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2. Light induction of nonphotochemical quenching, CO2 fixation, and photoinhibition in woody and fern species adapted to different light regimes

Creator:
Wong, S.-L., Huang, M.-Y., Chen, C.-W., and Weng, J.-H.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, light adaptation, NPQ, photoinhibition, photosynthetic induction, photosynthetic rate, 2, and 581
Language:
Multiple languages
Description:
We aimed to find out relations among nonphotochemical quenching (NPQ), gross photosynthetic rate (PG), and photoinhibition during photosynthetic light induction in three woody species (one pioneer tree and two understory shrubs) and four ferns adapted to different light regimes. Pot-grown plants received 100% and/or 10% sunlight according to their light-adaptation capabilities. After at least four months of light acclimation, CO2 exchange and chlorophyll fluorescence were measured simultaneously in the laboratory. We found that during light induction the formation and relaxation of the transient NPQ was closely related to light intensity, light-adaption capability of species, and PG. NPQ with all treatments increased rapidly within the first 1-2 min of the light induction. Thereafter, only species with high PG and electron transport rate (ETR), i.e., one pioneer tree and one mild shade-adapted fern, showed NPQ relaxing rapidly to a low steady-state level within 6-8 min under PPFD of 100 μmol(photon) m-2 s-1 and ambient CO2 concentration. Leaves with low PG and ETR, regardless of species characteristics or inhibition by low CO2 concentration, showed slow or none NPQ relaxation up to 20 min after the start of low light induction. In contrast, NPQ increased slowly to a steady state (one pioneer tree) or it did not reach the steady state (the others) from 2 to 30 min under PPFD of 2,000 μmol m-2 s-1. Under high excess of light energy, species adapted to or plants acclimated to high light exhibited high NPQ at the initial 1 or 2 min, and showed low photoinhibition after 30 min of light induction. The value of fastest-developing NPQ can be quickly and easily obtained and might be useful for physiological studies., S.-L. Wong, M.-Y. Huang, C.-W. Chen, J.-H. Weng., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Zrození vývojové kosmologie

Creator:
Jurmanová, Jana
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
relativistická kosmologie, vesmír, relativistic cosmology, universe, 6, and 53
Language:
Czech
Description:
Základními kameny obecně relativistické kosmologie jsou tři články - Einsteinův, de Sitterův a Friedmannův. Zatímco Einstein a částečně i de Sitter setrvali u zažité představy v čase neměnného kosmu, Friedmann jako první upozornil, že Einsteinovy rovnice pro homogenní a izotropní model umožňují i řešení odpovídající rozpínajícímu se vesmíru. Jeho článkem (1922) byly položeny základy obecně relativistické vývojové kosmologie, rozvíjené pak řadou Friedmannových současníků i následovníků. Text zahrnuje základní ideje obsažené v uvedených článcích a naznačuje další změny výzkumu v oblasti vývojové kosmologie, od dobudováních jejích základů uplyne v letošním roce osmdesát let., Jana Jurmanová., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public