scholarly journals EFFECTS OF CARBON DIOXIDE ENRICHMENT AND IRRADIANCE ON EX VITRO ROOTING, ACCLIMATIZATION AND SUBSEQUENT GROWTH OF MICROPROPAGATED APPLE AND BLUEBERRY.

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 254A-254
Author(s):  
Marvin Pritts ◽  
Dorcas Isuta
Keyword(s):  
Survival Rate ◽  
Dry Weight ◽  
Great Sensitivity ◽  
High Light ◽  
Low Light ◽  
Light Levels ◽  
Significant Difference ◽  
Vigorous Growth ◽  
Set Up

Previous findings reveal that rooting and acclimatization of apple and blueberry plants is often difficult, inconsistent and inefficient. This experiment was set up in a fog chamber lo investigate the effects of CO2 enrichment (CDE) and irradiance on unrooted stage II microshoots. Two CO2 and 3 light levels tested were: 1350 +/- 150 (+ CDE), and 450 +/- 50 (- CDE) ppm; 30 +/- 5 (low), 55 + 10 (medium), and 100 + 20 (high) umolm-2s-1 respectively. Cultivars assessed were Berkeley and Northsky for blueberry. G65 and NY30 for apple. Blueberry microshoots acclimatized successfully and gave between 90 to 100% rooting and survival rate. Apple microshoots acclimatized and rooted slowly, exhibited great sensitivity to in vivo conditions and gave between 40 to 100% rooting and survival rate. High light induced photo-inhibition which disappeared after complete acclimatization. There was a significant difference between low light and the other two light levels. The effect of CDE was dependent on cultivar. In most cases, high light (-) CDE gave the most vigorous growth (highest plant dry weight and leaf area). There was a significant difference between (+) CDE and (-) CDE at low and medium light, but none at high light. Low light (-) CDE and medium light (+) CDE were superior over low light (+) CDE and medium light (-) CDE. respectively. Stalling out in apple microshoots was corrected by GA sprays.

scholarly journals The Effectiveness of Candidate Probiotic Bacteria to Control Vibriosis Disease

2017 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Mulyati Mulyati ◽  
Suryati Suryati ◽  
Irfani Baga
Keyword(s):  
Survival Rate ◽  
Sea Water ◽  
Challenge Test ◽  
Probiotic Bacteria ◽  
Pathogenicity Test ◽  
Inhibitory Ability ◽  
Significant Difference ◽  
Portunid Crab

The study aims to isolate, characterize, and examine probiotic bacteria's inhibitory ability against Vibrio harveyi bacteria, both in-vitro and in vivo. Methods used in the study consist of 1) An Isolation of Candidate Probiotic Bacteria, 2) An Antagonistic Test of Candidate Probiotic Bacteria in vitro, 3) An Identification of Bacteria, 4) A Pathogenicity Test of Candidate Probiotic Bacteria, 5) An Antagonistic Test of Candidate Probiotic Bacteria against V. harveyi in vivo. According to the isolation of candidate probiotic bacteria, there are 18 isolated candidate probiotic. After being tested for its inhibitory ability in vitro, there are 8 isolates with zone of inhibition as follows: isolate MM 7 from intestine (22 mm), isolate MM 6 from intestine (12 mm), isolate MM 10 from sea water (10 mm), isolate MM 5 from intestine (9 mm), isolate MM 4 from intestine (8 mm), isolate MM 3 from intestine (7 mm), isolate MM 2.2 from intestine (7 mm), isolate MM 2.1 from intestine (7 mm). Eight genera of the candidate probiotic bacteria is derived from Portunid crab, they are Staphylococcus, Streptococcus, bacillus, vibrio, Alcaligenes, Lactobacillus, micrococcus. Before proceeding the V. harveyi bacterial challenge test in vivo, three potential isolates consisting of MM6, MM7 and MM10 as the probiotic bacteria are pathogenicity-tested against V. harveyi. The survival rate of Portunid crab on pathogenicity test using MM6, MM7 and MM10 generates 91.11-100%, while the control generates 100% survival rate. Variance analysis result through post-hoc Tukey's Honest Significant Difference (HSD) test at 95% confidence interval indicates that isolate MM7 and MM10 are significantly able to increase hatchling Portunid crab's survival rate.

scholarly journals Light intensity regulates phototaxis, foraging and righting behaviors of the sea urchin Strongylocentrotus intermedius

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8001 ◽  
Author(s):  
Jiangnan Sun ◽  
Xiaomei Chi ◽  
Mingfang Yang ◽  
Jingyun Ding ◽  
Dongtao Shi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Foraging Behavior ◽  
Sea Urchins ◽  
High Light Intensity ◽  
High Light ◽  
Strongylocentrotus Intermedius ◽  
Low Light ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Significant Difference

Small sea urchins Strongylocentrotus intermedius (1–2 cm of test diameter) are exposed to different environments of light intensities after being reseeded to the sea bottom. With little information available about the behavioral responses of S. intermedius to different light intensities in the environment, we carried out an investigation on how S. intermedius is affected by three light intensity environments in terms of phototaxis, foraging and righting behaviors. They were no light (zero lx), low light intensity (24–209 lx) and high light intensity (252–2,280 lx). Light intensity had obvious different effects on phototaxis. In low light intensity, sea urchins moved more and spent significantly more time at the higher intensity (69–209 lx) (P = 0.046). S. intermedius in high light intensity, in contrast, spent significantly more time at lower intensity (252–690 lx) (P = 0.005). Unexpectedly, no significant difference of movement (average velocity and total distance covered) was found among the three light intensities (P > 0.05). Foraging behavior of S. intermedius was significantly different among the light intensities. In the no light environment, only three of ten S. intermedius found food within 7 min. In low light intensity, nine of 10 sea urchins showed successful foraging behavior to the food placed at 209 lx, which was significantly higher than the ratio of the number (two of 10) when food was placed at 24 lx (P = 0.005). In the high light intensity, in contrast, significantly less sea urchins (three of 10) found food placed at the higher light intensity (2,280 lx) compared with the lower light intensity (252 lx) (10/10, P = 0.003). Furthermore, S. intermedius showed significantly longer righting response time in the high light intensity compared with both no light (P = 0.001) and low light intensity (P = 0.031). No significant difference was found in righting behavior between no light and low light intensity (P = 0.892). The present study indicates that light intensity significantly affects phototaxis, foraging and righting behaviors of S. intermedius and that ~200 lx might be the appropriate light intensity for reseeding small S. intermedius.

Are resources allocated differently to symbiosis and reproduction in Geranium sylvaticum under different light conditions?

2004 ◽  
Vol 82 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Jarkko Korhonen ◽  
Minna-Maarit Kytöviita ◽  
Pirkko Siikamäki
Keyword(s):  
Resource Allocation ◽  
Forest Canopy ◽  
Light Availability ◽  
Growing Season ◽  
High Light ◽  
Mycorrhizal Colonization ◽  
Fungal Colonization ◽  
Low Light ◽  
Light Levels ◽  
Dark Septate Fungi

Light levels under the forest canopy are low and generally limit plant photosynthetic gains. We hypothesized that in low-light habitats, plant photosynthate acquisition is too low to allow the same magnitude of resource allocation to symbiosis and reproduction as in high-light habitats. We tested this hypothesis in a field study where Geranium sylvaticum L. plants were collected on three occasions during the growing season from shade and light habitats. In addition, we investigated the relationship between mycorrhizal colonization level and soil nutrient levels in shade and high-light habitats over a growing season. We found that light availability affects resource allocation in G. sylvaticum. Plants were intensively colonized with both arbuscular mycorrhizal and dark septate fungi, and the colonization intensities of these two different groups of fungi correlated positively with each other. In comparison with high-light meadows, mycorrhizal colonization levels were as high or higher in low-light forest habitats, but plants produced fewer flowers. This indicates that allocation to symbiosis was of higher priority than allocation to reproduction in low light. Seed size was not affected by light levels and did not correlate with fungal colonization levels. We found no relationship between fungal colonization levels and soil characteristics.Key words: arbuscular mycorrhiza, dark septate fungi, Geranium sylvaticum, reproduction, shade.

Effect of Vineyard Row Orientation on Growth and Phenology of Glyphosate-Resistant and Glyphosate-Susceptible Horseweed (Conyza canadensis)

Weed Science ◽  
2011 ◽  
Vol 59 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Marisa Alcorta ◽  
Matthew W. Fidelibus ◽  
Kerri L. Steenwerth ◽  
Anil Shrestha
Keyword(s):  
Leaf Area ◽  
Growth And Development ◽  
Dry Weight ◽  
Conyza Canadensis ◽  
Light Penetration ◽  
Low Light ◽  
Weed Growth ◽  
Light Levels ◽  
East West ◽  
Number Of Seeds

Horseweed has become increasingly common and difficult to control in San Joaquin Valley vineyards, due in part, to the evolution of glyphosate resistance. The development of weed-suppressive vineyard designs in which the trellis design, spacing, and row orientation combine to cast dense shade on the weed canopy zone (WCZ) may reduce weed growth. The relevance of such a system to horseweed, which can grow to be as tall, or taller, than a typical grapevine trellis, is uncertain. Also unknown is whether a glyphosate-resistant (GR) biotype and glyphosate-susceptible (GS) biotype would perform similarly under such conditions. Therefore, we compared the growth and development of two potted horseweed biotypes (GR and GS) in vinerows oriented east–west (EW) and north–south (NS). Rows oriented EW allowed less light penetration to the WCZ than NS rows throughout the study, and horseweed biotypes responded to low light levels by producing leaves with larger specific leaf area and leaf area ratios than those in the NS rows. Also, the leaf, stem, and root dry weight of the horseweed plants in the EW rows was reduced by 30% compared to the horseweed plants in NS rows. Leaf number was also reduced in the horseweed plants in the EW rows, but only for the GS biotype. Row orientation did not affect phenological development or the number of seeds produced by the GR or GS biotypes, but the GR biotype budded, flowered, and set seed approximately 1 wk earlier than the GS biotype. Thus, shade associated with the EW vinerows reduced horseweed growth, but not fecundity, and the GR biotype reached reproductive maturity earlier than the GS biotype.

scholarly journals Effects of rotifer densities on larval performance of spotted scat (Scatophagus argus)

2021 ◽  
Vol 13 (Aquaculture) ◽  
pp. 37-43
Author(s):  
Quoc Viet Le ◽  
Van Khanh Ly ◽  
Thi My Han Duong ◽  
Nguyen Duy Khoa Tran ◽  
Tomonari Kotani ◽  
...  
Keyword(s):  
Survival Rate ◽  
Growth Performance ◽  
Body Length ◽  
Fish Larvae ◽  
Larval Growth ◽  
Larval Performance ◽  
Scatophagus Argus ◽  
Wide Range ◽  
Significant Difference ◽  
Set Up

This study is aimed to determine the optimal rotifer feeding density for larviculture of spotted scat fish (Scatophagus argus). The experiment was randomly set up in triplicate with 5 treatments including 5, 10, 15, 20 and 25 rotifers/mL. The fish larvae with the initial body length and depth at 2,343 ± 110 µm and 812 ± 85µm, respectively, were stocked in 250-L tanks at 10 larva/L of density and 25‰ of salinity. After 21 days of rearing, the results showed that the larval growth were at 243 – 330 µm/day of DLG and 5.50 – 6.70 %/day of SGRL; 131 –204 µm/day of DDG and 7.20 – 8.93 %/day of SGRD, but no significant difference in larval growth performance was recorded among treatments (p>0.05). However, the highest survival rate of fish larvae (35.4-48.1%) was recorded in the treatments fed 5 and 10 rotifers/mL and was significantly higher than other treatments (p<0.05). The data demonstrated that spotted scat larvae fed effectively across as wide range of rotifer densities and the range at 5-10 rotifers/mL were suggested for the husbandry practices.

scholarly journals Substrate Acidification by Geranium: Light Effects and Phosphorus Uptake

2008 ◽  
Vol 133 (4) ◽  
pp. 515-520 ◽  
Author(s):  
Matthew D. Taylor ◽  
Paul V. Nelson ◽  
Jonathan M. Frantz
Keyword(s):  
Light Intensity ◽  
Phosphorus Uptake ◽  
Dry Weight ◽  
P Uptake ◽  
High Light Intensity ◽  
High Light ◽  
P Deficiency ◽  
Light Levels ◽  
Direct Light ◽  
Substrate Ph

Sudden pH decline (SPD) describes the situation where crops growing at an appropriate pH rapidly (within 1–2 weeks) cause the substrate pH to shift downward one to two units. ‘Designer Dark Red’ geraniums (Pelargonium ×hortorum Bailey) were grown in three experiments to assess possible effects of light on SPD and phosphorous (P) uptake. The first experiment tested the effect of four light intensities (105, 210, 575, and 1020 ± 25 μmol·m−2·s−1) on substrate acidification. At 63 days, substrate pH declined from 6.0 to 4.8 as light intensity increased. Tissue P of plants grown at the highest two light levels was extremely low (0.10%–0.14% of dry weight). P stress has been reported to cause acidification. Because plants in the two lowest light treatments had adequate P, it was not possible to determine if the drop in substrate pH was a direct light effect or a combination of light and P. The second experiment used a factorial combination of the three highest light levels from Expt. 1 and five preplant P rates (0, 0.065, 0.13, 0.26, or 0.52 g·L−1 substrate) to assess this question. When tissue P concentrations were deficient, pH decreased by 0.6 to 1.0 pH units within 2 weeks and deficiency occurred more often with high light intensity. These data indicated that P deficiency caused substrate acidification and indicated the possibility that P uptake was suppressed by high light intensity. The third experiment was conducted in hydroponics to determine the direct effect of high light intensity on P uptake. In this experiment, cumulative P uptake per gram root and the rate of P uptake per gram root per day both decreased 20% when light intensity increased from 500 to 1100 μmol·m−2·s−1. It is clear from this study that P deficiency causes geraniums to acidify the substrate and that high light suppresses P uptake.

47 CRYOPRESERVATION OF BOVINE GERM CELL USING ANTIFREEZE POLYAMINO-ACID (CARBOXYLATED POLY-L-LYSINE)

2017 ◽  
Vol 29 (1) ◽  
pp. 131
Author(s):  
T. Fujikawa ◽  
C. Kubota ◽  
T. Ando ◽  
S. Imamura ◽  
M. Tokumaru ◽  
...  
Keyword(s):  
Survival Rate ◽  
Germ Cell ◽  
Embryo Transfer ◽  
Conception Rate ◽  
Control Group ◽  
Vitro Fertilization ◽  
Polyamino Acid ◽  
Significant Difference

Carboxylated poly-l-lysine (CPLL) is an ampholytic polymer compound, and it is obtained by converting 65% amino groups to carboxyl groups after synthesising ε-poly-l-lysine aqueous solution and succinic anhydride. CPLL has cryoprotective property similar to antifreeze protein, and addition of CPLL into cryopreservation medium improves the post-thaw survival rate of cells and embryos. In this research, we examined the effectiveness of CPLL as a bovine germ cell cryoprotective material. In experiment 1 (in sperm), the conventional cryopreservation medium used for control group was consisted of 6.5% (vol/vol) glycerin, and the cryopreservation medium used for CPLL group was consisted of 3.25% (vol/vol) glycerin and 0.5% CPLL (wt/vol). The post-thaw survival and motility were assessed by using Sperm Motility Analysis System (DITECT Corp., Tokyo, Japan). There was no significant difference for post-thaw survival rate and motility (control v. CPLL; 98.8% v. 96.6% and 69.7% v. 62.2%, respectively). Artificial insemination was carried out in 65 cows (control v. CPLL; 34 v. 31), and the conception rate of the CPLL group was higher than that of the control group (80.6% v. 67.6%; P = 0.23). In experiment 2 (embryos), the conventional cryopreservation medium used for control group was consisted of 5% (vol/vol) ethylene glycol and 6% (vol/vol) propylene glycol in PBS. In the CPLL group, 7% (wt/vol) CPLL was added to the conventional medium. In vitro fertilization embryos were cryopreserved at Day 7 and Day 8. There was no significant difference in survival rate at 0, 24, and 48 h and hatched rate until 72 h after thawing (control v. CPLL: 93.6% v. 93.2%, 69.0% v. 64.7%, 56.1% v. 56.3%, 12.9% v. 10.2%, respectively). Embryos obtained by superovulation treatment and in vivo fertilization at Day 7 were cryopreserved using above 2 media, and transferred non-surgically into synchronized recipient cows (1 embryo per animal). Embryo transfer (ET) was carried out in 81 cows (control v. CPLL: 31 v. 50), and recipients were diagnosed for pregnancy ultrasonically 50 days after embryo transfer. Conception rate of CPLL group was higher than control group (50.0% v. 29.0%; P = 0.063). In both experiments, the significant differences between control group and CPLL group were determined by chi-squared test. The effectiveness of CPLL in cells and embryos has been reported; however, there is no report using CPLL in bovine germ cells. In this research, CPLL improved the conception rate of AI and ET, probably due to its low toxicity and protection of the cell membrane. These results suggest that CPLL is available as a new cryoprotective material for bovine sperm and embryo in slow freezing methods.

Matched filtering in the visual system of the fly : large monopolar cells of the lamina are optimized to detect moving edges and blobs

1990 ◽  
Vol 240 (1298) ◽  
pp. 279-293 ◽  
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
High Light ◽  
Vertical Stripe ◽  
Ambient Light ◽  
Low Light ◽  
Temporal Properties ◽  
Light Levels ◽  
Spatio Temporal ◽  
Temporal Inhibition

At high levels of ambient light, large monopolar cells (LMCS) display spatially antagonistic receptive fields and a biphasic response to a brief flash of light from an axially positioned point source. In low ambient light the response becomes monophasic everywhere within the receptive field. Using the theory of matched filters, we infer that the LMCS are optimal for the detection of moving edges at high light levels, and for ‘blobs’ in low ambient light. The spatio-temporal properties predicted by the theory are in agreement with experimental observation. At high light levels, the strong temporal inhibition, the weak, diffuse lateral inhibition, and the non-separability of the receptive field in space and time are all properties that promote the sensitivity to a moving edge. At low light levels, the lack of spatial or temporal antagonism enhances the sensitivity to a blob. Our hypothesis is reinforced by the observation that flies tend to walk toward the edges of a broad, dark vertical stripe at high light levels, but uniformly toward all regions within the stripe in low ambient light.

An Evaluative Study of Three Photographic Focusing Screens under Two Levels of Illumination

1980 ◽  
Vol 9 (1) ◽  
pp. 37-44
Author(s):  
John B. Bunch
Keyword(s):  
Light Level ◽  
Illumination Level ◽  
Low Light ◽  
Evaluative Study ◽  
Light Levels ◽  
High Illumination ◽  
Significant Difference ◽  
Low Illumination ◽  
Post Hoc

The purpose of this experiment was to evaluate the ability of photography students to focus a camera accurately under two levels of illumination (high/low) with three types of focusing screens (plain groundglass, split-image and microprism). The participants were required to focus each screen three times under each light level; scores were focus errors in feet. A 2 × 3 MANOVA design was used, and post hoc comparisons were made for plain vs. split-image, plain vs. microprism, and plain vs. microprism and split-image combined. There was significantly less focus error (p < .05) under the low illumination level, but no significant difference between screen types across both light levels. The screen type X light level interaction was much higher than the p .05 required in this study. Plain groundglass produced the least overall error; microprism yielded the least error under low illumination and the highest error under high illumination; and split-image was the most accurate under high illumination and the least accurate for the low light level condition.

Species variability in growth response to light across climatic regions in northwestern British Columbia

1998 ◽  
Vol 28 (6) ◽  
pp. 871-886 ◽  
Author(s):  
Elaine F Wright ◽  
K Dave Coates ◽  
Charles D Canham ◽  
Paula Bartemucci
Keyword(s):  
British Columbia ◽  
Shade Tolerance ◽  
Growth Response ◽  
High Light ◽  
Low Light ◽  
Climatic Regions ◽  
Light Levels ◽  
Tolerant Species ◽  
Trade Offs ◽  
Shade Tolerant Species

We characterize variation in radial and height growth of saplings of 11 tree species across a range of light levels in boreal, sub-boreal, subalpine, and temperate forests of northwestern British Columbia. Shade-tolerant species had the greatest response to an increase in light at low-light levels but had low asymptotic growth at high light. Shade-intolerant species had weaker responses to increases at low light but had the highest growth rates at high light. The effects of climate on intraspecific variation in sapling response to light were also related to shade tolerance: across different climatic regions, the most shade-tolerant species varied in their response to low-light but not high light, while shade-intolerant species varied only in their high-light growth. Species with intermediate shade tolerance varied both their amplitude of growth at high light and the slope of the growth response at low light. Despite the interspecific trade-offs between high- and low-light growth, there was a striking degree of overlap in the light response curves for the component species in virtually all of the climatic regions. Successional dynamics in these forests appear to be more strongly governed by interspecific variation in sapling survival than growth.

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