Search

Start Over Coverage 431-437

2. Photosynthetic characteristics, dark respiration, and leaf mass per unit area in seedlings of four tropical tree species grown under three irradiances

Creator:
Feng, Y.-L., Cao, K.-F., and Zhang, J.-L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
acclimation to irradiance, Anthocephalus, Barringtonia, Calophyllum, carboxylation efficiency, chlorophyll, leaf mass per unit area, Linociera, net photosynthetic rate, and nitrogen
Language:
Multiple languages
Description:
We investigated the effect of growth irradiance (I) on photon-saturated photosynthetic rate (Pmax), dark respiration rate (RD), carboxylation efficiency (CE), and leaf mass per unit area (LMA) in seedlings of the following four tropical tree species with contrasting shade-tolerance. Anthocephalus chinensis (Rubiaceae) and Linociera insignis (Oleaceae) are light-demanding, Barringtonia macrostachya (Lecythidaceae) and Calophyllum polyanthum (Clusiaceae) are shade-tolerant. Their seedlings were pot-planted under shading nets with 8, 25, and 50 % daylight for five months. With increase of I, all species displayed the trends of increases of LMA, photosynthetic saturation irradiance, and chlorophyll-based Pmax, and decreases of chlorophyll (Chl) content on both area and mass bases, and mass-based Pmax, RD, and CE. The area-based Pmax and CE increased with I for the light-demanders only. Three of the four species significantly increased Chl-based CE with I. This indicated the increase of nitrogen (N) allocation to carboxylation enzyme relative to Chl with I. Compared to the two shade-tolerants, under the same I, the two light-demanders had greater area- and Chl-based Pmax, photosynthetic saturation irradiance, lower Chl content per unit area, and greater plasticity in LMA and area- or Chl-based Pmax. Our results support the hypothesis that light-demanding species is more plastic in leaf morphology and physiology than shade-tolerant species, and acclimation to I of tropical seedlings is more associated with leaf morphological adjustment relative to physiology. Leaf nitrogen partitioning between photosynthetic enzymes and Chl also play a role in the acclimation to I. and Y.-L. Feng, K.-F. Cao, J.-L. Zhang.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Umělá fotosyntéza na povrchu přírodních materiálů (cyklus oxidu uhličitého)

Creator:
Civiš, Svatopluk
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, 6, and 53
Language:
Czech
Description:
Current scientific theories strive to find one theory, which would describe the origin of life on Earth, but so far none were successful. To succeed i this field, one has to broader their view and accompany the scientific question with philosophy and set firmly the framework of research and define its borders. In order to assess the philosophical part of the work, one needs not to resort to new ideas only, because men and women in the past have already expressed their thoughts. They are however nowadays remembered only in history of arts and philosophy. In our recent article published in Nature Astronomy, we presented a very complex model for the creation of methane and its reprocessing to more complex organic molecules including nucleic acid bases from simple gaseous precursors. The purpose of this work is to show the reoeating cycle of the creation of complex molecules from CO2 and their subsequent destruction back to their basic parent molecules in comparison with the idea of Hieronymus Bosch. and Svatopluk Civiš.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public