Experiments on photosynthesis in 14C 02 with L em na gibba and Lemna m inor showed that apiose oc... more Experiments on photosynthesis in 14C 02 with L em na gibba and Lemna m inor showed that apiose occurs only in the fraction insoluble in alcohol and water and may be released by hydrolysis. The portion of radioactivity in apiose increases in the course of photosynthesis to about the same extent as that in xylose. This differs markedly from starch (glucose) in which the portion of radioactivity decreases during photosynthesis. Darkening, following a longer period of photosynthesis in 14C 02, leads to a change in the ratio apiose-14C/glucose-14C and xylose-14C/glucose-14C, respectively, in favour of apiose and xylose. The same is obtained if labeled glucose is fed for a longer period. It is concluded that apiose is not part of storage m aterial but like xylose part of a cell w all com ponent. D er verzw eigte Fünferzucker d -A p iose war ur sprünglich nur als B estandteil des F la von glyk osid s A p iin bekannt, w o er äquim olar m it G lucose als Z uckerkom ponente v o r k o m m t1. N achdem A p iose auch in Taraxacum k o k sa g h ys 2, in H eve a brasiliens i s 3 und im H yd rolysat der Fasern von P o sid o n ia au stralis 4 gefu n d en w orden w ar, untersuchten D u ff und K n i g h t 5 d ie H yd rolysate von 175 P flanzen aus 100 F am ilien chrom atographisch auf A p io se und fa n den diese bei rund 50 P rozent. L em n a erw ies sich als eine der apiosereichsten Pflanzen (6 -7% A p io se ). In F ortführung dieser A rbeit w ies B a c o n 6 A p iose in den P olysaccharid-F raktionen von Z o ste r a m arin a und Tilia ssp. nach. 1958 zeigten G orin und P e r lin 7, daß die natürlich auftretende A p iose die D-Form b e sitzt, und W illia m s und Jones 8 w iesen D-Apiose, D -Xylose und 2-O -M ethyl-o-X ylose als B estandteile eines P olysaccharid s in Zostera m arina nach. Ü ber F un k tio n und A ufbau der apiosehaltigen Polym eren ist b isher nichts bekannt. F ü r geplante U ntersuchungen über Biosynthese und B edeutung der A piose w ar zunächst zu klären, ob es sich um Reservestoffe oder um S trak tu rk o m p o n en ten handelt. H ierfü r w urde vor allem die M ark ieru n g durch Photosynthese in 14C 0 2 m it anschließender chrom ato graphischer T ren n u n g der P ro d u k te eingesetzt. Die folgende M itteilung soll über diesen ersten A bschnitt der V ersuche berichten.
BAG. Journal of basic and applied genetics, Dec 1, 2013
An effective tissue culture is an indispensable basis for the production of transgenic plants. In... more An effective tissue culture is an indispensable basis for the production of transgenic plants. In this study, we investigated the induction of embryogenic callus production from the scutellum of spring wheat and subsequent regeneration of plants. Twenty-two Argentine spring wheat varieties from three breeders were screened to select promising genotypes for the optimization of the procedure. Experimental variables were the developmental stage of the immature embryos and the concentration of the growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D). Two developmental stages, termed H and W, respectively (according to , were selected, and their performance in culture media containing high and low concentrations of 2,4-D was examined. Parameters for the screening were: callus induction, callus proliferation on the scutellum, precocious germination of the immature embryo (as negative trait), regeneration and shoot formation and total efficiency of the in vitro culture. The best results were achieved with a combination of developmental stage H and a low concentration of 2,4-D. Scutellar callus induction and callus proliferation on the scutellum surface were positively correlated. However, scutellar callus induction, regeneration and number of shoots were independent of each other. Considerable genotype differences were found in the suitability of the varieties investigated for spring wheat propagation via in vitro culture. The cultivar Klein Brujo exhibited the highest overall culture efficiency (84.4 %) related to the number of immature embryos used and the number of plants regenerated from one embryo (9.5).
Our study investigates the host exploitation strategies of Eurytoma serratulae and E. robusta (Ch... more Our study investigates the host exploitation strategies of Eurytoma serratulae and E. robusta (Chalcidoidea, Eurytomidae), two parasitoid species that co-occur in gall populations of the tephritid Urophora cardui on Cirsium spp. The endoparasitoid E. serratulae detects the host larvae before an externally visible gall is formed. It profits from large galls, as its parasitization rate increases with increasing numbers of chambers per gall. Oviposition by the ectoparasitoid E. robusta does not occur until a distinct gall with chambers has been formed. Its parasitization rate reaches highest values in medium-sized galls. Eurytoma robusta is the dominant parasitoid in host populations with low and moderate gall densities, whereas E. serratulae is the superior exploiter of host populations with high gall densities. Within single galls E. robusta is an important hyperparasitoid of E. serratulae, but E. serratulae has no adverse influence on E. robusta. Parasitism by E. serratulae induces host larvae to promote gall growth, an effect that is profitable to both the parasitoid and the remaining host larvae in the gall. Parasitism by E. robusta often leads to smaller galls, as cases of unsuccessful parasitization result in empty gall cells.
The sequences have been deposited in GenBank and the articles listed online through the World Wid... more The sequences have been deposited in GenBank and the articles listed online through the World Wide Web. To cite an electronic Plant Gene Register article as a bibliographic reference, follow the style given below:
L iebe Leserin, lieber Leser, derzeit erlebt das Thema Rassismus aus bedauerlichen Gründen eine d... more L iebe Leserin, lieber Leser, derzeit erlebt das Thema Rassismus aus bedauerlichen Gründen eine dramatische mediale Hochkonjunktur. Rassistisches Denken rechtfertigt sich aus pseudowissenschaftlichen Analogieschlüssen aus biologischem Wissen und führt zur Bewertung von Menschengruppen und Ethnien (im Sinne einer Abstammungsgruppe). Auch wenn Rassismus hauptsächlich ein soziologisches Problem ist, wird diese Ideologie immer noch der Biologie angelastet. Biologen sind sich (weitgehend) einig, dass Rasse, Unterart, Varietät, Sorte, Zuchtform etc. keine realen Entitäten (Natural Kinds) darstellen, sondern dem wissenschaftlichen Imperativ zum Ordnen und Abstrahieren entspringen. Damit ist der Diskussion um Menschenrassen und Rassismus ohnehin der wissenschaftliche Nährboden entzogen.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Purified pullulanase (starch-debranching enzyme, R-enzyme, EC 3.2.1.41) from spinach (Spinacia ol... more Purified pullulanase (starch-debranching enzyme, R-enzyme, EC 3.2.1.41) from spinach (Spinacia oleracea L.) chloroplasts separated into at least seven individual enzymically active proteins (isomers, numbered 1-7) on isoelectric focusing or column chromatofocusing. At their isoelectric points (between pH 4n7 and 5n2) these forms were rather stable. At slightly alkaline pH, each converted into the whole set of isomers. PAGE of the purified enzyme under denaturing or non-denaturing conditions resulted in one protein band. When substrate (amylopectin or pullulan) was included in the gel, the native enzyme as well as any of the individual isomers separated into two (sometimes three) bands (' substrate-induced forms ', numbered I-III) with different specific activities, dissociation constants of the enzyme-substrate complexes and activation energies. Each substrate-induced form Abbreviations used : IEF, isoelectric focusing ; DTT, dithiothreitol. 1 To whom correspondence should be addressed (e-mail erwin.beck!uni-bayreuth.de).
This article investigates possible consequences of climate change for a hotspot of tropical biodi... more This article investigates possible consequences of climate change for a hotspot of tropical biodiversity, exemplified by a comparatively small area of a neotropical mountain rain forest in the eastern range of the South Ecuadorian Andes. In the introduction, several approaches for such predictions are evaluated with respect to their applicability to the eco-region. After a short presentation of the research area and its biodiversity, climate and vegetation development during the Holocene is described showing the range of possible fluctuations between Puna-like grassland and tropical mountain forest. Data of climate dynamics during the past 50 -60 years, covering several ENSO (El Niño Southern Oscillation) events, suggest a significant increase in temperature but no dramatic changes in the precipitation regimes of the region. Due to the altitudinal span of the area, the rise in temperature will shift the ecothermic belts by several hundred meters uphill and thus increase the distribution ranges of ectothermic organisms. To assess the consequences of this shift on biodiversity two model approaches were applied, namely the species-area-approach and the energetic-equivalence rule, using the extremely diverse insect group of moths. Combining both approaches the consequences of a climate change
Invasive Plant Science and Management, Dec 1, 2010
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Land-use and climate change are major threats to biodiversity and ecosystem functions. Most of th... more Land-use and climate change are major threats to biodiversity and ecosystem functions. Most of the current biodiversity monitoring systems are based on periodic records of the populations of a set of threatened or popular 'flagship' indicator species. In contrast to the abundance-based monitoring of species, also specific indicators of processes and functional interactions in an ecosystem may become targets of a more functional monitoring which can unveil early responses of an ecosystem to environmental changes at different spatial and temporal scales. The contributions of this Special Issue present such functional indicators for assessing and predicting responses to environmental changes of ecosystem functions in a hotspot of tropical biodiversity.
The synopsis summarises results of the previous chapters against the background of published lite... more The synopsis summarises results of the previous chapters against the background of published literature. It compares ecosystem stability and services of the natural ecosystem “tropical mountain forest” with its anthropogenic substitution systems: pastures, abandoned pastures and reforestation plantations. Examining the effects of different land use measures on ecosystem services, it confronts the ecology of a hotspot of biological diversity in the humid tropical Andes with economic benefits for the rural population of the region. It discusses consequences of potential climate changes and, based on the available knowledge of the ecosystems recommends a sustainable land use portfolio which can have model character for similar regions in Ecuador and beyond.
The relationship between canopy-level evapotranspiration (ET Sci) and leaf-level transpiration (T... more The relationship between canopy-level evapotranspiration (ET Sci) and leaf-level transpiration (T leaf ) as well as photosynthesis (P leaf ) for a homogeneous tropical montane pasture was analyzed over five days using a combination of methods involving a laser scintillometer and a porometer. Weather conditions ranged from overcast to sunny during the period of study. The gas exchange of the leaves of the dominant pasture grass Setaria sphacelata (transpiration vs. photosynthetic CO 2 net uptake ) was measured with a porometer and physiologically interpreted on the background of microclimate variables (photosynthetic active radiation (PAR) as proxy for total light intensity, temperature, water vapor deficit of the air) and soil moisture data. Water use efficiency (WUE, photosynthetic CO 2 net uptake vs water loss by leaf transpiration) of the pasture was used to analyze the grass' range of response to the environmental variables of the research area. PAR and water vapor deficit of the air (VPD) appeared to be the determinant factors for T leaf and ETS ci . WUE for the Setaria sphacelata pasture ranged from 1.9 to 5.8 µmol CO 2 mmol -1 H 2 0 day -1 and is particularly low during periods of high VPD combined with enhanced insolation during cloudless periods. ET measurements collected by the scintillometer demonstrated a strong correlation with water flux calculated using the Penman-Monteith approach (TPM) (r² = 0.95). Also, T leaf measured with the porometer showed reasonable coincidence with the ET observations (r² = 0.78). Values of ETS ci ranged from 2.26 to 4.96 mm day -1 and T leaf ranged from 0.83 to 2.41 mm day -1 , but only ETS ci showed good correspondence with the available energy (net radiation). The lower correlation between T leaf and canopy-level ETS ci compared to that between ETS ci and TPM was tested against contaminations from the adjacent fetch area of the scintillometer path, but no effects were found. Likewise, soil water limitations of T leaf could be ruled out. Therefore, different correlations of ETS ci and T leaf with the incoming energy and VPD may be traced back to a direct effect of the VPD on ET in contrast to its indirect effect on T leaf which is additionally regulated by physiological processes in the leaf stomata. Zusammenfassung: Eine Kombination von Laser-Szintillometer-und Porometer-Messungen wurde verwendet, um die Beziehung zwischen der Pfad-Evapotranspiration (ETS ci ) und der Blatt-Transpiration (T leaf ) sowie der photosynthetischen Netto-CO 2 Aufnahme (P leaf ) für eine homogene tropisch-montane Weidefläche zu analysieren. Die Messungen erfolgten an fünf Tagen mit unterschiedlichen Wetterbedingungen (bewölkt bis wolkenfrei). Der Gasaustausch der Blätter des dominierenden Weidegrases Setaria sphacelata (Photosynthese-CO 2 -Nettoaufnahme versus Transpiration T leaf ) wurde mit einem Porometer gemessen und physiologisch auf der Basis von Mikroklimadaten (photosynthetisch aktive Strahlung PAR für Lichtintensität, Temperatur, Sättigungsdefizit der Luft) und der Bodenfeuchtigkeit interpretiert. Die Wassernutzungseffizienz (WUE, als Quotient aus Photosynthese-CO 2 -Nettoaufnahme und Wasserabgabe durch Blatttranspiration) wurde verwendet, um die Bandbreite der Reaktion der Weidefläche und des Grases auf die Umgebungsvariablen der Untersuchungsfläche zu analysieren. PAR und das Sättigungsdefizit der Luft (VPD) erscheinen als bestimmende Faktoren für T leaf und ETS ci . Die WUE von Setaria sphacelata ist bei hohem VPD und gleichzeitig hoher Sonneneinstrahlung bei wolkenlosem Himmel besonders niedrig. Die mit dem Szintillometer gemessenen Verdunstungsraten (2.26 bis 4.96 mm Tag -1 ) korrelieren sehr gut mit den mittels des Penman-Monteith Ansatz errechneten Werten für ET (r² = 0.95). Auch die mittels Porometer gemessene Blatttranspiration (0.83 bis 2.41 mm Tag -1 ) zeigt einen guten, wenn auch statistisch schwächeren Zusammenhang mit ETS ci (r² = 0.78). Die geringere Korrelation zwischen T leaf und ETS ci resultierte nicht aus einer Signalkontamination durch Luftmassenadvektion aus dem Einzugsbereich (fetch) des Szintillometer-Pfads. Die Überprüfung zeigte keine derartigen Effekte. Bodenwasserlimitierung der Verdunstung konnte ebenfalls ausgeschlossen werden. Da ET direkt vom Wasserdampfsättigungsdefizit der Luft abhängt, die Verdunstung durch die Blätter aber hauptsächlich durch die Stomata erfolgt, sind physiologische Prozesse in der Stomataregulation für die etwas geringere Korrelation von ETS ci und T leaf im Tagesverlauf verantwortlich.
Experiments on photosynthesis in 14C 02 with L em na gibba and Lemna m inor showed that apiose oc... more Experiments on photosynthesis in 14C 02 with L em na gibba and Lemna m inor showed that apiose occurs only in the fraction insoluble in alcohol and water and may be released by hydrolysis. The portion of radioactivity in apiose increases in the course of photosynthesis to about the same extent as that in xylose. This differs markedly from starch (glucose) in which the portion of radioactivity decreases during photosynthesis. Darkening, following a longer period of photosynthesis in 14C 02, leads to a change in the ratio apiose-14C/glucose-14C and xylose-14C/glucose-14C, respectively, in favour of apiose and xylose. The same is obtained if labeled glucose is fed for a longer period. It is concluded that apiose is not part of storage m aterial but like xylose part of a cell w all com ponent. D er verzw eigte Fünferzucker d -A p iose war ur sprünglich nur als B estandteil des F la von glyk osid s A p iin bekannt, w o er äquim olar m it G lucose als Z uckerkom ponente v o r k o m m t1. N achdem A p iose auch in Taraxacum k o k sa g h ys 2, in H eve a brasiliens i s 3 und im H yd rolysat der Fasern von P o sid o n ia au stralis 4 gefu n d en w orden w ar, untersuchten D u ff und K n i g h t 5 d ie H yd rolysate von 175 P flanzen aus 100 F am ilien chrom atographisch auf A p io se und fa n den diese bei rund 50 P rozent. L em n a erw ies sich als eine der apiosereichsten Pflanzen (6 -7% A p io se ). In F ortführung dieser A rbeit w ies B a c o n 6 A p iose in den P olysaccharid-F raktionen von Z o ste r a m arin a und Tilia ssp. nach. 1958 zeigten G orin und P e r lin 7, daß die natürlich auftretende A p iose die D-Form b e sitzt, und W illia m s und Jones 8 w iesen D-Apiose, D -Xylose und 2-O -M ethyl-o-X ylose als B estandteile eines P olysaccharid s in Zostera m arina nach. Ü ber F un k tio n und A ufbau der apiosehaltigen Polym eren ist b isher nichts bekannt. F ü r geplante U ntersuchungen über Biosynthese und B edeutung der A piose w ar zunächst zu klären, ob es sich um Reservestoffe oder um S trak tu rk o m p o n en ten handelt. H ierfü r w urde vor allem die M ark ieru n g durch Photosynthese in 14C 0 2 m it anschließender chrom ato graphischer T ren n u n g der P ro d u k te eingesetzt. Die folgende M itteilung soll über diesen ersten A bschnitt der V ersuche berichten.
BAG. Journal of basic and applied genetics, Dec 1, 2013
An effective tissue culture is an indispensable basis for the production of transgenic plants. In... more An effective tissue culture is an indispensable basis for the production of transgenic plants. In this study, we investigated the induction of embryogenic callus production from the scutellum of spring wheat and subsequent regeneration of plants. Twenty-two Argentine spring wheat varieties from three breeders were screened to select promising genotypes for the optimization of the procedure. Experimental variables were the developmental stage of the immature embryos and the concentration of the growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D). Two developmental stages, termed H and W, respectively (according to , were selected, and their performance in culture media containing high and low concentrations of 2,4-D was examined. Parameters for the screening were: callus induction, callus proliferation on the scutellum, precocious germination of the immature embryo (as negative trait), regeneration and shoot formation and total efficiency of the in vitro culture. The best results were achieved with a combination of developmental stage H and a low concentration of 2,4-D. Scutellar callus induction and callus proliferation on the scutellum surface were positively correlated. However, scutellar callus induction, regeneration and number of shoots were independent of each other. Considerable genotype differences were found in the suitability of the varieties investigated for spring wheat propagation via in vitro culture. The cultivar Klein Brujo exhibited the highest overall culture efficiency (84.4 %) related to the number of immature embryos used and the number of plants regenerated from one embryo (9.5).
Our study investigates the host exploitation strategies of Eurytoma serratulae and E. robusta (Ch... more Our study investigates the host exploitation strategies of Eurytoma serratulae and E. robusta (Chalcidoidea, Eurytomidae), two parasitoid species that co-occur in gall populations of the tephritid Urophora cardui on Cirsium spp. The endoparasitoid E. serratulae detects the host larvae before an externally visible gall is formed. It profits from large galls, as its parasitization rate increases with increasing numbers of chambers per gall. Oviposition by the ectoparasitoid E. robusta does not occur until a distinct gall with chambers has been formed. Its parasitization rate reaches highest values in medium-sized galls. Eurytoma robusta is the dominant parasitoid in host populations with low and moderate gall densities, whereas E. serratulae is the superior exploiter of host populations with high gall densities. Within single galls E. robusta is an important hyperparasitoid of E. serratulae, but E. serratulae has no adverse influence on E. robusta. Parasitism by E. serratulae induces host larvae to promote gall growth, an effect that is profitable to both the parasitoid and the remaining host larvae in the gall. Parasitism by E. robusta often leads to smaller galls, as cases of unsuccessful parasitization result in empty gall cells.
The sequences have been deposited in GenBank and the articles listed online through the World Wid... more The sequences have been deposited in GenBank and the articles listed online through the World Wide Web. To cite an electronic Plant Gene Register article as a bibliographic reference, follow the style given below:
L iebe Leserin, lieber Leser, derzeit erlebt das Thema Rassismus aus bedauerlichen Gründen eine d... more L iebe Leserin, lieber Leser, derzeit erlebt das Thema Rassismus aus bedauerlichen Gründen eine dramatische mediale Hochkonjunktur. Rassistisches Denken rechtfertigt sich aus pseudowissenschaftlichen Analogieschlüssen aus biologischem Wissen und führt zur Bewertung von Menschengruppen und Ethnien (im Sinne einer Abstammungsgruppe). Auch wenn Rassismus hauptsächlich ein soziologisches Problem ist, wird diese Ideologie immer noch der Biologie angelastet. Biologen sind sich (weitgehend) einig, dass Rasse, Unterart, Varietät, Sorte, Zuchtform etc. keine realen Entitäten (Natural Kinds) darstellen, sondern dem wissenschaftlichen Imperativ zum Ordnen und Abstrahieren entspringen. Damit ist der Diskussion um Menschenrassen und Rassismus ohnehin der wissenschaftliche Nährboden entzogen.
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Purified pullulanase (starch-debranching enzyme, R-enzyme, EC 3.2.1.41) from spinach (Spinacia ol... more Purified pullulanase (starch-debranching enzyme, R-enzyme, EC 3.2.1.41) from spinach (Spinacia oleracea L.) chloroplasts separated into at least seven individual enzymically active proteins (isomers, numbered 1-7) on isoelectric focusing or column chromatofocusing. At their isoelectric points (between pH 4n7 and 5n2) these forms were rather stable. At slightly alkaline pH, each converted into the whole set of isomers. PAGE of the purified enzyme under denaturing or non-denaturing conditions resulted in one protein band. When substrate (amylopectin or pullulan) was included in the gel, the native enzyme as well as any of the individual isomers separated into two (sometimes three) bands (' substrate-induced forms ', numbered I-III) with different specific activities, dissociation constants of the enzyme-substrate complexes and activation energies. Each substrate-induced form Abbreviations used : IEF, isoelectric focusing ; DTT, dithiothreitol. 1 To whom correspondence should be addressed (e-mail erwin.beck!uni-bayreuth.de).
This article investigates possible consequences of climate change for a hotspot of tropical biodi... more This article investigates possible consequences of climate change for a hotspot of tropical biodiversity, exemplified by a comparatively small area of a neotropical mountain rain forest in the eastern range of the South Ecuadorian Andes. In the introduction, several approaches for such predictions are evaluated with respect to their applicability to the eco-region. After a short presentation of the research area and its biodiversity, climate and vegetation development during the Holocene is described showing the range of possible fluctuations between Puna-like grassland and tropical mountain forest. Data of climate dynamics during the past 50 -60 years, covering several ENSO (El Niño Southern Oscillation) events, suggest a significant increase in temperature but no dramatic changes in the precipitation regimes of the region. Due to the altitudinal span of the area, the rise in temperature will shift the ecothermic belts by several hundred meters uphill and thus increase the distribution ranges of ectothermic organisms. To assess the consequences of this shift on biodiversity two model approaches were applied, namely the species-area-approach and the energetic-equivalence rule, using the extremely diverse insect group of moths. Combining both approaches the consequences of a climate change
Invasive Plant Science and Management, Dec 1, 2010
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Land-use and climate change are major threats to biodiversity and ecosystem functions. Most of th... more Land-use and climate change are major threats to biodiversity and ecosystem functions. Most of the current biodiversity monitoring systems are based on periodic records of the populations of a set of threatened or popular 'flagship' indicator species. In contrast to the abundance-based monitoring of species, also specific indicators of processes and functional interactions in an ecosystem may become targets of a more functional monitoring which can unveil early responses of an ecosystem to environmental changes at different spatial and temporal scales. The contributions of this Special Issue present such functional indicators for assessing and predicting responses to environmental changes of ecosystem functions in a hotspot of tropical biodiversity.
The synopsis summarises results of the previous chapters against the background of published lite... more The synopsis summarises results of the previous chapters against the background of published literature. It compares ecosystem stability and services of the natural ecosystem “tropical mountain forest” with its anthropogenic substitution systems: pastures, abandoned pastures and reforestation plantations. Examining the effects of different land use measures on ecosystem services, it confronts the ecology of a hotspot of biological diversity in the humid tropical Andes with economic benefits for the rural population of the region. It discusses consequences of potential climate changes and, based on the available knowledge of the ecosystems recommends a sustainable land use portfolio which can have model character for similar regions in Ecuador and beyond.
The relationship between canopy-level evapotranspiration (ET Sci) and leaf-level transpiration (T... more The relationship between canopy-level evapotranspiration (ET Sci) and leaf-level transpiration (T leaf ) as well as photosynthesis (P leaf ) for a homogeneous tropical montane pasture was analyzed over five days using a combination of methods involving a laser scintillometer and a porometer. Weather conditions ranged from overcast to sunny during the period of study. The gas exchange of the leaves of the dominant pasture grass Setaria sphacelata (transpiration vs. photosynthetic CO 2 net uptake ) was measured with a porometer and physiologically interpreted on the background of microclimate variables (photosynthetic active radiation (PAR) as proxy for total light intensity, temperature, water vapor deficit of the air) and soil moisture data. Water use efficiency (WUE, photosynthetic CO 2 net uptake vs water loss by leaf transpiration) of the pasture was used to analyze the grass' range of response to the environmental variables of the research area. PAR and water vapor deficit of the air (VPD) appeared to be the determinant factors for T leaf and ETS ci . WUE for the Setaria sphacelata pasture ranged from 1.9 to 5.8 µmol CO 2 mmol -1 H 2 0 day -1 and is particularly low during periods of high VPD combined with enhanced insolation during cloudless periods. ET measurements collected by the scintillometer demonstrated a strong correlation with water flux calculated using the Penman-Monteith approach (TPM) (r² = 0.95). Also, T leaf measured with the porometer showed reasonable coincidence with the ET observations (r² = 0.78). Values of ETS ci ranged from 2.26 to 4.96 mm day -1 and T leaf ranged from 0.83 to 2.41 mm day -1 , but only ETS ci showed good correspondence with the available energy (net radiation). The lower correlation between T leaf and canopy-level ETS ci compared to that between ETS ci and TPM was tested against contaminations from the adjacent fetch area of the scintillometer path, but no effects were found. Likewise, soil water limitations of T leaf could be ruled out. Therefore, different correlations of ETS ci and T leaf with the incoming energy and VPD may be traced back to a direct effect of the VPD on ET in contrast to its indirect effect on T leaf which is additionally regulated by physiological processes in the leaf stomata. Zusammenfassung: Eine Kombination von Laser-Szintillometer-und Porometer-Messungen wurde verwendet, um die Beziehung zwischen der Pfad-Evapotranspiration (ETS ci ) und der Blatt-Transpiration (T leaf ) sowie der photosynthetischen Netto-CO 2 Aufnahme (P leaf ) für eine homogene tropisch-montane Weidefläche zu analysieren. Die Messungen erfolgten an fünf Tagen mit unterschiedlichen Wetterbedingungen (bewölkt bis wolkenfrei). Der Gasaustausch der Blätter des dominierenden Weidegrases Setaria sphacelata (Photosynthese-CO 2 -Nettoaufnahme versus Transpiration T leaf ) wurde mit einem Porometer gemessen und physiologisch auf der Basis von Mikroklimadaten (photosynthetisch aktive Strahlung PAR für Lichtintensität, Temperatur, Sättigungsdefizit der Luft) und der Bodenfeuchtigkeit interpretiert. Die Wassernutzungseffizienz (WUE, als Quotient aus Photosynthese-CO 2 -Nettoaufnahme und Wasserabgabe durch Blatttranspiration) wurde verwendet, um die Bandbreite der Reaktion der Weidefläche und des Grases auf die Umgebungsvariablen der Untersuchungsfläche zu analysieren. PAR und das Sättigungsdefizit der Luft (VPD) erscheinen als bestimmende Faktoren für T leaf und ETS ci . Die WUE von Setaria sphacelata ist bei hohem VPD und gleichzeitig hoher Sonneneinstrahlung bei wolkenlosem Himmel besonders niedrig. Die mit dem Szintillometer gemessenen Verdunstungsraten (2.26 bis 4.96 mm Tag -1 ) korrelieren sehr gut mit den mittels des Penman-Monteith Ansatz errechneten Werten für ET (r² = 0.95). Auch die mittels Porometer gemessene Blatttranspiration (0.83 bis 2.41 mm Tag -1 ) zeigt einen guten, wenn auch statistisch schwächeren Zusammenhang mit ETS ci (r² = 0.78). Die geringere Korrelation zwischen T leaf und ETS ci resultierte nicht aus einer Signalkontamination durch Luftmassenadvektion aus dem Einzugsbereich (fetch) des Szintillometer-Pfads. Die Überprüfung zeigte keine derartigen Effekte. Bodenwasserlimitierung der Verdunstung konnte ebenfalls ausgeschlossen werden. Da ET direkt vom Wasserdampfsättigungsdefizit der Luft abhängt, die Verdunstung durch die Blätter aber hauptsächlich durch die Stomata erfolgt, sind physiologische Prozesse in der Stomataregulation für die etwas geringere Korrelation von ETS ci und T leaf im Tagesverlauf verantwortlich.
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