摘要:

AbstractRoot‐knot nematodes,Meloidogyne incognita, were grown in tobacco pith tissue culturedin vitroon modifired white's medium. The nematodes did not secrete detectable amounts of auxin or cytokinin, but did promote growth in the presence of both types of growth substance. When both IAA and kinetin were supplied, the nematode‐infected tissue was larger, more irregularly shaped than control tissue; nematodes induced syncytia and developed past the second larval stage. When either IAA or kinetin was omitted from the medium, nematodeinfected and control tissue failed to grow and the nematodes failed to induce syncytia or deve

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09079.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractTo investigate the mechanism of frost damage in trees, the temperature fluctualions in the stems and leaves of some wintering trees were recorded with copperconstantan thermocouples.In Sapporo, even the trunk of large elm trees with diameter of 86 cm are frozen during the winter. In a Kalopanax trunk with a diameter of 13.5 cm, the bark temperature on the south side which is exposed to direct sunshine reaches nearly 20°C about midday in midwinter; while, on the north side, the temperature remains nearly the same as the environmental temperature (0 to ‐5°C). The rise in the bark temperature in trees is considerably affected by factors such as the intensity of sunshine, the environmental temperature, the diameter of the trunk, the side of the trunk which the bark is on, the height above the ground, and the colour of the bark surface, etc. This rise is far less in small twigs, slender stems, and small leaves than in large ones. The south side of the bark 10 to 15 cm above the snow surface or above the ground in a slender stem is exposed to a remarkable fluctuation in temperature, especially when the ground is covered with snow.Even in northern trees, the cortical cells on the south side of trunks and twigs are less resistant to freezing than those on the no

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09080.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe specific effects of pH on the accumulation mechanism of Rb+ by excised barley roots were investigated.Exposure of roots to solutions of a wide range of pH values did not result in any noticeable damage. It is therefore suggested that even pH 3.5 is within the physiological range of pH for barley roots.It is assumed that the inhibitory effect of pH on Rb+ accumulation is due to competition of H ions on binding sites of the temperature dependent metabolic accumulation mechanism. When this mechanism is saturated with Rb ions, no inhibition of H ions occurs, even at pH 3.5.Temperature coefficients provide hints that the inhibitory effects of Na and H ions on Rb+ accumulation are similar.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09081.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractWhen the white mutant ofHelianthus animusis grown in full sunlight, leaf expansion and differentiation of the mesophyll are inhibited.More normal development results when incident wavelengths, shorter than 450nm, are removed by appropriate filters.A short wavelength photoreaction has been proposed which results in cessation of leaf development at a juvenile stage, and is analogous in its mechanism to the effects of 2‐thiouracil on leaf developmien

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09082.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe effect of UV light on germination of lettuce seeds and on the unfolding of wheat leaves was studied.A small improvement in germination was noted on exposure lo light of 254, 265, 334, 405 nm, and in unfolding on exposure to light of 254, 265, 313, 334, 360 and 405 nm.The low germination rate at 238 nm shows, that light energy absorbed by the high‐absorbing protein part of the phylochrome (Siegelman and Butler 1965) cannot be used in the germination proces

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09083.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractSpores ofPolytrichum conwtuinewere grown on a mineral salt solution with or without sucrose and exposed to continuous white light, continuous darkness, red light and/or far‐red light. With sucrose, germination and filament growth occurred in all conditions, Without sucrose, germination and filament growth occurred only in light. Two phytochrome mediated responses of the chloroplasts were demonstrated. Chloroplast replication occurred in continuous white light and red light of 15 min/6 hours. In continuous darkness and in far red light of 15 min/6 hours, the size of the chloroplasts increased; but no replication occurred. Both the chloroplast replication and chloroplast size were red, far‐red light reversible. When changed from one continuous light environment to another, a lag period occurred before the chloroplasts responded to the new environment. Electron micrographs of sections andin vivostaining of the chloroplasts with iodine solution demonstrated that the change in size of the chloroplasts was at least partially due to the synthesis and degradation of sta

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09084.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractAsynchronous as well as synchronous cultures were used to study the effect of phenylethyl alcohol on Chlorella pyrenoidosa. The following observations were made:1Autotrophic growth and the synthesis of DNA and chlorophyll were inhibited more than 80% by 8.4 mM phenylethyl alcohol when added to synchronous suspensions containing autospores.2Autospore formation did not occur when fully grown cells capable of division were transferred to 4.2 mM phenylethyl alcohol.3Photosynthetic oxygen evolution of asynchronous cultures was inhibited more than 70 % by 21 mM phenylethyl alcohol.4Endogenous respiration in the dark was stimulated by 8.4 mM, while higher concentrations were inhibitory.5Glucose respiration in the dark was inhibited by all concentrations in the range from 8.4 mM to 21 mM. Assimilation of glucose in darkness was retarded by phenylethyl alcohol at concentrations which gave maximal stimulation of endogenous respiration.It is concluded that phenylethyl alcohol is not a specific inhibitor of DNA synthesis. The prime effect appears to be on respiration and photosynthesis.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09085.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe elongation of the second leaf sheaths of rice seedlings was promoted strongly by helminthosporol as well as by gibberellic acid. A greater dosage of helminthosporol was required in order to induce the same amount of elongation.Cells of treated plants were somewhat longer than those of controls. The elongation of the second leaf sheath was caused mainly by an increase in cell number.Both helminthosporol and gibberellic acid promoted the elongation of cells in the basal portion of the second leaf sheath.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09086.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractFactors influencing the growth ofPhytophthora parasitionvar.nicotionaon vegetable oil liquid media were studied. This fungus grew poorly on oleic acid, triolein, and tristearin. Cholesterol and α‐tocopherol reversed the toxicity of oleic acid. Growth was often stimulated by addition of mineral oil to a glucose medium, and sterols dissolved in mineral oil frequently stimulated grwoth.Shaking produced a 5‐fold or more increase in growth on either glucose or cottonseed oil media. Cholesterol (20 μ/ml further increased growth on glucose meidum in shake culture by at least 100%. Growth was usually better at pH 6.7 than at 5.4 or 7.7. Growth in shake culture on a glucose medium supplemented with cholesterol and α‐tocopherol approached that occuring on vegetable o

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09087.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractGrowth reactions of wbeat coleoptile sections following a brief pretreament in indole‐3‐acetic acid (LAA) were studied. The growth versus concentration curves 24 hours after the treatment showed a minimum value surrounded by bigber values. The minimum was never at concentrations lower than 10‐5MlAA but it could be found at higher concentrations after short pretreatment periods.The growth versus time curves reveated that the hormone treatment cansed the growth rate initially to increase but later on to decrease. The decrease was followed by a second increase for some treatments.Analysis of IAA content after the pretreatment showed that the attered growth patterns could be ascribed to declining auxin content with time, but not to thc actual concentration in the sections.The results indicate that the metabolic activation brought about by IAA leads to its own disappearance. Such a phenomenon was mirroretl in effects of IAA on hte net synthesis of ribonucleic

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09088.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY