摘要:

AbstractThe nutrient requirements of mesophyll protoplasts fromPisum sativumL. cv. Timo have been investigated and a synthetic and completely defined medium has been designed. A high calcium concentration (12 mM) stimulated both protoplast survival and cell division. The content of iron and zinc was also critical. Additions of nicotinic acid, pyridoxine and thiamine were necessary. The protoplast growth was enhanced when some amino acids were included in the medium. An absolute requirement for auxin and cytokinin was shown.In the revised medium about 90% of the isolated protoplasts survived and formed a cell wall. The first divisions were observed after 5 days and after 1 week 10–20% of the cells had divided at least onc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01879.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe uptake and distribution of inorganic mercury (HgCl2) within higher plants (Pisum sativumandMentha spicata) was examined using solution culture and radiotracer techniques. Plants were found to tolerate an external level of 1 mgHg/kg of solution but both physiological and biochemical processes were affected at 5 mgHg/kg and 10 mgHg/kg. The uptake of Hg into plants grown in hydroponic solution was a function of external concentration. Over the concentration range considered the accumulation of Hg in the roots was linear on a log‐log basis although the uptake of the element into the shoots appeared to be two‐phased. The distribution of Hg in plants was asymmetrical with much greater amounts of the element in the roots than the shoots. Although the level of Hg increased generally in plant tissues with increasing external levels, the proportion retained in the roots, relative to the shoots, was constant (approximately 95%). Two binding characteristics of the Hg within plant tissue were detected. A major proportion of Hg was tightly bound, being unaffected by treatment with ethanol and hydrochloric acid. The remaining Hg in the tissue was removed by either water or hydrochloric acid treatment. Cell fractionation indicated that the major binding component of Hg in plant tissues was the cell w

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01880.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractAlthough quantitative differences were observed in the cytokinin content of mature leaves and bark ofSalix babylonicait would appear as if these tissues contained the same cytokinin complement. Ringing resulted in a decrease in the level of cytokinins in the leaves and an increase in the bark, both above and below the girdle. In the leaves the decrease was due mainly to a drop in the level of those compounds that co‐chromatographed with the cytokinin glucosides. These compounds were also almost undetectable in the bark above the girdle, where callus was formed. The observed increase in the cytokinin content of the bark above the girdle was due to higher activity in those parts of the chromatograms where zeatin and zeatin riboside occurred. Ringing stimulated the growth of lateral buds below the girdle. These developing buds as well as the bark below the girdle contained very high levels of cytokinins that cochromatographed with zeatin and zeatin ribosid

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01881.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractIn vitrocultivated apple pedicels without a primary abscission layer can form a secondary (adventitious) abscission layer, especially under the influence of auxins.In the apple cv. Cox's Orange Pippin abscission can only be induced by auxins, while the site of the abscission layer, a few millimetres from the basal ends of the pedicels, is fixed and independent of the auxin concentration. The auxin treatment has to last at least 5–6 days to induce abscission, which is not affected by the presence of a flower. A secondary layer does not occur when pedicels are placed inverted on the media. Although abscission occurs both in light and in darkness, it is strongly promoted by light. Abscission is also accelerated by raising the temperature from 9°C to 21–25°C. High concentrations of 2,3,5‐triiodobenzoic acid reduce the percentage of auxin‐induced abscission. Sugar is required, but the presence of macro‐elements is no

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01882.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractContinuous measurements of CO2‐release from intact roots ofLolium multiflorumgrowing in nutrient solution were carried out during 3–7 weeks. Periods of days with high level of irradiance and periods with low level alternated. Root respiration rate was found to depend on photosynthesis. The change in root respiration, induced by change in photosynthesis, was delayed. The root respiration rate showed diurnal fluctuations with two characteristic peaks occurring 4–6 and 14–16 hours after onset of the photoperiod. The amplitudes increased with increasing photosynthesis. The frequencies were independent of the length of photoperiod, when this varied between 8 and 16 hours. The fluctuations are discussed in relation to diurnal fluctuations in protein sy

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01883.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractA morphactin formulation containing methyl‐2‐chloro‐9‐hydroxyfluorene‐9‐carboxylate as the major component caused abnormal stem growth inPinus radiataD. Don seedlings when applied as a bark band. The banded region swelled due to increased cell division in the periderm and cambium. The abnormal stem development in treated trees did not cause a localized girdling effect. The morphactin treatment inhibited shoot elongation and root growth. Treated trees exposed to14CO2translocated significantly less assimilate to the roots than did control trees although fixation of14CO2by the shoots was not reduced. Label from a bark band of14C‐morphactin was rapidly translocated to the roots indicating that direct inhibition of root growth by the inhibitor prob

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01884.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractExposure of peach plants to the blue plus far‐red (B/FR) portions of the sunlight spectrum caused a rapid rise in ethylene evolution from their apices. Two days were enough to produce a significant rise in ethylene evolution relative to blue without far‐red or to neutral shade. Maximal level of ethylene evolution in the B/FR light, more than eight times that of the blue or the neutral shade, was reached after four days of exposure. A higher endogenous ethylene content was also found under B/FR relative to blue or to neutral shade conditions. The level of ethylene evolution from peach apices was correlated with their arrested growth as observed a few days later.Exposure of peach plants to dense leaf shade, under the canopy of a big avocado tree, enhanced ethylene evolution from their apices, relative to unfiltered sunlight and to neutral shade. It was suggested that the rise in ethylene evolution in both B/FR and leaf shade conditions resulted from a high far‐red: red ratio. Ethylene was further suggested to act as a mediator of photomorphogenetic regulation of vegetative development in far‐red‐rich t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01885.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe permeability of bulb tissues of onion (Allium cepaL.), amaryllis (Hippeastrumhybrids), tulip (Tulipa × hybrida) and daffodil (Narcissus tazettaL.) treated with Ethephon and 5‐methyl‐7‐chloro‐4‐ethoxycarbonylmethoxy‐2,1,3‐benzothiadiazole (TH6241), to water and solutions of 1,3‐dimethylurea was determined by the plasmometric methods. Ethylene treatments promoted, while those with TH6241 generally decreased the cell membrane permeability; TH6241 negated the effects of ethylene on c

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01886.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractTissue cultures of the garden paeony,Paeonia suffruticosahave been established using explants of etiolated stems. Callus formation was induced on agar‐solidified media containing ammonium ions or amino acids together with the hormones 2,4‐dichlorophenoxyacetic acid and kinetin, but not on media lacking the reduced nitrogen component. Attempts to induce callus from explants from green plants were completely unsuccessful and were characterized by the production of intense brown colorations, both of the explant and the medium. Subcultured tissue without the added hormones produced roots, both on solid and liquid media.Growth was tested on a range of liquid media, SH/2, SH, SH × 2 and SH—M, containing 1250, 2500, 5000 and 2500 mg/l potassium nitrate. The SH—M medium also contained 1650 mg/l ammonium nitrate. Growth measured as increased fresh weight was best in the SH/2, SH and SH—M media and was curtailed in the SH × 2 medium. Soluble protein content was highest at the lowest nitrogen concentration.A histochemical comparison of tissue grown on the SH/2, SH—M and SH—M lacking hormones showed that the cells in all the cultures remained diploid while differences were established in total nuclear protein, measured using the ninhydrin‐Schiff procedure. Nuclei from SH—M grown cells have a higher protein content than those from the SH/2 medium while cells from the SH—M medium lacking hormones show a further increase in nuclear protein. This raises the question whether this change in nuclear protein is related to the morphogenesis of roots which

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01887.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractAbsorption of Amino Acids by Lutoids from the Latex of Hevea brasiliensis.The latex ofHevea brasiliensisis a fluid protoplasm containing organelles with a single membrane that are called lutoids. They are microvacuoles of a lysosomal character. The intact lutoids can easily be isolated in an isotonic medium by the usual procedures of cellular fractionation.Previous studies have shown the existence of a compartmentation of the free amino acids in latex. While acidic components dominate in the cytoplasmic serum, the lutoid serum contains mainly basic components. These findings, as well as the part played by the lutoids in the latex flow and in the process of latex coagulation, led the authors to study the penetration of acidic, neutral and basic amino acids into the lutoids. Labelled amino acids were used for the purpose. Special interest was given to the uptake of lysine, which is transported into the lutoids against a concentration gradient in the absence of a metabolic energy source. The process is linear for at least 30 min and follows Michaelis–Menten kinetics as a function of the lysine concentration. The uptake is strictly temperature and pH dependent. It increases in the presence of ATP. Lysine uptake by lutoids is also increased by application of Ethrel, ethylene generator, to the bark of tapped trees. 2,4‐Dinitrophenol (2,4‐DNP), ammonium chloride and N‐ethylmaleimide (NEM) inhibit the influx. Neutrall‐amino acids do not affect the uptake ofl‐lysine, whilelarginine inhibits lysine transport competitively.d‐lysine is without effect onl‐lysine uptake by lutoids. Under conditions used in this study no lysine efflux is observed. A mechanism governing the penetration of basic amino acids against a concentration gradient is discussed, and the possible role of a proton gradie

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01888.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY