摘要:

Books reviewed in this article:THE PHYSICAL CHEMISTRY AND MINERALOGY OF SOILS, VOLUME 2.C. E. MarshallPLANT DISEASE EPIDEMIOLOGY. Edited by P. R. Scott&A. BainbridgeFUNGI, MAN, AND HIS ENVIRONMENT. R. C. CookePHYSIOLOGY AND BIOCHEMISTRY OF SEEDS IN RELATION TO GERMINATION. J. D. Bewley&M. BlackAPPLIED AND FUNDAMENTAL ASPECTS OF PLANT CELL TISSUE AND ORGAN CULTURE. Edited by J. Reinert&Y. P. S. Bajaj, 1977

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00767.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00768.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe response of the kinetic properties of NAD malate dehydrogenase (MDH) was compared for two clones ofLathy rus japonicusWilld. collected in two contrasting climatic sites in Eastern North America. MDH from the cold adapted maritime genotype (Hudson Bay, Québec) had lower thermostability, reduced apparent (Ea) and free (ΔG†) energy of activation and lower specific activity when compared to MDH of plants from the warm summer continental site (Lake Michigan). Electrophoretic analyses show little differentiation in the isozyme profiles of the two genotypes. Thermostability differences were primarily associated with the mitochondrial isozymes which, however, were not differentiated electrophoretically Substrate binding ability of MDH, as measured by apparent Km, was more sensitive to high assay temperature in the cold adapted maritime genot

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00770.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe speed of acclimatory changes in apparent energy of activation (Ea)of NAD malate dehydrogenase was analysed in four clones ofLathyms japonicusWilld. collected over a 16° latitudinal gradient in eastern North America. Plants were grown initially for six months at either 7° night/15° day or 22° night/30° days. Following reciprocal switches in these two contrasting thermo‐periods, energy of activation was relatively stable for 12 h, then oscillated until 48 h, and stabilized in about 72 h. The results suggest that the acclimation response inEais not due to near‐instantaneous conformational changes in isozymes, but is directed primarily by temperature‐mediated structural and/or functional modifications duringde novosynthesis of the forms of t

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00771.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractDissociation of active H+extrusion (−ΔH+) from K+uptake in pea and maize root segments was attempted by substituting K+in the incubation medium with lipophilic cations assumed to enter the cell by passive, non‐specific, permeation through the lipid component of the plasmalemma. Among the compounds tested, tributylbenzylammonium significantly stimulated −ΔH+in the absence of other monovalent cations in the medium. This effect was much more evident when the experiment was carried out in the presence of fusicoccin, which strongly stimulates proton extrusion and monovalent cation uptake, and hyperpolarizes the trans‐membrane electric potential in these materials. Also the lipophilic cations tetraphenylphosphonium, dimethyldibenzylammonium and hexylguanidine markedly stimulated FC‐promoted −ΔH+. Octylguanidine at a low concentration induced an early stimulation followed by a strong inhibition of −ΔH+. A complete lack of additivity was observed between the effects of lipophilic cations and that of K+on H+extrusion. Lipophilic cations severely inhibited K+uptake.These data are interpreted as supporting the view of an electric, rather than a chemical, (namely, involving the same carrier system) nature of the coupling of active H+extrus

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00772.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractPotted seedlings of four lines of maize andSorghumof differing drought tolerance were subjected to a single soil drying cycle and were only rewatered when the plants showed the first signs of wilting. Other plants remained well‐watered throughout the experimental period. As plant water potentials decreased in the unwatered plants of three of the lines investigated (SorghumPiper and M35‐1, V‐4146 and maize Farz 27), endogenous levels of farnesol‐like antitranspirants increased. Closure of stomata correlated well with the increase in endogenous antitranspirant. In the fourth line (SorghumM35‐1, V‐4184), stomata did not close as the level of plant water stress increased, although leaf diffusion resistance of even the well‐watered plants of this line was quite high. In this line, there was no consistent relationship between plant water stress and antitranspirant level or between stomatal behaviour and antitranspirant level. The involvement of farnesol‐like antitranspirants in the control of stomatal behaviour in water‐stressed pl

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractPhytochrome photoequilibria within a model green leaf have been calculated. The results show a gradient in photoequilibria within the leaf lamina due to selective attenuation of incident light by the leaf tissue. Large differences were observed between photoequilibria calculated for a leaf under natural daylight and photoequilibria calculated for a leaf receiving daylight filtered through a vegetation canopy.

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractTwo phytochrome‐dependent processes are compared inAnagallis arvensis, an absolute long‐day plant: flowering and internode elongation. The effectiveness of red or far red radiation is different according to the length of the treatment and its position within the photoperiodic cycle: for both flowering and internode elongation, 15 h treatments with wavelengths above 700 nm are promotive, whilst wavelengths below 700 nm are inhibitory. In contrast, night breaks of 3 h red light (λ<700 nm), given after the middle of the dark period, are promotive for flowering and inhibitory for internode elongation. These results are discussed in context with data reported in the literature on photoperiodic control of long‐day

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractParameters of Crassulacean Acid Metabolism (carbon isotope composition [δ13C values], diurnal acid cycles) were studied together with properties of phosphoenolpyruvate carboxylases (PEP‐C) in eight species of the genusSedum. The δ13C values indicate a considerable variability of CAM capacity among the species investigated. The spectra of organic acids were similar in all species. Malate, citrate, and isocitrate were the main components of the acid fraction. Quinic acid occurred only during the light period. Molecular weights of PEP‐C were in the range of 160,000 and showed no correlation to CAM as indicated by the δ13C values. However, there were differences in the kinetic data of PEP‐C.Sedumspecies with less negative δ13C (i.e. with high CAM capacity) have PEP‐C with higher Vmax, higher Km (PEP) and higher sensitivity for malate

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1979.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY