摘要:

AbstractDuring the course of the growing seasonGinkgo bilobaleaves undergo both quantitative and qualitative changes in their cytokinin content. In young expanding leaves the major cytokinins cochromatograph with zeatin and zeatin riboside. In mature and aging leaves most of the cytokinin activity was due to slow moving compounds (paper chromatography) which could be hydrolysed by β‐glucosidase. After hydrolysis the active compounds co‐chromatographed with zeatin and zeatin riboside respectively. This indicates that both zeatin glucoside and zeatin riboside glucoside are present in the mature leaves. It is suggested that these glucosides are formed when the xylem transported cytokinins are metabolized (inactivated) in the le

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04848.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractGrowth and differentiation of the imperfect fungusGeotrichum candidumwere followed in submerged cultures containing a simple synthetic glucose salt medium. Uptake of glucose, ammonium and oxygen from the medium were measured during the entire growth perod. In 0.1% glucose the fungus grows with one exponential growth phase until all the glucose has been consumed. The arthrospores are formed in the stationary phase. In 0.5% glucose the growth curve has two exponential growth phases, one with a doubling time of 1.8 h and a second one with a doubling time of 4.9 h. The second exponential growth phase, which starts when less than 15% of the glucose and less than 30% of the ammonium have been consumed, is shown to be the sporulation phase. During this growth phase the oxygen saturation in the culture remained constant at about 50%.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04849.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractTotal (Kjeldahl) nitrogen content of manganese‐deficient lemon leaves was found to be about 40% higher (on a dry weight basis) than in the analog control leaves. The nitrate‐N content rose in the deficient leaves from 18.2 mg/100 g to 95.6 mg/100 g dry weight. Among the N constituents studied, the free amino acids increased by about 42%, the protein amino acids by about 22%, and the total protein by more than 22%, all on a fresh weight basis. Acrylamide gel electrophoresis and ammonium sulfate fractionation showed qualitative differences in the various proteins. The increase of the protein fraction in the ‐Mn leaves may be attributed in part to the decrease of dry matter in these leaves (25.8% as compared to 30.7% in the control leaves) and in part to accumulation of apparent proteinous material in manganese‐deficient

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04850.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractCallus cultures have been established from the seed, root and leaf ofNicotiana rusticaL. var.brasiliain a synthetic medium containing 1 μM2,4‐D and μMkinetin. These callus tissues behaved similarly not only in growth and organogenesis but also in nicotine production. The nicotine contents of callus cultures, which were in the order of 0.25–0.58% of dry weight during a few passages subsequent to callus induction, rapidly decreased to trace amounts in succeeding subcultures in association with the decline of the root‐regenerating activity. On the other hand, free cells prepared from a callus tissue in the third passage developed into individual clones showing wide differences in growth and nicotine production. One of these clones gave rise to a relatively stable strain which is capable of producing nicotine at a high rate (0.29% of dry weight) in the absence of organization. The significance of these findings is discussed in connection with some results which have been reported for other callus cultures ofNicotiana

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04851.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractGrowth and nodulation response of soybean (Glycine max(L.) Merr.) to various single nitrogen sources in solution culture is confounded by unequal shifts in solution pH. A recirculating ion exchange system was designed in which a cation exchange resin (Amberlite IRC 50) was used to control the pH of solutions in which soybeans were grown. Nutrient solution pH levels were established at range extremes of 9.0 to 3.7 with 100% Ca2+or H+forms of resin, respectively. Intermediate pH levels were established by varying the ratio of Ca2+to H+forms of resin. The system is capable of maintaining pH within 0.5 to 0.9 units of the initial pH over a two‐week growth period of soybeans with either nitrate‐ or urea‐N sources. In the absence of the resin column, pH of the urea nutrient solution rapidly declined to less than pH 4 which resulted in depressed plant nodule development. The optimum pH range for nodule mass and N2fixation (measured by acetylene reduction) was between 5.2 and 7.0 with urea nutrition. Both nitrate‐ and ammonium‐N sources were inhibitory to acetylene reduction in comparison with urea which allowed extensive nodule development and

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04852.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractExperiments on nutrient requirements of the ecologically very different plant speciesBetula verrucosaEhrh.,Cucumis sativusL., andVaccinium vitis idaeaL. are discussed with regard to the nitrogen and cation nutrition. The nutrient solution technique used allows a strict control of nitrogen source and cation uptake at maximum growth rate.The nitrogen sources were equally efficient except for growth reductions in cucumber at ammonium nutrition. Increase in tissue pH resulting from a high total uptake rate of NH4+and other cations is probably an important factor in ammonium toxicity. No evidence was found for the concept of “ammonium plants”; but at high nitrate supply to Vaccinium a high cation uptake may account for decrease in growth rate.No large or fundamental differences in cation or anion requirements among the species were found; the difference in ion balance (C — A) in relation to dry matter depends mainly on differences in xeromorphy.In cucumber, the relations between cation and nitrate nutrition are in agreement with models proposed in the literature. Vaccinium and birch have a cation uptake and retention of high efficiency at low nutrient availability and ammonium nutrition indicating independence between cation and nitrate nutrition in these species.The properties found are regarded as significant and functional in relation to the ecological character of the sp

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04853.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractN‐4‐pyridyl‐N′‐phenyl urea (NC5392) showed similar activity to N6‐benzyladenine (BA) in stimulating lateral bud development on Brussels sprout (Brassica oleraceavar.gemmifera) seedlings particularly on de‐rooted plants, but increased average bud weight far more than did BA. Both compounds increased flowering of young plants given an insufficient cold stimulus and seeds from treated plants showed a higher germination percentage than those from unt

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04854.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractRelationship between the Geotropic Response and the Evolution of the Statenchyma in Roots of Asparagus officinalis.The evolution of the statenchyma in roots ofAsparagus of ficinalisseedlings, grown in obscurity, was followed during the first 17 days. After 7 days of etiolation, a decrease of both the average diameter of the amyloplasts and the average number of these organelles was observed in the central root cap cells. If the seedlings were illuminated (with white light) from the 7th day, the average number of statoliths increased rapidly in the statocytes. The volume of these organelles undergoes the same variation in etiolated and in illuminated plants.The initial rate of curvature (Vi) of the roots (stimulated in a horizontal position) and the volume of amyloplasts (Vac) in their caps were analysed as a function of the time of germination in obscurity (from the 8th to the 17th day). It was found thatViincreased as a linear function of the logarithm ofVac, which confirms that the weight of the amyloplasts of the statocytes may play a role in the geotropic stimulation of the roots.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04855.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe movement of14C assimilate from shoots to roots and its subsequent metabolism in the root ofLolium perenneL. was studied using variable N nutrition supplied to halves of a divided root system. Half of the N‐deficient root system was supplied with either high NO3‐N or high NH4‐N for 16 hours or 6 days before14CO2labeling of the shoots.The distribution of14C in sugars, ethanol‐soluble nitrogen and organic acids in roots appeared to be related to the N content of the tissue. Supply of high NO3‐N for 6 days resulted in significant internal translocation of N into the low N supplied root half. Both root halves also had similar patterns of14C distribution among soluble and insoluble metabolites. However, NH4‐N supply for 6 days did not result in a significant increase of N in the low N supplied roots, thus only the high NH4‐N supplied roots displayed stimulated sugar metabolism, similar to that in both root halves in the high NO3‐N supply treatment.Percent transport of14C assimilates from shoot to root was influenced by form and level of N supplied to root halves. Root halves supplied with either high N source for 6 days accumulated greater amounts of14C assimilate than the corresponding low N root half. However NH4‐N supply appeared to make roots stronger sinks since NH4supply resulted in significantly greater14C accumulation in both the high NH4supplied and the low N root halves than did NO3‐N supply in corresponding root halves.The data suggest that factors other than root metabolism, such as N mediated metabolism in the shoot, may also influence the percent transport of assimilates to the root. Internal distribution of the incoming assimilate within the root system could be regulated by the metabolic activity or assimilate

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04856.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractGA3as well as SA (salicylic acid) and β‐N (β‐naphthol) induce floral buds inImpatiens balsaminaunder strictly non‐inductive photoperiods. The floral bud initiation is accelerated when 1 mg/1 SA is used in combination with 100 mg/1 GA3. 100 mg/1 GA3+ 1 mg/1 SA and 100 mg/1 GA3+ 100 mg/1 β‐N increase the number of floral buds as compared with 100 mg/

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04857.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY