scholarly journals Growth and Flowering Performance of Potted Gerbera, Gerbera Jamesonii L. Under Different Light Intensity

2012 ◽  
Vol 36 (2) ◽  
pp. 221-226
Author(s):  
AFM Jamal Uddin ◽  
C Das ◽  
F H Shammy ◽  
M Foysal ◽  
M S Islam
Keyword(s):  
Light Intensity ◽  
Gerbera Jamesonii ◽  
Full Sunlight ◽  
Flower Production ◽  
Light Intensities ◽  
Academy Of Sciences

The influence of different light intensities (L0: full sunlight; L1: reduced sunlight; L2: 60% reduced sunlight) showed significant variations on growth and flower characteristics. Forty per cent reduced sunlight was more effective on growth and flower production than 60% reduced or in full sunlight. Tallest and thickest peduncles were produced (28.5 and 1.7 cm, respectively) with L1, similarly bigger flowers (6.0 cm diameter) were also found with L1 in comparison to L0 and L2. The maximum number of flowers per plant (15.6) was found from L1 and lowest (11.9) from L2.DOI: http://dx.doi.org/10.3329/jbas.v36i2.12965Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 213-220, 2012

scholarly journals The Physiology of Sugar-Cane. IX.·Factors Affecting Photosynthesis and Sugar Storage

1967 ◽  
Vol 20 (6) ◽  
pp. 1043 ◽  
Author(s):  
JC Waldron ◽  
KT Glasziou ◽  
TA Bull
Keyword(s):  
Light Intensity ◽  
Sugar Cane ◽  
Incident Radiation ◽  
High Light ◽  
Factors Affecting ◽  
Full Sunlight ◽  
Light Intensities

Photosynthesis in sugar-cane was linearly related to light intensity up to full sunlight when leaf geometry was similar to that of field-grown plants_ Individual leaves orientated at right angles to the incident radiation were saturated at about two-thirds full sunlight irrespective of whether the leaves developed in low or high light intensities.

scholarly journals Effect of light intensities on the flowering and growth of spiny coriander (Eryngium foetidum L.)

1969 ◽  
Vol 75 (4) ◽  
pp. 383-389
Author(s):  
Luis R. Santiago-Santos ◽  
Arturo Cedeño-Maldonado
Keyword(s):  
Light Intensity ◽  
Block Design ◽  
Second Phase ◽  
Fresh Weight ◽  
Full Sunlight ◽  
Leaf Chlorophyll ◽  
Light Intensities ◽  
Eryngium Foetidum ◽  
Two Phases ◽  
Effect Of Light

An experiment was performed at the Alzamora Experiment Farm of the Mayagüez Campus, University of Puerto Rico, to evaluate the effect of light intensity on the growth and flowering of spiny coriander, Eryngium foetidum L. The study was divided in two phases: 1) the seedling phase, which lasted from seeding to the first harvest, and 2) the second phase, from the first to the second harvest. All plants were placed under cover of transparent polyethylene. Three of the treatments were covered by Saran plastic with different densities to reduce light intensity to 47, 63, and 73%. Treatments were arranged in a randomized complete block design with three replications. A significant delay in flowering was observed in plants grown at 63 and 73% shade. An increase was observed in fresh weight of leaves of plants grown at 63 and 73% shade levels vs those in full sunlight. Plants grown under shade had fewer inflorescences with lower fresh weight than plants grown under full sunlight. No significant differences were found on leof number between plants grown at different light intensities. Leaf chlorophyll content of spiny coriander increased in plants grown under low light intensities.

scholarly journals Effect of chlorophyll biosynthesis-related genes on the leaf color in Hosta (Hosta plantaginea Aschers) and tobacco (Nicotiana tabacum L.)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jingying Zhang ◽  
Changhai Sui ◽  
Huimin Liu ◽  
Jinjiao Chen ◽  
Zhilin Han ◽  
...  
Keyword(s):  
Light Intensity ◽  
Antioxidant Capacity ◽  
Aminolevulinic Acid ◽  
Chlorophyll Biosynthesis ◽  
Expression Level ◽  
Virus Induced Gene Silencing ◽  
Leaf Color ◽  
Color Changes ◽  
Light Intensities ◽  
Structure Changes

Abstract Background ‘Regal Splendour’ (Hosta variety) is famous for its multi-color leaves, which are useful resources for exploring chloroplast development and color changes. The expressions of chlorophyll biosynthesis-related genes (HrHEMA, HrPOR and HrCAO) in Hosta have been demonstrated to be associated with leaf color. Herein, we isolated, sequenced, and analyzed HrHEMA, HrPOR and HrCAO genes. Subcellular localization was also performed to determine the location of the corresponding enzymes. After plasmid construction, virus-induced gene silencing (VIGS) was carried out to reduce the expressions of those genes. In addition, HrHEMA-, HrPOR- and HrCAO-overexpressing tobacco plants were made to verify the genes function. Changes of transgenic tobacco were recorded under 2000 lx, 6000 lx and 10,000 lx light intensity. Additionally, the contents of enzyme 5-aminolevulinic acid (5-ALA), porphobilinogen (PBG), chlorophyll a and b (Chla and Chlb), carotenoid (Cxc), superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), proline (Pro) and catalase (CAT) under different light intensities were evaluated. Results The silencing of HrHEMA, HrPOR and HrCAO genes can induce leaf yellowing and chloroplast structure changes in Hosta. Specifically, leaves of Hosta with HrCAO silencing were the most affected, while those with HrPOR silencing were the least affected. Moreover, all three genes in tobacco were highly expressed, whereas no expression was detected in wild-type (WT). However, the sensitivities of the three genes to different light intensities were different. The highest expression level of HrHEMA and HrPOR was detected under 10,000 lx of illumination, while HrCAO showed the highest expression level under 6000 lx. Lastly, the 5-ALA, Chla, Cxc, SOD, POD, MDA, Pro and CAT contents in different transgenic tobaccos changed significantly under different light intensities. Conclusion The overexpression of these three genes in tobacco enhanced photosynthesis by accumulating chlorophyll content, but the influential level varied under different light intensities. Furthermore, HrHEMA-, HrPOR- and HrCAO- overexpressing in tobacco can enhance the antioxidant capacity of plants to cope with stress under higher light intensity. However, under lower light intensity, the antioxidant capacity was declined in HrHEMA-, HrPOR- and HrCAO- overexpressing tobaccos.

A laboratory study of vertical migration

1955 ◽  
Vol 144 (916) ◽  
pp. 329-354 ◽  
Keyword(s):  
Light Intensity ◽  
Vertical Migration ◽  
Time Course ◽  
Tap Water ◽  
Low Light ◽  
Overhead Light ◽  
Light Intensities ◽  
Orientation Response ◽  
Reduced Light ◽  
Characteristic Maximum

In a tank filled with a suspension of indian ink in tap water, a population of Daphnia magna will undergo a complete cycle of vertical migration when an overhead light source is cycli­cally varied in intensity. A ‘dawn rise’ to the surface at low intensity is followed by the descent of the animals to a characteristic maximum depth. The animals rise to the surface again as the light decreases, and finally show a typical midnight sinking. The light intensities at the level of the animals in this experiment are of the same order as those which have been reported in field observations; the time course of the movement also repeats the natural conditions in the field. The process is independent of the duration of the cycle and is related only to the variation in overhead light intensity. At low light intensity the movement of the animal is determined solely by positive photo-kinesis; the dawn rise is a manifestation of this, and is independent of the direction of the light. At high light intensities there is an orientation response which is superimposed upon an alternating positive (photokinetic) phase and a negative phase during which movement is inhibited. The fully oriented animal shows a special type of positive and negative phototaxis, moving towards the light at reduced light intensities and away from it when the light intensity is increased. In this condition it follows a zone of optimum light intensity with some exactness. Experiments show that an animal in this fully oriented condition will respond to the slow changes of intensity characteristic of the diurnal cycle, while being little affected by tran­sient changes of considerable magnitude.

Pycnidium production by Botryodiplodia theobromae. I. The relation of light to the induction of pycnidia

1969 ◽  
Vol 47 (7) ◽  
pp. 1153-1156 ◽  
Author(s):  
J. A. Ekundayo ◽  
R. H. Haskins
Keyword(s):  
Light Intensity ◽  
Ultraviolet Radiation ◽  
Exposure Period ◽  
Fluorescent Light ◽  
Botryodiplodia Theobromae ◽  
Continuous Irradiation ◽  
Long Wave ◽  
Light Intensities ◽  
Glass Color ◽  
Color Filters

Cultures of Botryodiplodia theobromae Pat. produced pycnidia abundantly on several media under continuous irradiation with fluorescent light. The fungus did not sporulate when grown in darkness. Irradiation of cultures with a light intensity of 15 foot-candles for 4 days was sufficient to stimulate pycnidial production, but for appreciable sporulation to occur over the same exposure period, higher light intensities are required. Irradiation of cultures through glass color filters showed that long-wave ultraviolet radiation stimulated sporulation.

Sensory Behaviour in Dictyostelium Discoideum Slugs: Phototaxis and Thermotaxis are not Mediated by a Change in Slug Speed

1982 ◽  
Vol 54 (1) ◽  
pp. 329-339
Author(s):  
ELIZABETH SMITH ◽  
PAUL R. FISHER ◽  
WARWICK N. GRANT ◽  
KEITH L. WILLIAMS
Keyword(s):  
Molecular Weight ◽  
Temperature Gradient ◽  
Light Intensity ◽  
Dictyostelium Discoideum ◽  
Low Molecular Weight ◽  
Light Intensities ◽  
Slug Movement

The speed of sustained migration of Dictyostelium discoideum slugs was similar in a temperature gradient and at different light intensities, including a light intensity sufficient to cause significant disorientation of slugs. No change was observed in slug speed in the presence of high levels of Slug Turning Factor (STF), a low molecular weight compound through which phototaxis and thermotaxis are mediated. Thus orientation of D. discoideum slugs is not mediated by a sustained changed in slug speed and we propose that slug movement is not directly coupled to tactic responses. Slug speed depended on the size, age and genotype of slugs as well as the nature of the substratum (charcoal-containing water agar versus water agar).

scholarly journals Effects of light intensity and temperature on Cylindrospermopsis raciborskii (Cyanobacteria) with straight and coiled trichomes: growth rate and morphology

2012 ◽  
Vol 72 (2) ◽  
pp. 343-351 ◽  
Author(s):  
MC. Bittencourt-Oliveira ◽  
B. Buch ◽  
TC. Hereman ◽  
JDT. Arruda-Neto ◽  
AN. Moura ◽  
...  
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Morphological Changes ◽  
Population Control ◽  
Distinct Species ◽  
Cylindrospermopsis Raciborskii ◽  
Climatic Chamber ◽  
Light Intensities ◽  
Different Temperatures ◽  
Lower Temperature

Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju (Ordem Nostocales) is one of the most troublesome bloom-forming species in Brazil. Understanding the population dynamics of the different morphotypes of C. raciborskii (straight and coiled) could assist in the prediction of favourable conditions for the proliferation of this potentially toxin-producing species. The aim of the present study was to assess the effects of two different light intensities and temperatures on the growth rate and morphology of the trichomes of the straight and coiled morphotypes. For such, two non-toxin producing strains of C. raciborskii were used - one with a coiled trichome (ITEP31) and another with a straight trichome (ITEP28). The strains were cultured in BG-11 medium in a climatic chamber under controlled conditions. Two light intensities (30 and 90 µmol.m-2.s-1 ) were combined at temperatures of 21 and 31 °C and the growth rate and morphological changes were analysed. The morphotypes responded differently to the different temperatures and light intensities. Both strains exhibited faster growth velocities when submitted to higher light intensity and temperature. The lower temperature and higher luminosity hampered the development of both strains. Variations in cellular morphology and an absence of akinetes in both strains were related to the lower temperature (21 °C). The coiled morphotype demonstrated considerable phenotype plasticity, changing the morphology of trichome throughout its growth curve. Although molecular analysis does not sustain the separation of the morphotypes as distinct species, their different eco-physiological responses should be considered further knowledge of extreme importance for the population control of these potentially toxic organisms.

COMBINATION AND DISPROPORTIONATION OF ETHYL RADICALS: INFLUENCE OF THE REACTION H+C2H5 = C2H6

1955 ◽  
Vol 33 (5) ◽  
pp. 821-829 ◽  
Author(s):  
Moyra J. Smith ◽  
Patricia M. Beatty ◽  
J. A. Pinder ◽  
D. J. Le Roy
Keyword(s):  
Light Intensity ◽  
Excellent Agreement ◽  
Mercury Concentration ◽  
Rate Constants ◽  
Room Temperature ◽  
Low Light ◽  
Ethylene Concentration ◽  
Light Intensities ◽  
Ethyl Radicals ◽  
Hydrogenation Of Ethylene

The mercury (3P1) photosensitized hydrogenation of ethylene has been studied at room temperature as a function of ethylene concentration, mercury concentration, and light intensity. In addition to combination and disproportionation, ethyl radicals have been shown to take part in the reaction[Formula: see text]The conditions favoring this reaction have been established and anomalous values previously found for the ratio of ethane to butane have been explained. The value obtained for the ratio of the rate constants for the disproportionation and combination of ethyl radicals, 0.15 ±.01, is in excellent agreement with the values obtained by other methods. Hexane formation is of some importance at low light intensities and high ethylene concentrations, and is adequately accounted for by the reactions[Formula: see text]

scholarly journals Growth and Yield Response of Rodent Tuber (Typhonium flagelliforme (Lodd.) Blume) under Different Light Intensities and Concentrations of Paclobutrazol

2016 ◽  
Vol 1 (3) ◽  
pp. 29-35
Author(s):  
Noorwitri Utami ◽  
Lukita Devy ◽  
Arief Arianto
Keyword(s):  
Light Intensity ◽  
Concentration Level ◽  
Dry Weight ◽  
Leaf Length ◽  
Growth And Yield ◽  
Yield Response ◽  
Full Sunlight ◽  
Anticancer Treatment ◽  
Main Plot ◽  
Number Of Leaves

Rodent tuber (Typhonium flagelliforme (Lodd) Blume) is one of the medicinal plants used for anticancer treatment, but the information on the cultivation of the plant is limited. The objectives of this research was to study the effect of light intensity and concentration level of paclobutrazol on growth and yield of rodent tuber. This research was conducted at Puspiptek Serpong, Tangerang Selatan, Indonesia. This experiment arranged in a split plot design with three replications. The main plot is light intensity (35, 55, and 100%). The sub plot is concentration level of paclobutrazol (0, 50, 100, and 150 ppm). Paclobutrazol applied as soil drench at one month after planting. In each application 500 ml solution was used. Variables observed consisted of plant height, number of leaves, leaf length, leaf width, leaf and tuber fresh weight; and leaf and tuber dry weight. Data were analyzed using analysis of variance and Duncan Multiple Range test at 5%. The result showed that interaction between light intensity and paclobutrazol affected the whole observed variable. Dry weight of tuber under 35% light intensity was lower than those in other light intensity for all treatments of paclobutrazol. Full sunlight intensity showed better dry weight in all treatments of paclobutrazol. However the dry weight decreasing significantly at 150 ppm paclobutrazol, but still higher than those in 35% light intensity. Therefore, rodent tuber is better cultivated under full sunlight and 55% light intensity with 100 ppm paclobutrazol.

scholarly journals Identification and molecular characterization of a Chlamydomonas reinhardtii mutant that shows a light intensity dependent progressive chlorophyll deficiency

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 142
Author(s):  
Phillip B Grovenstein ◽  
Darryel A Wilson ◽  
Kathryn D Lankford ◽  
Kelsey A Gaston ◽  
Surangi Perera ◽  
...  
Keyword(s):  
Light Intensity ◽  
Insertional Mutagenesis ◽  
Protoporphyrin Ix ◽  
Model Organism ◽  
Genomic Region ◽  
Oxygenic Photosynthesis ◽  
Autotrophic Growth ◽  
Wild Type ◽  
Light Intensities ◽  
In The Wild

The green micro-alga Chlamydomonas reinhardtii is an elegant model organism to study all aspects of oxygenic photosynthesis. Chlorophyll (Chl) and heme are major tetrapyrroles that play an essential role in energy metabolism in photosynthetic organisms. These tetrapyrroles are synthesized via a common branched pathway that involves mainly nuclear encoded enzymes. One of the enzymes in the pathway is Mg chelatase (MgChel) which inserts Mg2+ into protoporphyrin IX (PPIX, proto) to form Magnesium-protoporphyrin IX (MgPPIX, Mgproto), the first biosynthetic intermediate in the Chl branch. The GUN4 (genomes uncoupled 4) protein is not essential for the MgChel activity but has been shown to significantly stimulate its activity. We have isolated a light sensitive mutant, 6F14, by random DNA insertional mutagenesis. 6F14 cannot tolerate light intensities higher than 90-100 μmol photons m-2 s-1. It shows a light intensity dependent progressive photo-bleaching. 6F14 is incapable of photo-autotrophic growth under light intensity higher than 100 μmol photons m-2 s-1. PCR based analyses show that in 6F14 the insertion of the plasmid outside the GUN4 locus has resulted in a genetic rearrangement of the GUN4 gene and possible deletions in the genomic region flanking the GUN4 gene. Our gun4 mutant has a Chl content very similar to that in the wild type in the dark and is very sensitive to fluctuations in the light intensity in the environment unlike the earlier identified Chlamydomonas gun4 mutant. Complementation with a functional copy of the GUN4 gene restored light tolerance, Chl biosynthesis and photo-autotrophic growth under high light intensities in 6F14. 6F14 is the second gun4 mutant to be identified in C. reinhardtii. Additionally, we show that our two gun4 complements over-express the GUN4 protein and show a higher Chl content per cell compared to that in the wild type strain.

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