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2482. The residual effects of bensulfuron-methyl on growth and photosynthesis of soybean and peanut
- Creator:
- Su, W. C., Sun, L. L., Ge, Y. H., Wu, R. H., Xu, H. L., and Lu, C. T.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fytotoxicita, phytotoxicity, podzemnice olejná, chlorofylová fluorescence, výměna plynu, relativní obsah chlorofylu, Arachis hypogaea, chlorophyll fluorescence, gas exchange, Glycine max (Linn.) Merr., relative chlorophyll content, 2, and 581
- Language:
- Multiple languages
- Description:
- The effects of various concentrations of bensulfuron-methyl residues (BSM, 0-500 μg kg-1) on the growth and photosynthesis of soybean and peanut were studied. Shoot length, root length, root-to-shoot ratio, and biomass of soybean and peanut seedlings declined with the increase of BSM residue concentrations. As the concentration of BSM increased, SPAD value, net photosynthetic rate, stomatal limitation, stomatal conductance, and transpiration rate also declined with varying extent, but dark respiration rate and intercellular CO2 concentration increased gradually. PSII maximum quantum yield, actual quantum yield, and electron transport rate were significantly reduced by the BSM residues in soil, and the reduction was mostly attributed to the decrease in photochemical quenching coefficient. The results showed that photosynthesis in both crops was limited by nonstomatal factors. The residues of BSM caused reversible damage in PSII reaction centers and decrease the proportion of available excitation energy used for photochemistry., W. C. Su, L. L. Sun, Y. H. Ge, R. H. Wu, H. L. Xu, C. T. Lu., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2483. The responses of photosynthetic rate and stomatal conductance of Fraxinus rhynchophylla to differences in CO2 concentration and soil moisture
- Creator:
- Zhang, S. Y., Zhang, G. C., Liu, X., and Xia, J. B.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, CO2 response, net photosynthetic rate, photorespiration, relative water content, soil moisture, 2, and 581
- Language:
- Multiple languages
- Description:
- The photosynthetic parameters in leaves of three-year-old seedlings of Fraxinus rhynchophylla L. were studied under different soil water conditions and CO2 concentrations ([CO2]) with a LI-COR 6400 portable photosynthesis system. The objective was to investigate the response of photosynthesis and stomatal conductance (gs) to various [CO2] and soil water conditions, and to understand the adaptability of F. rhynchophylla to such conditions. The results showed that the soil water content (RWC) required to maintain high photosynthetic productivity in F. rhynchophylla was 49.5-84.3%; in this range, net photosynthetic rate (PN) rose with [CO2] increasing from 500 to 1,400 μmol mol-1. Outside this RWC range, PN decreased significantly. The apparent maximum photosynthetic rate (Pmax,c) and carboxylation velocity (Vc) increased with increasing RWC and remained relatively high, when RWC was between 49.5 and 96.2%. CO2 compensation points and photorespiration rate exhibited a trend opposite to that of Pmax,c and Vc, indicating that moderate water stress was beneficial for increasing plant assimilation, decreasing photorespiration, and increasing production of photosynthates. gs declined significantly with increasing [CO2] under different water supplies, but the RWC range maintaining high gs increased. gs reached its maximum, when RWC was approximately 73% and then decreased with declining RWC. The maximal gs was found with increasing RWC. Thus, based on photosynthetic characteristics in artificial, vegetation construction in semiarid loess hill and gully area, F. rhynchophylla could be planted in habitats of low soil water content. and S. Y. Zhang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2484. The salinity tolerance of freshwater cyanobacterium Synechococcus sp. PCC 7942 is determined by Its ability for osmotic adjustment and presence of osmolyte sucrose
- Creator:
- Ladas, N. P. and Papageorgiou, G. C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- absorption spectra, cell doubling, chlorophyll content and fluorescence, cytoplasmic osmolality, glucose, NaCl, saccharose, and sugars
- Language:
- Multiple languages
- Description:
- We investigated the factors that impose an upper limit of salinity tolerance to the unicellular freshwater cyanobacterium Synechococcus sp. PCC 7942. Above approx. 0.4 M NaCl, Synechococcus cells cease to proliferate, after having accumulated 0.3 M sucrose. Cells that pre-accumulated sucrose could tolerate up to 0.5 M NaCl, but not 0.6 M NaCl. After exposure to 0.5 M NaCl or higher, the cells were irreversibly modified becoming unable for osmotic volume adjustments. and N. P. Ladas, G. C. Papageorgiou.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2485. The short- and long-term response of Scrippsiella trochoidea (Pyrrophyta) to solar ultraviolet radiation
- Creator:
- Guan, W. C. and Lu, S. H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, growth, photochemical efficiency, Scrippsiella trochoidea, UVR, and ΦPSII
- Language:
- Multiple languages
- Description:
- To assess the short- and long-term impacts of UV radiation (UVR, 280-400 nm) on the microalga Scrippsiella trochoidea, we exposed cells to three different radiation treatments (PAB: 280-700 nm, PA: 320-700 nm, and P: 400-700 nm). A significant decrease in the photochemical efficiency (ΦPSII) at high irradiance (100% of incident solar radiation, 216.0 W m-2) was observed. Photoinhibition was reduced from 62.7 to 10.9% when the cells were placed in 12% solar radiation (26.1 W m-2). In long-term experiments (11 days) using batch cultures, cell densities during the first 5 days were decreased under treaments P, PA, and PAB, reflecting a change in the irradiance experienced in the laboratory to that of incident solar irradiance. Thereafter, specific growth rates increased and UV-induced photoinhibition decreased, indicating acclimation to solar UV. Cells were found to exhibit both higher ratios of repair to UV-related damage, shorter period for recovery and increased concentrations of UV-absorbing compounds (UVabc), whose maximum absorption was found to be at 336 nm. Our data indicate that S. trochoidea is sensitive to ultraviolet radiation, but was able to acclimate relatively rapidly (ca. 6 days) by synthesizing UVabc and by increasing the rates of repair processes of D1 protein in PSII. and W. C. Guan, S. H. Lu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2486. The substrate utilization and concentration of 14C photosynthates in citronella under Fe deficiency
- Creator:
- Srivastava, N. K., Misra, A., and Sharma, S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- acetate, amino acids, 14CO2, Cymbopogon winterianus, oil, organic acids, primary and secondary metabolites, sugars, and [U-14C]; [U-14C] saccharose incorporation
- Language:
- Multiple languages
- Description:
- Changes in the utilization pattern of primary substrate, viz. [U-14C] acetate, 14CO2 and [U-14C] saccharose, and the contents of 14C fixation products in photosynthetic metabolites (sugars, amino acids, and organic acids) were determined in Fe-deficient citronella in relation to the essential oil accumulation. There was an overall decrease in photosynthetic efficiency of the Fe-deficient plants as evidenced by lower levels of incorporation into the sugar fraction and essential oil after 14CO2 had been supplied. When acetate and saccharose were fed to the Fe-deficient plants, despite a higher incorporation of label into sugars, amino acids, and organic acids, there was a lower incorporation of these metabolites into essential oils than in control plants. Thus, the availability of precursors and the translocation to a site of synthesis/accumulation, severely affected by Fe deficiency, is equally important for the essential oil biosynthesis in citronella. and N. K. Srivastava, A. Misra, S. Sharma.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2487. The susceptibility of cucumber and sweet pepper to chilling under low irradiance is related to energy dissipation and water-water cycle
- Creator:
- Li, X.-G., Meng, Q.-W., Jiang, G.-Q., and Zou, Q.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Multiple languages
- Description:
- The photoprotection of energy dissipation and water-water cycle were investigated by comparing chilling sensitivity of photosystems 2 (PS2) and 1 (PS1) in two chilling-sensitive plants, cucumber and sweet pepper, upon exposure to 4 °C under low irradiance (100 μmol m-2 s-1) for 6 h. During chilling stress, the maximum photochemical efficiency of PS2 (Fv/Fm) decreased only slightly in both plants, but the oxidisable P700 decreased markedly, which indicated that PS1 was more sensitive to chilling treatment under low irradiance than PS2. Sweet pepper leaves had lower Fv/Fm, higher non-photochemical quenching (NPQ), and higher oxidisable P700 during chilling stress. Activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX) in cucumber leaves was higher, but APX activity decreased apparently compared to that at room temperature. The productions of active oxygen species (H2O2, O2 -) increased in both plants, faster in cucumber leaves than in sweet pepper leaves. In sweet pepper leaves, a stronger de-epoxidation of the xanthophyll cycle pigments, a higher NPQ could act as a major protective mechanism to reduce the formation of active oxygen species during stress. Thus sensitivity of both plants to chilling under low irradiance was dominated by the protective mechanisms between PS1 and PS2, especially the energy dissipation and the water-water cycle. and X.-G. Li ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2488. The synapse-like interaction between chloroplast, dictyosome, and other cell compartments during increased ethylene production in leaves of rye (Secale cereale L.)
- Creator:
- Selga, T. and Selga, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- electron microscopy, endoplasmic reticulum, ethephon, Golgi appaaratus, intercellular signalling, and mitochondrion
- Language:
- Multiple languages
- Description:
- Rye (Secale cereale L.) plants were treated with an ethylene releaser ethephon (2-chloroethylphosphonic acid) in concentration of 4×10-2 M. We studied electron microscopically, if and how chloroplasts interact with well-documented sites of ethylene production/binding, i.e., with endoplasmic reticulum, dictyosomes, mitochondria, plasma membrane, and tonoplast. During the sharp increase of ethylene synthesis in mesophyll cells of rye leaves, the direct local continguity of chloroplast envelope or envelope protrusions with the above mentioned cell compartments was typical. Moreover, a large number and diversity of versatile chloroplast-dictyosome associations were conspicuous, in which both the chloroplast and each cisterna of dictyosome were capable to exo/endocytosis. The dictyosomes were directed towards the chloroplasts, plasma membrane, or tonoplast both with cis-face, trans-face, or with the rim, they could change their direction or shut up the trans-face, developing simultaneously several flexible chains of vesicular dispatches among chloroplasts and some other cell compartments. This reflects interaction of protein/ethylene producing, photosynthesising, DNA containing compartments, and regulated action of lysosomal system. Structural contacts and vesicular transport among compartments of symplastic system equalises concentrations of H+, Ca2+, etc. ions, as well as provide connection with an apoplast. We propose that ethylene functions in plant mesophyll cells are both as intra/intercellular signalling substance and as phytohormone that regulates gene expression in nuclei, chloroplasts, and mitochondria in a complicated synapse-like process and causes programmed death of leaves of the main stalks of rye for the sake of promoted growth of side shoots. and T. Selga, M. Selga.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2489. The ultrastructure of chloroplasts, content of photosynthetic pigments, and photochemical activity of maize (Zea mays L.) as influenced by different concentrations of the herbicide amitrole
- Creator:
- Pechová, R., Kutík, J., Holá, D., Kočová, M., Haisel, D., and Vičánková, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- 3-amino-1,2,4-triazole, carotenoids, chlorophylls, Hill reaction, and photosystems 1 and 2
- Language:
- Multiple languages
- Description:
- The effect of three different concentrations of amitrole (AM), a bleaching herbicide affecting carotenogenesis, on chloroplast ultrastructure, photosynthetic pigment contents, and photochemical activity was studied in two maize genotypes differing in photosynthetic characteristics. The content of photosynthetic pigments in leaves of plants treated with low (20 μM) AM concentration was similar to control plants and no damaging effect of the herbicide on the ultrastructure of either mesophyll (MC) or bundle-sheath (BSC) cell chloroplasts was observed. Higher (60 and 120 μM) concentrations of AM caused a significant decrease in the content of carotenoids (especially xanthophylls), which was followed by photooxidative destruction of chlorophylls and some alterations of chloroplast ultrastructure. MC chloroplasts appeared more sensitive to the damaging effect of AM compared to BSC chloroplasts. A significant decrease in the amount of both granal and intergranal thylakoids in MC chloroplasts was observed with the increasing concentration of AM. As regards BSC chloroplasts, rapid decrease in the volume density of starch inclusions was found in plants treated with higher concentrations of AM. When 120 μM AM was used, both MC and BSC chloroplasts contained just a few thylakoid membranes that were strongly altered. The changes in the ultrastructure of MC chloroplasts were accompanied by the changes in their photochemical activity. The formation of chloroplast protrusions after treatment of plants with AM as well as in control plants was also observed. and R. Pechová ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2490. The use of a portable non-destructive type nitrogen meter for leaves of woody plants in field studies
- Creator:
- Ichie, T., Kitahashi, Y., Matsuki, S., Maruyama, Y., and Koike, T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Agriexpert PPW-3000, chlorophyll, comparison of methods, and SPAD-502
- Language:
- Multiple languages
- Description:
- The practicality of the portable, non-destructive type nitrogen meter (Agriexpert PPW-3000) was tested on ten forest species. Also investigated was the potential relationship between leaf nitrogen and chlorophyll (Chl) contents and the readings taken with the PPW-3000 and a Chl meter (SPAD-502). There was a significantly positive correlation between the readings of PPW-3000 and N content in the same leaves, whereas the correlation between leaf Chl content and the PPW-3000 values was less positive. Similarly there was a significant positive correlation between actual Chl content and the SPAD-502 readings and the less positive correlation between actual N content and the SPAD-502 readings. Thus using both the PPW-3000 and SPAD-502 enables to determine leaf N and Chl contents simply and non-destructively in the field. and T. Ichie ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public