Photoacclimation involves modulation of the photosynthetic oxygen-evolving reactions in Dunaliella tertiolecta and Phaeodactylum tricornutum

2003 ◽  
Vol 30 (3) ◽  
pp. 301 ◽  
Author(s):  
Antonietta Quigg ◽  
John Beardall ◽  
Tom Wydrzynski
Keyword(s):  
Phaeodactylum Tricornutum ◽  
Higher Plants ◽  
Dunaliella Tertiolecta ◽  
Oxygen Evolving Complex ◽  
Net Energy ◽  
Photosynthetic Physiology ◽  
Oxygen Flash ◽  
Species Specific ◽  
Oxygen Evolving

Net energy accumulation by marine microalgae at very low photon fluxes involves modulation of several attributes related to both the growth and photosynthetic physiology of these organisms. Here we studied flash-induced oscillatory patterns in oxygen evolution by previously dark-adapted cells of the green alga Dunaliella tertiolecta (Butcher) and the diatom Phaeodactylum tricornutum (Bohlin). The activity of the oxygen-evolving complex was found to be species-specific and influenced by photoacclimation. Results from measurements of oxygen flash yield obtained for these organisms grown under light-saturating conditions are directly comparable to those previously reported in the literature for other microalgae and higher plants. However, similar measurements on cells grown in low-light and/or light-starved conditions indicate an increased level of backward transitions (double misses) leading to the formation of super-reduced states (i.e. S–1 and S–2). Thus, in this communication, we present the first evidence that super-reduced states can be generated in vivo and speculate, on how they may be physiologically important.

scholarly journals Changes of Photosynthetic Behaviors inKappaphycus alvareziiInfected by Epiphyte

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Tong Pang ◽  
Jianguo Liu ◽  
Qian Liu ◽  
Wei Lin
Keyword(s):  
Photosynthetic Activity ◽  
Oxygen Evolving Complex ◽  
Morphological Studies ◽  
Active Reaction ◽  
Performance Indexes ◽  
Chlorophyll Fluorescence Transient ◽  
Oxygen Evolving ◽  
Harmful Effects

Epiphytic filamentous algae (EFA) were noted as a serious problem to reduce the production and quality ofK. alvarezii. The morphological studies revealed that the main epiphyte onK. alvareziiwasNeosiphonia savatieriin China. Though the harmful effects of EFA on the production ofK. alvareziihave been reported, the detailed mechanism of theN. savatieriin limiting the production ofK. alvareziihas not been studied yet. The present paper studied the effects ofN. savatieriinfection on photosynthetic behaviors inK. alvareziiby detecting chlorophyll fluorescence transient in vivo. The results revealed that damage of oxygen-evolving complex (OEC), decrease of active reaction centers (RCs), and the plastoquinone (PQ) pool as well as significant reduction in the performance indexes (PI) of PSII were caused by the infection ofN. savatieri. The influence ofN. savatierion photosynthetic activity ofK. alvareziishould be one of the important reasons to reduce the production ofK. alvareziiinfected byN. savatieri.

Quantitative assessment of the high-light tolerance in plants with an impaired photosystem II donor side

2019 ◽  
Vol 476 (9) ◽  
pp. 1377-1386 ◽  
Author(s):  
Sam Wilson ◽  
Alexander V. Ruban
Keyword(s):  
Photosystem Ii ◽  
Redox State ◽  
Photochemical Quenching ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Donor Side ◽  
Acceptor Side ◽  
Oxygen Evolving ◽  
The Impact

Abstract Photoinhibition is the light-induced down-regulation of photosynthetic efficiency, the primary target of which is photosystem II (PSII). Currently, there is no clear consensus on the exact mechanism of this process. However, it is clear that inhibition can occur through limitations on both the acceptor- and donor side of PSII. The former mechanism is caused by electron transport limitations at the PSII acceptor side. Whilst, the latter mechanism relies on the disruption of the oxygen-evolving complex. Both of these mechanisms damage the PSII reaction centre (RC). Using a novel chlorophyll fluorescence methodology, RC photoinactivation can be sensitively measured and quantified alongside photoprotection in vivo. This is achieved through estimation of the redox state of QA, using the parameter of photochemical quenching in the dark (qPd). This study shows that through the use of PSII donor-side inhibitors, such as UV-B and Cd2+, there is a steeper gradient of photoinactivation in the systems with a weakened donor side, independent of the level of NPQ attained. This is coupled with a concomitant decline in the light tolerance of PSII. The native light tolerance is partially restored upon the use of 1,5-diphenylcarbazide (DPC), a PSII electron donor, allowing for the balance between the inhibitory pathways to be sensitively quantified. Thus, this study confirms that the impact of donor-side inhibition can be detected alongside acceptor-side photoinhibition using the qPd parameter and confirms qPd as a valid, sensitive and unambiguous parameter to sensitively quantify the onset of photoinhibition through both acceptor- or donor-side mechanisms.

Chemical reduction of graphene enhances in vivo translocation and photosynthetic inhibition in pea plants

2019 ◽  
Vol 6 (4) ◽  
pp. 1077-1088 ◽  
Author(s):  
Lingyun Chen ◽  
Chenglong Wang ◽  
Shengnan Yang ◽  
Xin Guan ◽  
Qiangqiang Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photosystem Ii ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Oxygen Evolving Complex ◽  
Donor Side ◽  
Photosynthetic Inhibition ◽  
Reduced Graphene ◽  
Oxygen Evolving

Reduced graphene oxide (RGO) was translocated into leaves and inhibited the activity of photosystem II by damaging the oxygen-evolving-complex on the donor side.

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.

scholarly journals Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 371
Author(s):  
Koua
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Long Range ◽  
Electron Acceptor ◽  
Structural Changes ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Long Range Interactions ◽  
Structural Perturbations ◽  
Oxygen Evolving

The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.

Sign in / Sign up

Export Citation Format

Share Document