Radiationless Transitions as a Protection Mechanism against Photoinhibition in Higher Plants and a Red Alga

1987 ◽  
pp. 181-187
Author(s):  
David C. Fork ◽  
Salil Bose ◽  
Stephen K. Herbert
Keyword(s):  
Higher Plants ◽  
Red Alga ◽  
Protection Mechanism ◽  
Radiationless Transitions

Radiationless transitions as a protection mechanism against photoinhibition in higher plants and a red alga

1986 ◽  
Vol 10 (3) ◽  
pp. 327-335 ◽  
Author(s):  
David C. Fork ◽  
Salil Bose ◽  
Stephen K. Herbert
Keyword(s):  
Higher Plants ◽  
Red Alga ◽  
Protection Mechanism ◽  
Radiationless Transitions

scholarly journals Primary carbohydrate metabolism genes participate in heat stress memory at the shoot apical meristem of Arabidopsis thaliana

2020 ◽  
Author(s):  
Justyna Jadwiga Olas ◽  
Federico Apelt ◽  
Maria Grazia Annunziata ◽  
Sarah Isabel Richard ◽  
Saurabh Gupta ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
Carbohydrate Metabolism ◽  
Higher Plants ◽  
Fructose Bisphosphate ◽  
Protection Mechanism ◽  
Stress Memory ◽  
Heat Shock Transcription Factors ◽  
Fructose Bisphosphate Aldolase ◽  
Carbohydrate Metabolism Genes

AbstractAlthough we have a good understanding of the development of shoot apical meristems (SAM) in higher plants, and the function of the stem cells (SCs) embedded in the SAM, there is surprisingly little known of its molecular responses to abiotic stresses. Here, we show that the SAM of Arabidopsis thaliana senses heat stress (HS) and retains an autonomous molecular memory of a previous non-lethal HS, allowing the SAM to regain growth after exposure to an otherwise lethal HS several days later. Using RNA-seq, we identified genes participating in establishing a SAM-specific HS memory. The genes include HEAT SHOCK TRANSCRIPTION FACTORs (HSFs), of which HSFA2 is essential, but not sufficient, for full HS memory in the SAM, the SC regulators CLAVATA1 (CLV1) and CLV3, and several primary carbohydrate metabolism genes, including FRUCTOSE-BISPHOSPHATE ALDOLASE 6 (FBA6). We found that expression of FBA6 during HS at the SAM complements that of FBA8 in the same organ. Furthermore, we show that sugar availability at the SAM is essential for survival at high-temperature HS. Collectively, plants have evolved a sophisticated protection mechanism to maintain SCs and, hence, their capacity to re-initiate shoot growth after stress release.

scholarly journals CHROMATOPHORE DEVELOPMENT, PITS, AND OTHER FINE STRUCTURE IN THE RED ALGA, LOMENTARIA BAILEYANA (HARV.) FARLOW

1962 ◽  
Vol 12 (3) ◽  
pp. 553-569 ◽  
Author(s):  
G. Benjamin Bouck
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Higher Plants ◽  
Red Alga ◽  
Cellular Structures ◽  
Secretory Function ◽  
Thin Sections ◽  
Floridean Starch ◽  
Oriented Parallel

Thin sections of the red alga, Lomentaria baileyana, a tubular member of the Rhodymeniales, were examined after permanganate fixation and Araldite embedding. Many of the cellular structures in Lomentaria were found to be similar to analogous structures in animals and higher plants. However, in the walls between cells are modified areas generally known as pits which are unique to the higher orders of red algae (Florideae). In this study the pits were found to consist of a plug-like structure surrounded by an uninterrupted membrane apparently continuous with the plasma membrane. Examination of the chromatophore revealed a characteristic limiting membrane, a relatively sparse distribution of plates, no grana, and a single disc apparently oriented parallel to the limiting membrane. In addition to their origin from non-lamellate proplastids, chromatophores were found capable of division by simple constriction. Floridean starch grains were observed outside the chromatophore and the possibility of an association of the first formed grains with portions of the endoplasmic reticulum is considered. Gland cells seem to have a high proportion of Golgi components (dictyosomes), and are believed to have some kind of secretory function. Many of the Golgi vesicles seem to open on the wall and presumably discharge their contents.

scholarly journals Unique organization of photosystem I–light-harvesting supercomplex revealed by cryo-EM from a red alga

2018 ◽  
Vol 115 (17) ◽  
pp. 4423-4428 ◽  
Author(s):  
Xiong Pi ◽  
Lirong Tian ◽  
Huai-En Dai ◽  
Xiaochun Qin ◽  
Lingpeng Cheng ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Photosystem I ◽  
Light Harvesting ◽  
Higher Plants ◽  
Red Alga ◽  
Cyanidioschyzon Merolae ◽  
Higher Plant ◽  
Light Harvesting Complex ◽  
Red Algal ◽  
Eukaryotic Organisms

Photosystem I (PSI) is one of the two photosystems present in oxygenic photosynthetic organisms and functions to harvest and convert light energy into chemical energy in photosynthesis. In eukaryotic algae and higher plants, PSI consists of a core surrounded by variable species and numbers of light-harvesting complex (LHC)I proteins, forming a PSI-LHCI supercomplex. Here, we report cryo-EM structures of PSI-LHCR from the red alga Cyanidioschyzon merolae in two forms, one with three Lhcr subunits attached to the side, similar to that of higher plants, and the other with two additional Lhcr subunits attached to the opposite side, indicating an ancient form of PSI-LHCI. Furthermore, the red algal PSI core showed features of both cyanobacterial and higher plant PSI, suggesting an intermediate type during evolution from prokaryotes to eukaryotes. The structure of PsaO, existing in eukaryotic organisms, was identified in the PSI core and binds three chlorophylls a and may be important in harvesting energy and in mediating energy transfer from LHCII to the PSI core under state-2 conditions. Individual attaching sites of LHCRs with the core subunits were identified, and each Lhcr was found to contain 11 to 13 chlorophylls a and 5 zeaxanthins, which are apparently different from those of LHCs in plant PSI-LHCI. Together, our results reveal unique energy transfer pathways different from those of higher plant PSI-LHCI, its adaptation to the changing environment, and the possible changes of PSI-LHCI during evolution from prokaryotes to eukaryotes.

Identification and characterization of phospholipase D in a unicellular red alga (Porphyridium cruentum)

1970 ◽  
Vol 48 (6) ◽  
pp. 643-648 ◽  
Author(s):  
N. J. Antia ◽  
E. Bilinski ◽  
Y. C. Lau
Keyword(s):  
Heavy Metal ◽  
Phospholipase D ◽  
Metal Ion ◽  
Cultured Cells ◽  
Higher Plants ◽  
Sulfhydryl Group ◽  
Red Alga ◽  
Porphyridium Cruentum ◽  
Ph Optimum ◽  
Surface Active Agents

Axenically cultured cells of Porphyridium cruentum were assayed for enzymes catalyzing the hydrolysis of lecithin. The sonicated cells showed virtually exclusive and complete conversion of 14C-choline-labelled lecithin to 14C-choline, with no significant formation of glycerylphosphorylcholine or phosphorylcholine. The enzymatic activity showed a sharp pH optimum at 7.0, and was strongly inhibited by chelating agents (two types), sulfhydryl-group binding reagents (three types), and surface-active agents (anionic and non-ionic). The inhibition from ethylenediamine tetraacetate (EDTA) was reversed by Ca2+ or Sr2+ but not by Mg2+ or Ba2+, and that from —SH binding reagents was reversed by dithiothreitol. Heavy metal ions (Zn2+, Cu2+, Ba2+, Co2+, Mn2+, Fe2+) inhibited the activity, Ca2+ caused stimulation, while Mg2+ and Sr2+ had little effect. The results indicate the occurrence of a pH and heavy-metal ion sensitive, Ca2+-(or Sr2+-) requiring phospholipase D in the red alga, and the involvement of sulfhydryl groups in the expression of its activity. The algal enzyme resembles those from higher plants in its Ca2+ requirement and sensitivity to EDTA and organomercurial sulfhydryl binding reagent, but differs markedly in its optimum pH and several other properties.

Fine structure in the red algae - I. X-ray and electronmicroscope investigation of Griffithsia flosculosa

1956 ◽  
Vol 144 (917) ◽  
pp. 450-459 ◽  
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Higher Plants ◽  
Amorphous Material ◽  
Red Alga ◽  
Cellulose Ii ◽  
X Ray ◽  
Thin Sectioning ◽  
Polarization Optics ◽  
Obvious Relation

Filaments of the red alga Griffithsia flosculosa have been examined by the methods of X-ray analysis, polarization optics, and electron microscopy, including ultra-thin sectioning. The main structural component of the wall consists of cellulose II (mercerized cellulose) organized into microfibrils about 200 Å wide and 100 Å thick. These are embedded in an amorphous material. The X-ray diagram resembles very closely that of the green alga Ulothrix flacca . Examination of sections in the electronmicroscope shows that the wall is finely lamellated and in addition there are periodic inclusions which appear to be cytoplasmic. The limiting layer of the cytoplasm bordering the vacuole is very distinct; the layer bordering on the wall has a series of peg-like protuberances into wall and cytoplasm. It is tentatively concluded that the site of wall formation lies, not at the cytoplasm-wall interface, but deeper in the cytoplasm. The chromatophores are lamellated much as the chloroplasts are known to be in higher plants. These lamellae consist here, however, of granules whose size (some 220 Å diameter) bears no obvious relation to known constituents of the chromatophores.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

1972 ◽  
Vol 30 ◽  
pp. 230-231
Author(s):  
James Cronshaw ◽  
Jamison E. Gilder
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Higher Plants ◽  
High Surface ◽  
Root Tip ◽  
Animal Cells ◽  
Physiological Processes ◽  
Tip Cells ◽  
Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

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