Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Reconstitution of chlorophylls and photosynthetic CO2 assimilation upon rehydration of the desiccated poikilochlorophyllous plant Xerophyta scabrida (Pax) Th. Dur. et Schinz (1994)
    Springer
    Planta 192 (1994), S. 414-420 
    Details
    ISSN: 1432-2048
    Keywords: Carotenoid ; Chlorophyll fluorescence ; Photosynthesis ; Rehydration respiration ; Variable-fluorescence decrease ratio ; Xerophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Resynthesis of the photosynthetic apparatus and resumption of CO2 assimilation upon rehydration is reported for the monocotyledonous and poikilochlorophyllous desiccation-tolerant (PDT) plant Xerophyta scabrida (Pax) Th. Dur. et Schinz (Velloziaceae). During desiccation there was a complete breakdown of chlorophylls whereas the total carotenoid content of air-dried leaves was reduced to about 22% of that of functional leaves. The prerequisites for the resynthesis of photosynthetic pigments and functional thylakoids were the reappearance of turgor and maximum leaf water content at 2 and 10 h after rehydration, respectively. The period of increased initial respiration after rewetting leaves (rehydration respiration) lasted up to 30 h and was thus 6 to 10 times longer than in homoiochlorophyllous desiccation-tolerant plants (HDTs) in which chlorophylls are retained during desiccation. Accumulation of chlorophylls a + b and total carotenoids (xanthophylls and βcarotene) started 10 h after rehydration. Normal levels of chlorophyll and carotenoids were obtained 72 h after rehydration. Values for the variable-fluorescence decrease ratio (Rfd690 values), an indicator of photochemical activity, showed that photochemical function started 10 h after rehydration, but normal values of 2.7 were reached only 72 h after rehydration. Net CO2 assimilation started 24 h after rewetting and normal rates were reached after 72 h, at the same time as normal values of stomatal conductance were obtained. The increasing rates of net CO2 assimilation were paralleled by decreasing values of the intercellular CO2 concentration. All photosynthetic parameters investigated showed values normal for functional chloroplasts by 72 h after the onset of rehydration. Fully regreened leaves of the presumed C3 plant X. scabrida exhibited a net CO2 assimilation rate which was in the same range as that of other C3 plants and higher than that of recovered HDT plants. The fundamental difference between air-dried PDT plants, such as X. scabrida, which have to resynthesize the photosynthetic pigment apparatus, and air-dried HDT plants, which only undergo a functional recovery, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198578
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Early morning photosynthesis of the moss Tortula ruralis following summer dew fall in a Hungarian temperate dry sandy grassland (2000)
    Springer
    Plant ecology 151 (2000), S. 51-54 
    Details
    ISSN: 1573-5052
    Keywords: Carbon balance ; Desiccation tolerance ; Rehydration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Air temperature and humidity, moss surface temperature, moss water content, and photosynthetically active radiation were measured through a clear dry night and early morning in July 1998; CO2 gas exchange of the moss was measured by infra-red gas analysis. The measurements showed progressive absorption of water by the moss through much of the night. The moss reached sufficient water content for about 1.5 h of positive net CO2 uptake immediately after dawn. The cumulative net carbon balance on this occasion was negative, but mornings with heavier dew could give a positive daily carbon balance, and short, early morning periods of photosynthesis during prolonged dry weather may mitigate long-term desiccation damage and allow for regular molecular repair.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026590506740
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    ABA treatment increases both the desiccation tolerance of photosynthesis, and nonphotochemical quenching in the moss Atrichum undulatum (2000)
    Springer
    Plant ecology 151 (2000), S. 65-71 
    Details
    ISSN: 1573-5052
    Keywords: Abscisic acid ; Chlorophyll fluorescence ; Desiccation ; Moss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pulse amplitude modulation fluorescence was used to investigate whether abscisic acid (ABA) pretreatment increases the desiccation tolerance of photosynthesis in the moss Atrichum undulatum. In unstressed plants, ABA pretreatment decreased the F V/F m ratio, largely as a result of an increase in F o. This indicated a reduction in energy transfer between LHCII and PSII, possibly hardening the moss to subsequent stress by reducing the production of the reactive oxygen species near PSII. During desiccation, F 0, F m, F v/F m, ΦPSII, and NPQ and F 0 quenching declined in ABA-treated and nontreated mosses. However, during rehydration, F 0, F m, F v/F m, and ΦPSII recovered faster in ABA-treated plants, suggesting that ABA improved the tolerance of photosystem II to desiccation. NPQ increased upon rehydration in mosses from both treatments, but much more rapidly in ABA-treated plants; during the first hour of rehydration, NPQ was two-fold greater in plants treated with ABA. F 0quenching followed a similar pattern, indicating that ABA treatment stimulated zeaxanthin-based quenching. The implications of these results for the mechanisms of ABA-induced desiccation tolerance in A. undulatum are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026546707649
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ecophysiological responses of homoiochlorophyllous and poikilochlorophyllous desiccation tolerant plants: a comparison and an ecological perspective (1998)
    Springer
    Plant growth regulation 24 (1998), S. 211-217 
    Details
    ISSN: 1573-5087
    Keywords: chlorophyll a+b ; CO2 assimilation ; desiccation-tolerance mechanism ; ecological adaptation ; homoiochlorophyllous ; poikilochlorophyllous ; rehydration ; respiration ; resynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract There is an apparently stark contrast in ecophysiological adaptation between the poikilochlorophyllous desiccation-tolerant (PDT) angiosperm Xerophyta scabrida and homoichlorophyllous desiccation-tolerant (HDT) lichens and bryophytes. We summarise measurements on Xerophyta and on the temperate dry-grassland lichen Cladonia convoluta and the moss Tortula ruralis through a cycle of desiccation and rehydration. Considered in a broad ecological and evolutionary context, desiccation tolerance in general can be seen as evading some of the usual problems of drought stress, and these plants as particular instances drawn from an essentially continuous spectrum of adaptive possibilities – related on the one hand to the physical scale of the plants, and on the other to the time-scale of wetting and drying episodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005951908229
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Ecophysiological responses of homoiochlorophyllous and poikilochlorophyllous desiccation tolerant plants: a comparison and an ecological perspective (1998)
    Springer
    Plant growth regulation 26 (1998), S. 71-71 
    Details
    ISSN: 1573-5087
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006180005360
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Thermoluminescence studies on the function of Photosystem II in the desiccation tolerant lichen Cladonia convoluta (1996)
    Springer
    Photosynthesis research 48 (1996), S. 205-212 
    Details
    ISSN: 1573-5079
    Keywords: thermoluminescence ; Photosystem II ; desiccation tolerance ; lichen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of desiccation and rehydration on the function of Photosystem II has been studied in the desiccation tolerant lichen Cladonia convoluta by thermoluminescence. We have shown that in functional fully hydrated thalli thermoluminescence signals can be observed from the recombination of the S2(3)QB − (B band), S2QA − (Q band), Tyr-D+QA − (C band) and Tyr-Z+(His+)QA − (A band) charge stabilization states. These thermoluminescence signals are completely absent in desiccated thalli, but rapidly reappear on rehydration. Flash-induced oscillation in the amplitude of the thermoluminescence band from the S2(3)QB − recombination shows the usual pattern with maxima after 2 and 6 flashes when rehydration takes place in light. However, after rehydration in complete darkness, there is no thermoluminescence emission after the 1 st flash, and the maxima of the subsequent oscillation are shifted to the 3rd and 7th flashes. It is concluded that desiccation of Cladonia convoluta converts PS II into a nonfunctional state. This state is characterized by the lack of stable charge separation and recombination, as well as by a one-electron reduction of the water-oxidizing complex. Restoration of PS II function during rehydration can proceed both in the light and in darkness. After rehydration in the dark, the first charge separation act is utilized in restoring the usual oxidation state of the water-oxidizing comples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00041010
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...