摘要:

Upon greening of sorghum leaves (Sorghum vulgarePers. cv. INRA 450) under white light illumination, phosphoenolpyruvate carboxylase activity increases. 17 times; at the same time, a new isoform of the enzyme appears.The aim of the present work has been to identify the process responsible for the appearance of this isoform. Greening. of the leaves in the presence of D2O did not lead to a significant increase in the buoyant density of the enzyme. On the other hand, cycloheximide was a powerful inhibitor of the rise in PEP carboxylase activity. In order to clarify these conflicting data a procedure based on the immunoprecipitation of the enzyme and its quantification by gel electrophoresis was developed in order to estimate the amount of enzyme in leaf tissue. The results clearly demonstrate that light triggers an increased synthesis of the enzyme protein during greening of sorghum leaves.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00741.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Methanolic extracts ofZea maysL. cv. Fronica root segments which had been incubated in [14C] indole‐3‐acetie acid were analysed by reverse‐phase high‐performance liquid chromatography. Metabolism of indole‐3‐acetic acid was found to be rapid and extensive with at least 11 products apparent after a 2 h incubation. A comparison of metabolites of [1‐14C]– and [2‐14C] IAA, calculations of14CO2evolution, and data on the polarity of products indicated that decarboxylation had not occurred. An average of 34% of the radioactivity remained associated with the indole

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00742.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Vegetative plants ofPoa pratensisL. cv. Holt (origin 69°N) raised in short days gave large and significant increases in plant dry weight, plant height and leaf area upon exposure to continuous light, compared with 8‐h short days, at essentially identical daily inputs of radiant energy (8‐h summer daylight ± low intensity extension). For example, by the fourth harvest (after 26, 34 and 46 days at 21, 15 and 9°C, respectively), the dry weights of plants in long days were 81, 163 and 195% greater than those of the corresponding short‐day controls at the respective temperatures. Plant leaf areas in long days were between two and four times as large as control values by the end of the experiment. This was mainly due to increased leaf length caused by long‐day stimulation of cell extension and division. However, the photoperiod did not affect the partitioning of assimilates amongst leaves, culms and stolons. Most of these effects could also be brought about by exogenous gibberellin application to plants in short days. However, in contrast to the effect of long days, gibberellin treatment also induced stem internode elongation even in these vegetative plants. Examination by standard growth analysis procedures revealed that the observed increases in relative growth rate were dueprimarily toincreased net assimilation rate followed, several days later, by increases in leaf area ratio when newly‐emerged leaves began to constitute a significant proportion of the leaf area. It is concluded that these reactions are of great adaptive significance for growth at the marginal temperatures prevailing at hi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00743.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Demonstration of amines connected with cellular structures inNicotiana tabacumandLycopersicum esculentum.The level of free and bound amines in various tissues ofNicotiana tabacumcv. Xanthi was investigated. After acid hydrolysis of different pellets from ethanol or buffer extractions, three aliphatic polyamines (putrescine, spermidine, spermine) and one aromatic monoamine (tyramine) were found in different proportions according to the nature of the tissue. Roots contain high quantities of insoluble tyramine bound very strongly to cellular structures. On the contrary, there were only traces of bound tyramine in leaves and stem. After extraction and purification of cell structures, tyramine was shown to be bound to one component of the cell wall. Addition of pronase or cellulase to the extract did not break the tyramine complex. In tobacco roots, insoluble tyramine concentration increased with plant development. High content of bound tyramine was also found inLycopersicum esculentumroots. The possibility that tyramine binds with lignin is discussed.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00744.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The length of the auxin‐sensitive phase of root initiation ‘in vitro’ in the apple rootstock M.9 (Malus pumilaMill.) has been determined using the auxins indol‐3yl‐acettc acid (IAA) at 2.8 × 10−5Mand indol‐3yl‐butyric acid (IBA) at 1.5 × 10−5Min the presence and absence of 10−3Mphloroglucinol (PG). PG synergised IBA‐induced rooting after 4 days exposure, but contact times exceeding 8 days decreased root number. In contrast, PG consistently synergised IAA‐induced rooting in the dark for contact periods up to 13 days with the highest rooting being recorded at 9 days. An irradiance of 20 W m−2from fluorescent lamps halved IAA‐induced rooting irrespective of the presence or absence of PG. The culture of shoots at temperatures of 22,25 and 29°C during the root initiation phase (auxin present) and the root emergence phase (auxin absent) produced no difference in rooting response. In the presence of PG the use of liquid culture in place of agar‐solidified culture during the auxin‐sensitive phase reduced root

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00745.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

During the auxin‐sensitive phase of root initiation, rates of 3‐indolyl‐ [2‐14C] acetic acid (IAA) uptake into the 1 cm bases of shoots of the apple rootstock M.9 (Malus pumilaMill.) ‘in vitro’ were not significantly affected by the presence of 10−3Mphloroglucinol (PG) using either liquid or agar‐solidified media. The use of a liquid medium did however reduce rates of uptake over a 10‐day period of auxin application. The distribution of labelled IAA between the 1‐cm base and the shoot remainder was not affected by PG.Exposure of shoots of the difficult‐to‐root M.9 and the easy‐to‐root M.26, to 2.8 × 10−5MIAA containing [2‐14C] IAA revealed no positive correlation between the amount of label taken up by the 1‐cm base and rooting performance. M.9 bases absorbed almost twice as much label as M.26 after 9 days but had produced only one‐third as many roots. Measurements of label distribution between the 1‐cm base and the shoot remainder showed that less than 10% of the label moved to the shoot remainder over a 6‐day period of auxin application. Dose‐response curves of IAA and rooting over the range 1 × 10−5Mand 3 × 10−3Mshowed that root number in M.9 was at an optimum at 1 × 10−3MIAA after 6 days whilst M.26 required only 1 × 10−4Mfor a similar response. These data support the hypothesis that differences in rooting of the two rootstocks reflect differences in the endogenous metabolism of exogenous IAA and not difference

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00746.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Tissue cultures ofSolanum nigrumL. were initiated from leaf explants on a solid medium containing inorganic salts [Murashige and Skoog (1962), Physiol. Plant. 15: 473–497], vitamins [Gamborg et al. (1968) Exp. Cell Res. 50:151–158], 3% sucrose and combinations of indoleacetic acid and benzyladenine. Solasodine content was determined in differentiated and undifferentiated (callus) tissues by a colorimetric technique and thin layer chromatography. Indoleacetic acid and sucrose in the medium markedly stimulated the production of solasodine in the tissue cultures. In the cultures grown in darkness the differentiated tissues produced significantly more (anywhere from 1.5 to 10 times) solasodine than the callus in several media. When sucrose concentration was increased to 4, 6 and 10% level in the medium which contained 10 μMbenzyladenine as the sole growth regulator, a significant increase of solasodine production in cultures was f

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00747.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The effects of a wide concentration range of NaCl and sorbitol on three photosynthetic electron transport reactions ofPisum sativumL. cv. Feltham First chloroplasts were examined as a function of time from thylakoid membrane isolation. Rates of electron flow from water to diaminodurene (DAD) and ferricyanide were determined polarographically, whilst photoreduction of 2,6‐dichlorophenolindophenol (DCPIP) was monitored spectrophotometrically. Assay of thylakoids immediately after isolation showed that the rate of photoreduction of all three electron acceptors decreased with increasing salt concentration. However, 100 min after leaf homogenisation the response pattern of ferricyanide and DCPIP photoreduction to increasing NaCl, but not increasing sorbitol concentration, became significantly modified. This was not the case for DAD photoreduction. The results are discussed in relation to the assessment of the possible effect of salinity on photosynthetic electron transport in viv

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00748.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Potato plants (Solanum tuberosumL. cvs ‘Up‐to‐Date’, ‘Desiree’, ‘Alpha’, ‘Spunta’, ‘Elvira’ and ‘Troubadour’) were exposed to cycles of water stress and relief during growth. Severe water deficit induced increased proline content 6‐ to 7‐fold in nonturgid leaves which just started to wilt, and 8‐ to 27‐fold in fully wilted leaves of potatoes. However, proline content was not affected during the early stages of stress development over a range of osmotic potentials in the leaves. The rising proline content was related to turgor loss of leaves independent of changes in the osmotic potentials, which indicates that proline involvement in osmoregulation of potato leaves is unlikely.Repeated cycles of water stress and relief resulted in increased proline and α‐amino nitrogen content in the tuber tissue of some of the cultivars. The smallest increase in proline content was obtained in ‘Alpha’ tubers and the content of α‐amino nitrogen remained unaffected by the water stress. Concomitantly, ‘Alpha’ was the most drought‐tolerant cultivar, as determined by its capacity to accumulate dry matter in tubers under stress conditions. On the other hand, in tubers of cultivars which were more susceptible to drought, a marked increase in proline and α‐amino nitrogen was observed in response to water stress. The possible association of these findings with tolerance of pota

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00749.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00750.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY