Differential Responses of Growth and Photochemical Performance of Marine Diatoms to Ocean Warming and High Light Irradiance

2020 ◽  
Vol 96 (5) ◽  
pp. 1074-1082
Author(s):  
Yaping Wu ◽  
Mengjuan Zhang ◽  
Zhenzhen Li ◽  
Juntian Xu ◽  
John Beardall
Keyword(s):  
High Light ◽  
Ocean Warming ◽  
Marine Diatoms ◽  
Light Irradiance ◽  
Differential Responses

Hypobaria, hypoxia, and light affect gas exchange and the CO2 compensation and saturation points of lettuce (Lactuca sativa)This paper is one of a selection published in a Special Issue comprising papers presented at the 50th Annual Meeting of the Canadian Society of Plant Physiologists (CSPP) held at the University of Ottawa, Ontario, in June 2008.

Botany ◽  
2009 ◽  
Vol 87 (7) ◽  
pp. 712-721 ◽  
Author(s):  
Chuanjiu He ◽  
Fred T. Davies ◽  
Ronald E. Lacey
Keyword(s):  
Gas Exchange ◽  
Partial Pressure ◽  
Lactuca Sativa ◽  
Crop Production ◽  
Ambient Pressure ◽  
High Light ◽  
Compensation Point ◽  
Saturation Point ◽  
Low Light ◽  
Light Irradiance

There are important engineering and crop production advantages in growing plants under hypobaric (reduced atmospheric pressure) conditions for extraterrestrial base or spaceflight environments. The objectives of this research were to determine the influence of hypobaria and reduced partial pressure of oxygen (pO2) (hypoxia) under low and high light irradiance on carbon dioxide (CO2) assimilation (CA), dark-period respiration (DPR), and the CO2 compensation and CO2 saturation points of lettuce (Lactuca sativa L. ‘Buttercrunch’). Plants were grown under variable total gas pressures [25 and 101 kPa (ambient)] at 6, 12, or 21 kPa pO2 (approximately the partial pressure in air at normal pressure). Light irradiance at canopy level of the low-pressure plant growth system (LPPG) was at 240 (low) or 600 (high) µmol·m–2·s–1. While hypobaria (25 kPa) had no effect on CA or the CO2 compensation point, it reduced the DPR and the CO2 saturation point, and increased the CA / DPR ratio. Hypoxia (6 kPa pO2) and low light reduced CA, DPR, and the CA / DPR ratio. Hypoxia decreased the CO2 compensation point regardless of total pressure. Hypoxia also decreased the the CO2 saturation point of ambient-pressure plants, but had no effect on hypobaric plants. While low light reduced the CO2 saturation point, it increased the CO2 compensation point, compared with high-light plants. The results show that hypobaric conditions of 25 kPa do not adversely affect gas exchange compared with ambient-pressure plants, and may be advantageous during hypoxic stress.

Multiple stressor effects of high light irradiance and photosynthetic herbicides on growth and survival of the green alga Chlamydomonas reinhardtii

2010 ◽  
Vol 29 (10) ◽  
pp. 2211-2219 ◽  
Author(s):  
Beat B. Fischer ◽  
Karin Rüfenacht ◽  
Kerstin Dannenhauer ◽  
Manuela Wiesendanger ◽  
Rik I.L. Eggen
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Green Alga ◽  
High Light ◽  
Growth And Survival ◽  
Light Irradiance ◽  
Multiple Stressor

scholarly journals High light induced accumulation of two isoforms of the CF1 alpha-subunit in mesophyll and bundle sheath chloroplasts of C4 plants.

2008 ◽  
Vol 55 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Elzbieta Romanowska ◽  
Marta Powikrowska ◽  
Maksymilian Zienkiewicz ◽  
Anna Drozak ◽  
Berenika Pokorska
Keyword(s):  
Atp Synthase ◽  
Light Stress ◽  
Protective Role ◽  
Bundle Sheath ◽  
High Light ◽  
Alpha Subunit ◽  
Strong Increase ◽  
Panicum Maximum ◽  
Low Light ◽  
Light Irradiance

The effect of light irradiance on the amount of ATP synthase alpha-subunit in mesophyll (M) and bundle sheath (BS) chloroplasts of C(4) species such as maize (Zea mays L., type NADP-ME), millet (Panicum miliaceum, type NAD-ME) and guinea grass (Panicum maximum, type PEP-CK) was investigated in plants grown under high, moderate and low light intensities equal to 800, 350 and 50 micromol photons m(-2) s(-1), respectively. The results demonstrate that alpha-subunit of ATP synthase in both M and BS chloroplasts is altered by light intensity, but differently in the investigated species. Moreover, we identified two isoforms of the CF(1) alpha-subunit, called alpha and alpha. The CF(1) alpha-subunit was the major isoform and was present in all light conditions, whereas alpha was the minor isoform in low light. A strong increase in the level of the alpha-subunit in maize mesophyll and bundle sheath thylakoids was observed after 50 h of high light treatment. The alpha and alpha-subunits from investigated C(4) species displayed apparent molecular masses of 64 and 67 kDa, respectively, on SDS/PAGE. The presence of the alpha-subunit of ATPase was confirmed in isolated CF(1) complex, where it was recognized by antisera to the alpha-subunit. The N-terminal sequence of alpha-subunit is nearly identical to that of alpha. Our results indicate that both isoforms coexist in M and BS chloroplasts during plant growth at all irradiances. We suggest the existence in M and BS chloroplasts of C(4) plants of a mechanism(s) regulating the ATPase composition in response to light irradiance. Accumulation of the alpha isoform may have a protective role under high light stress against over protonation of the thylakoid lumen and photooxidative damage of PSII.

scholarly journals Substrate regulation leads to differential responses of microbial ammonia-oxidizing communities to ocean warming

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhen-Zhen Zheng ◽  
Li-Wei Zheng ◽  
Min Nina Xu ◽  
Ehui Tan ◽  
David A. Hutchins ◽  
...  
Keyword(s):  
Ocean Warming ◽  
Substrate Regulation ◽  
Differential Responses

Nitrate starvation associated with strong light induces astaxanthin accumulation in a new green microalga Haematococcus pluvialis isolated from Algerian freshwater

2019 ◽  
Vol 9 (2) ◽  
pp. 40-49
Author(s):  
Sadoud Meryem ◽  
Mokhtar Meriem ◽  
Bouamar Sarah ◽  
Bouziane Nabil ◽  
Belabbas Meryem ◽  
...  
Keyword(s):  
Light Intensity ◽  
Haematococcus Pluvialis ◽  
Basal Medium ◽  
High Light Intensity ◽  
High Light ◽  
Strong Light ◽  
Light Irradiance ◽  
Morphological Criteria ◽  
Green Microalga ◽  
Nitrate Starvation

The unicellular microalgae Haematococcus pluvialis is of great interest because it is an exclusive and the richest source of natural astaxanthin (3, 3’- dihydroxy-β-carotene-4, 4’-dione). We carried out an isolation and screening of a new H. pluvialis strains with high astaxanthin production potential from Algerian freshwater. The isolated strains were assessed for their growth and astaxanthin accumulation under different stress conditions associated with high light intensity. The main goal of the present study was to select highly astaxanthin-producing H. pluvialis strains from the Algerian environment. Eighteen microalgae strains in total were isolated on a Bold’s basal medium from 48 aseptically collected freshwater samples from 5 different regions of Algeria. The identification of H. pluvialis was made according to morphological criteria. Growth tests have led to the selection of the best H. pluvialis strain that will be grown under stress (nutrient starvation and variable salinity) associated to high light intensity (200 µmol photons.m-2.s-1) to determine the optimal conditions of astaxanthin accumulation. Optimal nitrate concentration giving rise to maximum biomass was 0.50 g/L. Nitrate starvation associated with high light irradiance was most effective in induction of astaxanthin accumulation which reached 67.25 ± 2.28 mg/L in H. pluvialis cells. H. pluvialis morphology under such stress has shown the occurrence of mature aplanospores with thick cell wall. These results clearly show that the isolated H. pluvialis strain has a good performance to synthesize astaxanthin under nitrate starvation associated with high light irradiance suggesting its possible industrial culture for the production of this pigment.

Common Sunflower (Helianthus annuus) Interference in Onions (Allium cepa)

Weed Science ◽  
1981 ◽  
Vol 29 (6) ◽  
pp. 641-647 ◽  
Author(s):  
Robert M. Menges ◽  
Simon Tamez
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Helianthus Annuus ◽  
Allium Cepa ◽  
Climatic Factors ◽  
High Light ◽  
Fresh Weight ◽  
Weed Density ◽  
Light Irradiance ◽  
High Soil Temperature

Common sunflower (Helianthus annuusL.) interference in onions (Allium cepaL. ‘Yellow Granex PRR’) was studied at different weed densities and periods of interference. Onion yields were reduced when the highest density (360/m2) of common sunflower interference with onions from 6 weeks after emergence and when sunflower at densities of 50/m2and 5/m2interfered for 12 and 15 weeks after emergence, respectively. Yield was not reduced if the crop was kept weed-free for 2 to 12 weeks after emergence with the shortest weed-free periods of 2 and 6 weeks requiring high light irradiance and high soil temperature and intermediate soil moisture. Climatic factors were more useful than weed density in explaining differential interference of sunflower in onions. Onion yield was negatively linearly correlated (P<0.05) with sunflower fresh weight, but was not linearly correlated with sunflower height.

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