摘要:

AbstractAt least nine acid phosphatases and a distinct phytase are present in different cell fractions of germinating lettuce. The enzymes could be partially characterised using acrylamide gel electrophoresis. Phosphatase formation is only partially inhibited by cycloheximide. A new soluble ATPase arises between 24 and 48 hours of germination. Its formation is not inhibited by cycloheximide. Phosphatase activity in the particulate fraction of the cell can be liberated and activated by detergent or trypsin treatment. It is suggested that the newly formed soluble ATPase arises by release and activation of a particulate phosphatase.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06724.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe changes of granule bound starch synthetase activity in cucumber leaves (Cucumis sativusL. cv. Suisei No. 2) were investigated during ammonium toxicity. Generally speaking the quantity of starch granules of injured plants were less than that of normal plants. ADPG is a more effective glucose donor to starch synthesis than UDPG. It was found that the starch synthetase activity of injured plants was decreased compared to the normal plants. This variation of enzyme activity was higher when UDPG was used as glucose donor. The addition of K+and NH4+generally inhibited the enzyme activity when UDPG was used as glucose donor, but stimulated it when ADPG was used. This stimulation was found to be more effective in enzymes prepared from injured plants than from normal plants. The level of potassium bound to starch granules was not changed markedly between normal and injured plants.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06725.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractWatermelon seeds were analyzed 4, 7, 9, 11, 19, 25 and 35 days after pollination. The gibberellin‐like substances were low up to 7 days after pollination, but increased rapidly in the next two days attaining a peak on the 9th day after pollination. The amount then declined and remained low till the seeds matured. Since the peak of gibberellin‐like activity coincided with (butdid notprecede) the time when the seeds attained their maximum size, it was concluded that it could not account for their growth. Instead, evidence was obtained to show that the peak may be correlated with the growth of the embryo and endosperm. Thin‐layer chromatography revealed the presence of three active gibberellin‐like factors at the 9th day after pollination. The chromatographic behavior of two of these active factors are similar to gibberellins A1and A3. The data currently available are insufficient regarding the identification of a third gibberellin from watermelo

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06726.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe study of the physiological significance of polyamines in higher plants has induced us to examine both the relationship between these compounds with indol‐3yl‐acetic acid (IAA) and the site of action of polyamines in the cell.Slices of dormant tubers ofHelianthus tuberosuswere activated with water, 2 × 10‐6MIAA, 10‐4Mspermidine and two different concentrations of actinomycin D alone and with spermidine.The RNA synthesis caused by spermidine was similar to that caused by IAA. These data agreed with the hypothesis that the nucleic acid synthesis caused by IAA could be mediated by polyamine synthesis previously observed.Besides 10‐4Mspermidine removed the inhibition of 1.5 × 10‐6Mactinomycin D on nucleic acid synthesis. As the interaction necessarily occurs between spermidine and actinomycin at the DNA level, it therefore was possible to demonstrate that the primary site of action of spermidine in protein synthesis might occur on DN

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06727.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe aim of the experiments described was to specify further the nutrient requirements of birch seedlings. A growth method is described in which the nutrients consumed at maximum growth of birch seedlings can be replaced, without change of the nutrient solution, by means of additions made as pH and conductivity titrations so that three conditions are satisfied: 1) All necessary mineral nutrients are present in the plant in optimum proportions. 2) The nitrogen sources NH4+ and NO3‐ are present in the nutrient solution in an optimum ratio. 3) Total concentration in the solution is optimum. The three conditions may be regarded as criteria in a definition of nutrient requirements. The possible use of criterion 1 as an expression of the optimum nutrient status is also discussed. A considerable increase in light intensity had no significant effect on the optimum nutrient proportions or the optimum total concentration. A tendency to lower ammonium uptake in relation to nitrate was induced when both nitrogen sources were present. Simple stock nutrient solution systems are listed and discusse

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06728.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe paper presents effects of phosphorus deficiency and seasonal variations on nitrogen and carbohydrate metabolism of Japanese mint (Mentha arvensisL. var.piperascens, Holmes). Mint plants were grown in sand cultures under full nutrition and under phosphorus deficiency conditions during winter and summer. Various nitrogen and sugar fractions were determined in the component parts at specified periods of growth stages. Phosphorus deficiency disturbed the nitrogen metabolism at the stages for amide and amino acid formation, which resulted in an accumulation of carbohydrates. The content of total soluble and total nitrogen was higher and that of insoluble nitrogen was lower in summer as compared with winter plants. Of the soluble fractions, the ammonia, amide and nitrate nitrogen were higher and the ‘rest’ nitrogen lower in winter plants. Nitrate formed the highest bulk of the pool of soluble nitrogen in winter, whereas in summer ‘rest’ nitrogen was most abundant. The content of total sugar in winter plants far exceeded that of summer plants, which was wholly due to increase in sucrose content. Glucose was the predominant reducing sugar in both seasons. However, the summer plants were richer in glucose than those from the

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06729.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractD‐Mannose, 2‐deoxy‐D‐glucose, 6‐deoxy‐D‐galactose, and 2‐deoxy‐D‐galactose inhibit germination of pine pollen (Pinus mugoTurra) probably competitively with a metabolizable sugar. Inhibition by D‐mannose, 2‐deoxy‐D‐glucose, or 6‐deoxy‐D‐galactose is reversed by transfer of pollen to sucrose medium, if the inhibitors was addedbeforetube growth has started. In contrast, inhibition by 2‐deoxy‐D‐galactose is irreversible except after very short exposures to the inhibitor, in which case the transfer results in reduced growth and germination.Incubation with 2‐deoxy‐D‐glucose, 6‐deoxy‐n‐galactose, or 2‐deoxy‐D‐galactoseaftertube growth has started, results in irreversible inhibition of growth. If D‐mannose is used, growth is resumed if the pollen are transferred to sucrose medium. Addition of D‐mannose or lowering of the temperature prior to incubation with the deoxyhexoses protected against the irreversible growth inhibition.Uptake of oxygen and32P‐labelled

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06730.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe growth of two strains ofMyxococcus virescensexhibiting dispersed growth was followed in casamino acids (N III‐C) media and casitone media. The changes in optical density, pH, pigmentation as well as the secretion of bacteriolytic and proteolytic enzymes, DNA and polysaccharides during growth were recorded.In both media the bacteria grew exponentially with a generation time of 4 (casitone) and 20 hours (N III‐C) respectively. The maximal cell mass was about 4 times higher in casitone than in casamino acids media.The amounts of bacteriolytic enzymes produced by the two strains in N III‐C medium were different but in casitone medium they were about equal and considerably higher. The maximal values of proteolytic enzymes were about the same in both media and always occurred later than the bacteriolytic maxima. Both activity peaks appeared before the phase of decline.The polysaccharide production reached a maximum during the stationary growth phase in both media. A higher value was reached during growth in casitone medium than in N III‐C medium. During the phase of decline a second increase of polysaccharide in the medium appeared. No DNA could be detected in the cell‐free solutions until the beginning of the phase o

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06731.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThreeEucalyptusspecies indigenous to Australia and successfully acclimatised in the subtropical and northern desert regions of Israel have been grown in pots. Two of them, which contained loess‐like desert soil, and one, which contained sandy soil, out of doors, have been exposed to extreme semi‐arid climatic conditions with only soil moisture under control. In each species one group has been kept at 15.5% and a second at 7% moisture. The groups grown in water deficient soil had a 31.0–42.8% smaller leaf area and a 2–4 fold lower transpiration rate, the values varying with species. When soil moisture was raised to the same level for the water deficient groups and the plants grown at field capacity an equal or a higher transpiration rate was obtained. This happened although both groups had been exposed to the same intensity of solar radiation and in spite of the significantly smaller leaf area in the groups grown in water deficient soil. In woody xerophytes grown in water deficient soil under arid conditions, the quantity of available soil moisture and the inherent biological properties of the species decide the rate of transpiration and not the area of the foliage or the intensity of solar radiation, or physical evap

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06732.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY