摘要:

AbstractEMD‐IT‐5914 (5‐dimethylamino‐methylene‐2‐oxo‐4‐phenyl‐2,5‐dihydrofurane‐carbonitril‐(3)) inhibited chlorophyllaformation almost completely and chlorophyllband total carotenoids up to 80% of the control, but did not appreciably affect the activity of the enzyme system succinyl‐CoA synthetase/δ‐aminolevulinic acid synthetase. The activity of δ‐aminolevulinic acid dehydratase was not found limiting. In contrast, the herbicide strongly inhibited the activity of porphobilinogenase, and the reaction kinetics pointed towards a non‐competitive type of inhibition. The results are discussed in relation to the possible role of EMD‐

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03764.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractCallus tissue of Swiss stone pine,Pinus cembraL. var.sibiricaLoud., has been grown successfully for 9 months through 7 transfers. Excellent initial growth was obtained from hypocotyl segments of 7‐day‐old seedlings. A complex agar medium was used supplemented with 2 mg/l 2,4‐D, 0.05 mg/l kinetin, 1 g/l Edamin and 10% v/v coconut milk. No deterioration of growth was observed on this medium after numerous transfers. The callus tissue did not produce shoots or roots, but showed an ability for cytodifferentiation. Tracheids or tracheid‐like structures were formed in every passage, but the tracheids of the primary callus culture differed markedly from those of the subcultures. The tracheids of the primary culture probably already existed in the hypocotyl, whereas those of the subcultures were formedin vitro.The callus tissue was mainly diploid during the period studied, and more than 86% of the mitoses were diploid. A few mitoses with tetraploidy or a higher ploidy also occurred, but the tissue did not show any tendency to polyploid

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03765.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe factors responsible for the low transpiration rates of citrus were investigated. Leaf resistance to water vapor exchange by orange seedlings (Citrus sinensisL. cv. Koethen) including a substantial boundary layer resistance, was as low as 1 s cm−1in humid air. Leaf resistance of well watered plants increased to values as large as 5 s cm−1when the difference in absolute humidity between leaf and air was increased. Leaf resistance was only slightly influenced by temperature between 20 and 30°C providing the humidity difference between leaf and air was kept constant. Leaf resistance increased when leaf temperature was increased between 20 and 30°C when the absolute humidity external to the leaf was kept constant. Increased humidity differences resulted in greater increases in leaf resistance during initial experiments than when the experiments were repeated with the same leaves indicating acclimation by the plant. It was concluded that the effects of humidity differences on leaf resistance are partially responsible for the low transpiration rates of c

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03766.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractIntact plants ofZea maysL. were treated with foliar sprays ofcis‐trans‐abscisic acid (ABA) at concentrations from 10−9to 10−4M.Even the lowest concentration caused a reduction of the transpiration rate as measured between 1 and 33 h after spraying. With increasing ABA concentrations, there was a nearly linear relationship between the logarithm of the ABA concentration and the (decreasing) transpiration rate within that period. Subsequently a partial recovery of the transpiration rate set in, beginning progressively later as the ABA concentration was increased. After 5 1/2 days the transpiration rate of plants treated with 10−9and 10−8Mwas nearly back to normal, whereas plants treated with 10−4Mtranspiration at only about 2/3 their normal rate.In experiments with detached maize leaves supplied with water or ABA solutions (10−8to 10−5M) through their cut bases, the transpiration of control leaves decreased gradually to a low level in 24 h. ABA caused a marked and rapid reduction of the transpiration rate compared to that of the controls. After a few hours, the transpiration of the treated leaves decreased at a slower rate than that of the controls, thus approaching the control values. After 35 h, the transpiration of leaves treated with 10−5MABA was nearly the same as in untreated leaves. Exchanging the ABA solution for distilled water after 24 h had little effect on the subsequent course of the

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03767.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractFormation of xylem in sterile culture of isolated pine stem segments supplied with synthetic media continues only for 4–6 weeks. The stem segments originally do not contain an eluable inhibitor affecting elongation in the test of pine hypocotyl sections. After 4 weeks inhibition is detected. Supplying the medium with a methanolic extract from the cambial region of pine stem prolongs xylem production up to 15 weeks. IAA interacts synergistically with a natural stimulator of cambial activit

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03768.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractAddition of aescin to mycelia ofOphiobolus graminisandNeurospora crassainduced leakage of ribonucleotide material together with pentose phosphate or pentose.InO. graminisa rapid release of mono‐ and dinucleotides together with nucleosides and pentose occurred. In addition some oligonucleotides were released during the first 30 min of the treatment. A slow leakage of polynucleotides was also observed.InN. crassaaescin induced only slight leakage during the first hour, and the mono‐ and dinucleotide leakage was actually decreasing. From that time on, however, a rapid release of mono‐ and dinucleotides together with nucleosides and pentose phosphate or pentose was observed. Only small amounts of poly‐ and oligonucleotides leaked and the cell content of oligonucleotides seemed to be released only during the last hour of the treatment period.InAspergillus niger, which was insensitive to the inhibitor, aescin only induced leakage of pentose or pentose phosphate and small amounts of mono‐ and dinucleotides.Loss of viability in mycelia ofO. graminisandN. crassaseemed to be correlated with the loss of oligonucleotides from

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03769.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractChromatography of partially purified extracts of Danish cabbage (Brassica oleraceavar.capitataL.) heads on polyvinylpyrrolidone columns using a weak phosphate buffer indicated a cytokinin complex containing nine components active in the modified Amaranthus betacyanin bioassay. Similar elution patterns were obtained with extracts of four different cabbage varieties but varietal differences occurred in the biological activity from each component peak. Paper and thin‐layer chromatography indicated the presence of both zeatin and zeatin riboside in the extracts but the other cytokinin‐active components were not identified. Separation of sweet‐corn extracts by this technique indicated that most of the cytokinin activity occurred in the elution volume where zeatin and zeatin riboside would normally

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03770.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractGrowth and mineral composition of fruits in potted trees were studied at two temperatures (19 and 24°C) in two experiments with Golden Delicious and one with Cox's Orange Pippin under a controlled environment. In Golden Delicious the high temperature promoted fruit growth markedly, but in Cox's Orange Pippin the stimulation was much less pronounced.The levels of K, N, Mg, and P (expressed as amounts per fruit) were increased at the higher temperature. This increase was almost completely the result of differences in fruit growth. With respect to Ca the high temperature reduced Ca influx in one Golden Delicious experiment and had hardly any effect in the other, but favoured influx in Cox's Orange Pippin. In one Golden Delicious experiment the temperature was raised 7 weeks after blossoming, which resulted in a temporary drop of Ca. When the same temperature change was applied 4 weeks earlier, Ca continued to increase.It is assumed that mineral influx occurs via the xylem during the first few weeks after fruit set and via the phloem throughout. The results are discussed in terms of differences in mobility in the phloem for the various minerals and of a shift in the ratio between xylem and phloem movement induced by differences in the growth rate of the fruits

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03771.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe positive geotropic response of the apical segments prepared from the primary roots ofZea maysdepends upon at least one growth inhibitor, produced by the root cap, moving basipetally into the extending zone of the root in which it accumulates in the lower part. Anjou maize reacts in both darkness and light while Kelvedon maize is, for the first few hours, geotropic only in light. The production (or activity) of the growth‐inhibiting substance — tested by using vertical half‐decapitated root segments — is quite similar to the georeaction. This finding provides strong evidence that, in the case of Kelvedon maize roots, the inhibitory substance may depend on light. Observations related to the root segment of Anjou and Kelvedon maizes of which the tips are exchanged, are in agreement with the above

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03772.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe saturated long chain fatty acid methyl esters of the triglyceride fraction ofPolytrichum communespores were separated by silver nitrate TLC and identified by a combination of gas chromatographic‐mass spectrometric technique. The saturated fatty acid methyl esters were straight‐chained, and even‐numbered with carbon numbers ranging from 12 to 26 or odd‐numbered with carbon numbers ranging from 13 to 25. The major components of the fraction containing saturated fatty acid methyl esters were methyl palmitate and methyl stearate.The fatty acid methyl esters of the monoenoic fraction isolated by silver nitrate TLC were converted to TMSO derivates which were analysed by gas chromatography‐mass spectrometry. The analysis gave evidence of positional isomers. The fraction contained the following straight chain monoenoic fatty acid methyl ester isomers: methyl 7‐cis‐hexadecenoate, methyl 9‐cis‐hexadecenoate, methyl 9‐cis‐heptadecenoate, methyl 9‐cis‐octadecenoate, methyl 11‐cis‐octadecenoate, and methyl 11‐cis‐eicosenoate. The major components were methyl 9‐cis‐octadec

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1975.tb03773.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY