摘要:

AbstractSeveral indolic compounds are formed when tryptophan or tryptamine is metabolized byRhizobium. Among these are indole‐3‐acetaldehyde (IAAld), tryptophol (Tr‐ol), and indole‐3‐acetic acid (IAA). The metabolic relationship among the three compounds was investigated. The experiments were carried out either in the culture medium of growing Rhizobium cultures or in suspensions of washed bacterial cells. In neither case Tr‐ol would function as a precursor of IAA, but tryptophan‐2‐14G gave rise to the formation of both IAA and Tr‐ol. The ratio of IAA to Tr‐ol depended on the experimental conditions, shaking favoring the formation of IAA. Also IAAld gave rise to the formation of IAA and Tr‐ol when incubated with suspensions of washed cells. The ratio of the two compounds depended on experimental conditions such as pH value and shaking, the latter reducing the formation of Tr‐ol. These results cannot be explained by the assumption of a dismutation mechanism catalyzed by a single enzymatic unit. The operation of two enzyme systems, responsible for the reduction and the oxidation, respectively, of IAAld is

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1970.tb06405.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractWhen localized areas of blades of recently excised mustard cotyledons were fed with14CO2it was found that the fixation products passed rapidly into the veins and then were translocated to the petiole. Since other cotyledons similarly treated subsequently rooted at the petiole base, this suggested that it acted as a sink for assimilates. Treatment of excised cotyledons with benzylaminopurine (BAP) resulted in the enhancement of blade growth and the suppression of root initiation and development. Quantitative determinations of labelled assimilate in both the cotyledon blade and the terminal 2 mm portion of the petiole were made. It was found that cotyledons treated with BAP at a concentration high enough to suppress completely root initiation had a higher level of radioactivity in the petiole base than the terminal segments in untreated petioles, whether expressed as specific activity or as a percentage of the total radiocarbon fixed. BAP‐treated cotyledons also fixed consistently higher levels of14CO2, probably due to an increase in photosynthetic area. The results suggest that BAP alters the pattern of differentiation at the base of the petiole rather than the polarity of movement of assimilates to the petiole bas

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1970.tb06406.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effects of a non‐ionic detergent. Triton × 100, on protoplasmic streaming in some plant cells, on plasmolysis, and on leakage of solutes from beet cells were investigated. The results of the different tests showed some features in common: (1) There is a critical range between 0.007 and 0.01 % v/v. (2) Above this concentration of the surfactant, that is at a concentration close to 0.01 %, the effect is manifested in the following ways. Plasmolysis with sucrose is anomalous or impossible. Protoplasmic streaming ceases within a short time. Definite leakage of ions and sugars starts from beet tissues. (3) At concentrations lower than 0.01 to 0.007 % there is enhanced retention of solutes in beet disks. — It is thought that the critical micelle concentration is of paramount importance. The micelle effect may consist in solubilizing or in forming mixed micelles or a complex with the globular lipoprotein units of the outermost plasma layer, the plasmalemma. The effect of the lower Triton concentrations is discu

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1970.tb06407.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe influence of activated carbon and aseptic conditions has been studied on the growth of the primary root of wheat seedlings in order to ascertain whether or not the growth effect of activated carbon is connected with the occurrence of epiphytic bacteria. Growth was measured as mitotic activity, rate of cell elongation and duration of cell elongation. The surface infection of the septic roots probably consisted of common airborn and waterborn bacteria. Aseptic conditions increased the rate of cell elongation by ca 70 % but had no effect on the meristem activity. Activated carbon increased mitoses in the meristem and slightly augmented the duration of cell elongation but had no effect on the rate of elongation. The effects of sepsis and carbon were independent and appeared additative. Activated carbon removed inhibitors produced by the root tip itself but not those formed by the bacteria. In these experiments neither group of inhibitors seemed to contain IAA‐like substance

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1970.tb06408.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe ultrastructure of the blue‐green algaSpirulina platensishas been investigated. The appearance of photosynthetic thylakoids, polyphosphate and cyanophycin granules and nucleoplasm was studied. Cells of Spirulina have also been disintegrated and extracted with different concentrations of sodium hydroxide and the amount of extractable and isoelectrically precipitable nitrogen has been determined. High yields were obtained with about 60 % of the nitrogen precipitable after extraction of disintegrated cell

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1970.tb06409.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1970.tb06410.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY