ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02325.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02326.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02327.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

In recent years there has been a considerable increase in our understanding of the manner by which light affects gene expression during chloroplast development. In most systems that have been studied, light acts through sensitive photoreceptor molecules and quantitatively increases or represses the level of expression of specific nuclear‐and plastid‐encoded genes. Although the mechanisms are obscure, a picture is beginning to emerge in which the coordination of nuclear and plastid gene expression is controlled by regulatory mechanisms originating within their respective subcellular compartments. This review summarizes some of our current knowledge concerning the nature of light‐regulated gene expression in higher plants and provides a prospectus for future research in this

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02328.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Benzyladenine (BA) stimulated 5‐aminolevulinic acid (ALA) accumulation in the presence of levulinic acid during illumination with 43 μmol m−2s−1light in excised etiolated cotyledons of cucumber (Cucumis sativusL. cv. Aonagajibai). A short dark‐pretreatment (6 h) with BA eliminated the lag phase of ALA accumulation. The rate of ALA accumulation during the steady‐state phase in cotyledons pretreated with BA for a long period (14 h) was considerably accelerated compared to that in cotyledons pretreated with BA for 6 h. The rate of ALA accumulation during the lag phase was saturated at a very low light fluence (<1.4 μmol m−2s−1) in both BA‐pretreated and water‐control cotyledons. The steady‐state rate of ALA accumulation increased with increasing light fluence up to 43 μmol m−2s−1(parallel to that of Chl formation) in water‐control cotyledons. In contrast, in cotyledons pretreated with BA for either 6 or 14 h, the steady‐state rate reached a plateau at a very low light fluence. Based on the above results together with our finding that there are two components of Chl formation (M. Dei, 1984. Physiol. Plant. 62: 521–526) possible intermediate steps of Chl biosynthesis pathway affected by BA a

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02329.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Cytokinin bioassay material from six sources (Amaranthus caudatusL.;Avena sativaL.;Cucumis sativusL.;Funaria hygrometricaHedw.;Pisum sativumL., cv. Alaska and cv. Progress No. 9;Xanthium pensylvanicumWallr.) was analyzed for cyanide‐resistant oxygen consumption (alternative respiration) during the course of a response to benzyladenine (40 μM). In five of the six bioassay systems, the alternative pathway was found to be present but disengaged (ϱ=0) in the cytokinin‐treated material while untreated controls continued to fully utilize the pathway (ϱ=1). The moss,Funaria hygrometrica, was the exception to this pattern, with the alternative pathway fully engaged in both treated and untreated protonemata throughout the period of cytokinin‐induced bud formation. Respiration via the alternative pathway was not inhibited by benzyladenine in this latter tissue, although titrations with benzyladenine in carrot (Daucus carotaL.) cell suspensions mimicked those obtained using salicylhydroxamic acid, an inhibitor of the alternative pathway. The dwarf pea, Progress No. 9, showed no response to cytokinin application in terms of increased ethylene production, and was also found to lack any capacity for the alternative pathway. Taken together, these results point to a role for the alternative pathway in responses of at least some plant tissues to cy

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02330.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Root restriction may be of importance for productivity in both forestry and agriculture. To study the physiological effects of root restriction in European alder (Alnus glutinosaGaertn.), seedlings were grown in aerated liquid culture under one of four root volumes to induce the following levels of root restriction: 1.5, 6,16 and 500 ml. Root restriction for 96 days reduced shoot elongation, plant dry weight, leaf area and chlorophyll levels and increased leaf area/root dry weight ratio and correlative bud inhibition in seedlings. The initial reduction in root/shoot ratios of severely restricted seedlings was followed by a reduction in leaf water potential, the development of internal water deficits in the upper shoots, a reduction in stomatal opening and transpiration rates and, eventually, stomatal closure. Severe prolonged root restriction (1.5 ml root volume) resulted in a decline in seedling vigour and ultimately, senescence as determined by increased electrical impedance ratios, followed by visible leaf senescence and later, by whole plant senescence. Of the severely restricted seedlings, 40% were dead after 96 days of restriction. The results suggest that imbalanced root/shoot ratios caused the development of internal water stress and the consequent reduction in stomatal aperture, culminating in leaf and whole plant senescence.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02331.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The growth of crown‐gall cells cultured in vitro (Nicotiana tabacumL. cv. White Burley andParthenocissus tricuspidatacv. Veitchii) is inhibited by alstonine (BG‐8), a plant alkaloid, the anti‐cancer effect of which has previously been demonstrated on animals and plants. The growth of normal cells is only slightly affected. The inhibitory effect of BG‐8 on crown‐gall cells is antagonized by indole‐3‐acetic acid (IAA) added to the culture medium. Kinetin associated with IAA does not prevent this inhibitory effect. BG‐8 present in the culture medium containing the two types of hormones seems to modify the later hormonal requirement ofParthenocissuscrown‐gall tissues.BG‐8 exhibits high binding affinity for crown‐gall DNA and, therefore, strongly inhibits its in vitro synthesis. The alkaloid has practically no effect on DNA from healthy cells. The inhibition by BG‐8 is dependent on the level of DNA strand separation and on the origin and nature of the tissues (crown‐gall DNA is more destabilized than healthy DNA; DNA from habituated tissues is intermediate). IAA and kinetin have opposite effects on the in vitro strand separation of the DNAs from crown‐gall cells and, consequently, antagonistic effects on DNA replication (IAA stimulates and kinetin inhibits). It is possible to establish a close relationship between in situ development of crown‐gall tissues of the two species studied (in the presence or absence of BG‐8 or cell‐growth factors), in vitro DNA sy

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02332.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Tunicamycin, 0.25 to 2.5 μM, promotes elongation of rice coleoptile sections after a 2 h lag. Tunicamycin decreased the minimum stress‐relaxation time of the cell wall, T0; and the wall loosening is recognized as the cause of this growth promotion. Bacitracin did not have significant effects on growth or T0except for inhibition of elongation at high concentration. Coleoptile sections were incubated with [14C]‐glucosamine, and the synthetic pathway of the hexosamine‐containing cell wall component was examined by a pulse‐chase experiment. This component seems to be synthesized in the particulate fraction and secreted mainly into the hemicellulose I fraction. Tunicamycin strongly inhibited glucosamine incorporation into the particulate fraction and stopped the labeling of the cell wall. At 2.5 μM, tunicamycin had no effect on incorporation of mannose, leucine or proline. These results suggest that the hexosamine‐containing wall component is a kind of asparagine‐linked glycoprotein, and that this component plays a principal role in formation of the cell wall network and in grow

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02333.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The influence of P on N2fixation and dry matter production of young pea (Pisum sativumL. cv. Bodil) plants grown in a soil‐sand mixture was investigated in growth cabinet experiments. Nodule dry weight, specific C2H2reduction and P concentration in shoots responded to P addition before any growth response could be observed. The P concentration in nodules responded only slightly to P addition. A supply of P to P‐deficient plants increased both the nodule dry weight, specific C2H2reduction and P concentration in shoots relatively faster than it increased shoot dry weight and P concentration in nodules. Combined N applied to plants when N2fixation had commenced, increased shoot dry weight only at the highest P levels. This indicates that the smaller plant growth at the low P levels did not result from N deficiency. The reduced nodulation and N2fixation in P‐deficient plants seem to be caused by impaired shoot metabolism and not by a direct effect of P deficiency of the no

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb02334.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY