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

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.

Author(s):  
D. Setyaningrum ◽  
M.T.S Budiastuti ◽  
B. Pujiasmanto ◽  
D. Purnomo ◽  
Supriyono Supriyono

This research investigated the effect of light intensity and biofertilizer on the yield, which includes the production of indigo compounds and plant nutrient uptake. The study used a randomized complete block design with a split plot design with 4 levels of light intensity as the main plots and 4 levels of biofertilizer as a sub plots with 3 replications. The combination of light intensity and biofertilizer affects fresh weight, biomass and tissue nitrogen. The highest fresh weight and biomass was found at 100% light intensity with double inoculation of mycorrhizae and rhizobium. Whereas the highest tissue nitrogen was at 10% light intensity with double inoculation of mycorrhizae and rhizobium. The production of indigo affected by light intensity, ie at 10% light intensity indicates the highest indigo. Mycorrhizae and rhizobium have a synergistic relationship as biofertilizer in increasing plant yields and nutrient uptakes in 100% light intensity.


Author(s):  
Maria Theresia Sri Budiastuti ◽  
Djoko Purnomo ◽  
Supriyono Supriyono ◽  
Bambang Pujiasmanto ◽  
Desy Setyaningrum

<p class="Default"><em>Indigofera tinctoria</em> is a legume that is cultivated as a source of natural indigo dyes. As a legume, <em>Indigofera tinctoria</em> is capable of symbiosis with soil microbes. This study evaluates the effects of light intensity and microbial inoculation on root growth and nodulation. The study used a complete randomized block design with a split-plot pattern. Light intensity was the main plot with four levels of light intensity 100%, 50%, 25%, and 10%. Microbial inoculation was a subplot with four levels without inoculation, mycorrhizae inoculation, rhizobium inoculation, and double inoculation with both mycorrhizae and rhizobium. The results obtained show that light intensity and microbial inoculation affected root length, root fresh weight, root biomass, and the number of nodules. 50% light intensity was optimum for root length, while 100% light intensity was optimum for root fresh weight, root biomass, and a number of nodules. Root growth and nodulation were further increased with double inoculation. The combination of light intensity and microbial inoculation affected root biomass and nodulation. The combination of 100% light intensity and double inoculation resulted in the highest root biomass and nodule numbers. Mycorrhizae and rhizobium have a synergistic relationship to nodulation and root growth. Double inoculation with mycorrhizae and rhizobium efficiently increased root biomass and the number of nodules under low or high light intensity.</p>


2012 ◽  
Vol 36 (2) ◽  
pp. 221-226
Author(s):  
AFM Jamal Uddin ◽  
C Das ◽  
F H Shammy ◽  
M Foysal ◽  
M S Islam

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


Author(s):  
Yuzuru Ikeda ◽  
Kingo Ito ◽  
Gen Matsumoto

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


1994 ◽  
Vol 45 (1) ◽  
pp. 43 ◽  
Author(s):  
TJ Wassenberg ◽  
BJ Hill

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.


1999 ◽  
Vol 47 (4) ◽  
pp. 231-236
Author(s):  
Shimon Lavee ◽  
Elizabeth Van Volkenburgh ◽  
Robert Cleland E.

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.


2019 ◽  
Author(s):  
Kalpana Arambam ◽  
Pradyut Biswas ◽  
Soibam Khogen Singh ◽  
A. B. Patel ◽  
Alok Kumar Jena ◽  
...  

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.


1983 ◽  
Vol 38 (7-8) ◽  
pp. 544-548 ◽  
Author(s):  
J. M. Steyns ◽  
G. van Nigtevecht ◽  
G. J. Niemann ◽  
J. v. Brederode

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.


1959 ◽  
Vol 7 (3) ◽  
pp. 252 ◽  
Author(s):  
RL Bieleski

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.


2011 ◽  
Vol 1359 ◽  
Author(s):  
Ali Bilge Guvenc ◽  
Cengiz Ozkan ◽  
Mihrimah Ozkan

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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