摘要:

AbstractEthanol (68.2 mM) did not appreciably affect the growth of Dipodascus aggregatus with glucose (55.5 mM] as carbon source. Growth with fructose was inhibited whereas growth with galactose was stimulated by ethanol in this concentration. The fungus could grow with ethanol as the sole carbon source. D. aggregatus did not grown with maltose as the sole carbon source. Growth with maltose + ethanol started much earlier than growth with ethanol alone. The maltose concentration of the medium did not measurably decrease during growth with maltose‐n ethanol. D. aggregatus did not grow with sucrose as the sole carbon sour

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07446.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractNonanal (80 μ) in ethanolic solution stimulated the growth ofDipodascus aggregatuswith fructose (55.5 mM) as carbon source (inoculum grown with fructose or glucose). If the inoculum had been grown with galactose, neither growth with galactose nor growth with glucose was affected by nonanal. If the inoculum had been grown with glucose, growth with galactose was weakly. stimulated. —Growth with galactose (galactose‐grown inoculum) was strongly stimulated by nonanal if xylose at a low concentration (0.53 mM) was added. — The oxygen uptake of glucose grown cells with glucose as substrate was stimulated by 200 μM nonanal in the absence of ethanol. The respiratory activity of galactose‐grown cells was also stimulated with galactose as well as with glucose as substrate. In the absence of exogenous substrate the oxygen uptake of glucose‐grown cells was weakly stimulated by nonanal whereas that of galactose‐grown cells was strong

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07447.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe experiments were carried out to investigate whether other plant species, in addition to tomato plants, show injury symptoms when grown for 2 to 4 weeks in an aperiodic environment and to obtain information about physiological mechanisms involved in the response to the absence of environmental periodicity. The growth of seedlings of pea, peanut, and soybean, exposed to different daylengths at constant temperature, increased with Increasing length of the light period up to 16 to 20 hours, defending on the species. Further lengthening of the photoperiod did not result in significant increases in dry matter accumulated. The absence of environmental periodicity did not cause injury in these three species. Tomato plants responded in an entirety different manner. The optimal photoperiod for dry matter production by tomato plants was 18 hours and photoperiods longer than 20 hours caused interveinal chlorosis. Thus, tomato plants have an absolute requirement for a daily periodicity, white the other species do not in short‐term experiments. Under conditions of constant temperature development of chlorosis by tomato plants may be prevented by a daily dark period of 4 hours or longer or by a daily period of drastically lowered tight intensity. Complete darkness is not essential, however. This suggests that development of chlorosis is not mediated through a photoperiodic response system. Involvement of a circadian oscillation may also be excluded. Aperiodic environmental conditions appear to affect the physiology of the tomato plant in a direct manner, possibly by influencing chlorophyll synthesis or degradatio

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07448.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe mechanism of red pigment formation in tuber slices ofHelianthus tuberosusduring incubation with auxins has been studied and the following results were obtained. 1. The degree of expansion of the tissue slices in the presence of indole‐acetic acid (IAA), 2,4‐dichloropbenoxyacetic acid (2,4‐D), or α‐naphthaleneacetic acid (NAA) was not parallel to the colour intensity which developed during incubation. 2. The pigment solutions which were extracted by pyridine. ethanol, or dioxane commonly showed a peak at around 515 nm in the absorption spectrum. 3. The o‐diphenol oxidase activity in the tissue slices was increased by incubation with 2.4‐D. 4. I.‐Proline or hydroxy‐L‐proline as reactants in the formation of red pigment by the o‐diphenol oxidase system could not be replaced by L‐arginine, L‐histidine and L‐tryptophan. 5. The red pigment may resemble 4‐(4′‐hydroxy‐2′‐carbethoxy ‐1′‐pyrrolidyl)‐5‐methyl‐o‐benzoquinone, formed by the o‐diphenol oxidase system

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07449.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractUnder average tight intensities, 57,800 (sunlight, L), 12,900 (l1), 3900 (12) and 3300 (13) lux, during the fortnight after anthesis, the increase in the average shoot weight (excluding roots) of wheat cultivars, NP 823 and NP 824, varied as 100, 43, 24 and 10, and of cultivars, Ph C 281 and NP720, as 100, 35, 15 and 9; the corresponding increase in weight of ear varied as 100, 59, 45 and 40, in the first group and as 100, 58, 53 and 33, in the second. The increase in ear weight was relatively less affected by low light intensity than increase in shoot weight, probably because the stem‐sugars were utilized in grain‐filling. The stem‐sugars increased only in L and decreased in 11, 12and 13. The grain number and its weight were also reduced under l1, 12and l3. Assuming that increase in shoot weight is a measure of photo‐synthetic activity, it is inferred that during the fortnight after anthesis, current photosynthesis determines largely, but not entirely, the rate of growth of grain. After transfer to full sunlight, the grain weights of l1, 12and 13plants amounted, at maturity, to 93, 78 and 77 % of the value of L. The actual increase in grain weight was the same in L and l1and slightly lower in l2, and 13. It is inferred that the same amount of photosynthate was produced in all the four treatments hut was not fully utilized in 12and 13because of considerable reduction in grain number. Since the sugar content of the stem in l1, I2and l3plants, on the 15th day after anthesis, was half as much as, or even lower than, in L, whereas the increase in grain weight was much less affected, it follows that the level of stem‐sugars does not determine the rate of growth of grain. During the fortnight before maturity, light intensity as low as 2500 lux had little effect on grain development. It is concluded that light intensity equal to that of full sunlight may not be required during the entire course of grain development. Considering that sugars accumulate in the stem during the fortnight after anthesis, and their concentration does not control the subsequent rate of growth of the grain, it is suggested that a more efficient sink (ear) may be the means by which photosynthates can be more effectively utilized and the yield potential raise

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07450.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe cytokinin activities of extracts of organs developed from the apple fruit bud were compared using the carrot phloem bioassay, and the identity of the cytokinins in the apple fruitlet was investigated. The activity of apple fruitlet extracts was slightly greater than the activity of pedicel extracts, and considerably greater than the activities of extracts of other organs. Extracts of the developing seeds of fruitlets were much more active than extracts of fruitlet flesh. Apple fruitlet extracts contained three principal cytokinins. One was identified as a 6‐(substituted amino)purine and was either zeatin or some very closely related compound. The two other cytokinins exhibited the chromatographic behaviour of zeatin riboside and zeatin ribotide. A cytokinin extracted from vegetative apple shoots was chromatographically indistinguishable from zeati

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07451.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractRooting is shown to occur in excised cotyledons ofSinapis albawhen grown in petri dishes on moist filter paper. Cotyledons were excised at intervals from 6 hours after the start of imbibition, when they were yellow, unexpanded and enclosed within the testa, to 27 days after sowing when the cotyledons were green and fully expanded and on plants possessing up to 3 foliage leaves. Rooting generally began 5 or 6 days after excision and was completed dining the following 5 days. The age of cotyledons at t ho time of excision had three effects on rooting: the lag period be‐fore rooting began and the period during which rooting took place both increased with age: but the most marked effect was on the total number of cotyledons which were able to form roots, which increased until cotyledon expansion was almost complete, then decreased as the mature cotyledons became older. Optimal rooting was shown by cotyledons detached 8 days alter sowing, when they were half expanded. At this age S5 % of them formed roots between 6 days and 8 days after excisio

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07452.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractTwenty‐four peroxidase isoenzymes were identified by starch gel electrophoresis of 250 varieties of maize. Twelve of these bands corresponded in electrophoretic mobility to bands observed in commercial horseradish peroxidase. Maize tissues varied greatly in isoenzyme pattern, many tissues having a characteristic and distinguishing complement. Ontogenetic variations were observed for the leaf blade, leaf sheath, and internodes during maturation, and were related to the rates of tissue enlargement. Genetic studies of two isoenzymes, C10 and C20, indicated that they were conditioned by alleles of a single locus, here designated Px

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07453.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe aim of the investigation was to identify a readily exchangeable fraction of sulfate in wheat roots and to study the nature of the fraction and its possible connection to the active mechanism for sulfate uptake. The amount of sulfate absorbed during the initial phase of uptake was higher in plants with a low sulfate status (low sulfate plants) than in plants with a high sulfate status (high sulfate plants). By adding selenate to the test solution, the same amount of sulfate belonging to this phase was obtained both in high sulfate plants and in low sulfate plants. The variations between plants of different sulfate status were believed to be due lo different capacities for labile binding of sulfate to positive sites in the roots. Selenate replaced sulfate at these sites. By leaching experiments, the positive sites were shown to be located on or outside of a very delicate barrier in the cells. The maintenance of the positive sites was demonstrated to be dependent on concurrent metabolism by adding 2.4‐dinitrophenol to the test solution and by varying the root temperature. The amount of sulfate bound to positive sites in labile binding was shown to be dependent on the pH of the test solution. At low sulfate concentrations in the test solutions, there was a quantitative connection between the magnitude of the labile‐bound fraction and the rate of active uptake into the symplasm. At higher sulfate concentrations than 0.1 mM, sulfate positive sites of lower affinity to sulfate were believed lo disturb the quantitative connection mentioned ab

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07454.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe brown algaeLithosiphon pusillus, Ectocarpus fasciculatusandPylaiella litoraliswere cultivated in bacteria‐free cultures in artificial sea water, ASP 6F. The growth was tested with different additions of vitamins and other metabolites. Lithosiphon pusillus and Ectocarpus fasciculatus were found to require vitamin B12for optimal growth.The zoospores of Pylaiella litoralis, when cultured in medium Asp 6F with kinetin added, had an absolute requirement for vitamin B1

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07455.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY