Here we report the theory formulation and the experiment realization of sum-frequency generation vibrational spectroscopy （SFG-VS） in the cross-propagation （XP） geometry or configuration. In the XP-SFG-VS, the vis...Here we report the theory formulation and the experiment realization of sum-frequency generation vibrational spectroscopy （SFG-VS） in the cross-propagation （XP） geometry or configuration. In the XP-SFG-VS, the visible and the infrared （IR） beams in the SFG experiment are delivered to the same location on the surface from visible and IR incident planes perpendicular to each other, avoiding the requirement to have windows or optics to be transparent to both the visible and IR frequencies. Therefore, the XP geometry is applicable to study surfaces in the enclosed vacuum or high pressure chambers with far infrared （FIR） frequencies that can directly access the metal oxide and other lower frequency surface modes, with much broader selection of visible and IR transparent window materials. The potential applications include surface science, material science, fundamental catalytic sciences, as well as low temperature molecular sciences, etc.展开更多
Aims Seed dispersal by endozoochory is an important process in plant regeneration and the establishment of new populations.Seeds with dormancy may especially benefit after disperser gut passage.However,the ways in whi...Aims Seed dispersal by endozoochory is an important process in plant regeneration and the establishment of new populations.Seeds with dormancy may especially benefit after disperser gut passage.However,the ways in which gut passage affect the germination of plant species with physiological dormancy remain unclear.Here,we experimentally assessed the mutualistic interaction between the Austral parakeet(Enicognathus ferrugineus)as a disperser of calafate(Berberis microphylla),a thorny bush inhabiting the understory of the Austral temperate forests of South America with seeds that are characterized by deep physiological dormancy.Methods Germination success and viability of calafate seeds obtained from faeces and from intact fruits were tested under four treatments:(i)digested seeds,(ii)digested seeds with faecal extract,(iii)intact seeds from fruit and(iv)intact seeds from fruit with pulp.Important Findings About 65%of the Austral parakeet droppings contained calafate seeds.Viability of seeds did not differ between treatments.However,germination was significantly higher in digested seeds than in intact seeds from fruits,while no difference was found between faecal and pulp extracts.Neither faecal matter nor fruit pulp provided seeds with any ecological advantages derived from enhancing germinability,but did confer some disadvantage in germination time.Faecal matter is expected to be completely lacking around seeds after several months under snow before germinating in the following spring,given intense washing due to persistent rain and the spring thaw in the Patagonian Andes.The higher germinability along with faster germination of digested seeds supports the hypothesis of a legitimate mutualistic interaction between Austral parakeets and calafate.We hypothesized that the passage through the disperser digestive tract might break physiological dormancy as differences in germinability between ingested and non-ingested seeds.Our results highlight the relevant role of endozoochory in plant species with physiological dormancy living in highly seasonal environments.展开更多
文摘Here we report the theory formulation and the experiment realization of sum-frequency generation vibrational spectroscopy （SFG-VS） in the cross-propagation （XP） geometry or configuration. In the XP-SFG-VS, the visible and the infrared （IR） beams in the SFG experiment are delivered to the same location on the surface from visible and IR incident planes perpendicular to each other, avoiding the requirement to have windows or optics to be transparent to both the visible and IR frequencies. Therefore, the XP geometry is applicable to study surfaces in the enclosed vacuum or high pressure chambers with far infrared （FIR） frequencies that can directly access the metal oxide and other lower frequency surface modes, with much broader selection of visible and IR transparent window materials. The potential applications include surface science, material science, fundamental catalytic sciences, as well as low temperature molecular sciences, etc.
基金K.S.and S.A.L.were funded by the projects PICT 2015-2072 and PICT 2018-1623.
文摘Aims Seed dispersal by endozoochory is an important process in plant regeneration and the establishment of new populations.Seeds with dormancy may especially benefit after disperser gut passage.However,the ways in which gut passage affect the germination of plant species with physiological dormancy remain unclear.Here,we experimentally assessed the mutualistic interaction between the Austral parakeet(Enicognathus ferrugineus)as a disperser of calafate(Berberis microphylla),a thorny bush inhabiting the understory of the Austral temperate forests of South America with seeds that are characterized by deep physiological dormancy.Methods Germination success and viability of calafate seeds obtained from faeces and from intact fruits were tested under four treatments:(i)digested seeds,(ii)digested seeds with faecal extract,(iii)intact seeds from fruit and(iv)intact seeds from fruit with pulp.Important Findings About 65%of the Austral parakeet droppings contained calafate seeds.Viability of seeds did not differ between treatments.However,germination was significantly higher in digested seeds than in intact seeds from fruits,while no difference was found between faecal and pulp extracts.Neither faecal matter nor fruit pulp provided seeds with any ecological advantages derived from enhancing germinability,but did confer some disadvantage in germination time.Faecal matter is expected to be completely lacking around seeds after several months under snow before germinating in the following spring,given intense washing due to persistent rain and the spring thaw in the Patagonian Andes.The higher germinability along with faster germination of digested seeds supports the hypothesis of a legitimate mutualistic interaction between Austral parakeets and calafate.We hypothesized that the passage through the disperser digestive tract might break physiological dormancy as differences in germinability between ingested and non-ingested seeds.Our results highlight the relevant role of endozoochory in plant species with physiological dormancy living in highly seasonal environments.
