ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
Filter
  • 2015-2019  (17)
  • 1975-1979  (30)
  • 1910-1914  (20)
  • 1905-1909  (24)
  • 11
    Electronic Resource
    Electronic Resource
    Environmental control of crassulacean acid metabolism in Welwitschia mirabilis Hook. Fil. in its range of natural distribution in the Namib desert (1976)
    Springer
    Oecologia 24 (1976), S. 323-334 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Within the area of its natural distribution in South West Africa, Welwitschia mirabilis has a less negative δ13C value than C3 plants and a more negative δ13C value than C4 species. This indicates that Welwitschia m. assimilates CO2 partially via CAM when growing in its natural habitat. The difference between the δ13C values of Welwitschia m. and of the C3 species is significant in the savanna, whereas it is only small and statistically not significant in the grassland zone. The proportion of CO2 fixed via CAM is largest in the coastal desert zone. There was no correlation between the δ13C values and the Cl- or ash content of the tissue. Thus, CAM in Welwitschia m. seems not to be induced by salt stress. There is no change in the δ13C values along the persistent Welwitschia m. leaf. The present data indicate that on a broad geographical scale in the area of distribution temperature regime, and water stress as a modifying factor, determine CAM in Welwitschia m. The ecological implications are discussed by comparing the behaviour of Welwitschia m. with other CAM, C3 and C4 species of the accompanying flora.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381138
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Spacial distribution of photosynthetic capacity and performance in a mountain spruce forest of Northern Germany (1977)
    Springer
    Oecologia 30 (1977), S. 239-248 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Growth and CO2 uptake in the crown of a spruce tree is described and the production processes of this evergreen conifer are compared with those of a deciduous beech. Spruce had 60% lower rates of net photosynthesis per dry weight than beech. But, beech had a 30% shorter growing season and a 84% smaller biomass than spruce. The annual CO2 gain was 40% lower in beech than it was in spruce. An analysis shows the following conclusions for this habitat. (1) The effect of a prolonged growing season is small. The annual CO2 gain of spruce would be reduced only by 9% if the growing season was the same length as for beech. (2) The annual CO2 gain would increase 14% if all needles in spruce were deciduous, because the current year needles have a higher average rate of CO2 uptake than 3-year old and older needles, but a lower average rate than 1- and 2-year old ones. However, the carbon balance of the tree shows that spruce could not afford to produce the existing needle biomass (14 t ha-1) each year. (3) If spruce were to produce the same deciduous foliage biomass during the same growing season as beech then total production by spruce would be reduced 67%. (4) The annual CO2 uptake by evergreen spruce was higher than deciduous beech not because of a long growing season, but because of the longevity of its needles, which during their total life time (an average of 5 years) have a two to three times greater CO2 uptake than a deciduous leaf in one summer season. The relatively small investment in current year needles produces an annually low, but long lasting assimilation of CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01833630
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Seasonal and diurnal courses of water relations of the arido-active plant Hammada scoparia in the Negev desert (1975)
    Springer
    Oecologia 21 (1975), S. 175-192 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The photosynthesizing branches of Hammada scoparia, one of the typical dwarf shrubs of the Negev desert, undergo a seasonal change from succulent to xeromorphic anatomy. This trend is accompanied by a marked decrease of water content and of total water Ψ plant and osmotic Ψ π plant potential. Irrigated plants do not show such transitions. The daily courses of Ψ plant and Ψ π plant showed minima around noon and a tendency for maxima before sunrise. Turgor pressure Ψ p plant reached minima around noon and became negative (until ca.-10 bars). Generally, Ψ plant decreases with increasing water vapour concentration difference between plant and air (WD) in the first half of the day, and in the second half the reversal of this trend occurs. Mostly smaller increments of Ψ plant were correlated with larger increases in WD which lead to the conclusion that stomates closed enough to maintain transpiration at a constant value. Non-irrigated and irrigated plants showed different hysteresis loops of relation between Ψ plant and WD. Regulatory reduction of transpiration appears largely independently of Ψ plant which is in spring and with irrigated plants on a high level, with non-irrigated plants in summer on a low level. In summer the continous but decreasing drop of Ψ plant with increasing WD was interpreted as caused by a change in soil or root resistance. Independent of the seasonal state and of the Ψ plant level, H. scoparia regulates its water status within limited ranges of Ψ p plant changes: the irrigated plants on a higher level, the non-irrigated on a lower level of Ψ p plant . The water contents of the tissues of H. scoparia are linearily related to Ψ plant as well as Ψ p plant . Steeper slopes with non-irrigated plants in summer than with spring palnts and with irrigated plants during the whole season signify that in the latter a certain increment in turgor pressure corresponds to a large gain in water content while in the non-irrigated summer plants it varies only little for an identical change in Ψ p plant . This behaviour of non-irrigated wild plants apparently is due to the change of the elastic properties of the tissues in the assimilating branches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00345559
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    The temperature-related photosynthetic capacity of plants under desert conditions (1978)
    Springer
    Oecologia 34 (1978), S. 89-100 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary As described earlier, the native arido-active perennial Hammada scoparia and the cultivated Prunus armeniaca exhibit characteristic seasonal shifts of their temperature optimum of net photosynthesis (OP) under desert conditions in the Negev. In the present paper the OP values were compared with the actual tissue temperatures of the experimental plants. During the growing period from March to September the duration of optimal temperatures for net photosynthesis (OP±3°C) experienced by the plants was 32.2% of the total time at light saturation for P. armeniaca and 27.8% for H. scoparia. For optimal photosynthesis the branchlets of H. scoparia are too cold for 66.1% of the time span and too warm for 6.1% of the time. The respective values for the leaves of the apricot are 28.6% and 39.2%. Simulations at changed tissue temperature show, that for P. armeniaca neither a higher nor a lower temperature regime would lengthen the time span for optimal thermal conditions. For H. scoparia, however, an increase of the general temperature level by 6°C would considerably improve the temperature-related photosynthetic efficiency. The natural temperature responses of the plants were compared with simulations using OP values which are supposed not to shift but to stay constant from March through September at their spring minimum, their summer maximum, or at an intermediate value. For P. armeniaca such constant OP values would result in a shorter duration of optimal temperature conditions. With this plant the natural seasonal shift of the temperature characteristics appears to provide an advantage in respect to its photosynthetic capacity. Contrary to this, for H. scoparia a constant OP value at the low spring level or even at the intermediate level during all the season would result in a substantially prolonged period of favourable temperature conditions for photosynthesis. In this case the seasonal change of optimum temperature for photosynthesis with higher OP values in summer signifies a disadvantage with respect to the temperature-related photosynthetic capacity at the habitat in the central Negev. Apparently this C4 plant is adapted to higher temperatures than were present. It appears that “acclimations” of native plants are not always beneficial.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00346243
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Comparison between pressure-volume and dewpoint-hygrometry techniques for determining the water relations characteristics of grass and legume leaves (1979)
    Springer
    Oecologia 41 (1979), S. 77-88 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The water relations characteristics of three grass species (Panicum maximum var. trichoglume, Cenchrus ciliaris, Heteropogon contortus), and a legume (Macroptilium atropurpureum) grown in the field were measured using both a modified pressure/volume technique with pressure bomb measurements on single leaves and a dewpoint hygrometry technique applied to fresh and to frozen and thawed leaf discs. The two techniques agreed well in the estimates of osmotic potential at full turgor and the water potential at zero turgor. However, for parameters such as the relative water content at zero turgor, bound water and bulk modulus of elasticity there was a poor correlation between the estimates from the two methods. The pressure/volume technique gave less variable results and is more convenient for field use than the hygrometry technique. The determination of the modulus of elasticity from various functions relating pressure potential to relative water content is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00344838
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Short-term and long-term effects of plant water deficits on stomatal response to humidity in Corylus avellana L. (1979)
    Springer
    Planta 146 (1979), S. 319-326 
    Details
    ISSN: 1432-2048
    Keywords: Humidity response ; Stomata ; Transpiration ; Water potential ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Short-term (hours) changes in plant water status were induced in hazel (Corylus avellana L.) by changing the evaporative demand on a major portion of the shoot while maintaining a branch in a constant environment. Stomatal conductance of leaves on the branch was influenced little by these short-term changes in water status even with changes in leaf water potential as great as 8 bars. Long-term (days) changes in plant water status were imposed by soil drying cycles. Stomatal conductance progessively decreased with increases in long-term water stress. Stomata still responded to humidity with long-term water stress but the range of the conductance response decreased. Threshold responses of stomata to leaf water potential were not observed with either short-term or long-term changes in plant water status even when leaves wilted. It is suggested that concurrent measurements of plant water status may not be sufficient for explaining stomatal and other plant responses to drought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387804
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Die Bestimmung des Wassergehaltes der Kohlehydrate (1908)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 47 (1908), S. 67-68 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01490371
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Für das Cholesterin (1908)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 47 (1908), S. 76-76 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01490383
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Bestimmung der alkalischen Erden in Kalkdüngemitteln und Bodenproben (1912)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 51 (1912), S. 323-324 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01469497
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Über die Konstitution des Stachydrins (1909)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 42 (1909), S. 4654-4659 
    Details
    ISSN: 0365-9496
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19090420472
    Location Call Number Expected 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...