摘要:

AbstractActivity of acetyl CoA carboxylase was determined in germinating and maturing sunflower (Helianthus annuusL.) cv. Rum Sun Record seeds. A constant decrease was observed in germi nating embryos. Exposure of etioplasts to light intensity of 500 (74 mW . cm−2) lux for different time intervals decreased the activity of the enzyme in the embryos. A reverse trend was observed in ripening embryos where the ATP‐Pi exchange rate was found to be directly correlated to the activity of acetyl CoA carboxyl

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08607.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractTwo‐week‐old Balbo rye seedlings cultured in aerated sea water are similar in fresh weight and linear dimensions to plants grown in aerated fresh and brackish waters. No significant differences were found in dry matter, nitrogen, sulfur or phosphorus content but tissue chloride increased markedly. Most of the Cl uptake was retained as chloride, but a small quantity was water insoluble and possibly in organic combination.We suggest that rye is a good prospect for development of lines suitable for sea water agricult

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08608.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractSeedlings of Sundangrass (Sorghum Sudanese[Piper] Stapf.) were grown 10 to 13 days of age in a nutrient solution containing nitrate and then placed under treatment conditions for 24 h before assays of nitrate assimilation were begun. Nitrate uptake was determined by its disappearance from the ambient solution.In vivoreduction of nitrate was determined by the overall balance between the amount taken up and the change in tissue concentration of nitrate during the experiments. Nitrate reductase activity was determined from tissue slices.In vivoreduction was strongly regulated by uptake in response to time and ambient nitrate concentration, temperature and light. Nitrate reduction responded to the concentration of nitrate supplied by uptake and by a storage pool, since reduction often exceeded uptake. Nitrate reductase activity in tissue slices was exponential in initial response to increasing temperature. After a 24‐h equilibration period at each temperature, the activity was lower at higher temperatures. In contrast, actual reduction of nitrate increased linearly with increasing temperature between 15 and 24°C in the plants equilibrated 24 h at each temperature. Nitrate uptake and reduction were greatly inhibited under low light conditions, with reduction inhibited more than uptake., The effect of ambient nitrate, temperature, and light on the nitrate assimilatory processes help to explain observations reported on nitrate accumulation by Sudangrass fora

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08609.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractEffects of exogenous free fatty acid application on percentage germination and radicle length were investigated with more chill sensitive (Pima S‐4) and less chill sensitive (Pima S‐5) cottonseed (Gossypium barbadenseL.) at chilling (14°C) and optimal (34°C) temperatures. Of the organic solvents able to solubilize free fatty acids, aqueous solutions as high as 5% dimethyl sulfoxide did not adversely affect germination at 34°C. Palmitic, oleic and linoleic acids (120μM) were solubilized in 5% DMSO.At 14°C, percent germination of fatty acid treated Pima S‐5 significantly increased, while no difference was observed for Pima S‐4. Conversely, radicle length of fatty acid treated Pima S‐4 significantly increased especially with oleate and linoleate, while no difference was detected for Pima S‐5. Fatty acid supplementation influenced neither germination nor radicle length for Pima S‐4 an

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08610.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe pH effect was analysed in relation to the georeaction and the elongation of apical maize root segments. Two kinds of citrate‐disodium phosphate buffers were used for pretreatment and application on the fresh cut section of the segments. Both reactions to gravity and to growth seem to be more affected by the buffer components than by the proton concentration. Such results were confirmed by the comparison of several buffer

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08611.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe metabolism of isopentenyl adenine, Δ‐isopentenyl pyrophosphate, DL‐mevalonic acid and adenine in detached inflorescence stalks ofYuccahas been studied using radioactive tracer techniques.Xylem feeding of detached stalks with Δ‐isopentenyl pyrophosphate, DL‐mevalonic acid or adenine did not result in the formation of zeatin‐ or isopentenyl adenine cytokinins.In contrast isopentenyl adenine fed to a detached inflorescence stalk lead to the formation of isopentenyl‐ and zeatin nucleotides in the exudate. After alkaline phosphatase treatment of this exudate an unknown compound, presumably isopentenyl adenine‐7‐glucoside was also detected. The same compound was found after incubation of phloem exudate with isopentenyl adenine.The occurrence of both zeatin‐ and isopentenyl adenine nucleotides in phloem exudate from an attached inflorescence stalk

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08612.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractActivity of endogenous cytokinin of cuttings was investigated in relation to the process of rotting. The levels of cytokinin in hardwood cuttings of easy‐to‐rootPopulus × euramericana(Dode) Guinier and difficult‐to‐rootPopulus tremulaL. were monitored at various stages of root formation. In cuttings ofP. tremulawas found a higher cytokinin activity than inP. × euramericanaand this condition persisted throughout the rooting period. There was a general initial decrease of cytokinin activity in both upper and lower halves of cuttings of both species. The declining level was reversed in the easy‐to‐root species when roots had formed and to a lesser extent in the difficult‐to‐root species when leaves expanded. In both cases this increase was relatively higher in the lower halves than in

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08613.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractSeeds and seedlings of mung bean(Phaseolus aureusRoxb.) were treated separately with NaCl, KCl, Na2SO4and K2SO4solutions of 5 and 10 S/cm conducitivity. The activity of RNase, DNase and protease were estimated in cotyledons, embryo axis, leaves, and roots. Salinity caused inhibition of RNase activity in the cotyledons and roots, but increase in embryo axis and leaves. Activity of DNase was also increased; sodium salt was more effective than potassium irrespective of associated anion. Salinity in general either reduced or had no effect on protease activity in all organs, with the exception of NaCl which doubled it in leaves.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08614.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe culture of isolated stem sogments was used as a technique to study polarity of xylem formation inPinus silvestris L. Cambial activity was greatest at the apical or the basal end, whichever received the complete fresh medium, but decreased more abruptly with increasing distance when the basal end was so supplied. Whether gradients of activity increased basipetally or acropetally also depended upon the end to which the auxin and the sugar components were supplied. Ring‐barking of segments, then cultur‐ing them with apical supply of medium to the xylem, resulted in inhibition of xylem production below, and above, the ring. Cambial activity at the apical ends of such segments was expressible as a logarithmic function of the uninterrupted length of contiguous extraxylary tissues. The involvement of polarity phenomena in control of cambial activity in isolated stem segments is confir

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08615.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe seasonal changes in the relative distribution of P700 chlorophyll‐protein complex a1and light harvesting chlorophyll‐protein complex a/b were studied in a natural stand ofPinus silvestris. Similar measurements were made after artificial photobleaching of chlorophyll in pine seedlings or in isolated pine chloroplasts. The chlorophyll‐protein complexes were solubilized by sodium dodecyl sulphate and separated by polyacrylamide gel electrophoresis. When autumn and winter destruction of chlorophyll occurs, the chlorophyllaantenna associated with P700 in photosystem 1 (P700‐CPa1) is relatively more affected than the light harvesting complex, which lacks a reaction centre. These results are further supported by low‐temperature fluorescence emission properties of isolated chloroplasts presented in this work and elsewhere. The destruction of chlorophyll in stressing autumn and winter climates is most probably caused by photosensitized oxidation of ch

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb08616.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY