摘要:

AbstractProtein synthetic activity of polysomes isolated during dehydration‐rehydration cycles of black locust seedlings (RobiniapseudoacaciaL.) was investigated. Polysomes of black locust seedlings were reduced by only 20% during water stress and were capable of incorporating3H‐leucine into peptide chins. RNase activity increased during stress and declined following irrigation. The presence of a protective mechanism is suggested which, if present in other drought hardy species, could help to explain the ability of these species to withstand various levels of water str

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01482.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe intra‐cellular location of ABA was investigated in relation to its sites of synthesis. Chloroplasts were isolated from stressed and non‐stressed spinach leaves and their ABA content determined. Virtually all of the ABA from non‐stressed leaves was contained in the chloroplasts compared with only a small fraction of ABA isolated from stressed leaves. Chloroplasts prepared from turgid leaves and subsequently lysedin vitroretained most of their ABA and phaseic acid (PA) complement but this was removed with organic solvents.While the possibility of extra‐chloroplastic synthesis cannot be discounted the data indicate that stress‐induced ABA synthesis occurs in the chloroplast and that the ABA readily migrates from there to other parts of

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01483.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractGermination capacity, and α‐amylase production in relation to the peroxidase and isoperoxidase activities in the grains of three varieties of wheat have been analysed and compared. A high percentage of germination and α‐amylase producation at 25°C are associated with low peroxidase activity of the isolated embryo. This correlation is lacking when the intact grain is considered. A 2‐day treatment at 4°C which further increases the percentage germination and enhances α‐amylase synthesis, lowers the activity of peroxidase in the embryos. A general decrease in activity of all the isoenzymes is observed.Based on the above data and on differences in the activity of the most cathodic isoperoxidasic bands, a hypothesis is put forward which suggests that a sufficiently low peroxidase activity and a minimum auxin level of the embryo are responsible for the onset of

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01484.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractHydroxylated metabolites of isopropylm‐chlorocarbanilate (chlorpropham) are found in intact soybean plants (Glycine maxMerr.). The metabolites are isopropyl 2‐hydroxy‐5‐chloro‐carbanilate (2OH) and isopropyl 3‐chloro‐4‐hydroxycarbanilate (4OH). The phytotoxicity of these metabolites and chlorpropham was tested in cell suspensions and roots of intact soybean seedlings and cell cultures of carrot (Daucus carotaL.). The growth of soybean cell suspensions was inhibited with 50 μMchlorpropham. Ten μMchlorpropham usually slowed initial growth of the cultures while 5 μMand 0.1 μMchlorpropham had no effect. The 2OH and 4OH metabolites had no significant effect on dry weight over the same concentration range. Some metabolism of chlorpropham, 2OH and 4OH occurred during 6 and 48 h of incubation with soybean cells. The results are interpreted to mean that all three analogs penetrated into the cells, were metabolized, and some of the metabolites excreted back into the medium. Mitotic index studies of intact 3‐day‐old soybean roots showed that 2OH inhibited mitosis to a greater extent than chlorpropham, whereas 4OH produced only a slight and insignificant reduction compared to controls. Chlorpropham, 2OH and 4OH (at 50 μM) all reduced the growth of wild carrot cultures grown in the presence or absence of 2,4‐D. Therefore, hydroxylation of chlorpropham at the 2′ or 4′ positions of the 5′ chlorinated benzene ring is not sufficient to render the compound no

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01485.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractGrowth and flowering of strawberry cultivars were studied in controlled environments. Early cultivars adapted to marginal growing areas in Scandinavia initiated flower buds in all photoperiods including continuous light at temperatures of 12 and 18°C. At 24°C they remained vegetative in photoperiods above 14 or 16 h. The later cultivars ‘Senga Sengana’ and ‘Abundance’ did not initiate flower buds in 24‐h photoperiods at any of these temperatures. Their critical photoperiod changed from above 16 h at 12°C to about 14 and 13 h at 18 and 24°C, respectively. It is concluded that at high latitudes temperature is as important as photoperiod in controlling flowering in the strawberry.Stolon formation, petiole elongation, and leaf area growth were stimulated by high temperature and long days, usually with optima at 16 h and 18°C for petiole elongation and 16 h and 24°C for stolon formation. Although growth and flowering responses in general were opposite, the results indicate that they are to some extent independent. The photoperiodic growth responses were mainly of morphogenetic nature. Dry weight of stem and leaves was little influenced by photoperiod when the irradiance wa

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01486.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractDNA polymerase preparations from incubated sugar beet (Beta vulgaris) root tissue exhibited multiple activities following DEAE‐cellulose chromatography and glycerol density gradient centrifugation (600‐fold purification). The two major polymerase activities eluted from DEAE‐cellulose differed in heat lability, pH and Mg2+optima, and in response to ethanol,p‐hydroxymercuribenzoate, and N‐ethylmaleimide. Further purification by glycerol gradient centrifugation indicated the presence of a low molecular weight molecule (3.4 S), heterogeneous larger molecules (6.2, 6.8 S), and apparent aggregates (11–11.5 S). This investigation indicates similarities between sugar beet polymerases and the small (β) and large (α) molecular weight polymerases from mamm

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01487.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractLeaves ofQuercus roburL. were infected with conidia ofMicrosphaera alphitoidesGriffon and Maublanc. Crude enzyme extracts of healthy and infected tissue, taken during a 7‐day experimental period, were assayed, using spectrophotometric and manometric techniques, for glycolate oxidase, NAD‐ and NADP‐glyoxylate reductase activities. After 2 days, extracts from infected tissue contained significantly higher activities of glycolate oxidase and NAD‐glyoxylate reductase than extracts from controls, but the activity of NADP‐glyoxylate reductase, after an initial rise, was significantly reduced below that in control extracts. The reduction in glycolate oxidase activity may be partly due to a deficiency in flavin mononucleotide in infected tissue. A possible connection between the reduction in flavoprotein enzyme activity, photorespiration and susceptibility to infection is

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01488.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe time course of freezing damage in pine needles and in bark of apple trees was followed at different subzero temperatures. From these data the killing rate by freezing was determined for trees which differed in degree of cold hardiness.The activation energy of the killing reaction was also calculated. The killing rate was lowest in cold‐acclimated trees, but the activation energy of the killing reaction was very high indicating a high degree of structured water in the cells. Non‐acclimated trees showed uniform low values of the activation energy of the killing reaction at all subzero temperatures studied.It is suggested that intracellular supercooling could be a part of the mechanism of frost protection in cold‐acclimated apple trees within the – 30 to – 20°C range, but not in the –20 to

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01489.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractIt is demonstrated that photographic images of plants can be produced in the absence of external illumination using an image intensifier. The image is produced by the weak delayed light emission (afterglow) from photosynthetically active chloroplasts.We propose the use of such “phytoluminographs’ for the study and diagnosis at an early stage of disturbances due to parasites, mineral deficiency, herbicides, frost

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01490.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractMesophyll cells of leaf slices of bean (Phaseolus vulgarisL.) absorb six to ten times more K+than Rb+from 0.1 mMsingle chlorides of these cations. Absorption of42K+from 0.1 mM42KCl is much more inhibited by low concentrations of Rb2SO4than by K2SO4. The isotherm for K+absorption is biphasic in the range 0.1–1.1 mM, and K+is more effective than Rb+in causing transition from phase 1 to phase

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01491.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY