摘要:

AbstractThe activity of glutamate dehydrogenase (l‐glutamate: NAD oxidoreductase, EC 1.4.1.2.; GDH) of rice plants changes in response to the nitrogen source supplied to the culture solution. The activity of NADH‐GDH(aminating) in roots is rapidly increased by the addition of ammonia, whereas the activity in shoots is much less affected by nitrogen supply. The activity increased with increasing concentration of ammonia at least up to 14.3 mM. In roots GDH activity was found in both the mitochondrial and soluble fractions. The increase of NADH‐GDH activity caused by the ammonia treatment occurs mainly in the latter fraction. The new band with GDH activity was detected on the zymogram of polyacrylamide gel electrophoresis and this inducible enzyme is active with both NAD and NADP. On the other hand, the constitutive enzyme activity active with NAD is also increased by the ammonia treatment. The increase of enzyme activity is prevented by the addition of cycloheximide or chloramphenicol to culture medium. The incorporation of14C‐leucine(U) into GDH proteins was also studied using polyacrylamide gel electrophoresis. Higher radioactivity was found in induced samples than in non‐induced ones. These results show that the increase of GDH activity in roots by ammonia treatment seems to depend onde novoprotein

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03536.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractLack of correlation between spectrophotometric phytochrome assays and physiological experiments has led to the concept of a ‘bulk’ phytochrome that is measurable but inactive, in contrast to an active form that is not measured in the standard assay. Because of suggestions that phytochrome action involves changes in membrane permeability, particularly to potassium ions, we investigated potassium and sodium uptake and efflux inPisum sativumepicotyl sections which were equally de‐etiolated yet differed three‐fold in their phytochrome contents. Although dependent on the metabolic integrity of cell membranes (as shown by respiratory inhibitors) the selective uptake of potassium in this tissue is not under phytochrome control. Experiments were also conducted to see whether a three‐fold difference in phytochrome content affects chlorophyll synthesis in Pisum. Differences in chlorophyll synthesis observed can be related to the effectiveness of the pretreatments in eliminating the lag phase, not to their differences in phytochrome; Pfrdecay rate has no effect on chlorophyll synthesis. The failure to find any correlation with the amount or state of ‘bulk’ phytochrome in these and previous experiments indicates that no function of this material

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03537.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractApplications of 1,2−14C‐(2‐chloroethyl)phosphonic acid (ethephon) were made to the surface of matureVitis viniferacv. Thompson Seedless berries. After 7 days, 62 % of the recovered radioactivity was still on the outside surface and was easily washed off. Within the berry, radioactivity was present only in the carbon‐labeled ethephon fraction, as revealed by chromatographic analysis. Similar results were obtained when the compound was injected directly into the berries. Application of ethephon to the first leaf above the cluster, or to a berry pedicel or a peduncle, failed to result in measurable movement of the compound into the berries. Autoradiographic studies with young shoots indicated that ethephon translocated in the phloem in a source to sink relat

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03538.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractColeoptile sections fromAvena sativaL. were exposed to non‐lethal concentrations of peroxyacetyl nitrate (PAN). The sections were then incubated in solutions of 50 mMglucose plus 2.5 mMpotassium phosphate with various concentrations of 2,4‐dichlorophenoxyacetic acid (2,4‐D). Growth after 4 hours was measured. A corresponding series of experiments was carried out and the effect of the 2,4‐D treatments on enzymes utilizing uridine diphosphate glucose (14C‐glucose) to form glucolipid and β‐glucans including cellulose was determined. Growth in the PAN‐treated sections was inhibited less at optimal and superoptimal auxin levels than at low auxin levels. Glucolipid synthetase activity was only slightly inhibited by PAN pretreatment and was reduced by increasing levels of auxin. Responses of alkali‐soluble glucan and cellulose synthetases were similar to growth in both control and PAN treated tissues. It was concluded that the earlier reported response of cell wall metabolism in vivo probably is due to effects on the

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03539.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractTobacco, rice, carrot and tomato tissue cultures were grown in liquid media containing l‐phenylalanine or l‐tyrosine, or both together. The addition of these amino acids increased their respective cellular levels (4–20 fold), but did not lower the level of chorismate mutase, an enzyme in the biosynthetic pathway of phenylalanine and tyrosine. These results indicate that the biosynthesis of phenylalanine and tyrosine in cultured plant cells is not regulated by repression of the synthesis of chorismate mutase by phenylalanine or tyr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03540.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractTwo dimensional thin‐layer chromatography on anion‐exchange cellulose enables the separation of the normally occurring ribo‐ and deoxyribonucleoside triphosphates. This technique was applied to perchloric acid extracts of callus tissue of sycamore and tobacco and of pine pollen grown in32P‐orthophosphate labelled media to quantitate the nucleoside triphosphate pools under different growth conditions.The results showed that the ratio of the deoxyribonucleo‐side triphosphates to their corresponding ribonucleoside triphosphates is low in plant cells, similar to the ratio previously found for animal cells.During the period of most rapid DNA synthesis in the callus tissue, the deoxyribonucleoside triphosphate pools reach their highest values. This effect is also demonstrated with cells ofEscberi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03541.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractMalate dehydrogenase isoenzymes from the blades of different aged leaves of the cotton plant have been investigated. The total extractable malate dehydrogenase activity varied widely between leaves of different ages and different locations on the plant. Malate dehydrogenase zymograms developed from the extracts which contained significantly different levels of enzyme activity appear to indicate the presence of different groups of malate dehydrogenase isoenzymes in leaves of different ages. However, under appropriate conditions of polyacrylamide gel electrophoresis, the same number of malate dehydrogenase isoenzymes with the same relative mobilities were detected in all the leaves studied.These findings are discussed in relation to reports that malate dehydrogenase isoenzymes change with plant development or that they have different roles in the plant.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03542.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractSeedlings ofTriticum aestivumL. were sprayed with menadiol disulfate in water solution. Eight days after spraying, the content of phylloquinone in the shoots was more than twice as high as in shoots of untreated control plants. The application of menadiol disulfate caused a stimulation of the synthesis of phylloquinone. It is possible that menadiol is an intermediate in the biosynthesis of phylloquinone.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03543.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractA theory for the geotropic movements of theHeliunthus unnuushypocotyl has been given earlier by Johnsson et ul. In the present paper this theory is tested by extensive experiments. The magnitude as well as the rate of geotropic curvature are found to be in agreement with the theoretical predictions.Further, the geotropic reaction time, defined as the time between the start of geotropic stimulation and the start of the geotropic reaction is determined as a function of the stimulation angle with respect to the plumb line. A slight variation found in the reaction time is included in the theory.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03544.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe effects of periodically repeated geotropic stimulations (geotropic pulses) on sunflower hypocotyls are studied. The experimental results agree with predictions from a theory for geotropic movements of the hypocotyl.A sunflower hypocotyl performs circumnutations around or across the plumb line with a period of about 2.5 hours. These oscillations can be entrained to periodically repeated geotropic pulses with a period in a region around 2.5 hours. The limits of this “region of entrainment’ for geotropic pulses are studied. In the region of entrainment resonance curves,i.e., the amplitude of the oscillations plotted as a function of the period of the geotropic pulses, are obtained. The phase differences (measured as time differences) between the geotropic pulse rhythms and the resulting oscillations are also studied. Beat phenomena are predicted and recorded outside the region in which the plants can be entrained.The results are discussed in relation to oscillating phenomena of circadian type (i.e., with a period close to 24 hours), and many similarities are pointed

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1972.tb03545.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY