and P-700 were measured. The light regime during growth had no effect on the amount of P-700 per chlorophyll but there were large differences with respect to PQ and Cyt f. The molar ratio for Cyt f and PQ between high- and low-light leaves was 2.2 and 1.9, respectively.Two models are proposed, showing the functional organization of the pigment system and the electron transport chain in thylakoids of high-light and low-light leaves of mustard plants.

scholarly journals Perceptually based tone mapping for low-light conditions

2011 ◽  
Vol 30 (4) ◽  
pp. 1-10 ◽  
Author(s):  
Adam G. Kirk ◽  
James F. O'Brien
Keyword(s):  
Tone Mapping ◽  
Light Conditions ◽  
Low Light

scholarly journals Olfactory acuity in theropods: palaeobiological and evolutionary implications

2008 ◽  
Vol 276 (1657) ◽  
pp. 667-673 ◽  
Author(s):  
Darla K Zelenitsky ◽  
François Therrien ◽  
Yoshitsugu Kobayashi
Keyword(s):  
Olfactory Bulb ◽  
Cerebral Hemisphere ◽  
Home Ranges ◽  
Light Conditions ◽  
Low Light ◽  
Olfactory Bulbs ◽  
Theropod Dinosaurs ◽  
Olfactory Acuity ◽  
Predicted Values ◽  
Omnivorous Diet

This research presents the first quantitative evaluation of the olfactory acuity in extinct theropod dinosaurs. Olfactory ratios (i.e. the ratio of the greatest diameter of the olfactory bulb to the greatest diameter of the cerebral hemisphere) are analysed in order to infer the olfactory acuity and behavioural traits in theropods, as well as to identify phylogenetic trends in olfaction within Theropoda. A phylogenetically corrected regression of olfactory ratio to body mass reveals that, relative to predicted values, the olfactory bulbs of (i) tyrannosaurids and dromaeosaurids are significantly larger, (ii) ornithomimosaurs and oviraptorids are significantly smaller, and (iii) ceratosaurians, allosauroids, basal tyrannosauroids, troodontids and basal birds are within the 95% CI. Relative to other theropods, olfactory acuity was high in tyrannosaurids and dromaeosaurids and therefore olfaction would have played an important role in their ecology, possibly for activities in low-light conditions, locating food, or for navigation within large home ranges. Olfactory acuity was the lowest in ornithomimosaurs and oviraptorids, suggesting a reduced reliance on olfaction and perhaps an omnivorous diet in these theropods. Phylogenetic trends in olfaction among theropods reveal that olfactory acuity did not decrease in the ancestry of birds, as troodontids, dromaeosaurids and primitive birds possessed typical or high olfactory acuity. Thus, the sense of smell must have remained important in primitive birds and its presumed decrease associated with the increased importance of sight did not occur until later among more derived birds.

scholarly journals Study of nitrate levels in fruits and vegetables to assess the potential health risks in Bangladesh

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rayhan Uddin ◽  
Mostak Uddin Thakur ◽  
Mohammad Zia Uddin ◽  
G. M. Rabiul Islam
Keyword(s):  
Cluster Analysis ◽  
Health Risks ◽  
Fruits And Vegetables ◽  
Risk Index ◽  
Daily Intake ◽  
Point Estimate ◽  
Nitrate Content ◽  
Nitrate Accumulation ◽  
Health Risk Index ◽  
Potential Health

AbstractNitrate is a chemical compound naturally present in fruits and vegetables. This study aims at assessing the nitrate levels and health risks arising from high consumption of fruits and vegetables in Bangladesh. Sixteen species of fruits and vegetables were examined for nitrates using High-Performance Liquid Chromatography with Photo Diode Array (PDA) detector. Ward’s hierarchical cluster analysis was carried out to identify the cluster of tested fruits and vegetables for the nitrate contents. A point estimate of the daily intake was applied to find the health risks that arise due to elevated levels of nitrate in fruits and vegetables. The results show that root and tuber vegetables accumulate significantly higher levels of nitrate in comparison to fruits and fruit vegetables (P < 0.05). In cluster analysis, the nitrate accumulation of fruits and vegetables show four clear clusters contributing to 29.54%, 7.17%, 4.42%, and 58.57% of the total nitrate content in the entire sample. The risk assessment of the Estimated Daily Intake (EDI) and Health Risk Index (HRI) of almost all the tested samples was in the acceptable range, except for radish, thereby indicating the acceptance of risk due to nitrate intake in Bangladesh. As nitrate may have had risk factor for health, during cultivation and storing the product should be properly monitored.

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