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Start Over Creator Bauer, H.

1. Effects of cold acclimation on chlorophyll fluorescence in winter rape leaves

Creator:
Macijewska, U. and Bauer, H.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
Changes in various parameters of room temperature chlorophyll fluorescence were found during cold acciimation at 2.5 of Brassica napiis L, var. oleifera plants. At the beginning of cold stress the non-radiative energy dissipation was enhanced, and afterwards, the photochemistry was affected. After prolonged cold acciimation the fiill recovery of photochemical activity was observed when the plants had been transferred to higher temperature (20/15 oC) for several days.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Photosynthesis after freezing stress in plants with various degrees of freezing tolerance

Creator:
Bauer, H., Nagele, M., Comploj, M., Galler, V., Mair, M., and Unterpentinger, E.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
The aim of ťhis study was to clarify whether there are generál differences between the woody and herbaceous plants in their responses to a single non-lethal freezing stress, when measured under comparable conditions. Activity of net photosynthesis (^N33)» th® curves of versus photosynthetic photon fluence density and versus intercellular partial pressure of CO2, and ratio of variable to maximal fluorescence (F^Fm) were measured at optimal temperatures in the leaves of six woody and six herbaceous plant species prior to frost-hardening, after frost-hardening at low positive temperatures and after a single over-night freezing stress (-10 ®C, 12 h) of the shoots. Recovery of at 20/15 “C was also followed. There were no generál differences between woody and herbaceous plants in their photosynthetic responses to freezing stress. In most plants, Pn33 was strongly reduced after freezing mainly due to the disturbances in fimctioning of the chloroplasts, but it recovered within a few days. However, of some herbaceous plants (Cochlearia, one cultivar of spinách) was insensitive to non-lethal freezing. Furthermore, stomatal opening of a few herbaceous plants (Cochlearia, Valerianella) was disturbed after freezing without any sign of an impairment in fimctioning of the chloroplasts.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Similar susceptibility to excess irradiance in sun and shade acclimated saplings of Norway spruce [Picea abies (L.) Karst.] and stone pine (Pinus cembra L.)

Creator:
Gamper, R., Mayr, S., and Bauer, H.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, frost hardening, low temperature, and net photosynthetic rate
Language:
Multiple languages
Description:
We compared the responses of sun and shade acclimated saplings of Picea abies and Pinus cembra to excess photosynthetic photon flux density (PPFD) equivalently exceeding the level for saturating net photosynthetic rate (PN). Exposure for 2 h up to 2000 µmol(photon) m-2 s-1 did not affect radiant energy saturated PN. Photoinhibition of photosynthesis was indicated by a small (10 %) reduction of the potential efficiency of photosystem 2 as derived from measurements of chlorophyll fluorescence (FV/FM). However, the extent of FV/FM reduction and half-time for recovery were similar in sun and shade acclimated saplings of both species. Furthermore, the effect on FV/FM was not stronger when the plants were exposed to excess PPFD at 5 °C instead of 15 °C. Frost-hardening of plants increased slightly their resistance to excess PPFD. Establishment of these conifer saplings usually acclimated to shade in their natural habitat may hardly be endangered by a sudden increase of PPFD, e.g., by gap formation. and R. Gamper, S. Mayr, H. Bauer.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public