scholarly journals HOREHOUND (Marrubium vulgaris L.) PRODUCTION IN NORTHERN AMERICA: RESPONSES TO MULCH, SHADING, AND NITROGEN TREATMENT

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1162b-1162
Author(s):  
Z.Y. Mao ◽  
Lyle E. Craker
Keyword(s):  
Nitrogen Fertilization ◽  
Leaf Size ◽  
Light Level ◽  
High Nitrogen ◽  
Light Levels ◽  
Leaf Chlorophyll ◽  
Nitrogen Treatment ◽  
Reduced Light ◽  
Field Production ◽  
Number Of Branches

Mulch, light level, and nitrogen fertilization were tested for their effects on productivity of horehound (Marrubium vulgaris L.). Yield of this plant increased under mulched conditions and with the addition of nitrogen fertilizer. Yield decreased with reduced light levels. Productivity of individual plants correlated with the number of branches per plant, leaf size, and leaf chlorophyll content. The number of branches per plant decreased with increased shading, but increased with increased nitrogen fertilization. The influence of mulch and shading on productivity could be due to the changes in soil temperature and in soil water potentials. Full-sun, high nitrogen, and mulch are suggested for optimum field production of horehound.

scholarly journals 018 EFFECTS OF ANCYMIDOL, PACLOBUTRAZOL, AND UNICONAZOLE ON GROWTH AND FLOWERING OF ACHIMENES cv HILDA UNDER TWO LIGHT LEVELS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 430b-430
Author(s):  
J. C. Vlahos
Keyword(s):  
Plant Height ◽  
Light Level ◽  
The Other ◽  
Growth Retardants ◽  
Axillary Shoots ◽  
Full Sunlight ◽  
Foliar Sprays ◽  
Light Levels ◽  
Mode Of Application ◽  
Reduced Light

Plants of Achimenes cv Hilda were treated with foliar sprays of Ancymidol, Paclobutrazol and Uniconazole at 3 different concentrations each, and were placed in a greenhouse at 21°C under 2 light levels (0 and 40% light exclusion) for 12 weeks. Reduced light level decreased plant height, number of axillary shoots and flowers. The three growth retardants in any concentration, supressed development of axillary shoots and flowers. Ancymidol at 25 and 50 mg.1-1, Uniconazole at 5 mg.1-1 and Paclobutrazol at 25, 50 or 100 mg.1-1 decreased plant height and number of leaf whorls. Number of rhizomes was reduced by the 3 chemicals at the highest concentration only. Paclobutrazol was most effective than the other 2 growth retardants. Effects of treatments were more pronounced under shade rather than in full sunlight. Days to anthesis was not affected by any of the treatments except by Paclobutrazol at 100 mg.1-1. The use of these growth retardants in concentration and mode of application similar to those used in this study is not recommended for “Hilda” as height retardation significantly reduces number of flowers

Effects of shading on seagrass morphology and thermal optimal of productivity

2020 ◽  
Vol 71 (8) ◽  
pp. 913 ◽  
Author(s):  
Eunice Kong ◽  
Yan Xiang Ow ◽  
Samantha Lai ◽  
Siti Maryam Yaakub ◽  
Peter Todd
Keyword(s):  
Synergistic Effects ◽  
Light Availability ◽  
Temperature Response ◽  
Leaf Size ◽  
Net Photosynthesis ◽  
Shoot Density ◽  
Net Productivity ◽  
Halophila Ovalis ◽  
Light Levels ◽  
Reduced Light

Light and temperature are important factors affecting seagrass primary productivity. Acclimatisation to reduced light availability may affect the optimal temperature at which seagrasses photosynthesise, potentially causing synergistic effects between increasing water temperatures and decreasing light levels on coastal productivity. This study investigated the effects of reduced light availability on the morphology (leaf size, shoot density) and thermal optimal of net productivity in Halophila ovalis (R.Br.) Hook. A 12-week in situ shading experiment was conducted at Chek Jawa Wetlands, Singapore, testing high (68% shading), low (49%) and control (0%) shadings. Every 4 weeks, photosynthetic and respiration rates of H. ovalis leaves and the root–rhizome complex were measured in closed incubation chambers at temperatures from 22 to 42°C (at 4°C intervals). A fitted temperature-response model of net photosynthesis was used to estimate the thermal optimal for each shading treatment. High shading reduced shoot density (mean±s.e.) 87.06±7.86% and leaf surface area 31.72±24.74%. Net productivity (6mg O2 g–1 DW h–1) and its thermal optimal (28–30°C) were not significantly different among shading treatments throughout the experiment. Light levels appeared to have minimal influence on the thermal dependency of H. ovalis net productivity.

scholarly journals (50) Evaluating Low Light Level Effects on Chlorophyll Content and Commercial Quality in Several Species of Bambuseae

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1037B-1037
Author(s):  
Harry G. Simmons ◽  
Alisara Menakanit ◽  
Surawit Wannakrairoj ◽  
Poonpipope Kasemsap
Keyword(s):  
Chlorophyll Content ◽  
Extreme Temperature ◽  
Light Level ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Levels ◽  
Foliage Plant ◽  
Reduced Light

Bamboo has increasingly become a popular exterior ornamental plant because of its durability, versatility, and evergreen qualities in conditions of extreme temperature and moisture variations. Use as an interior foliage plant has been limited due to the difficulty of finding species adaptable to lower light levels. Nineteen species from seven genera (Bambusa, Cephalostachyum, Dendrocalamus, Gigantochloa, Schizostachyum, Thyrsostachys, and Vietnamosasa) were evaluated. Fifteen plants from each species were potted in like conditions (50% leaf mold; 50% topsoil; 5 g of 14–14–14 controlled-release fertilizer) and grown under a maximum daily photosynthetic photon flux density (PPFD) range between 1200 to 2000 μmol·m-2·s-1 for 6 weeks. Chlorophyll content of leaves was measured. The commercial quality of leaves, culms, and general appearance was also recorded. Light was then limited to a maximum PPFD of 150 to 300 μmol m-2s-1 for 6 weeks and all measurements were again recorded. Five species had significant increases in chlorophyll content after the 6-week period of reduced light levels. Species with a larger maturity size had a greater mortality percentage as well as lower quality leaf and overall appearance when grown under reduced light levels. Culm quality remained constant in 18 of the 19 species after the 6-week period. Vietnamosasa ciliata showed the greatest increase in chlorophyll levels as well as highest commercial quality of leaf and overall appearance.

Change of color appearance due to extremely high light level: corresponding colors under 100 and 3000 cd/m2

2019 ◽  
Vol 2019 (1) ◽  
pp. 320-325 ◽  
Author(s):  
Wenyu Bao ◽  
Minchen Wei
Keyword(s):  
Light Level ◽  
Limited Range ◽  
High Light ◽  
Color Preference ◽  
Color Appearance ◽  
Appearance Model ◽  
Color Matching ◽  
Light Levels ◽  
Appearance Models ◽  
Psychophysical Study

Great efforts have been made to develop color appearance models to predict color appearance of stimuli under various viewing conditions. CIECAM02, the most widely used color appearance model, and many other color appearance models were all developed based on corresponding color datasets, including LUTCHI data. Though the effect of adapting light level on color appearance, which is known as "Hunt Effect", is well known, most of the corresponding color datasets were collected within a limited range of light levels (i.e., below 700 cd/m2), which was much lower than that under daylight. A recent study investigating color preference of an artwork under various light levels from 20 to 15000 lx suggested that the existing color appearance models may not accurately characterize the color appearance of stimuli under extremely high light levels, based on the assumption that the same preference judgements were due to the same color appearance. This article reports a psychophysical study, which was designed to directly collect corresponding colors under two light levels— 100 and 3000 cd/m2 (i.e., ≈ 314 and 9420 lx). Human observers completed haploscopic color matching for four color stimuli (i.e., red, green, blue, and yellow) under the two light levels at 2700 or 6500 K. Though the Hunt Effect was supported by the results, CIECAM02 was found to have large errors under the extremely high light levels, especially when the CCT was low.

Influence of Light on Fruit Set of French Hybrid Grapes

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 510f-511 ◽  
Author(s):  
D.C. Ferree ◽  
S.J. McArtney ◽  
D.M. Scurlock
Keyword(s):  
Light Intensity ◽  
Linear Relationship ◽  
Fruit Set ◽  
Light Level ◽  
Fruit Color ◽  
Soluble Solids ◽  
Hue Angle ◽  
Reduced Light ◽  
Negative Linear Relationship ◽  
Grape Cultivars

Four French–American hybrid grape cultivars grown in a greenhouse were subjected to 5 days of 80% shade at four different times around bloom. Fruit set of `Seyval' was reduced by shade imposed before, during, or immediately after bloom. `Vidal' and `Chambourcin' were less sensitive, with fruit set reduced only by shade at bloom. Shade had little effect on fruit set of `DeChaunac'. In a second study, `Chambourcin' vines were exposed to ambient, ambient plus supplemental lights, and 30%, 50%, or 80% shade for 5 weeks beginning just prior to bloom. Fruit set was positively related to light intensity. At harvest, soluble solids, pH, and hue angle had a negative linear relationship to light level. Fruit color developed earliest and most rapidly with the reduced light treatments applied at bloom. Cluster weight was positively related to light intensity.

scholarly journals Genome-wide association of rice response to blast fungus identifies loci for robust resistance under high nitrogen

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mathias Frontini ◽  
Arnaud Boisnard ◽  
Julien Frouin ◽  
Malika Ouikene ◽  
Jean Benoit Morel ◽  
...  
Keyword(s):  
Nitrogen Fertilization ◽  
Rice Blast ◽  
Genome Wide Association ◽  
Japonica Rice ◽  
High Nitrogen ◽  
Initial Finding ◽  
Blast Fungus ◽  
Genome Wide ◽  
A Genome ◽  
Low Nitrogen

Abstract Background Nitrogen fertilization is known to increase disease susceptibility, a phenomenon called Nitrogen-Induced Susceptibility (NIS). In rice, this phenomenon has been observed in infections with the blast fungus Magnaporthe oryzae. A previous classical genetic study revealed a locus (NIS1) that enhances susceptibility to rice blast under high nitrogen fertilization. In order to further address the underlying genetics of plasticity in susceptibility to rice blast after fertilization, we analyzed NIS under greenhouse-controlled conditions in a panel of 139 temperate japonica rice strains. A genome-wide association analysis was conducted to identify loci potentially involved in NIS by comparing susceptibility loci identified under high and low nitrogen conditions, an approach allowing for the identification of loci validated across different nitrogen environments. We also used a novel NIS Index to identify loci potentially contributing to plasticity in susceptibility under different nitrogen fertilization regimes. Results A global NIS effect was observed in the population, with the density of lesions increasing by 8%, on average, under high nitrogen fertilization. Three new QTL, other than NIS1, were identified. A rare allele of the RRobN1 locus on chromosome 6 provides robust resistance in high and low nitrogen environments. A frequent allele of the NIS2 locus, on chromosome 5, exacerbates blast susceptibility under the high nitrogen condition. Finally, an allele of NIS3, on chromosome 10, buffers the increase of susceptibility arising from nitrogen fertilization but increases global levels of susceptibility. This allele is almost fixed in temperate japonicas, as a probable consequence of genetic hitchhiking with a locus involved in cold stress adaptation. Conclusions Our results extend to an entire rice subspecies the initial finding that nitrogen increases rice blast susceptibility. We demonstrate the usefulness of estimating plasticity for the identification of novel loci involved in the response of rice to the blast fungus under different nitrogen regimes.

Light or presence of host trees: which is more important for the strangler fig?

1999 ◽  
Vol 15 (5) ◽  
pp. 589-602 ◽  
Author(s):  
Vidya R. Athreya
Keyword(s):  
Host Species ◽  
National Park ◽  
Canopy Cover ◽  
Light Level ◽  
Southern India ◽  
Evergreen Forest ◽  
Primary Forest ◽  
Light Levels ◽  
Host Trees ◽  
Main Host

Strangler fig density varied considerably in the evergreen forest of Karian Shola National Park, southern India, with 11 individuals ha−1 in an open trail area and 5.6 individuals ha−1 within the primary forest area. The index of light level was assessed by estimating the percentage of upper canopy cover along the longitudinal centre of ten, 500-m × 20-m plots in each of the two areas of the evergreen forest. However, the increase in strangler fig density was not correlated to light levels but was significantly correlated to the numbers of their main host species in the two areas. In Karian Shola National Park, strangler figs occurred predominantly on a few host species with 20 and 50% of strangler figs growing on Vitex altissima, Diospyros bourdilloni and Eugenia/Syzygium spp. in the primary forest and trail areas respectively. Both young and established strangler figs were recorded mainly on larger individuals of their host trees indicating that older host trees are likely to be more suitable for the germination and establishment of strangler figs. The reason for the above could be the higher incidence of humus-filled and decaying regions in the older host trees which would provide an assured supply of nutrients for the establishing strangler fig.

scholarly journals Metabolomics Analysis Reveals Potential Mechanisms in Bupleurum L. (Apiaceae) Induced by Three Levels of Nitrogen Fertilization

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2291
Author(s):  
Jialin Sun ◽  
Weinan Li ◽  
Ye Zhang ◽  
Yun Guo ◽  
Zejia Duan ◽  
...  
Keyword(s):  
Nitrogen Fertilization ◽  
Total Content ◽  
Nitrogen Level ◽  
Gas Chromatography Mass Spectrometry ◽  
Control Group ◽  
High Nitrogen ◽  
Yield And Quality ◽  
High Nitrogen Level ◽  
The Impact ◽  
The Relationship

Bupleurum (Apiaceae) is widely used in traditional Chinese medicine to treat inflammatory and infectious diseases. Although roots are the only used parts in China, other countries use the whole plant. The yield and quality of Bupleurum depend mainly on fertilizers, especially nitrogen. The current study aimed to assess the relationship between the nitrogen fertilization level and the quality and metabolomic response of different parts (flowers, main shoots, lateral shoots and roots) of Bupleurum to three nitrogen fertilization levels (control group: 0 kg·ha−1; low-nitrogen group: 55 kg·ha−1; high-nitrogen group: 110 kg·ha−1). The results showed that a high nitrogen level increases Bupleurum yield and quality parameters only in aerial parts, especially flowers, but has no significant effect on roots. The HPLC method was exploited for simultaneous quantification of three saikosaponins (A, C and D), which are the main bioactive components in the plant. It was found that the total content of saikosaponins decreased with high nitrogen fertilization in roots but significantly increased in flowers. Moreover, nitrogen fertilizer promoted the content of saikosaponin A but inhibited saikosaponins C and saikosaponins D in most parts of the plant. To study the response of primary metabolites, we adopted gas chromatography–mass spectrometry (GC−MS) analysis; 84 metabolites were identified that were mostly up-regulated with a high nitrogen level in flowers but down-regulated in roots. Four differential metabolites—D-fructose, lactose, ether and glycerol—were recognized as key metabolites in Bupleurum under nitrogen fertilization. Meanwhile, The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results explained that the impact of nitrogen fertilization on Bupleurum was attributed to the C-metabolism, N-metabolism, and lipids metabolism. This research put forward new insights into potential mechanisms and the relationship between the quality and yield of Bupleurum and nitrogen fertilization.

scholarly journals The influence of different moisture contents and nitrogen levels on the formation of empty cavities in cucumbers (Cucumis sativus L.)

2013 ◽  
Vol 35 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Krystyna Elkner
Keyword(s):  
Soil Moisture ◽  
Cucumis Sativus ◽  
Nitrogen Fertilization ◽  
Fruit Development ◽  
High Nitrogen ◽  
Mechanical Tension ◽  
Cucumis Sativus L ◽  
Nitrogen Levels ◽  
Moisture Contents ◽  
Empty Cavity

Empty cavities were found already in very young cucumber fruits with diameter 1.5 cm. As the fruit develops the empty cavities augment and the number of fruits showing this defect increases. Low soil moisture and high nitrogen fertilization favour the formation of empty cavities. Their origination and changes were traced with anatomical methods in the course of fruit development. As a most plausible cause of their origination the author considers the enlargement of only part of the cells of the suture between the two (or three) carples. Due to this uneven enlargement of neighbouring cells strong mechanical tension probably arises amoung them, leading to the formation of ruptures separating these cells, consequently causing the separation of the carpel edges. Besides that, some of the cells of the suture which have markedly enlarged, often burst which also contributes to the formation of an empty cavity and enlarges its dimensions.

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