LIGHT-STIMULATED LEAF GROWTH ON INTACT AND EXCISED BEAN PLANTS (PHASEOLUS VULGARIS L.) III. EFFECT OF LIGHT INTENSITY

1999 ◽  
Vol 47 (4) ◽  
pp. 231-236
Author(s):  
Shimon Lavee ◽  
Elizabeth Van Volkenburgh ◽  
Robert Cleland E.
Keyword(s):  
Light Intensity ◽  
Leaf Growth ◽  
Energy Requirement ◽  
Red Light ◽  
Continuous Light ◽  
Leaf Expansion ◽  
Minimal Amount ◽  
Light Intensities ◽  
Bean Plants ◽  
Effect Of Light

The effect of light intensity on primary bean leaf unfolding and elongation was studied with intact and excised 10-day-old plants grown under red light. Continuous light of 40 μmol; m−2S−1 was enough to induce maximal leaf expansion both on intact and excised bean plants. Lower light intensities had a partial effect. The growth rate during the first 24 h in light was linearly related to light intensity up to 130 μmol; m−2S−1, although this light intensity was already supra-optimal for final leaf size. The minimal amount of light energy needed for full leaf expansion was about 15 mol photons m−2. The mode of light application, level of intensity, and irradiance duration were not critical when the total energy requirement was fulfilled. Under insufficient light applications for full leaf expansion, interrupted irradiance and longer low light intensity application induced leaf elongation more efficiently. Generally, the effect of different white light intensities on primary bean leaf expansion was the same on both intact and excised red-light-grown plants.

Influence of light intensity and photoperiod on frost-hardiness development in Douglas-fir seedlings

1970 ◽  
Vol 48 (12) ◽  
pp. 2129-2134 ◽  
Author(s):  
R. van den Driessche
Keyword(s):  
Light Intensity ◽  
Rapid Development ◽  
Red Light ◽  
Continuous Light ◽  
Douglas Fir ◽  
Frost Hardiness ◽  
Conductivity Method ◽  
Rapid Hardening ◽  
Effect Of Light ◽  
Electrical Conductivity Method

Effect of light intensity and photoperiod on frost-hardiness development in 2-year-old Douglas-fir seedlings was studied using an electrical conductivity method to assess stem hardiness. Hardiness increased with light intensity to 1000 ft-c at 7.5 °C, under both 8-h and 16-h photoperiods, after about 8 weeks. This response suggested photosynthesis was necessary for rapid hardening, as also did the more rapid hardening obtained under continuous light at 40 ft-c, compared with 8-h photoperiods of the same intensity. By contrast, short photoperiods enhanced the rate of hardening at a light intensity of 3000 ft-c and 500 ft-c (after 7 weeks), compared with long photoperiods. After 7 weeks plants under short photoperiods with supplementary red light hardened like plants under long photoperiods, but after 10 weeks this effect of red light was no longer apparent. Far-red light did not produce any effect. Evidently a certain amount of photosynthesis must be carried out by Douglas-fir seedlings for rapid development of hardiness, but, with sufficient light for this to occur, short photoperiods hasten hardening.

LIGHT-STIMULATED LEAF GROWTH ON INTACT AND EXCISED BEAN PLANTS (PHASEOLUS VULGARIS L.). I. CHARACTERIZATION OF BASIC RESPONSES

1999 ◽  
Vol 47 (3) ◽  
pp. 141-145 ◽  
Author(s):  
Shimon Lavee ◽  
Elizabeth Van Volkenburgh ◽  
Robert E. Cleland
Keyword(s):  
Phaseolus Vulgaris ◽  
Leaf Growth ◽  
Red Light ◽  
Leaf Expansion ◽  
Light Conditions ◽  
Whole Plant ◽  
Bean Plants ◽  
Bright White Light ◽  
Root Excision

The effect of root excision on the growth of primary leaves, petioles, and epicotyls of bean plants (Phaseolus vulgaris L.) has been investigated for plants growing in various light conditions. Plants were initially grown in either continuous dim red light (RL; 4 μmol m−2S−1) or bright white light (WL; 100 μmol; m−2S−1, 16 h light: 8 h dark photoperiod) for 10 days. On day 10, some plants were excised. Then, both intact and excised plants were returned to RL or WL, or switched to the other light treatment (RL to WL, WL to RL). Exposure to WL on day 10 promoted leaf expansion and inhibited petiole and epicotyl growth, regardless of light pretreatments before day 10. Root excision reduced leaf expansion by 40–50% both in WL and RL. Petiole and epicotyl growth were less affected. Removal of the cotyledons or the stem apex caused a slight but significant reduction of leaf elongation in both intact and excised plants. Apex removal reduced epicotyl elongation but did not stop it. Although excision of roots partially inhibited leaf and epicotyl development, the relative response of excised plants to the light treatments was similar to that of intact plants. These results justify the use of derooted plants to study leaf growth in a “whole plant” excised system.

LIGHT-STIMULATED LEAF GROWTH ON INTACT AND EXCISED BEAN PLANTS (PHASEOLUS VULGARIS L.). II. EFFECT OF LIGHT DURATION AND TIMING OF APPLICATION

1999 ◽  
Vol 47 (3) ◽  
pp. 147-152
Author(s):  
Shimon Lavee ◽  
Elizabeth Van Volkenburgh ◽  
Robert E. Cleland
Keyword(s):  
Phaseolus Vulgaris ◽  
White Light ◽  
Leaf Growth ◽  
Relative Rate ◽  
Red Light ◽  
Leaf Expansion ◽  
Leaf Elongation ◽  
Leaf Unfolding ◽  
Light Duration ◽  
Partial Unfolding

The dependence of bean (Phaseolus vulgaris L. cv. Contender) leaf unfolding and expansion on light has been explored in intact and excised plants by varying the duration and timing of exposure to white light. Plants were grown for 10 days in dim red light (RL), and then some were excised. Both the intact and the excised plants were then exposed to varying white light (WL) treatments. In continuous WL, leaf unfolding began after 8 h, and was maximal after 36 h. For plants exposed to short WL treatments, as little as 2 h WL elicited partial unfolding when leaves were returned to RL and measured after 60 h. The relative rate of leaf elongation was most rapid during the first 2 h of WL and it rapidly decreased during the following 6–8 h. An 8 h exposure to WL followed by 52 h RL produced only a slightly lower leaf expansion than continuous WL for 32 h. Leaf elongation after 24 h constant WL irradiance was no longer light-dependent. The response of leaves on excised plants to WL was progressively less if treatment was delayed for 24 h after excision. In contrast, leaves on intact plants did not lose their ability to respond to light even after 48 h in the dark. The ability of leaves on intact or excised plants to elongate in RL decayed rapidly after day 10. These results indicate that light-stimulated leaf expansion in beans is mediated by some factors whose transport to the leaves is influenced by the presence of roots.

Does light intensity affect embryonic development of squid (Heterololigo bleekeri)?

2004 ◽  
Vol 84 (6) ◽  
pp. 1215-1219 ◽  
Author(s):  
Yuzuru Ikeda ◽  
Kingo Ito ◽  
Gen Matsumoto
Keyword(s):  
Body Size ◽  
Light Intensity ◽  
Embryonic Development ◽  
Early Stage ◽  
Constant Darkness ◽  
Light Intensities ◽  
Development Duration ◽  
Experimental Group ◽  
Effect Of Light

The effect of light intensity on the course of embryonic development of squid (Heterololigo bleekeri) was examined. Heterololigo bleekeri embryos at an early stage were incubated in the egg cases under six to seven gradients of light intensities which varied from constant darkness to intensive light >1000 lx (12L:12D for all experimental groups except for the constant darkness group). Duration of hatching in every experimental group ranged from seven to 15 days with a peak for ≈30–50% of total number of hatchlings. However, there were no particular relationships between light intensities and duration of embryonic development, duration of hatching, number of hatchlings at hatching peak, and body size of hatchlings. In all groups, body size of hatchlings increased up to seven days post-hatching and thereafter did not change remarkably. Just after hatching, strongly positive photo taxis was observed for H. bleekeri

Laboratory study of the effect of light on the emergence behaviour of eight species of commercially important adult penaeid prawns

1994 ◽  
Vol 45 (1) ◽  
pp. 43 ◽  
Author(s):  
TJ Wassenberg ◽  
BJ Hill
Keyword(s):  
Light Intensity ◽  
Laboratory Study ◽  
Carapace Length ◽  
Rate Of Change ◽  
Metapenaeus Ensis ◽  
The Third ◽  
Light Intensities ◽  
Commercially Important ◽  
Penaeus Merguiensis ◽  
Effect Of Light

The emergence behaviour of eight species of commercial prawns (between 25.0 and 30.0 mm carapace length) was studied in the laboratory. All except Penaeus merguiensis were nocturnal: they emerged from the substratum in the evening when the light was dimmed and buried themselves in the morning, usually before dawn. P. merguiensis generally remained on the substratum during the day. The species can be grouped on the basis of their behaviour: the first group (P. plebejus and P. latisulcatus) was most sensitive to light, the second group (P. semisulcatus, Metapenaeus ensis, P. esculentus, M. endeavouri and M. bennettae) was less sensitive to light, and the third (P. merguiensis) was least sensitive to light. To find out what triggered emergence, two species (P. esculentus and P. plebejus) were exposed to different rates of light dimming at dusk. Both species responded to absolute light intensity, but the response of P. plebejus was affected by the rate of change of light intensity. The different responses of the species to different light intensities explains some of the differences in catchability in a multi-species prawn fishery.

scholarly journals Larval growth and survival in Indian Butter Catfish, Ompok bimaculatus (Bloch): effect of light intensity and photoperiod

2019 ◽  
Author(s):  
Kalpana Arambam ◽  
Pradyut Biswas ◽  
Soibam Khogen Singh ◽  
A. B. Patel ◽  
Alok Kumar Jena ◽  
...  
Keyword(s):  
Light Intensity ◽  
Larval Growth ◽  
Maximum Growth ◽  
Continuous Darkness ◽  
Growth And Survival ◽  
Light Intensities ◽  
Randomized Design ◽  
Significant Difference ◽  
Ompok Bimaculatus ◽  
Effect Of Light

AbstractTwo sequential indoor rearing trials each of 21 days duration were conducted to investigate the effect of light intensity and photoperiod respectively on the growth and survival of Ompok bimaculatus larvae. In first trial, five different light intensities viz. 0, 300, 500, 900, 1200 lx were applied randomly to 800 larvae (0.003 g; 0.51 cm) stocked in triplicate following a completely randomized design into aquarium (30.0 x 15.0 x 15.0 cm) tanks. Sequentially, in second trial, five photoperiod cycles (light: dark, L: D) namely, 24L: 0D, 16L: 8D, 12L: 12D, 8L: 16D and 0L: 24D in combination with the best performing light intensity (300 lx) as observed from the first trial were employed in triplicates in similar set up. From the first trial, significantly higher survival was observed in 0 and 300 lx, whereas growth was highest in 900 lx (P < 0.05). In the second trial, survival was higher in continuous darkness (0L: 24D), whereas, maximum growth was recorded in 24L: 0D and 16L: 8D groups (P < 0.05). Performance index (PI) showed no significant difference (P > 0.05) among 0 and 300 lx light intensities, but were reduced at higher light intensities. The lowest PI was found in 12L: 12D and 8L: 16D condition but did not have any effect in other photoperiod cycles. Overall, from the present study it can be concluded that growth of the larvae is found to be higher in higher light intensity (900lx) and longer photoperiodic cycles (24L: 0D and 16L: 8D), however, better survival was recorded in total dark conditions suggesting that continuous dark condition is recommended for better hatchery performance of the larvae.

scholarly journals THE EFFECT OF PHOTOPERIOD ON WHITE PINE SEEDLING GROWTH

1961 ◽  
Vol 37 (2) ◽  
pp. 133-143 ◽  
Author(s):  
D. P. Fowler
Keyword(s):  
Light Intensity ◽  
Soil Fertility ◽  
Root Length ◽  
Continuous Light ◽  
Stem Diameter ◽  
Day Length ◽  
Time Data ◽  
White Pine ◽  
Hypocotyl Length ◽  
Light Intensities

White pine seedlings from freshly germinated seed were subjected to different photoperiods and light intensities for a period of nine months. The photoperiods consisted of normal, normal plus eight hours, and continuous day length while the supplementary light intensities were 25-50 foot candles and 200-400 foot candles. Three levels of soil fertility obtained from mixtures of acid sand and white pine humus were also tested.Observations were recorded over the nine month period and at the termination of this time data from the following measurements were obtained: hypocotyl length, top length, root length, stem diameter, and oven-dry weight.Hypocotyl length was found to be independent of soil fertility, whereas both continuous light and light of high intensity caused seedlings to have short hypocotyls.Top length and root length were found to be dependent upon soil fertility as well as upon photoperiod but were independent of light intensity. Continuous light caused the greatest root length whereas eight hours additional light caused the greatest crown length.Stem diameter was found to be dependent upon soil fertility, photoperiod and light intensity. No significant differences in this respect were found between photoperiods consisting of eight hours additional light and continuous light. The greatest stem diameter resulted from high light intensity.Oven-dry weight was found to depend upon soil fertility, photoperiod, and light intensity. The richer the soil, the longer the photoperiod, and the greater the light intensity, the greater was the weight of the seedlings produced.

Differential Regulation of Flavone Glycosylation during Ontogeny of Silene pratensis

1983 ◽  
Vol 38 (7-8) ◽  
pp. 544-548 ◽  
Author(s):  
J. M. Steyns ◽  
G. van Nigtevecht ◽  
G. J. Niemann ◽  
J. v. Brederode
Keyword(s):  
Light Intensity ◽  
Differential Regulation ◽  
Low Light ◽  
Leaf Pair ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Flower Stem ◽  
Pair Number ◽  
Silene Pratensis ◽  
Effect Of Light

Two isovitexin glycosides have been found in the cotyledons and foliage leaves of Sitene pratensis plants that are unable to glycosylate isovitexin in their petals (genotype gg glgl fgfg). The glycosides (isovitexin 7-O-galactoside and isovitexin 7-O-galactose 2″-O-arabinoside) were present only in the lower leaves: leaves produced later in the development of the flower stem accumulated only the aglycon isovitexin. The transition in the flavone composition during the ontogeny of the plants could be influenced by light intensity. In plants grown at low light intensity, glycoside production continued until a higher leaf pair number than in plants grown at higher light intensities. However, the effect of light intensity is indirect: the transition in the flavone composition is correlated with the transition from rosette leaves to stem leaves. The presence of the 7-O-galactosides in cotyledons and rosette leaves suggests that in addition to the g, gl and fg loci, there are further glycosylating loci which are not expressed in stem leaves and petals.

Factors affecting growith and distribution of kauri (Agathis australis Salisb.) I. Effect of light on the establishment of Kaura and of Phyllocladus trichomanoides D.Don

1959 ◽  
Vol 7 (3) ◽  
pp. 252 ◽  
Author(s):  
RL Bieleski
Keyword(s):  
Light Intensity ◽  
Frequency Distribution ◽  
High Light Intensity ◽  
High Light ◽  
Low Light ◽  
Factors Affecting ◽  
Light Intensities ◽  
Seedling Distribution ◽  
Conifer Seedling ◽  
Effect Of Light

A method for determining the effect of light on seedling distribution in the field is described. It can be applied when seedling frequencies are as low as 1/m2. The frequency distribution of light intensities occupied by seedlings in a quadrat is compared with the frequency distribution of light intensities measured on a grid in the quadrat. This method was used to study the effect of light intensity on the establishment of two New Zealand gymnosperms, kauri (Agathis australis) and Phyllocladus trichomanoides, in the nursery community, a semimature Leptospermum scoparium – L. ericoides associes. Kauri and Phyllocladus did not occur at light intensities below 0.015 and 0.018 full daylight respectively. This limitation appeared to be due to the low light intensity presumably limiting photosynthesis. Kauri, but not Phyllocladus, also showed a high light intensity limit, at 0.30 full daylight, above which seedlings did not establish. Reasons are given for considering this as an indirect effect, probably through related solar heating affecting soil temperature or moisture. The optimal light intensity for kauri and Phyllocladus seedling establishment was close to the modal light intensity under the Leptospermum community: Leptospermum spp. were incapable of regenerating under their own cover. These two reasons appear to explain the suitability of the Leptospermum community as a nurse crop for the two conifer seedling species.

Effect of Light Intensity on Schottky Barrier Widths and I-V Characteristics of Polymer Heterojunction Photodiodes

2011 ◽  
Vol 1359 ◽  
Author(s):  
Ali Bilge Guvenc ◽  
Cengiz Ozkan ◽  
Mihrimah Ozkan
Keyword(s):  
Experimental Data ◽  
Light Intensity ◽  
Mathematical Models ◽  
Schottky Barrier ◽  
Butyric Acid ◽  
Organic Semiconductor ◽  
Schottky Barriers ◽  
Light Intensities ◽  
Effect Of Light

ABSTRACTThe Schottky barriers that forms on the interface between aluminum and organic semiconductor of polymer heterojunction photodiodes based on poly(3-hexylthiophene): [6,6]-phenyl-C61-butyric acid methylester blend, has been investigated according to Mott-Schottky curves. We focused on the effect of light intensity on the Schottky barrier widths and I-V characteristics of the devices. Comparison of the mathematical models and experimental data measured under different light intensities indicate a dependency of Schottky barrier to the light intensity.

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