摘要:

Seasonal changes in adenylate levels and adenylate energy charge (AEC) of four perennial marsh plant species growing in their natural environment were monitored. Leaf tissue was collected bimonthly fromSpartina patens(Aiton) Muhl.,S. cynosuroides(L.) Roth.,S. alternifloraLoisel. andDistichlis spicata(L.) Greene using a method designed for field sampling of adenine nucleotides. The AEC of all four plant species exhibited a strong seasonal variability. Comparison with above‐ground biomass (g m−2) demonstrated a close relationship between AEC and growth. The AEC ratios peaked in early spring or summer (0.78‐0.85) and then declined in late summer and early fall. The ATP/ADP and ATP/AMP ratios also fluctuated seasonally and in a pattern similar to that of th

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05914.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Seeds ofOlea europaeaL. ssp.oleasterHoffm. and Link freed from the sclerous endoearp and incubated in water at 15 or 25°C in darkness or in 12:12 h white light:dark conditions, did not germinate, due to dormancy imposed by the endosperm. Seeds also did not germinate when incubated in abscisic acid, gibberellic acid, kinetin or zeatin in darkness and at cither 15 or 25°C. SAN 9789 |4‐chloro‐5‐(methylamine)‐2‐(a,a,a‐trifluoro‐m‐tolyl)‐3‐(2H)‐pyridazmone] did not promote germination at 15°C but it did to a 75% level at 25°C. This promoting effect of SAN was counteracted by abscisic acid. Cultures of naked embryos grew equally well in the presence or absence of SAN 9789. 6‐Benzylaminopurine promoted whole seed

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05915.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The surface structure and chemistry of symbiotic bacteria from the genusRhizobiumare probably important for the outcome of the infection of legume hosts. Exopolysaccharide, capsular polysaccharide, lipopolysaccharide and a low‐molecular‐weight polysaccharide were isolated fromR. trifoliiUTC 110‐1 andR. leguminosarumUTC 114‐5 and partially characterized. No or only minor differences in sugar composition could be found for the corresponding fractions from the two organisms. A general method to measure low activities of polymer‐degrading enzymes was developed, and used to determine enzyme activities in root extracts ofTrifolium repensL. cv. Lena andPisum xativiiniL. cv. Little Marvel against the isolated rhizobial polysaccharides. An enzyme preparation fromT. repenspartially degraded all polysaccharides isolated from its symbiontR. trifoliiwhile polysaccharides fromR. leguminosarum, symbiont ofP. sativum, were degraded to a much lesser extent. Correspondingly, an enzyme preparation fromP. sativumdegraded all polysaccharides isolated from both its symbiontR. leguminosarumand its non‐symbiontR. trifolii.The amount of symbiont polysaccharides degraded was larger than the amount of polysaccharides degraded from the non‐symbio

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05916.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Ethanol (50‐200mM)induced germination in four genetically pure dormant lines ofAvena fatuaL. The sensitivity to this treatment was moderate immediately after harvest and increased steadily during six months of after‐ripening. This sensitivity to ethanol was detectable much earlier during after‐ripening than with two other germination promoters, NaN3, and NaNO3, Because ethanol can overcome dormancy in freshly harvested caryopses, the mode of action of ethanol in these caryopses apparently differs from that of the two other promoters, azide and nitrate. Nevertheless, it is clear that induction of germination by the three promoters is fully gibberellin‐dependent since in each case this response can be blocked by the administration of 2‐chlorocthyl trimethylammonium chloride, an inhibitor of gibberellin biosynthesis. Short‐term incubation treatments with ethanol were relatively more effective than continuous treatments. These brief treatments were most effective when presented near the beginning of seed imbibition. Among other organic compounds tested only acetaldehyde significantly promoted germination in all lines tested. Propan‐1‐ol, butan‐l‐ol, chloral hydrate, procaine, methanol and chloroform were marginally effective on the least dormant lines, while ether, formaldehyde, acetone and ethyl acetate were ineffective. The mode of action of ethanol in overcoming dormancy in both freshly harvested and partly after‐ripened caryopses is discussed and the possible role as a metabolic substrate or ana

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05917.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Cell walls extracted from cv. Rutgers, 7711 (ripening inhibited), andnor(non‐ripening) tomato (Lycopersicon eseulentumMill.) pericarp tissue at various stages of post‐maturation development have been separated into four distinct fractions and their carbohydrate composition characterized. The amount of ionically‐associated, chelator‐soluble (CDTA, cyclohexanediaminetetraacetic acid) uronic acid in ‘Rutgers’ fruit cell walls remained constant during ripening, whereas the amount of residual pectin, which was extracted with cold alkali (Na2CO3) and was apparently covalently bound, decreased. These changes did not occur inrinandnormutant fruit at a similar chronological age. The galactose content in pectic polysaccharide preparations extracted from tomato cell walls with CDTA and Na2,CO3, decreased by 65% during ripening. A similar but diminished decrease also occurred inrinandnorfruit. A non‐cellulosic polysaccharide(s) was present in walls which resisted extraction with Na‐acetate/CDTA, Na2CO3, and 4MKOH. In ‘Rutgers’ fruit, the content of galactose in this polysaccharide(s) decreased 44% during ripening, whereas little or no significant change was observed inr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05918.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Using the conventional methods of compartmental analysis has led us to recognize three main compartments in theLemnacells: the cell‐wall, cytoplasm and vacuolc. The half‐times of Li+isotopic exchange were of the order of a few minutes, a few hours and a few days, respectively. The possible existence of a 4th, small, and almost non‐exchangeable compartment cannot be excluded. Despite different possible sources of uncertainty (ambiguity of the kinetic solutions, no uniformity of cell types in the plant material, uncertainties in the estimations of electric potentials), the data were consistent with i) Li+being actively extruded from the cytoplasm, both towards the exterior and the vacuole, ii) the electrochemical potential difference of Li+ being of the order of ‐25 kj mol across the plasmalemma, and in the range of 5 to 10 kJ mol across the tonoplast, and iii) the passive permeability coefficients of Li+ being in the range of 10 to 10 m s both for the plasmalemma and the to

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05919.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The activities of several enzymes related to amino acid metabolism were investigated in senescing detached wheat leaves (Triticum aestivum L.cv. Diplomat) in light and darkness and after kinetin treatment. Glutamine synthetase and glutamate synthase activities rapidly declined in darkness. In light, the decline of glutamate synthase activity was retarded, while the activity of glutamine synthetase remained high and even increased transitorily. Kinetin treatment counteracted the decline of the activities of both enzymes. The activity of glutamate dehydrogenase markedly increased during senescence, particularly in light, and kinetin treatment lowered its activity. The activities of glutamate‐oxaloacetate and glutamate‐pyruvate amino‐transferases and of NADP‐dependent isocitrate dehydrogenase also increased in detached wheat leaves in light. Kinetin treatment prevented the rise of these enzyme activities. In darkness, the activities of glutamate‐oxaloacetate aminotransferase and NADP‐dependent isocitrate dehydrogenase decreased slowly while the decline of glutamate‐pyruvate aminotransferase activity was more rapid. The activity of NAD‐dependent malate dehydrogenase decreased both in light and, more rapidly, in darkness. The pattern of changes of the enzyme activities provides an explanation for the amino acid transformations and the flow of amino nitrogen into transport metabolites in s

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05920.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The presence of hydrogen uptake (Hup+) activity was demonstrated in root nodules formed on the pea cultivar Bodil (Pisum sativumL. cv. Bodil) by 19 out of 23 tested strains ofRhizobium leguminosarum.Only 3 of the 19 Hup+strains showed significant hydrogen recycling efficiency in the nodules. The correlation between N; fixation in nodules and N content of aerial parts of the plants was poor. The reasons for this and for the luck of significant hydrogen recycling in 16 of the 19 Hup+strains is discussed.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05921.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Plasma membrane‐enriched preparations from fibrous roots of three citrus genotypes differing in their abilities for chloride exclusion, and grown in the presence of 0,50 or 100 mMNaCl for 4 weeks, were analysed for phospholipid and free sterol content and vanadate‐sensitive adenosine triphosphatase (ATPase) activity over a range of temperatures. The best chloride excluder, Rangpur lime(Citrus reticulaiaBlanco var.austerahyb.?), had significantly higher maximal ATPase activity than both the moderate chloride excluder. Kharna khatta(Citrus kharnaRaf.), and the worst chloride excluder, Etrog citron(Citrus medicoL.), at all assay temperatures below 28°C. Salt treatment had no effect on maximal ATPase activity of either Rangpur lime or Etrog citron but resulted in increased activity of the enzyme in Kharna khatta at temperatures below 28°C.Arrhenius plots of ATPase activity from the three citrus genotypes showed that, in controls, the activation energy (E.,) of Rangpur lime ATPase was significantly lower than that of both Kharna khatta and Etrog citron. The thermotropic phase transition temperature (Tf) for Rangpur lime (27°C) was also lower than for the other citrus genotypes (31°C). Salt treatment resulted in increases in both Ea and T, for Rangpur lime, decreases in both parameters for Kharna khatta and no change of either parameter for Etrog citron.An inverse relationship between Eaand the phospholipid to free sterol ratio was evident for plasma membrane preparations from all three citrus genotypes in the presence and absence of salt treatment suggesting that changes in membrane fluidity, particularly those induced by free sterols, have the potential to influence active as well as passive ion transport processes and thus may play a significant role in the chloride exclusion me

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05922.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Smooth bromegrass plants (Bromus inermisLeyss.) have a dual photoperiodic requirement for flowering. At temperatures ranging from 6 to 24°C, short days (SD) are necessary for primary induction while a transition to long days (LD) is required for initiation of flower primordia, culm elongation and flower development (secondary induction). Critical photoperiods for primary induction (50% flowering) were 13.5 h (15°C) and 12 h (24°C) in the American cv. Manchar and 14.5 and 13 h, respectively, in the Norwegian cv. Löfar. For the secondary induction the respective critical photoperiods were 14 and 15 h in ‘Manchar’ and 16 and 17.5 h in ‘Löar’, which also appeared to be better adapted to low temperatures. Low temperature vernalization in LD for up to 16 weeks at 3°C was unable to cause primary induction and temperatures below 12°C also strongly reduced the SD effect. At optimum temperature (15‐2TC) 4 to 6 weeks of 8‐10 h SD treatments were needed for optimal primary induction effect. A minimum of 8 LD cycles of 24 h were required for complete secondary induction in ‘Manchar’, while more than 16 cycles were needed in ‘Löfar’. Seedlings grown in SD developed a rosette type of growth with shoots growing in a decumbent position, while those in LD grew upright and formed elongated vegetative culms. Rate of leaf initiation was enhanced by about 60% by LD while t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1984.tb05923.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY