scholarly journals GROWTH OF TREE SEEDLINGS IN RELATION TO LIGHT INTENSITY AND CONCENTRATION OF NUTRIENT SOLUTION

1932 ◽  
Vol 7 (4) ◽  
pp. 742-745 ◽  
Author(s):  
George P. Steinbauer
Keyword(s):  
Light Intensity ◽  
Nutrient Solution ◽  
Tree Seedlings

Morphoanatomical characteristics of leaves of Anacardium othonianum seedlings subjected to different nitrogen doses under hydroponic conditions

2017 ◽  
Vol 65 (7) ◽  
pp. 524
Author(s):  
Layara A. Bessa ◽  
Marialva A. Moreira ◽  
Fabiano G. Silva ◽  
Luciana C. Vitorino ◽  
Cássia L. Rodrigues ◽  
...  
Keyword(s):  
Secondary Metabolism ◽  
Nutrient Solution ◽  
Stomatal Density ◽  
Tree Seedlings ◽  
Anatomical Structures ◽  
Quantitative Anatomy ◽  
Essential Nutrient ◽  
N Dose ◽  
Cashew Tree ◽  
Hydroponic Conditions

Nitrogen is an essential nutrient that plants generally require in large amounts. Knowing the nitrogen dose that stimulates primary and secondary metabolic pathways is important for the management of nitrogen fertilisation in plants in general; however, this information is still unavailable for seedlings of the cerrado cashew tree. Based on the hypothesis that the availability of nitrogen for Anacardium othonianum Rizz. seedlings can affect can affect the development of anatomical structures, as well as the synthesis of secondary metabolism compounds in leaves, an experiment was conducted to determine the qualitative and quantitative anatomy this tissue collected from plants of this species subjected to N doses of 0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 mmol L−1 in nutrient solution and evaluated the effect at 30 and 90 days after transplanting (DAT). The largest leaf morphoanatomical changes were observed under the doses of 0 and 15.0 mmol L−1 of N. The lowest stomatal density being observed in the plants exposed to an N dose of 15 mmol L−1. The level of flavonoids was not influenced by the availability of N in the solution; however, the absence of nitrogen directly affected the accumulation of phenolic compounds, alkaloids and polysaccharides present in the leaves, whereas the doses of 7.5, 10.0 and 12.5 mmol L−1 were essential to stimulate the presence of this latter compound in cerrado-cashew-tree seedlings maintained in nutrient solution. Regarding the epochs of evaluation, effect was observed only for the thickness of the adaxial epidermis. These data confirm the hypothesis that the leaf anatomy as well as the accumulation of secondary metabolism compounds in leaves of A. ohonianum can be modified because of the availability of N to the plant.

scholarly journals Flavonoid Productivity Optimized for Green and Red Forms of Perilla frutescens via Environmental Control Technologies in Plant Factory

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Na Lu ◽  
Michiko Takagaki ◽  
Wataru Yamori ◽  
Natsuko Kagawa
Keyword(s):  
Light Intensity ◽  
Nutrient Solution ◽  
Environmental Control ◽  
Total Yield ◽  
Perilla Frutescens ◽  
Leafy Vegetables ◽  
Plant Materials ◽  
Environmental Treatment ◽  
Plant Factory ◽  
Control Technologies

Perilla frutescens (Lamiaceae) is a dietary staple in Asia. It is an abundant source of flavonoids that are bioactively beneficial to human health and fitness. The current popularity of plant-based consumption is being driven by the healthful benefits of bioactive nutrition, and the concentration of bioactive agents found in raw plant materials is an important factor in the assessment of food quality. To test the feasibility of promoting flavonoid productivity in perilla plants via environmental treatment, plant factory technology was applied to perilla plant cultivation. Apigenin (AG) and luteolin (LT) are two of the most potent anticarcinogenic flavonoids in perilla, and these are also found in many vegetables and fruits. Quantitative analysis of AG and LT was conducted on plants cultivated under nine environmental forms of treatment imposed by three levels of light intensity (100, 200, and 300 µmol·m−2·s−1) combined with three levels of nutrient-solution concentration (1.0, 2.0, and 3.0 dS·m−1) for hydroculture. The contents of AG in green and red perilla plant were increased by high nutrient-solution levels under the same light intensity. In green perilla, the highest concentration of AG (8.50 µg·g−1) was obtained under treatment of the highest level of nutrient-solution (3.0 dS·m−1) and 200 µmol·m−2·s−1 of light intensity, whereas in red perilla, the highest concentration of AG (6.38 µg·g−1) was achieved from the highest levels of both of these forms of treatment (300 µmol·m−2·s−1 and 3.0 dS·m−1). The increase in AG content per plant between the lowest and the highest levels was recorded by 6.4-fold and 8.6-fold in green and red perilla, respectively. The behavior of LT concentration differed between green and red forms of perilla. LT concentration in red perilla was enhanced under nutrient deficiency (1.0 dS·m−1) and affected by light intensity. Different responses were observed in the accumulations of AG and LT in red and green perilla during treatments, and this phenomenon was discussed in terms of biosynthetic pathways that involve the expressions of phenylpropanoids and anthocyanins. The total yield of flavonoids (AG and LT) was improved with the optimization of those forms of treatment, with the best total yields: 33.9 mg·plant−1 in green Perilla; 10.0 mg·plant−1 in red perilla, and a 4.9-fold and a 5.4-fold increase was recorded in green and red perilla, respectively. This study revealed that flavone biosynthesis and accumulation in perilla plants could be optimized via environmental control technologies, and this approach could be applicable to leafy vegetables with bioactive nutrition to produce a stable industrial supply of high flavonoid content.

scholarly journals Influence of Mean Leaf Angles and Irrigation Volumes on Water Capture, Leaching, and Growth of Tropical Tree Seedlings

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1198
Author(s):  
Richardson Barbosa Gomes da Silva ◽  
Mônica Moreno Gabira ◽  
Débora Zanoni do Prado ◽  
Gláucia Uesugi ◽  
Danilo Simões ◽  
...  
Keyword(s):  
Nutrient Solution ◽  
Irrigation Water ◽  
Projection Area ◽  
Leaf Angle ◽  
Tree Seedlings ◽  
System Quality ◽  
Tree Seedling ◽  
The Mean ◽  
Crown Projection Area ◽  
Irrigation Volume

Research Highlights: The mean leaf angle and crown projection area can be used as criteria for grouping tree seedling species in different irrigation zones in tree nurseries with overhead microsprinkler systems, preventing water and fertilizer waste, and increasing growth. Background and Objectives: There are important gaps in current functional knowledge about how plant architecture, especially the mean leaf angles of tree seedlings, affect water and nutrient solution capture in overhead microsprinkler systems. These gaps contribute to water and fertilizer waste in tree nurseries. This research aimed to ascertain how mean leaf angles affect irrigation water capture, leaching, and the growth of tree seedlings given different volumes of irrigation. Materials and Methods: Nine species of tree seedlings with different mean leaf angles were submitted to four irrigation volumes (8, 10, 12, and 14 mm) applied daily by overhead microsprinklers in a split-plot design completely randomized. The variables leaching fraction, height, stem diameter, shoot, root, and total dry mass, Dickson quality index, crown projection area, root system quality, and leachate electrical conductivity were evaluated. Results: For species with mean leaf angles of −54, 31, 38, 42, 55, 57, and 58°, the 8 mm irrigation volume was sufficient to produce greater growth and less leaching. For species with angles of −56 and −14°, the 14 mm irrigation volume was required to produce greater growth. Conclusions: The tree seedling species with positive mean leaf angles facilitate irrigation water and nutrient solution capture, allowing the application of lower irrigation volume. On the other hand, some tree seedling species with negative mean leaf angles hinder irrigation water and nutrient solution capture, requiring the application of higher irrigation volume. When the tree seedling species have a negative mean leaf angle, but the crown projection area is small, the difficulty of water and nutrient solution reaches directly the substrate is attenuated.

Influences of light intensity on weed-induced stresses of tree seedlings

1990 ◽  
Vol 20 (5) ◽  
pp. 503-507 ◽  
Author(s):  
T. E. Kolb ◽  
T. W. Bowersox ◽  
L. H. McCormick
Keyword(s):  
Soil Moisture ◽  
Light Intensity ◽  
Tree Species ◽  
Red Oak ◽  
Tree Seedlings ◽  
Northern Red Oak ◽  
White Pine ◽  
White Ash ◽  
Reduced Height ◽  
Four Levels

Growth of northern red oak (Quercusrubra L.), white ash (Fraxinusamericana L.), and white pine (Pinusstrobus L.) seedlings was evaluated for 2 years after germination in 12 environments that consisted of four levels of herbaceous interference (fern, fern free, grass, grass free) crossed with three levels of light intensity (100, 45, and 20% full sun), at two clear-cuts in central Pennsylvania. Grass and fern interference reduced soil moisture content and reduced height or diameter growth of all species. Shading ameliorated soil moisture, reduced herbaceous growth, generally reduced growth of all tree species in interference-free environments, and had no effect on growth of any tree species in fern and grass environments. Reduction in growth due to herbaceous interference was lower for northern red oak and white pine than for white ash, while shading had similar effects on growth of all species. Results suggest that stresses induced by shading alone have little short-term effect on the establishment of these species under conditions of heavy herbaceous interference.

Measurement of Light Transmission in Young Conifer Plantations: A New Technique for Assessing Herbicide Efficacy

1992 ◽  
Vol 9 (3) ◽  
pp. 112-115 ◽  
Author(s):  
Robert Jobidon
Keyword(s):  
Light Intensity ◽  
Treatment Efficacy ◽  
Light Transmission ◽  
Black Spruce ◽  
Tree Seedlings ◽  
Full Sunlight ◽  
Herbicide Treatment ◽  
Standard Procedures ◽  
A New Technique ◽  
Subjective Standard

Abstract A rapid and accurate technique, using a simple measure of light intensity, for assessing the efficacy of herbicide treatment is proposed. Herbicide treatment efficacy was independently measured 1, 2, and 3 years after a single application of glyphosate on three adjacent plantations of black spruce reinvaded by red raspberry and fireweed in eastern Quebec. Each plantation represents a given time, 1, 2 or 3 years, after herbicide application. Light intensity, expressed as percent of full sunlight in the PAR spectral region (400-700 nm) reaching the upper one-half of the tree seedlings, significantly discriminates released and unreleased tree seedlings. Spruce seedlings receiving 60 to 100% of full sunlight grew significantly better in height and basal stem diameter and had significantly fewer stems and less height growth of competing vegetation than seedlings receiving less than 60% of full sunlight. This indicates that measuring the intensity of light reaching the tree seedlings is an easy and effective way to assess efficacy of herbicide treatment and also competition between spruce seedlings and surrounding vegetation. It is suggested that light reaching tree seedlings be measured instead of quantifying the competition variables. The proposed technique eliminates all potential bias from subjective standard procedures which in turn makes possible quantitative comparisons between evaluations of herbicide treatment efficacy. North. J. Appl. For. 9(3):112-115.

scholarly journals Impact of Light Intensity and Nitrogen of Nutrient Solution on Nitrate Content in Three Lettuce Cultivars Prior to Harvest

2018 ◽  
Vol 10 (6) ◽  
pp. 99 ◽  
Author(s):  
Khurshid Ahmed Khan ◽  
Zhengnan Yan ◽  
Dongxian He
Keyword(s):  
Light Intensity ◽  
Nutrient Solution ◽  
Nitrogen Supply ◽  
Leafy Vegetables ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Nitrate Content ◽  
High Accumulation ◽  
Important Indicator ◽  
Fluorescent Lamps

Nitrate smoothly accumulates in leafy vegetables and poses serious health hazards if connected excessively in the human diet. The objective of this study was to improve the cultivation method of low nitrate lettuce grown in plant factory. A substantial decrease of nitrate content (NO3-) in three lettuce cultivars were subjected by short-term pre-harvest treatment combined with lowing nitrogen supply of nutrient solution to half concentration and high photosynthetic photon flux density (PPFD) by LED lighting. The lettuce (Lactuca sativa L. cv. Frill ice, Lvzhu, Ziwei) were hydroponically grown in full strength of nutrient solution based on Yamasaki formula up to harvest time within a controlled environment under two light sources using fluorescent lamps and LEDs. The results demonstrated that a subsequent 3-days treatment of additional PPFD from 250 µmol m-2 s-1 to 350 µmol m-2 s-1 from 18 days after transplanting and half concentrations of nitrogen (NO3--N) in nutrient solution which is composition to standard resulted in the decrease of nitrate content as compared to plants grown under initial PPFD and full concentration of NO3--Ncomposition. The gradual decrease in nitrate content was accompanied by an increased concentration of nutritionally carbohydrates. Another important indicator of nutritional quality such as vitamin C content exhibited some variation, fresh weight of cultivars in cv. Frill ice and Ziwei observed higher with fluorescent lamps and for cv. Lvzhu with LED treatment section followed by lowest nitrate content of fresh leaves, respectively. Further, presented results disclosed that to avoid high accumulation of nitrate in leafy vegetables, the strategy of lowering nitrogen supply and increasing light intensity prior to harvest benefiting growers and consumers by improving quality of the product also making it consumer friendly.

Factors affecting growth and distribution of kauri (Agathis australis Salisb.) II. Effect of light intensity on seedling growth

1959 ◽  
Vol 7 (3) ◽  
pp. 268 ◽  
Author(s):  
RL Bieleski
Keyword(s):  
Light Intensity ◽  
Seedling Growth ◽  
Seedling Establishment ◽  
Dry Weight ◽  
Forest Tree ◽  
Stem Length ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Seedling Morphology ◽  
Effect Of Light

The effect of various light intensities on the growth of kauri seedlings is described. Daylight was screened to the required level with lath screens. There was no significant effect of light on seedling mortality in the light intensity range 0.40–0.02 full daylight. Seedling morphology was affected by light intensity, the ratios stem dry weight/root dry weight, stem length/root length, and fresh weight / dry weight increasing significantly with decreasing light intensity. Seedling growth was a linear function of log (light intensity), the growth rates and assimilation rates being similar to those for other forest tree seedlings. The compensation point was at 0.009 full daylight, close to the low light intensity limit to seedling establishment in the field but low compared with those of other tree seedlings. There was no high light intensity limit to seedling growth, such as that shown for seedling establishment in the field. The apparent discrepancy is discussed.

scholarly journals Suppression of Powdery Mildew on Greenhouse-Grown Cucumber by Addition of Silicon to Hydroponic Nutrient Solution Is Inhibited at High Temperature

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Andrew C. Schuerger ◽  
William Hammer
Keyword(s):  
Powdery Mildew ◽  
Light Intensity ◽  
Nutrient Solution ◽  
Potassium Silicate ◽  
Disease Suppression ◽  
Effect Of Temperature ◽  
Rooting Medium ◽  
Canadian Studies ◽  
The Difference ◽  
Nutrient Solutions

Silicon amendments to hydroponic nutrient solutions have been used successfully in Canada to suppress powdery mildew (PM) caused by Sphaerotheca fuliginea on cucumber (Cucumis sativus). In contrast, preliminary trials in Florida greenhouses failed to achieve the level of disease suppression reported in the literature for Canadian studies. A series of greenhouse experiments were conducted in Florida to determine the factors involved in reducing the effectiveness of silicon amendments for PM suppression on cucumber. Three horticultural practices (cultivar, nutrient solution formula, and rooting medium) and two environmental factors (light intensity and temperature) were tested in combination with silicon amendments for their effects on the suppression of PM on cucumber. When plants were irrigated with a standard nutrient solution amended with potassium silicate at 0 mg/liter, the cucumber cv. Vetomil was found to be resistant and cvs. Corona, Cilla, Farbio, and Toska were found to be susceptible to PM. Susceptible cultivars irrigated with potassium silicate at 100, 150, or 200 mg/liter exhibited a slight but statistically significant reduction in PM over the course of a 49-day trial. Although PM in the cultivar trial was slightly lower in treatments with added silicon, disease suppression with silicon was not commercially useful because it failed to increase fruit yields. Nutrient solution formula, rooting medium, and light intensity had no effects on the levels of PM suppression, regardless of whether plants were irrigated with potassium silicate at 0 or 100 mg/liter. Temperature was found to act in a synergistic manner with silicon. The greatest effect of temperature on PM suppression was observed at 20°C in which cucumber plants, irrigated with silicon at 100 mg/liter, exhibited significant reductions in the numbers of PM colonies per leaf. Disease suppression by silicon was observed at 25 and 30°C, but the magnitude of the disease suppression was significantly lower than when plants were maintained at 20°C. The effect of temperature on PM suppression by silicon may explain the difference in results between previous experiments in Canada, where greenhouse temperatures averaged 20 to 25°C, and the current study in Florida, where greenhouse temperatures averaged 24 to 32°C.

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