摘要:

By rapid scan spectrometry, spectral changes of redox components have been followed during the oxidation of substrates by coupled potato (Solanum luberosumL.cv. Bintje) mitochondria under different redox conditions. The redox changes of thebcytochromes, the changes in the base line level and in the slope of the spectra during aerobiosis appear to be connected with changes of the membrane potential. As the latter does not collaps at anaerobiosis, cytochrome o3remains in an oxidized state. Collapse of the membrane potential by uncouplers induces partial oxidation of thebcytochromes and reduction of cytochrome a3, so that toe resulting redox states derive from thermodynamic equilibrium with the redox conditions of the substrates. However, in aerobiosis as well as in anaerobiosis, the amplitude changes of thebcytochromes vary with the substrate oxidized as if these components were not always completely connected with the cytochrome oxidase complex. Thebcytochromes become fuliy reduced only after dithionite reduction.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08487.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Barley grains contain two imrnunochemically distinct inhibitors of chymotrypsin and microbial serine proteases. Both inhibitors are rich in lysine (9.5 and 11.5 g Lys/g protein). Hiproly high‐lysine barley contains twenty‐fold higher, high‐lysine mutant 1508 five‐fold higher amounts of these inhibitors than normally cultivated varieties. Inhibitors were extracted from Hiproly barley, and ammonium sulfate fractionation followed by gel filtration resulted in a neariy complete separation of the two inhibitors. No inactive protein impurities could be detected in a number of isoinhibitor preparations obtained in subsequent cation exchange chrotnatography steps. One inhibitor (CI‐1) was composed of at leas# 4 molecular forms with isoelecfric points in the range 4.75–5.55 and a monomer molecular size of about 9 000. Most of this inhibitor was apparently present as dimer forms in grain extracts. The other inhibitor (CI‐2) included at least 7 different molecular forms with isoelectric points in the range 6.05–7.90 and different molecular sizes in the range 6 500–9 000. Both dimer and monomer forms were present in grain extracts. In contrast to previously purified protease inhibitors of plant origin, the two barley inhibitors contain no cysteine. No interactions between the two inhibitors and trypsin were observed, but the inhibitors were immediately inactivated by pepsin at pH 2.0. Monospecific antibodies towards the two inhibitors were obtained after immunization with glutaraldehyde‐polymerized inhibitor.Inhibitor CI‐1 is identical with an inhibitor of microbial alkaline proteases previously purified (Mikola and Suolinna 1971. Arch. Biochem. B

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08488.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The germination of the negatively photoblastic seedsof Phacelia tanacetifoliaBenth. (cv. Bleu Clair) is promoted by gibberellic acid and fusicoccin. In the dark, or in the light in the presence of fusicoccin, seed germination is accompanied by an increase of gibberellic acid‐like substances. In these conditions, the inhibition of the synthesis of gibberellic acid‐like substances does not prevent seed germination, but it affects the growth and the survival of the seedlings. Seed germination, growth, and survival of seedlings are discussed in relation to phytochrome, fusicoccin, and gibberellic acid‐iite subst

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08489.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Numerous lateral branches of the concealed aerial roots of the grasstreeKingia australisramify through the persistent leaf bases, suggesting a role in uptake of water and nutrients localed up to 8 m above ground. These leaf bases were shown to hold up to more than three times their weight in water. Water and nutrients (N, P and K) available in the leaf bases may greatly exceed that in an equal volume of surface soil, especially during the dry summer months. At this time,32P injected# among the leaf bases is strongly absorbed by the aerial roots and translocated to the meristematic regions of other laterals beneath the point of application, but mostly to the stern and leaves above it. Scattered vascular bundles in the pith are the major routes for the rapid distribution of “P up and down the trunk following its departure from the aerial roots. Water and nutrients stored in the leaf bases and their subsequent uptake by the associated aerial roots may therefore contribute significantly to this species’ tolerance of long summer droughts and extremely impoverished so

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08490.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Proliferating shoot cultures ofTrifolium repens L. cv. Grasslands Huia have been established on Murashige and Skoog's medium containing 3% sucrose and 0.2 mg l−1benzylamino purine. The shoots could be readily rooted on media without cytokinin and transferred to potting mix with 100% survival. The cultured shoots have been stored for 10 months, at 5°C in darkness without adversely affecting their potentiality for rapid multiplication. The significance of this approach for genotype storage is discuss

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08491.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The possible effects of altered nuclear complement size on the poiypeptide composition and photochemical activity of chloroplasts in haploid, diploid, and tetraploid cells, ofRicinus communisL. have been evaluated. The electron transport capacity in isolated chloroplasts decreases with the increase in nuclear genome size. Both Photosystem II (DCPIP reduction) and Photosystem 1 oxygen uptake (TMPD to methyl viologen) activities were lower in plastid preparations from tetraploid individuals than in diploid and haploid cell preparations. Photosynthetic O2‐evolution and CO2‐fixation rates in leaf tissue from euploid individuals were also found to decrease with the increase in size of the nuclear genome. Specific activity levels of RuBP‐carboxylase were observed to increase with ploidy. Electrophoretic examination of the poiypeptide composition of thylakoid membranes from haploid, diploid, and tetraploid celis revealed no difference in the relative proportions of the constituent polypeptides of these membranes. The regulation of chloroplast development and the basis for altered plastid function in the presence of altered nuclear genome size are disc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08492.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The upper shoot on decapitated rose branches (Rosa hybridscv. Marimba) grows faster than lower shoots on the same branch. Transport of radioactive assimilates to the upper shoot is higher than to the lower ones. Darkening of the uppermost shoot resulted in the reduction of growth andI4C‐assimilate accumulation in the darkened shoot as well as the promotion of growth and14C transport to the lower 2 shoots, thereby rendering dominance to the second shoot. Benzyladenine treatment to the uppermost shoot reversed the effect of darkening and restored the apical control of this shoo

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08493.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Blue and red light induce stomatal opening inCommelina comrnunisL. 3‐(3, 4‐di‐chlorophenyl)‐l, l‐dimethylurea (DCMU) slightly inhibits stomatal opening in blue light, while being strongly inhibitory in the presence of red light. Similar inhibition of red‐light‐induced opening is obtained by far red. Far red added to red light causes closure of open stomata almost to the degree obtained in darkness. Parallel to its effect on stomatal movement, far red increases86Rb leakage from guard cells. The antagonism of red and far red possibly indicates the involvement of phytochrome. It is proposed that chlorophyll fluorescence in the far red region, increased by DCMU, is responsible for the inhibitory effect of red light. Similarly, the stimulatory effect of blue light may be due to its fluorescence in t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08494.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Effects of actinomycin‐D (ACT), cycloheximide (CH), rifampicin (RIF) and chloramphenicol (CAP) on senescence of soybean leaf discs were investigated. All inhibitors tested are effective in retarding senescence of soybean leaf discs. However, CH is more effective than ACT, RIF and CAP, suggesting that activation of preexisting, latent metabolic systems present in the cytoplasm piays predominant role in the initiating of leaf senescence. However, the possibility that events taking place in the nucleus or chloroplast are essential for the initiation of leaf senescence cannot be exclude

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08495.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

5‐Oxo‐prolinase of cultured tobacco cells is a soluble enzyme predominantly localized in the cytoplasm. To get optimal enzyme activity, the presence of the monovalent cation ammonium and the divalent cations Mg2+and Mn2+in the assay mixture is necessary. The enzyme has an extremely alkaline pH—(9.5–10.5) and a high temperature ‐ optimum (55°C). In contrary to the 5‐oxo‐prolinase from animal cells, where heat‐stabilization by 5‐oxo‐proline is observed, the high temperature optimum of the tobacco enzyme is due to stabilization by ATP. High 5‐oxo‐prolinase activity in tobacco cell homogenates was not only shown with the co‐substrate ATP, but with other purine‐nucleotides, too, although ATP was the best co‐substrate of the compounds tested. Substrate affinity of the tobacco enzyme (Km5‐oxo‐proline = 30.5 μM) is similar to that demonstrated for wheat germ 5‐oxo‐prolinase. Competitive inhibition by the 5‐oxo‐proline analogues 2‐imidazolidone‐4‐carboxylic acid(K1= 14.5 μM) and dihydroorotic acid (K1=2 mM) revealed a much higher sensitivity of tobacco 5‐oxo‐prolinase to

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb08496.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY