scholarly journals Low Light Availability Reduces the Subsurface Sediment Carbon Content in Halophila beccarii From the South China Sea

2021 ◽  
Vol 12 ◽  
Author(s):  
Chanaka Premarathne ◽  
Zhijian Jiang ◽  
Jialu He ◽  
Yang Fang ◽  
Qiming Chen ◽  
...  
Keyword(s):  
Carbon Content ◽  
Light Availability ◽  
Seagrass Beds ◽  
Biomass Carbon ◽  
Light Conditions ◽  
Above Ground Biomass ◽  
Low Light ◽  
Subsurface Sediment ◽  
Light Intensities ◽  
Sediment Carbon

Eutrophication, dredging, agricultural and urban runoffs, and epiphyte overgrowth could reduce light availability for seagrass. This may affect “blue carbon” stocks in seagrass beds. However, little research is available on the effect of light intensities on carbon sequestration capacity in seagrass beds, especially small-bodied seagrasses. The dominant seagrass Halophila beccarii, a vulnerable species on the IUCN Red List, was cultured in different light intensities to examine the response of vegetation and sediment carbon in seagrass beds. The results showed that low light significantly reduced leaf length and above-ground biomass, while carbon content in both above-ground and below-ground tissues were not affected. Low light reduced both the above-ground biomass carbon and the total biomass carbon. Interestingly, while under saturating light conditions, the subsurface and surface carbon content was similar, under low light conditions, subsurface sediment carbon was significantly lower than the surface content. The reduction of subsurface sediment carbon might be caused by less release flux of dissolved organic carbon from roots in low light. Taken together, these results indicate that reduced light intensities, to which these meadows are exposed to, will reduce carbon sequestration capacity in seagrass beds. Measures should be taken to eliminate the input of nutrients on seagrass meadows and dredging activities to maintain the “blue carbon” storage service by enhancing light penetration into seagrass.

scholarly journals Hybrid tea-roses under controlled light conditions. 2. Flowering of seedlings as dependent on the level of irradiance.

1978 ◽  
Vol 26 (1) ◽  
pp. 128-132
Author(s):  
D.P. de Vries ◽  
L. Smeets
Keyword(s):  
Selection Procedure ◽  
Light Conditions ◽  
Low Light ◽  
Light Requirement ◽  
Experimental Conditions ◽  
Light Intensities

Under the experimental conditions described in the preceding abstract, mortality increased with decreasing light intensities. The percentage of flowering seedlings increased and that of aborting ones decreased with irradiance. For the populations studied, no genotype-environment interactions for the percentages of flowering seedlings occurred. A selection procedure for roses with a low light requirement for flowering is considered. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Interactions entre mitochondries et chloroplastes dans la cellule. II. Action du DBMIB, de l'antimycine A et du FCCP sur la spore de Funaria hygrometrica

1977 ◽  
Vol 55 (12) ◽  
pp. 1650-1659 ◽  
Author(s):  
D. Chevallier ◽  
R. Douce ◽  
F. Nurit
Keyword(s):  
Cytochrome Oxidase ◽  
Dark Respiration ◽  
High Light ◽  
Light Conditions ◽  
Oxygen Production ◽  
Low Light ◽  
Funaria Hygrometrica ◽  
Light Intensities

The effect of DBMIB, antimycine A, and FCCP on respiration and photosynthesis of intact chlorophyllic moss (Funaria hygrometrica) spore was investigated.Antimycine A (1 μM) strongly inhibited dark respiration, was without effect on photosynthesis at high light intensities (above the saturation plateau values), and stimulated photosynthesis at low light intensities (below the saturation plateau values).DBMIB (3 μM) inhibited photosynthesis and was without effect, even under light conditions, on the dark respiration. Low amount of FCCP (3 μM) partially inhibited oxygen production at high light intensities. In this case, the inhibition observed was partially relieved by 1 μM antimycine A or 30 μM of KCN; higher concentration of FCCP totally inhibited the oxygen production.It seems likely, therefore, that in the chlorophyllic moss spore the cytochrome oxidase pathway is not functioning under high light intensities and that this inhibition of respiration is attributable to the low cytoplasmic ADP:ATP ratio.

scholarly journals Selection of full-sib families of Panicum maximum Jacq under low light conditions

Revista CERES ◽  
2015 ◽  
Vol 62 (2) ◽  
pp. 199-207
Author(s):  
Douglas Mochi Victor ◽  
Liana Jank ◽  
Beatriz Lempp ◽  
Rosangela Maria Simeão ◽  
Marcos Deon Vilela de Resende ◽  
...  
Keyword(s):  
Shade Tolerance ◽  
Genetic Difference ◽  
Dry Mass ◽  
Panicum Maximum ◽  
Light Conditions ◽  
Low Light ◽  
Breeding Programs ◽  
Light Reduction ◽  
Light Intensities ◽  
Mass Accumulation

The silvopastoral system is a viable technological alternative to extensive cattle grazing, however, for it to be successful, forage grass genotypes adapted to reduced light need to be identified. The objective of this study was to select progenies of Panicum maximum tolerant to low light conditions for use in breeding programs and to study the genetic control and performance of some traits associated with shade tolerance. Six full-sib progenies were evaluated in full sun, 50% and 70% of light reduction in pots and subjected to cuttings. Progeny genotypic values (GV) increased with light reduction in relation to plant height (H) and specific leaf area (SLA). The traits total dry mass accumulation (DM) and leaf dry mass accumulation (LDM) had GV higher in 50% shade and intermediate in 70% shade. The GV of tiller number (TIL) and root dry mass accumulation (RDM) decreased with light reduction. The highest positive correlations were obtained for the traits H and RDM with SLA and DM; the highest negative correlations were between TIL and SLA and RDM, and H and LDM. The progenies showed higher tolerance to 50% light reduction and, among them, two stood out and will be used in breeding programs. It was also found that it is not necessary to evaluate some traits under all light conditions. All traits had high broad sense heritability and high genotypic correlation between progenies in all light intensities. There is genetic difference among the progenies regarding the response to different light intensities, which will allow selection for shade tolerance

scholarly journals Estimation of carbon stock in seagrass communities in Central Tapanuli

2021 ◽  
Vol 944 (1) ◽  
pp. 012064
Author(s):  
Z A Harahap ◽  
Khairunnisa ◽  
I E Susetya ◽  
Y P Rahayu
Keyword(s):  
Carbon Stock ◽  
Standing Stock ◽  
Seagrass Beds ◽  
Biomass Carbon ◽  
Above Ground Biomass ◽  
Loss On Ignition ◽  
Ground Biomass ◽  
Seagrass Ecosystem ◽  
Seagrass Biomass ◽  
Below Ground

Abstract This study aims to determine the carbon stock in seagrass communities in Central Tapanuli, North Sumatera, Indonesia. The research was conducted from July to August 2020 in the coastal areas of Hajoran and Jago Jago. The parameters measured in this study were density, coverage, biomass, carbon content, and carbon stock in seagrass. Biomass analysis and carbon measurement are divided into the top (above-ground biomass) and the bottom substrate (below-ground biomass). Carbon measurements are conducted using the loss on ignition (LOI) approach. The results showed that the seagrass ecosystem on the coast of Central Tapanuli Regency, which was covered by monospecies Enhalus acoroides, was in a less healthy condition with a cover percentage of 30.3-33.3% and a density of 59-67 shoots/m2. Above-ground and below-ground seagrass biomass reached 140.19-188.72 g/m2 and 368.13-423.69 g/m2 respectively, while carbon stock reached 70.57-94.86 g Corg/m2 and 18731-19603 g Corg/m2 and total standing stock range 257.87-290.90 g Corg/m2. The data obtained from this research can be used as a database to see the potential of seagrass beds as storage of CO2 and as an effort to mitigate and adapt to climate change.

scholarly journals Soil microbes alter seedling performance and biotic interactions under plant competition and contrasting light conditions

2020 ◽  
Vol 126 (6) ◽  
pp. 1089-1098
Author(s):  
Nianxun Xi ◽  
Juliette M G Bloor ◽  
Chengjin Chu
Keyword(s):  
Soil Microbes ◽  
Plant Competition ◽  
Light Availability ◽  
Interactive Effects ◽  
Light Conditions ◽  
Tree Seedling ◽  
Low Light ◽  
Feedback Effects ◽  
Seedling Biomass ◽  
Soil Feedback

Abstract Background and Aims Growing evidence suggests that the net effect of soil microbes on plants depends on both abiotic and biotic conditions, but the context-dependency of soil feedback effects remains poorly understood. Here we test for interactions between the presence of conspecific soil microbes, plant competition and light availability on tree seedling performance. Methods Seedlings of two congeneric tropical tree species, Bauhinia brachycarpa and Bauhinia variegata, were grown in either sterilized soil or soil conditioned by conspecific soil microorganisms in a two-phase greenhouse feedback experiment. We examined the interactive effects of soil treatment (live, sterilized), light availability (low, high) and plant competition (no competition, intraspecific and interspecific competition) on tree seedling biomass. We also investigated the linkages between the outcomes of soil feedback effects and soil microbial community structure. Key Results The outcomes of soil feedback effects on seedling biomass varied depending on both competition treatment and light availability. Under low light conditions, soil feedback effects were neutral irrespective of competition treatment and plant species. Soil feedback effects were negative in high light for seedlings with interspecific competition, but positive for seedlings growing alone or with intraspecific competition. Soil feedback effects for seedlings were driven by variation in the Gram-positive:Gram-negative bacteria ratio. Light and conspecific soil microbes had interactive effects on the competitive environment experienced by tree species; in low light the presence of conspecific soil microbes decreased plant competition intensity, whereas in high light both the intensity and the importance of competition increased for seedlings in the presence of soil microbes, irrespective of plant species. Conclusions Our findings underline the importance of light and plant competition for the outcomes of soil feedback effects on young tree seedlings, and suggest that reduced light availability may reduce the influence of conspecific soil microbes on plant–plant interactions.

Cold tolerance and winter hardiness in Lolium perenne: II. Influence of light and temperature during growth and hardening

1973 ◽  
Vol 80 (2) ◽  
pp. 341-348 ◽  
Author(s):  
T. Lawrence ◽  
J. P. Cooper ◽  
E. L. Breese
Keyword(s):  
Light Intensity ◽  
Cold Tolerance ◽  
Lolium Perenne ◽  
Water Soluble ◽  
Light Conditions ◽  
Low Light ◽  
Growing Period ◽  
Light Intensities ◽  
Lower Light ◽  
Light Input

SummaryIn the first paper of this series it was shown that Lolium perenne material required hardening periods involving low, but above freezing, temperatures before frost tolerance was achieved. The present experiments show that the light conditions during the hardening and prehardening periods are also important. At both stages a reduction in total light energy reduced subsequent cold tolerance but the relative effects of light intensity and photoperiod differed between the prehardening and hardening treatments. Thus low light input during the hardening period at 2 CC reduced cold tolerance most when given at higher intensities over shorter days (8 h) while during the prehardening growing period at 20 °C the reduction was greatest when the lower light input was given at low intensity over longer days (16 h).Varieties of different climatic origins reacted differentially to the treatments. The Mediterranean variety Fano was particularly adversely affected by low light intensities during hardening and also benefited from higher temperatures during the prehardening growing period. With higher light intensities and higher growth temperatures this Mediterranean variety approached the more northern material in cold tolerance; but as a corollary it was clear that the N. European variety Veja was able to harden under lower light conditions, and lower growing temperatures. The varieties Melle and S. 321 from intermediate latitudes, were intermediate in response.Although water soluble carbohydrate content was increased during the hardening period, except at the lowest light intensity (2·9 W/m2), no simple relationship between the WSC content and the cold tolerance of the different varieties could be detected.The results provide a useful guide to the pre-treatments necessary to discriminate between varieties for cold tolerance in such a way that the results can be correlated with field performance.

Growth responses of three contrasting Piper species growing under different light conditions

1990 ◽  
Vol 68 (6) ◽  
pp. 1182-1186 ◽  
Author(s):  
M. Esther Sanchez-Coronado ◽  
Emmanuel Rincòn ◽  
Carlos Vàzquez-Yanes
Keyword(s):  
Growth Chamber ◽  
Los Tuxtlas ◽  
Light Conditions ◽  
Growth Responses ◽  
Low Light ◽  
Light Intensities ◽  
Shade Tolerant Species ◽  
Piper Auritum ◽  
Plastic Responses ◽  
Tropical Station

The growth responses of Piper aequale, Piper auritum, and Piper hispidum under contrasting light conditions at Los Tuxtlas Tropical Station, Mexico, and in growth chamber experiments were investigated. The species showed contrasting growth responses; Piper auritum was the less shade-tolerant species and Piper aequale, on the contrary, showed the ability to exploit conditions of intermediate light intensities, similar to those found in small gaps. Piper hispidum was able to sustain growth in both high and low light conditions; this response appears to be related with morphological plastic responses.

scholarly journals Hybrid tea-roses under controlled light conditions. 3. Flower and blind shoot production in the glasshouse of seedlings selected for flowering or flower bud abortion at low irradiances in a growth room.

1978 ◽  
Vol 26 (4) ◽  
pp. 399-404
Author(s):  
D.P. de Vries ◽  
L.A.M. Dubois ◽  
L. Smeets
Keyword(s):  
Lower Percentage ◽  
Light Conditions ◽  
Flower Bud ◽  
Low Light ◽  
Light Intensities ◽  
Shoot Production ◽  
Growth Room ◽  
Selection For ◽  
Flower Bud Abortion ◽  
Made In

Seedlings of hybrid tea roses, previously selected in a growth room for flowering or flower bud abortion at low light intensities were grown in a greenhouse for periods of at least 14 months. Previously flowering seedlings whether grown on their own roots or on a rootstock yielded more flowers, particularly in winter, than previously aborting ones. This was due to a lower percentage of blind shoots and a tendency to produce more shoots. It was shown that selection for better winter performance under glass could be made in young seedlings. [For part 2 see HcA 48, 7528.] (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Influence of Irradiance and Temperature on the Virus MpoV-45T Infecting the Arctic Picophytoplankter Micromonas polaris

Viruses ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 676 ◽  
Author(s):  
Gonçalo Piedade ◽  
Ella Wesdorp ◽  
Elena Montenegro-Borbolla ◽  
Douwe Maat ◽  
Corina Brussaard
Keyword(s):  
Environmental Changes ◽  
Burst Size ◽  
Light Availability ◽  
Continuous Light ◽  
Virus Production ◽  
Cell Lysis ◽  
The Arctic ◽  
Low Light ◽  
Light Intensities ◽  
Ecological Importance

Arctic marine ecosystems are currently undergoing rapid changes in temperature and light availability. Picophytoplankton, such as Micromonas polaris, are predicted to benefit from such changes. However, little is known about how these environmental changes affect the viruses that exert a strong mortality pressure on these small but omnipresent algae. Here we report on one-step infection experiments, combined with measurements of host physiology and viability, with 2 strains of M. polaris and the virus MpoV-45T under 3 light intensities (5, 60 and 160 μmol quanta m−2 s−1), 2 light period regimes (16:8 and 24:0 h light:dark cycle) and 2 temperatures (3 and 7 °C). Our results show that low light intensity (16:8 h light:dark) delayed the decline in photosynthetic efficiency and cell lysis, while decreasing burst size by 46%. In contrast, continuous light (24:0 h light:dark) shortened the latent period by 5 h for all light intensities, and even increased the maximum virus production rate and burst size under low light (by 157 and 69%, respectively). Higher temperature (7 °C vs 3 °C) led to earlier cell lysis and increased burst size (by 19%), except for the low light conditions. These findings demonstrate the ecological importance of light in combination with temperature as a controlling factor for Arctic phytoplankton host and virus dynamics seasonally, even more so in the light of global warming.

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