摘要:

AbstractLateral shoot tips from youngAsparagus setaceus(Kunth) Jessop (syn.A. plumosusBaker) shoots were grown on a modified Murashige and Skoog medium. Tips from 5 to 20 mm lateral shoots had significantly better growth and development than tips from lateral shoots (2 mm) still covered by leaf‐scale. The optimum temperature for growth and development of the explants was 17 to 24°C. The initial growth was fast at 24°C but stopped after about 4 weeks. At 17°C the growth was slow but in return the cultures continued to grow. Kinetin was necessary for growth. Without any kinetin all cultures died. Optimum growth was found with 2 mg/l kinetin. There was no growth at all with IAA alone. A low IAA concentration had no effect, but at high concentrations IAA inhibited the kinetin induced gr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01497.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractA method is described for growing cell suspension cultures ofChenopodium rubrumphotoautotrophically for prolonged periods of time. By using a two‐tier culture vessel the growth medium with the cells was separated from the CO2reservoir. Definite CO2concentrations were established by a K2CO3/KHCO3buffer. Photoautotrophic growth in C. rubrum cell suspension cultures was correlated with the CO2level. At 0.5% CO2the cell cultures contained 68 μg chlorophyll/g fresh weight and showed an increase in fresh weight of about 80% in 18 days. At 1% CO2an increase in fresh weight of 165% in 18 days was observed. The chlorophyll content rose up to 84 μg/g fresh weight.The photoautotrophic growth was also greatly influenced by the 2,4‐D content of the medium. Cell growth was enhanced by lowering the auxin concentration. Best growth was attained (210% increase in fresh weight) at 10−8M2,4‐D.The photosynthetic activity of the cells was measured by the light dependent14CO2incorporation. At 0.5% CO2the cell suspensions assimilated about 100 μmol CO2/mg chlorophyll × h. In the presence of 1% CO2the light driven assimilation was raised up to 185 μmol CO2/mg chlorophyll × h. In both cases, the dark incorporation of CO2was merely 1.8% of the values obta

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01498.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe changes in germination, peroxidase activity and isoperoxidase spectrum have been studied in apple embryos at 5°C (stratification) and at 20°C in the presence or absence of seed coats. The embryo dormancy is progressively released at 5°C, but not at 20°C. The peroxidase activity in embryos covered with seed coats is very low at 5°C as well as at 20°C which corresponds to a restricted number of isoenzymes. In isolated embryos the peroxidase activity increases significantly. This is due to an increase in both the number and the activity of the isoperoxidases and it is more pronounced at 20°C than at 5°C.The obtained results suggest that the soluble peroxidases are not involved in the process of the release of embryo dormancy. The variations observed are attributed to the growth process following germination, which can occur even at low temp

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01499.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractFate of Putrescine‐1,4‐14C in Glycine maxPutrescine‐1,4‐14C was supplied to young decotylizedGlycine max(L.) Merr. cv. Chippewa plants growing under aseptic conditions on a liquid medium with nitrogen supplied either as ammonium chloride or nitrates. Whatever the source of nitrogen the diamine was quickly transformed to γ‐aminobutyric acid, succinic acid and malic acid; only a very minor part was utilized for the synthesis of polyamines. In the presence of ammonium chloride the putrescine catabolism may be slower than in the presence of nitrates. The results are explained by a weak isotopic dilution or by a diamine oxidase activity lower in “ammonium” plants than in “nitrate” plants; the two causes might co‐exist. The possibility of a diamine compartmentation

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01500.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractMetabolism of γ‐Aminobutyrate in Agaricus bisporus. III. The Succinate‐Semialdehyde: NAD (P)+Oxidoreductase.The succinate‐semialdehyde:NAD(P)+oxidoreductase (E.C. 1.2.1.16) is responsible for the second step in the catabolism of γ‐aminobutyrate: the irreversible enzymatic conversion of succinic semialdehyde (SSA) to succinate. Succinate semialdehyde dehydrogenase was extracted from mitochondrial fraction of fruit‐bodies ofAgaricus bisporusLge. The mitochondrial pellet was sonicated and centrifuged at 110,000 g; the supernatant obtained was designated the “crude extract”. The enzyme was extremely unstable on storage, unless 1 mMEDTA and 20% glycerol were added.Kinetic studies were carried out at 30°C, and the formation of NADH or NADPH was followed by measuring increase of absorbance at 340 nm with a spectrophotometer. The dehydrogenase was completely inactive when the reaction was run in the absence of thiol and was more active with NAD+than with NADP+. In the “crude extract” the activity with NADP+had a pH optimum between 8.6 and 9.1 and the Kmvalues for SSA and NADP+were 2.0 × 10−4Mand 1.4 × 10−4Mrespectively. The pH optimum with NAD+was found between 8.6 and 8.8 and theKmvalue for SSA is 4.8 × 10−4Mand for NAD+2.0 × 10−3M. With NAD+, the kinetic values (pH,Km) of the “crude extract” chromatographed on hydroxylapatite were unchanged. Inhibition by thiamine pyrophosphate (TPP) was uncompetitive with respect to NAD+, those by malate, ATP, ADP and NADPH non‐competitive and that by NADH competitive. These results and the fact that activity with NAD+was lost more slowly than with NADP+indicate the possibility of at least two mitochondrial succinate‐semialdehyde dehydrogenases, even though the activities of this enzyme assayed with NAD+and NADP+respectively were not able to be separated from each other by hydroxylapatite column chromatography.Some speculations on the metabolic regulation of this dehydrogenase and considerations on the significance of these results in the physiology of resp

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01501.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractHard compact calluses were initiated from the cotyledons of germinating cotton seedlings (Gossypium barbadenseL.) by use of a strong reducing agent (dithiothreitol) and a higher than normal concentration of an auxin, naphthalene‐acetic acid. Dithiothreitol was superior to other compounds such as ascorbic acid and polyvinyl‐pyrrolidone in preventing a toxic brown coloration of the initiated callus. After eight to ten subculturings, some of the hard callus tissues (c. 2 to 3%) proliferated into larger and faster growing ce

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01502.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractWinter wheat (Triticum sativumL. cv. Nisu) was grown in sand which contained 0, 0.25, 0.5 and 1.0 mg S‐ethyl dipropylthiocarbamate (EPTC) per kg air dry sand. The galactolipids of leaves of 21‐day‐old seedlings were isolated by preparative thin layer chromatography. The fatty acids of the mono‐ and digalactosyl diglycerides were analysed by gas liquid capillary chromatography. The major fatty acids of the wheat leaf galactolipids were palmitic, palmitoleic, stearic, oleic, vaccenic, linoleic and linolenic acids (in the monogalactosyl diglyceride fraction of untreated plants 22.5, 2.4, 3.1, 5.2, 2.5, 51.1 and 1526.6 μg and in the digalactosyl diglyceride fraction 108.8, 2.3, 10.4, 9.9, 8.2, 42.3 and 1120.7 μg/g leaf fresh weight, respectively). Total fatty acid content of the mono‐ and digalactosyl diglyceride fractions was decreased by 85 and 87%, respectively, at 1 mg EPTC/kg sand, while decrease in the fresh weight of the leaves was 79%. The content of linoleic and linolenic acids/g fresh weight of the leaves was decreased in the monogalactosyl diglyceride fraction by 27 and 43%, respectively, while the content of all other fatty acids was increased. In the digalactosyl diglyceride fraction the content of both linoleic and linolenic acids/g leaf fresh weight was decreased by 55%. The content of palmitic and vaccenic acids was also decreased, whereas the content of other fatty acids remained at the level of the untreated samples. The general quality of the fatty acids in the mono‐ and digalactosyl diglyceride fractions was altered sli

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01503.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe prenylquinone composition of two species of mosses (Polytrichum formosumHedw.,Sphagnum acutifoliumEhrh.) and two species of liver mosses (Lunularia cruciata(L.) Dum.,Pellia epiphylla(L.) Cord.) was determined and compared with the chlorophyll content and the photosynthetic activity of the intact moss and liver moss tissues.1Green moss and liver moss tissues possess in principle the same prenylquinone composition as higher plants with plastoquinone‐9, α‐tocopherol, α‐tocoquinone and the phylloquinone K1as main components. On a chlorophyll basis the lipoquinone levels are lower than in higher plants. Differences among the individual mosses as well as within one species only occur in the quantitative levels of the chloroplast prenylquinones, but there are no differences between musci and liver mosses.2There are differences in the maximal fluorescence of liver mosses and mosses. The variable fluorescence in turn, which is a measure ofin vivophotosynthetic activity, is very similar for all examined species of mosses and liver mosses (values from 0.7 to 1.0) but somewhat lower than in leaf pieces of higher plants. DCMU blocks the variable fluorescence and the concomitant oxygen evolution in all mosses and liver mosses.3From the lower prenylquinone levels and the low values for the variable fluorescence it is concluded that mosses and liver mosses exhibit on a chlorophyll basis fewer reaction centres and electron transport chains than chloroplasts of higher

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01504.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractWater stressedPhaseolus vulgarisL. plants were monitored to detect the relationships between net photosynthesis, transpiration, boundary layer plus stomatal resistance, mesophyll resistance, CO2compensation point, ribulose, 1,5‐diphosphate carboxylase activity and leaf water potential.At full expansion, the first trifoliate leaves of greenhouse grown bean plants were subjected to water stress by withholding irrigation. Gas exchange and enzyme activity of the central trifoliolate leaflets were monitored as leaf water potential decreased.Although increased stomatal resistance appeared to be the primary causal factor of reduced net photosynthesis, increased mesophyll resistance and decreased ribulose 1,5‐diphosphate carboxylase activity further documented the role of non‐stomatal fa

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01505.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractUsing the diethyl pyrocarbonate method, nucleic acids have been extracted from buds of European bird‐cherry (Prunus padusL.) in different developmental stages and analysed by sucrose gradient centrifugation. The ratio heavy to light ribosomal RNA was about I in extracts from dormant and non‐dormant but slowly growing buds. In extracts from sprouting buds the ratio was about 1.7. This increase probably reflects an increased extractability of heavy ribosomal RNA and may depend on a change of ribosomal structure during sprout

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1977.tb01506.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY