Leaf gas-exchange responses to shadefleck-sunfleck and sun-cloud transitions were determined for in situ Cycas micronesica K.D. Hill plants on the island of Guam to add cycads to the published gymnosperm data. Sequential sunfleck-shadefleck transitions indicated understory leaves primed rapidly but open field leaves primed slowly. Time needed to reach 90% induction of net CO2 assimilation (PN) was 2.9 min for understory leaves and 13.9 min for open field leaves. Leaf responses to sun-cloud transitions exhibited minimal adjustment of stomatal conductance, so PN rapidly returned to precloud values following cloud-sun transitions. Results indicate bi-directional leaf acclimation behavior enables mature C. micronesica trees to thrive in deep understory conditions in some habitats and as emergent canopy trees in other habitats. These data are the first nonconifer gymnosperm data; the speed of gas-exchange responses to rapid light transitions was similar to some of the most rapid angiosperm species described in the literature., T. E. Marler., and Obsahuje bibliografii
The paper presents results of mechanical testing of soft tissues (arterial walls) under biaxial stress conditions and analysis of the influence of some factors, such as specimen location, reconditioning, etc. Soft tissues are pseudoelastic materials, modelled mostly as hyperelastic, either isotropic or anisotropic ones. Therefore multiaxial (biaxial) mechanical tests are required for a credible identification of their mechanical parameters. As living tissue proporties change with time after excision and exhibit also viscoelastic behaviour, a much more specialized equipment is needed to perform biaxial tests of soft tissues. A test rig for biaxial tests is presented in the paper and a pronounced influence of stress state character on the specimen behaviour during several first cycles is analyzed. and Obsahuje seznam literatury
osobní bibliografii Františka Knoppa sestavila Stanislava Sýkorová ; uspořádali Pavel Janáček, Petr Šámal, Aleš Zach ; úvodní medailon napsal Vladimír Just., Obsahuje bibliografii, bibliografické odkazy a rejstřík., Anglické resumé, and born digital