摘要:

AbstractThe effect of auxin and acid solution on Young's modulus (E) and longitudinal growth has been studied on growing segments ofPisum sativum. The modulus has been determined by means of the resonance frequency method. 2.8·10−5MIAA produces a decrease in E within 4 minutes and an increase in length in about 7 minutes. A 10−4MHCl‐solution produces an almost immediate decrease in E and increase in length. The response to the acid solution only persists for about 10 minutes whereas the auxin response continues for hours. Therefore, it is improbable that the hydrogen ions activate a normal enzymatic process leading to increased elasticity and growth. Further the water permeability in potato parenchyma has been investigated by means of the resonance frequency method. Auxin as well as hydrogen ions increase the water permeability, auxin within 2 minutes and hydrogen ions immediately. The lag of the increase in permeability in the auxin solution and the immediate response in the acid solution indicate that auxin and hydrogen ions do not act in the same way, even if an increased membrane permeability is the most probable explanation in both cases. It is suggested that the hydrogen ions act directly on the membrane by changing the membrane potential and thus the permeability, whereas auxin may increase the proton concentration in the membrane enzymatically and thus change the permea

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb04998.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractHalf melting temperature (Tm) of DNA prepared from the nuclear fraction of vegetatively growing cells ofSpirogyrawas 86°C in the standard saline‐citrate solution and 68°C in the dilute saline‐citrate solution, and the major Tm values of soluble chromatin were 68°C and 78–80°C in the dilute saline‐citrate solution. The Tm value of DNA prepared from the nuclear fractions of conjugating and zygote cells was 88°C in the standard saline‐citrate solution and 70°C in the dilute saline‐citrate solution, and the major Tm values of soluble chromatin were 72°C, 78–80°C, and 84°C in the dilute saline‐citrate solution. The Tm values of DNA prepared from cells arrested at different stages of the life cycle of Spirogyra were raised by combining with different fractions of histones. The results agreed with an altered structure of the nucleoprotein complex during the

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb04999.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe effects of abscisic acid (ABA) on individual plants ofLemna minorL. were studied. The effects on growth and metabolism of the roots were the most noticeable and the most desirable to measure. Two mg/1 of ABA inhibited the root growth rate by 60% and this was accompanied by a 60% deceleration in the rate of uridine incorporation. The uptake of uridine and leucine and the incorporation of leucine were not affected by ABA. The latent period of root growth inhibition was 1 hour, whereas the inhibition of ribonucleic acid (RNA) synthesis occurred 2 to 4 hours after application. The growth inhibition caused an accumulation of starch in the peripheral, differentiated cell layer of the cortex. Apparently, the growth inhibition by ABA was not entirely due to an inhibition of RNA synthesis, and other plausible mechanisms of growth inhibition are discussed.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05000.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe bulblet formation inAchimenes longifloraD.C. cv. Major was investigated under controlled conditions in growth chambers. The bulblet formation in Achimenes longiflora cuttings was found to be inhibited by long‐day treatment such as continuous illumination. The degree of inhibition depended, however, on the quality of the light. High intensity far red and especially infrared emission was needed to effectively suppress the bulbing. As opposed to this, red light was found to be stimulatory. When red light (660 nm) was substituted for 20% of the white light, the bulbing was promoted over 400%.Gibberellic acid was totally inhibitory in all cases. The cytokinins benzyladenine and 6‐γ,γ‐dimethylallylaminopurine were strongly promotive and even inductive under inhibitory light conditions. The growth inhibitor N‐dimethylamino succinamic acid also stimulated bulblet formation. α‐Naphthyl‐acetic acid was strongly inhibitory, an effect which could not be overcome by

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05001.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractCompounds that account for cytokinin activity in fruitlets and tracheal fluids of cotton (Gossypium hirsutumL.) were determined using preparations purified by thin‐layer chromatography and gas–liquid chromatography and bioassayed with cultures of soybean stem callus tissue. At least five substances were found that stimulated growth of callus tissue. Among these, adenine and adenosine accounted for most of the growth stimulation of callus tissue. A compound with cytokinin activity was isolated with TLC properties similar to other known cytokinins, but its identity as zeatin, dihydrozeatin or N6‐(Δ2‐isopentenyl)‐adenine was not confirmed using GLC and GLC combined with mass spectrometry. It was estimated that less than 1% of the cytokinin activity of this unknown substance could have been due to N6‐substituted adenine

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05002.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractShoot formation was observed in callus from apical cells of pea (Pisum sativumL. cv. Century). Shoot apices from 4‐day‐old plants were macerated and the resulting cell masses grown on agar media. The callus formation and shoot production occurred within 4 to 6 weeks in defined media containing 0.2 to 5.0 μMbenzyladenine and 1 μMnaphthaleneacetic acid. While most callus produced one or more shoots at high frequency, root formation did not occur regularly. Plants obtained by these procedures were grown to maturity producing flowers and

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05003.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractA comparison of14CO2fixation rates in dehydrating tobacco leaf tissue, either intact or epidermis‐free, shows that stomatal closure is the primary cause for photosynthetic reduction due to dehydration. Rehydration of the dried, epidermis‐free tissue was accompanied by restoration of photosynthetic activity. The restoration was not only affected by hydration level but was notably time‐dependent, apparently for reorganization of the photosynthetic appa

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05004.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractIn constant white light, protonemata of different ages ofAsplenium nidusproduce a fixed number of cells before they become biplanar. Protonemata with a lower initial cell number require a longer time to become biplanar than those with a higher initial cell number. Increasing the photoperiod or the light intensity reduces the cell number in the filament at the time of initiation of biplanar morphology. It is suggested that inductive light acts directly on cell metabolism to induce biplanar morphology, rather than indirectly by inducing mitotic activity.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05005.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe inhibition of biplanar growth in the protonemata of different ages ofAsplenium nidusby the pyrimidine analog, 5‐fluorouracil has been investigated. Under favorable light conditions, older protonemata become biplanar in concentrations of 5‐fluorouracil which inhibit biplanar growth in younger ones. Treatment of 4‐ or 5‐celled protonemata with a high concentration of 5‐fluorouracil or transfer of germinated spores to progressively higher concentrations of the inhibitor lead to their continued filamentous growth. It is suggested that the age of the protonemata and the counteracting effects of light should be taken into account in evaluating the effect of metabolic inhibitors on the inhibition of biplanar growth in fern gam

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05006.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe pool size of protochlorophyllide in wheat leaves irradiated for 5 minutes to 6 hours was studied. Protochlorophyllide then accumulated in the dark, but the pool size of regenerated protochlorophyllide was considerably smaller in leaves irradiated for six hours than in leaves irradiated for 5 minutes. The decrease in pool size of regenerated protochlorophyllide was found to take place at the time when the chlorophyll formation had accelerated and reached the linear phase. The protochlorophyllide accumulated is the form with absorption maximum at 650 nm, which is phototransformed to chlorophyllide with maximum absorption at 684 nm. This species goes through the Shibata shift when formed even after 6 hours of irradiation.If leaves, irradiated for 1 or 6 hours, were fed with δ‐amino‐levulinic acid the protochlorophyllide synthesis was only 1.2 times faster in the leaves irradiated for 6 hours than in those irradiated for 1 hour. In the case of leaves fed with δ‐amino‐levulinic acid the absorption maximum of protochlorophyllide is at 636 nm and the absorption maximum of the chlorophyllide formed is

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1974.tb05007.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY