Orychophragmus violaceus, Brassica campestris cv. Chuanyou No.8, and Brassica juncea cv. Luzhousileng diurnal changes of net photosynthetic rate (PN) and activities of carbonic anhydrase (CA) of leaves were studied. One uni-modal curve occurred at the diurnal changes of PN in O. violaceus, but bimodal curves were found in B. campestris and B. juncea. Thus photosynthetic midday depression was not found in O. violaceus but in both Brassica species. Midday depression of PN in O. violaceus was not related to high temperature or low humidity at midday but to the activity of CA. and Y. Y. Wu ... [et al.].
A greenhouse experiment examined whether clonal integration improves photosynthesis of ramets of alligator weed [Alternanthera philoxeroides (Mart.) Griseb.], a widespread invasive clonal plant in China, in heterogeneous (He) nutrient habitats. The connected pairs of ramets experienced different nutrient levels [high homogeneous (Ho) nutrient, low Ho nutrient, and two He nutrient treatments]. Clonal integration significantly improved the net photosynthetic rate, stomatal conductance, transpiration rate, and minimal and maximal chlorophyll fluorescence of ramets of alligator weed in low nutrient condition. These characteristics may contribute to the success of the ramets of alligator weed in invading contrasting habitats. The clonal integration of the invasive clonal plants may contribute significantly to their invasiveness. and J. Liu ... [et al.].
In der vorliegenden Studie stellt die Autorin die etymologische Analyse des Verbs -pastovati sě vor, dass als Hapax Legomenon in der Form (v)pastováchu sě in Hradecký rukopis belegt ist. Es geht u. a. darum zu zeigen, welche methodologische Probleme bei der Etymologie von Hapax Legomenona entstehen und wie sie zu lösen sind.
Thick sun leaves have a larger construction cost per unit leaf area than thin shade leaves. To re-evaluate the adaptive roles of sun and shade leaves, we compared the photosynthetic benefits relative to the construction cost of the leaves. We drew photosynthetically active radiation (PAR)-response curves using the leaf-mass-based photosynthetic rate to reflect the cost. The dark respiration rates of the sun and shade leaves of mulberry (Morus bombycis Koidzumi) seedlings did not differ significantly. At irradiances below 250 µmol m-2 s-1, the shade leaves tended to have a significantly larger net photosynthetic rate (PN) than the sun leaves. At irradiances above 250 µmol m-2 s-1, the PN did not differ significantly. The curves indicate that plants with thin shade leaves have a larger daily CO2 assimilation rate per construction cost than those with thick sun leaves, even in an open habitat. These results are consistently explained by a simple model of PAR extinction in a leaf. We must target factors other than the effective assimilation when we consider the adaptive roles of thick sun leaves. and M. Tateno, H. Taneda.
A combination of titanium dioxide (TiO2 ) and silicon dioxide (SiO2 ) has been used for decades in the field of optical interference filters. Their combination is a frequently used deposition method for most application in the visible (VIS) and near infrared (NIR) spectral range. They are applied for simple coatings such as antireflective coatings as well as for demanding coatings consisting of dozens of layers. In spite of its common usage we found undescribed optical losses in our coatings. The losses appeared at the time when we introduced the combination in our laboratory process using the ion beam assisted deposition (IBAD) with e-gun. We did not find any piece of published information which covers using combination of TiO2 and SiO2 . In this article we focus on modifying process parameters so that the losses are reduced. and Kombinace oxidu titaničitého (TiO2 ) a oxidu křemičitého (SiO2 ) se pro interferenční filtry používá již desítky let. Ve většině aplikací pro oblast viditelného a blízkého infračerveného spektra je tato kombinace nejlepší volbou, a to jak pro jednoduché filtry, tak i pro složité soustavy desítek vrstev. Přesto se při depozici těchto materiálů vakuovým odpařováním z elektronového děla s iontovou asistencí v naší laboratoři objevil ve vrstvách problém nepředpokládaných ztrát světla. Podobný jev nebyl, dle naší rešerše, popsán v žádné dostupné literatuře. Článek popisuje experimenty směřující k nalezení původu těchto ztrát a jejich potlačení.
The Clark 8'' objective lens of the Astronomical Institute of the Czech Academy of Sciences is probably the oldest dublet used for a professional astronomical observation in the Czech Republic. Its optical imaging performances have became legendary among several generations of professional astronomers. The lens was manufactured by Alvan Clark in Cambridge, Massachusetts at the end of fifties of the 19th century. This 8'' refractor has became the main telescope of the astronomical observatory in Ondřejov for first half of the twentieth century. The objective was cleaned and restored twice times in the TOPTEC, Turnov. We had possibility to measure the optical parameters of dublet during its stay in Turnov and then we have evaluated its residual aberrations. This paper brings the results of optical simulations. and Osmipalcový Clarkův objektiv Astronomického ústavu Akademie věd České republiky je pravděpodobně nejstarší dublet používaný pro profesionální astronomická pozorování v České republice. Jeho optické vlastnosti se staly legendárními pro několik generací astronomů. Objektiv byl vyroben Alvanem Clarkem v Cambridge, Massachusetts, na konci 50. let 19. století. V první polovině 20. století se tento refraktor stal hlavním přístrojem Ondřejovské observatoře. Objektiv byl dvakrát čištěn a restaurován v centru TOPTEC v Turnově. Během jeho pobytu v Turnově jsme měli příležitost jej přeměřit a spočítat jeho zbytkové vady. Tento článek přináší výsledky měření a optickou simulaci jeho zbytkových vad.