Growth, photosynthesis and carbon metabolism in the temperate marine diatom Skeletonema costatum adapted to low temperature and low photon-flux density

In this study, we investigated the responses of Phaeodactylum tricornutum cells acclimated to 300 µmol m −2 s −1 photon flux density to an increase (1000 µmol m −2 s −1 ) or decrease (30 µmol m −2 s −1 ) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate. These intermediates were used differently by the cell as a function of the photon flux density: under low light, photosynthesis was depressed while respiration was increased. Under high light, lipids and proteins accumulated. Of great interest, under high light, the genes coding for the synthesis of aromatic amino acids and phenolic compounds were upregulated suggesting that the shikimate pathway was activated. This article is part of the themed issue ‘The peculiar carbon metabolism in diatoms’.

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A comparison of nitrogen and carbon metabolism in the shallow and deep-water phytoplankton populations of a subalpine lake: response to photosynthetic photon flux density

Journal of Plankton Research ◽

10.1093/plankt/6.5.733 ◽

1984 ◽

Vol 6 (5) ◽

pp. 733-749 ◽

Cited By ~ 10

Author(s):

John C. Priscu

Keyword(s):

Flux Density ◽

Deep Water ◽

Carbon Metabolism ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Photosynthetic Photon Flux ◽

Subalpine Lake

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Micropropagated dwarf off-type Cavendish bananas (Musa spp., AAA) show improved tolerance to suboptimal temperatures

Australian Journal of Agricultural Research ◽

10.1071/a96168 ◽

1997 ◽

Vol 48 (3) ◽

pp. 377 ◽

Cited By ~ 11

Author(s):

Olivia P. Damasco ◽

Mike K. Smith ◽

Ian D. Godwin ◽

Steve W. Adkins ◽

Robert M. Smillie ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Low Temperature ◽

Flux Density ◽

Environmental Conditions ◽

Photon Flux ◽

Photon Flux Density ◽

Leaf Production ◽

Musa Spp

The responses of micropropagated normal plants and dwarf off-types of Cavendish (Musa spp. AAA) bananas to suboptimal temperatures were evaluated under field and controlled environmental conditions. Compared with bananas grown at 30/25°C (day/night), leaf production at 18/14°C was inhibited by 51% in normal plants and 18% in dwarf off-types. The emergence of the first leaf that developed at low temperature was delayed by 11 days for normal plants and 5 days for the dwarf off-types. Photoinhibition of lamina, measured by decrease in the chlorophyll fluorescence variable Fv/Fm, occurred in all banana plants growing in the field during the winter months. The extent to which the plants were photoinhibited was significantly greater for the normal plants than dwarf off-types. Under controlled environmental conditions, photoinhibition was similarly greater in normal plants than dwarf off-types. After 153 h at 18/14C and a 9-h photoperiod of photon flux density (PFD) of 380 mmol/m2· s, Fv/Fm was reduced by 22 and 13% for normal and dwarf off-types, respectively. When plants were exposed to 18°C and a continuous PFD of 380 µmol/m2· s for 20 h, Fv/Fm was reduced by 50% for normal plants and 36% for dwarf off-types. The results of the study indicate that dwarf off-types generated from banana micropropagation showed improved tolerance to low temperature and light, showing better growth and lower susceptibility to low-temperature induced photoinhibition than normal plants.

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