The aim of this study was to explore how the mitochondrial alternative oxidase (AOX) pathway alleviates photoinhibition in chilled tomato (Solanum lycopersicum) seedlings. Chilling induced photoinhibition in tomato seedlings despite the increases in thermal energy dissipation and cyclic electron flow around PSI (CEF-PSI). Chilling inhibited the function of PSII and blocked electron transport at the PSII acceptor side, however, it did not affect the oxygen-evolving complex on the donor side of PSII. Upregulation of the AOX pathway protects against photoinhibition by improving PSII function and photosynthetic electron transport in tomato seedlings under chilling stress. The AOX pathway maintained the open state of PSII and the stability of the entire photosynthetic electron transport chain. Moreover, the protective role of the AOX pathway on PSII was more important than that on PSI. However, inhibition of the AOX pathway could be compensated by increasing CEF-PSI activity under chilling stress.
Our comparison of samples from the Záblacký Bible with the first, second and third editions of the Old Czech Bible translation confirms Kyas's classification of the Záblacký Bible as a compilation translation, containing parts with texts from different editions of the Old Czech Bible. Some of its books belong to the first edition of the Old Czech Bible translation, some to the second, or the first and the second edition against the third edition, and some indicate conformity to third edition bibles. Some parts show conformity with the second and simultaneously the third editions against the first edition. In some places the Záblacký Bible even has its own reading, which we have not found in any other bible that we have worked with.
Our comparison of samples from the Záblacký Bible with the first, second and third editions of the Old Czech Bible translation confirms Kyas's classification of the Záblacký Bible as a compilation translation, containing parts with texts from different editions of the Old Czech Bible. Some of its books belong to the first edition of the Old Czech Bible translation, some to the second, or the first and the second edition against the third edition, and some indicate conformity to third edition bibles. Some parts show conformity with the second and simultaneously the third editions against the first edition. In some places the Záblacký Bible even has its own reading, which we have not found in any other bible that we have worked with.
Our comparison of samples from the Záblacký Bible with the first, second and third editions of the Old Czech Bible translation confirms Kyas's classification of the Záblacký Bible as a compilation translation, containing parts with texts from different editions of the Old Czech Bible. Some of its books belong to the first edition of the Old Czech Bible translation, some to the second, or the first and the second edition against the third edition, and some indicate conformity to third edition bibles. Some parts show conformity with the second and simultaneously the third editions against the first edition. In some places the Záblacký Bible even has its own reading, which we have not found in any other bible that we have worked with.
Using ^^C02, ^^02 and H2O gas exchange as weU as metabolite analysis, net CO2 uptake (P]4) and transpiration rate (£) were measured in the water-stressed plants of Digitalis lanata EHRH. The leaf conductance (gcch). the gross CO2 uptake (Pq), Úie photorespiration (Rp) and reassíinilation (RA) rates were calculated from measuied parameters. The pulse modulated fluorescence was measured duiing the steady statě photosynthesis. After withholding iirigation, the leaf water potential decreased to -2.S MPa, but leaves remained turgid and fully exposed to iiradiance even at a severe water stress. Due to the stress-induced reduction of gcch. and E were drastically reduced, whereas Pq and Rp were less affected. Water use efficiency (WUE), which was higher in 1 000 than 350 cm3(C02) increased as the water stress developed. The stomatal closure induced an increase in the reassimilation (RA) of internally liberated CO2 (Rp). The increased CO2 recycling in relation to the water stress was high in 350 cm^(C02) m-^ and still substantial in 1 000 cm3(C02) and consumed a substantial amount of radiant energy in the form of ATP and reduction equivalents. Consequently, the metabolic demand for radiant energy was reduced by less than 40 %, whereas was diminished by more than 70 % in severely stressed plants at 350 cm3(C02) m*3. Additionally, the quantum efiBciency of photosystem 2 as a measure for the flux of photosynthetically generated electrons was reduced upon the stress. This (and possibly other mechanisms) enabled the stressed plants to avoid overreduction of the photosynthetic electron transport chain.
In three separate experiments, the effectiveness of a SPAD-502 portable chlorophyll (Chl) meter was evaluated for estimating Chl content in leaves of Eugenia uniflora seedlings in different light environments and subjected to soil flooding. In the first experiment, plants were grown in partial or full sunlight. In the second experiment plants were grown in full sunlight for six months and then transferred to partial sunlight or kept in full sunlight. In the third experiment plants were grown in a shade house (40% of full sunlight) for six months and then transferred to partial shade (25-30% of full sunlight) or full sunlight. In each experiment, plants in each light environment were either flooded or not flooded. Non-linear regression models were used to relate SPAD values to leaf Chl content using a combination of the data obtained from all three experiments. There were no significant effects of flooding treatments or interactions between light and flooding treatments on any variable analyzed. Light environment significantly affected SPAD values, chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll [Chl (a+b)] contents in Experiment I (p≤0.01) and Experiment III (p≤0.05). The relationships between SPAD values and Chl contents were very similar among the three experiments and did not appear to be influenced by light or flooding treatments. There were high positive exponential relationships between SPAD values and Chl (a+b), Chl a, and Chl b contents. and M. S. Mielke, B. Schaffer, C. Li.
Three cultivars of winter hexaploid triticales M2A/JAIN, DF 99/Yogu "S5", and Asseret were grown on nutrient solution with or without 75 mM NaCl. Stomatal permeability and transpiration rate decreased in all salt-stressed triticale cultivars. Net photosynthetic rate (PN) of cv. M2A and Asseret was not affected by NaCl. On the contrary, PN in cv. DF99 was reduced in relation to control plants. A higher water-use efficiency under saline conditions led to better salt tolerance of cv. M2A compared to cvs. Asseret and DF99. and A. Morant-Avice ... [et al.].
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
Partitioning of exogenously supplied U-14C-saccharose into primary metabolic pool as sugars, amino acids, and organic acids was analyzed and simultaneous utilization for production of alkaloid by leaf, stem, and root in twigs and rooted plants of Catharanthus roseus grown in hydroponic culture medium was determined. Twigs revealed comparable distribution of total 14C label in leaf and stem. Stems contained significantly higher 14C label in sugar fraction and in alkaloids [47 kBq kg-1(DM)] than leaf. In rooted plants, label in 14C in metabolic fractions in root such as ethanol-soluble, ethanol-insoluble, and chloroform-soluble fractions and in components such as sugars, amino acids, and organic acids were significantly higher than in stems and leaves. This was related with significantly higher content of 14C in alkaloids in stems and leaves. 14C contents in sugars, amino acids, and organic acids increased from leaf to stem and roots. Roots are the major accumulators of metabolites accompanied by higher biosynthetic utilization for alkaloid accumulation. and N. K. Srivastava, A. K. Srivastava.