Characterization of different component processes of photosynthesis is useful to understand the growth status of plants and to discover possible unintended effects of genetic modification on photosynthesis in transgenic plants. We focused on the changes in photosynthetic gas-exchange properties, reflectance spectra, and plant growth traits among groups of different transgenic barley T1 (TolT1) and its isogenic controls (TolNT1), TolT1, and group of its own transgenic progenies T2 (TolT2), TolNT1 and its wild type (WT), respectively. Gas-exchange measurements showed that only the net photosynthetic rate (P N) and the light-use efficiency (LUE) differed significantly between TolT1 and TolT2 with no obvious changes of other characteristics. Reflectance measurements indicated that the reflectance ratio was sensitive to identify the differences between two barley groups. Differences in reflectance expressed on an index basis depended on barley groups. The relationship between LUE and the photochemical reflectance index (PRI) at a leaf level among different barley groups of WT, TolNT1, TolT1 and TolT2 did not changed obviously. The differences in the total leaf area per plant (LA) between WT and TolNT1 as well as between TolT1 and TolT2 were significant. This study finally provided a plausible complex explanation for the unintended effects of genetic transformation on photosynthesis-related properties in barley at different levels. Furthermore, it was concluded that the photosynthesis-related properties of transgenic plants based on gas exchange, leaf reflectance, and plant growth measurements responded to the same environment in a more different way between two subsequent generations than to the processes of the gene insertion by Agrobacterium and associated tissue culture., C. X. Sun ... [et al. ]., and Obsahuje bibliografii
At present, chlorophyll meters are widely used for a quick and nondestructive estimate of chlorophyll (Chl) contents in plant leaves. Chl meters allow to estimate the Chl content in relative units - the Chl index (CI). However, using such meters, one can face a problem of converting CI into absolute values of the pigment content and comparing data acquired with different devices and for different plant species. Many Chl meters (SPAD-502, CL-01, CCM-200) demonstrated a high degree of correlation between the CI and the absolute pigment content. A number of formulas have been deduced for different plant species to convert the CI into the absolute value of the photosynthetic pigment content. However, such data have not been yet acquired for the atLEAF+ Chl meter. The purpose of the present study was to assess the applicability of the atLEAF+ Chl meter for estimating the Chl content. A significant species-specific exponential relationships between the atLEAF value (corresponding to CI) and extractable Chl a, Chl b, Chl (a+b) for Calamus dioicus and Cleistanthus sp. were shown. The correlations between the atLEAF values and the content of Chl a, Chl b, and Chl (a+b) per unit of leaf area was stronger than that per unit of dry leaf mass. The atLEAF value- Chl b correlation was weaker than that of atLEAF value-Chl a and atLEAF value-Chl (a+b) correlations. The influence of light conditions (Chl a/b ratio) on the atLEAF value has been also shown. The obtained results indicated that the atLEAF+ Chl meter is a cheap and convenient tool for a quick nondestructive estimate of the Chl content, if properly calibrated, and can be used for this purpose along with other Chl meters., E. V. Novichonok, A. O. Novichonok, J. A. Kurbatova, E. F. Markovskaya., and Obsahuje seznam literatury
One broad-leaved pioneer tree, Alnus formosana, two broad-leaved understory shrubs, Ardisia crenata and Ardisia cornudentata, and four ferns with different light adaptation capabilities (ranked from high to low, Pyrrosia lingus, Asplenium antiquum, Diplazium donianum, Archangiopteris somai) were used to elucidate the light responses of photosynthetic rate and electron transport rate (ETR). Pot-grown materials received up to 3 levels of light intensity, i.e., 100%, 50% and 10% sunlight. Both gas exchange and chlorophyll (Chl) fluorescence were measured simultaneously by an equipment under constant temperature and 7 levels (0-2,000 μmol m-2 s-1) of photosynthetic photon flux density (PPFD). Plants adapted to-or acclimated to high light always had higher
light-saturation point and maximal photosynthetic rate. Even materials had a broad range of photosynthetic capacity [maximal photosynthetic rate ranging from 2 to 23 μmol(CO2) m-2 s-1], the ratio of ETR to gross photosynthetic rate (PG) was close for A. formosana and the 4 fern species when measured under constant temperature, but the PPFD varied. In addition, P. lingus and A. formosana grown under 100% sunlight and measured at different seasonal temperatures (15, 20, 25, and 30°C) showed increased ETR/P G ratio with increasing temperature and could be fitted by first- and second-order equations, respectively. With this equation, estimated and measured PG were closely correlated (r2 = 0.916 and r2 = 0.964 for P. lingus and A. formosana, respectively, p<0.001). These equations contain only the 2 easily obtained dynamic indicators, ETR and leaf temperature. Therefore, for some species with near ETR/PG ratio in differential levels of PPFD, these equations could be used to simulate dynamic variation of leaf scale photosynthetic rate under different temperature and PPFD conditions., S.-L.. Wong ... [et al.]., and Obsahuje bibliografii
Heat stress is a major production constraint of sunflower worldwide. Therefore, various populations (parental, F1, F2, F3, and plant progenies) of sunflower were screened for leaf gas-exchange traits with the objectives to formulate selection criteria of heat resistance and development of heat-resistant lines. Initial screening and F2 seeds exposed to heat stress (45°C) resulted in the development of an adapted F2 population that showed leaf gas-exchange and morphological traits better than the unadapted population. Correlation coefficients of traits were partitioned into direct and indirect effects via a path analysis technique to determine the cause of their relationship with a basic parameter such as a reproductive head mass (HM). Path analysis showed a positive direct effect of leaf temperature (Tleaf) (0.32) on HM and also an indirect effect (0.77) of the transpiration rate (E) on HM. Moreover, Tleaf showed high heritability estimates. Tleaf was used to select superior plants within the F2 population. This selection brought about an improvement in the net photosynthetic rate (PN) and E as it was indicated from progeny performance and realized heritability. Progenies selected on the basis of Tleaf also showed an increase in achene yield and heat resistance over unselected F3 progenies and a commercial hybrid. and T. Kalyar ... [et al.].
Vnitrodruhová variabilita v chování zvířat, tj. personalita, výrazně ovlivňuje ekologické i evoluční procesy. V tomto článku se pojednává o tom, jak může personalita vzniknout u pavouků a její vliv na potravní sítě., Inter-individual behavioural differences, i.e. personalities, play a very important role in eco-evolutionary processes. Here, we describe how spiders’ personalities arise and how they influence the dynamics of food webs., and Radek Michalko.
Přes obrovský pokrok v molekulárních fylogenetických metodách a množství v nedávné době objevených fosilních taxonů nemáme o fylogenezi a evoluci mravenců (čeleď Formicidae) mnoho ověřených faktů. V současnosti se rozlišuje 16 žijících a tři fosilní podčeledi. Podčeleď Leptanillinae je považována za bazální, zatímco skupina Apoidea (včely a kutilky) se ukazuje jako sesterská k čeledi mravenců., In contrast to the huge progress of molecular phylogenetic methods and many recently discovered fossil taxa, the phylogeny and evolution of ants (Formicidae) remains poorly understood. Today 16 extant and three fossil ant subfamilies are known. The subfamily Leptanillinae is considered as basal, while Apoidea seems to be a sister family to the ants., and Pavel Pech.