摘要:

Purified mitochondria from potato (Solanum tuberosumL. cv. Bintje) tubers were incubated with [γ32P]‐ATP, respiratory substrates and various effectors. The total incorporation of32P into proteins was measured and the phosphoprotein pattern investigated by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis and autoradiography. Total incorporation was strongly reduced (by 70–80%) by the respiratory substrates, succinate, pyruvate and NADH. The half‐maximal inhibition was at 0.03, 0.3, and 0.3 mM, respectively. The labelling of the major phosphoproteins of 40 and 42 kDa (probably both the α‐subunit of the pyruvate dehydrogenase, EC 1.2.4.1) as well as of minor polypeptides of 26–33 kDa was reduced. A concomittant increase in the labelling of the 14 and 16 kDa bands occurred in the presence of succinate in fall but this increase could not be detected in late winter. The reduction in total labelling caused by NADH and succinate was unaffected by changes in the membrane potential (e.g. addition of uncouplers) or by inhibition of electron transport (e.g. by KCN). Malonate inhibition of succinate oxidation reversed the effects of succinate on labelling‐ The mechanism(s) by which respiratory substrates might affect protein kinase activi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05669.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Pectic (carbonate‐soluble, covalently‐bound pectin, CBP) material stimulated increased ethylene production when vacuum‐infiltrated into whole, mature green tomato (Lycopersicon esculentumMill. cv. Rutgers) fruit. Activity was greatest if CBP was extracted from mature green tomatoes with jellied locules. CBP extracted from mature green tomatoes with immature seeds had no elicitor activity, while CBP from turning or red ripe tomatoes was only moderately active. Infiltration of CBP from normal mature green fruit into ripening inhibitor (rin) mutant tomato fruit stimulated ethylene production and attenuated red pigmentation in these fruits. Partial purification of the active material was accomplished using DEAE‐Sephadex and BioGel P‐100 chromatography. The most highly purified fraction is comprised of neutral carbohydrate (95%) with a relatively low content of amino acids (1%) and a uronic acid content of less than 5%. This material may be an endogenous trigger of ethylene production and

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05670.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Small birch plants (Betula pendula Roth.) were grown at different rates of exponentially increasing nitrogen supply. This resulted in plants with different relative growth rates and different internal nitrogen concentrations. Within a nitrogen treatment, both of these variables remained constant with time.Free amino acids were measured in leaves and roots of the seedlings at two different harvests. At greater nitrogen supply, higher concentrations of total amino acid nitrogen were found in roots and leaves. The ratio of amino acid nitrogen to total nitrogen was low albeit greater at higher nitrogen supply. Higher concentrations of amino acid nitrogen were mainly due to high concentrations of citrulline, glutamine, γ‐aminobuitric acid and arginine.Greater leaf concentrations of amino acid nitrogen at higher nitrogen supply may be related lo increased concentrations in the xylem sap and/or may be indicative of small excesses of nitrogen with respect to current nitrogen usage in protein synthes

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05671.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Diamine oxidase (DAO, EC 1.4.3.6.) activity and polyamine content were measured in the shoot apex, leaves, epicotyl, cotyledons, hypocotyl and roots of light‐grown bean (Phaseolus vulgarisL. cv. Lingot) and soybean (Glycine maxL. cv. Sakai) seedlings at 3 different stages of germination (5, 8 and 14 days) as well as in embryos and cotyledons from soaked seeds. No DAO activity was detected in embryos and cotyledons of either plants. In bean seedlings DAO activity was only detectable in the shoot apex, primary leaves and cotyledons, while in soybean the activity was only detectable in the hypocotyl and roots. During seedling growth, in both plants, a different pattern of DAO activity was observed. In both species spermidine and spermine were the most abundant polyamines in embryos and cotyledons. Cadaverine, absent in bean, was only detected in soybean embryos. In the seedlings of both plants, increasing gradients of putrescine, spermidine and spermine from base to shoot apex were found. A high concentration of cadaverine was present in soybean hypocotyls and roots. A possible correlation between DAO activity and the endogenous content of the preferential substrate is discussed in relation to the possible involvement of the enzyme in regulating the cellular level of polyamine

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05672.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Seasonal changes in the relationship between stomatal responses and water potential components in detached leaves of sweet cherry (Prunus aviumL. cv. Bigarreau Morreau) and plum (Prunus domesticaL. cv. Queen Victoria) were examined by the simultaneous measurement of stomatal conductance and water relation parameters derived from pressure‐volume curves. The water potential threshold for stomatal closure in sweet cherry leaves throughout the season and in plum leaves until mid‐July varied nearly in parallel with changes in the osmotic potential at the turgor loss point. From August onward, closing reactions of plum stomata had no relationship to the turgor loss point. Stomata of sweet cherry leaves opened more widely and showed slower reactions to dehydration early in the season than later. Seasonal changes of stomatal conductance and stomatal responses to dehydration in both species seem thus to be influenced by fruit development and ripen

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05673.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Cuttings from seedlings ofPicea abiesL. (Karst.) grown under high light (HL). rooted slowly and incompletely, whereas rooting in cuttings from seedlings grown under low light (LL) was rapid and almost complete. Immunoaffinity chromatograpriy (IAC) with antibodies against isopentenyl adenosine ([9‐RIiP) and trans‐zeatin riboside (I9R]Z) was used to isolate cytokinin‐like compounds from extracts of the cuttings. These compounds were separated by HPLC and quantified with a UV‐detector. [9R]iP‐type and [9R]Z‐type compounds were also quantified using an enzyme immunoassay (ELISA). Levels of both [9R]iP‐type and [9R]Z‐type cytokinins were considerably higher in seedlings grown under HL than in those grown under LL. An unidentified compound (X), occurring in high amounts in the hypocotyls of HL seedlings and isolated by IAC and HPLC, inhibited rooting in cuttings from LL seedlings. Compound X was metabolised during the rooting period. Although X was retained on the imnimmoaffinity column, it did not bind to the antibodies to the degree necessary to allow quantification by ELISA. Treatment with acid phosphatase (EC 3.1.3.2) and β‐glucosidase (EC 3.2.1.21) converted X into other unknown compounds. Some of these cross‐ieacted with [9R)iP

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05674.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Cuttings were taken from 4‐week‐old seedlings of Norway spruce (Picea abiesL. Karst.) raised at two different irradiation levels. Rooting experiments showed that root formation was increased by the ethylene formed by adding 1‐aminocyclopropane‐1‐carboxylic acid ACC or Ethrel, especially in the slowly rooting cuttings grown under high light (HL). Cobaltousion. an ethylene synthesis inhibitor, delayed rooting, especially in the easily rooted cuttings grown under low light (LL).Compounds isolated from the cuttings using immunoaffinity chromatography, on a column with antibodies against cytokinins, and separated by HPLC decreased in amount during the first week of the rooting period. An increase in ethylene production accelerated this process, especially in cuttings grown under HL, whereas cobaltous ion delayed it. We suggest that ethylene stimulates rooting by enhancing the degradation of c

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05675.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Indole‐3‐acetaldehyde (IAAId) was identified as a natural compound in Chinese cabbage (Brassica campestrisL. ssp.pekinensiscv. Granat) seedlings by chemical conversion to indole‐3‐acetaldoxime (1AOX) followed by mass spectroscopy. The lAAId reductase (EC 1.2. 3.1), an enzyme with a molecular mass of 32 kDa, was extracted, purified 5‐fold and characterized. The enzymatic IAAld reduction showed a pH optimum at 6–7 and a marked preference for NADPH as cofactor The Kmvalue for IAAld was 125 μM, for NADPH 36 μM. The enzyme reaction was inhibited at high NADPH concentrations (>200 μM) and modulated by IAA and indole‐3‐ethanol (IEt). Sulfhydryl reagents inhibited IEt formation, suggesting the participation of SH‐groups in the reaction. Phenylacetaldehyde and benzaldehyde were competitive substrates, while acetaldehyde acted partly as an inhibitor, and partly as an activator on the IAAld reduction. IAAld reductase activity was also detected in otherBrassicaspecies. The importance of this enzyme is discussed with respect to the possibilities of IAA biosynthesis

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05676.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A homozygous, dominant, C2H4‐resistant line ofArabidopsis thaliana(L.) Heynh (cv. Columbia;er) was selected from ethylmethylsulfonate‐mutagenized seed, and used to test the role of C2H4and other growth regulators in senescence of mature leaves. Chlorophyll (Chl) loss from disks excised from leaves oferwas much slower than that from wild‐type (WT) disks, whether they were held in the light or in the dark. C2H4accelerated Che loss from WT disks but had no effect on the yellowing of mutant disks. C2H4biosynthesis was higher in disks from the mutant plants, particularly in the light. In the dark, treatment with the cytokinin, 6‐benzyladenine (BA), reduced Chl loss from wild‐type disks, but had no effect on mutant disks. In the light, BA treatment stimulated chlorophyll breakdown in both wild type and mutant disks. Treatment with abscisic acid (ABA) stimulated chlorophyll loss in wild‐type and mutant disks, whether they were held in the light or the dark. C2H4production was stimulated in ABA‐treated disks, but they still yellowed even when C2H4production was inhibited by application of aminooxyacetic acid (AOA). These data indicate that C2H4is only one of the factors involved in leaf senescence, and that the promotion of senescence by ABA is not mediated through its stimulation of C

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05677.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Total peroxidase activity increased during senescence of excised barley (Hordeum vulgareL. cv. Kashimamugi) leaves. Kinetin treatment furter increased total peroxidase activity but repressed chlorophyll degradation in excised barley leaves. When isoperoxidases were extracted from barley leaf segments. 4 cationic and 4 anionic isozymes were found in polyacrylamide gel electrophorests during leaf senescence. The chloroplasts contained only two cationic isoperoxidase activities. One (designated C4) was repressed by kinetin. and the other (C3) was increased by kinetin. Glucosamine, which also repressed the degradation of chlorophyll, completely repressed C4 activity but did not affect C3 activity. The induction with senescence, and the repression with kinetin and glucosamine, suggest chat chloroplast isoperoxidase C4 may function as a chlorophyll‐degrading enzyme during barley leaf senescenc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb05678.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY