摘要:

AbstractThe isouition and partial purification of succinyl CoA synthetase fromNicotiana tabacumis described. Enzynio activity had a pH optimum of pH 7.0 and apparent Km values for succinic acid. ATF and MgCl2. are 3.5 × 10−25.7 × 10−3and 4.0 × 10−3M, respectively. The euzyme is specific in requirement for ATP. Enzyme activity was low in seed, decreased during germination and seedling development, then increased to maximum in physiologically mature leaf tissue. Plauts with the apical apical meristem removed had less euzyme activity in leaves but more enzyme activity in the roots than plants with apical meristem intact. Most enzyme activity observed was associated with the soluble fractions of

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09097.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe severe chlorosis observed in the lower most of flooded sunflower plants (Helianthus annuusL. cv. Tall Single) may lie initiated by a reduction in the import of cytokinins by the stoot from the flooded root system. Experiment indicates that during 12 hours following the release of flooding, plants previously flooded for 72 hours or less recover their ability to exude sap when the root systems are aerated, and the root systems synthesize and export amino‐acids to the shoot. Plants flooded for longer periods lose these abilities. The metabolic activity of the root apices declines parallel with the decline in eytnkinin concentration in the sap with increase in flooding time up to 72 hours. Flooding for 96 hours drastically reduce all four parameters of root activity. After flooding for this period there was a large increase in the number of blackened and tetrazolium‐negative root apices which were in all probability dead. The correlation between the metabolic activity of the root apices and the total cytokinin content of the sap supports tbe view that root apices may be sites of cytokinin synthe

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09098.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe apical and basal ends of stem cuttings ofPopulus nigra, Salix tetrasperma, Ipomoea fistulosa and Hibiscus notoduswere treated with 10 mg/l solutions of IAA and IBA for 24 hours and were planted either erect or inverted both in light and dark. Observations for the number of cuttings that rooted and the roots produced on them were recorded at weekly intervals. In Salix, Ipomoea and Hibiscus rooting was more on cuttings planted erect, while in populus it did not differ much with the manner of planting. The reduced rooting in inverted cuttings may be ascribed to the low level of endogenous auxin at the apex due to polar transport. An exogenous application of auxins enhanced rooting on inverted cuttings. In dark, roots on Populus and Salix cuttings were produced both above and within the rooting medium. The weak polarity of these two plants may be due to the potential root primordia reported in their stem. The formation of callus occurred on the top of Populus cuttings whether planted erect or inverted but it differentiated into branches on erect cuttings only. In those planted in an inverted position the callus failed to differentiate in spite of the application of kinetin, auxins, TIBA, coumarin and sucrose, and dried ultimately.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09099.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractIf a single salt solution of CuSO4is used, Cu penetrates immediately iuto the plasma of Chlorella cells, reducing the rates of photosynthesis at both high and low illumination. If CuSO4is added to ordinary Österlind culture‐medium (pH 8) it takes some hours before any influence of deleterious concentrations of Cu is observed and initially only at light saturation. The algae must have been illuminated during the whole period. Maximum influence of CuSO4is found duriug the first 24 hours of treatment. A significant deleterious influence of Cu concentrations as low as about 1 μg/l is found. The influence of Cu increases with decreasing concentrations of the alga. If a culture medium at pH 5 is used instead of the ordinary one at pH 8, copper concentrations ahout 10 times as high must he used be order to obtain the same deleterious effect. An increase of the cotncentration of K reduces the influence of Cu to some extent. These facts show that the effect of deleterious concentrations of Cu in halanced solutions is not due to a marked penelration of this ion into the plasma but to a binding to the cytoplasmic membrane whereby the celts i.a. become more or less unable to divide. The cells become saturated with assimilation products which have a depressant effect on the rate of photosynthesis. Other cations compete with Cu for the “active sites” on the me

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09100.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractLeacthing the excised embryonic‐axes from dormant groundunt (Arachis hypogaea) seeds resulted in their growth. However, their growth was stunted compared to that of after‐ripened ones. It is attributed to (1) the lower amount of gibberellin‐like substances in the dry, dormant embryonic‐axes than in the after‐ripened ones, and (2) the inability of the former to sythesise tbe tibberetllin as indicated by the lower content compared to the after‐ripened ones kept in water. Exogenousty supplied GA3(0.1 mg/1) increased both the endogenous gibberellin and growth of the dormant, leached embryonic‐axes to the level of after

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09101.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractInbred corn varieties differing in their tolerance to the maize dwarf mosaic virus infection also differ in varietal character and host response to simazine. Oh 7B, a tolerant cv., has less total soluble and globulin proteins than the sensitive variety, H 55, but more Kjeldahl nitrogen, albumin protein and a doubling of catalase activity. Virus inoculation in Oh 7B causes a reduction in all three protein fractions, Kjeldahl nitrogen and catalase activity. Deleterious virus‐simazine interaction does not occur with either variety and the observed varietal and host response differences in protein may account for the conflicting reports of other worker

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09102.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractIn two locations, one subtropical and the other semidesert, the following three agricultural plant species were studied: cotton, maize and wheat. In each zone species were examined in irrigated and nonirrigated experimental plols for four leaf parameters: density of stomata and epidermis cells and length of stomala and leaf area. The following conclusions follow from the results: 1) The water deficit in the soil accompanied by extreme climatic conditions (August‐September) led to a significant increment in the density of stomata and epidermis cells; in some of the varieties a decrease in length of stomata was observed. The decrease in leaf area in the nonirrigated plant was accompanied by an increase in ash content. Identical xeromorphic changes were stated in selected leaves the area of which was equal to those of the irrigated plants. In spite of the maximal number of stomata per unit area on both sides of Ihe blade a full turgor was maintained in the cells of the nonirrigated plants during the hottest and driest months and they survived until rains started (Novemher), although no significant changes were then noted in soil moisture within the sphere of the root dispersio

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09103.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe study of chemical stress tolerance in a Penicillium mutant was continued using KCl‐ and H3BO3‐saturated glucose peptone broth as a basic growth medium. Growth was completely restricted to the mutant. Variations were the presence or absence of inosine‐5′‐phosphate (inosinic acid, IMP) and choice of carhohydrate which was substituted for glucose. All six monosaccharides used‐three hexoses, three pentoses – were essentially equivalent hence data are presented only for D‐glucose and D‐xylose. The other carbohydrates, sucrose, lactose, maltose and starch differed in their suitability as carbon sources. In the presence of the nionosaccharides the mutant can grow both in KCl and H3BO3media, but growth rates are greatly enhanced by IMP. Boric acid blocked sporulation under all conditions. KCl permitted spores of abnormal color to form without IMP, whereas spores of normal green color appeared in its presence. Media containing H3BO3and disaccharides or starch supported no growth, but addition of IMP stimulated growth without sporulation. In KCl media sucrose alone among the disaccharides and starch permit limited growth without IMP, but the nucleotide is required for sporogenesis. These results show that the role of nucleotides, especially IMP, is not limited to recovery from exposure to extreme salt effects, but also applies to growth in the continuing presence of quite different chemical

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09104.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractA defined medium forCosmarium turpiniiBréb. was established. The optimal concentrations of major elements (Ca, N, P, S, and Mg) were detemiined, with the calcium level found to be most demanding. Iron, boron, and manganese were found to be essential micronutrient elements. Vitamin B12is also required, eitber as the planar group of cyanocobalamin alone or with adenine or benziniizole derivatives. Survival of cells during plateau pbase of growth can be extended by tbe addition of eitber 10‐3M urea, isoleucine, or glyci

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09105.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractLight stimulates the assimilation of nitrate and nitrite by two green algae,Chlorella pyrenoidosaandAnkistrodesmus braunii. Assimilation can be observed when the algae are illuminated in the absence of carbon dioxide under both aerobic and anaerobic conditions. The rates of assimilation by Chlorella do not depend on the presence of carbon dioxide, but Ankistrodesmus assimilates nitrate and nitrite more rapidly when cultures are illuminated in the presence of carbon dioxide than in its absence.The ratios of O2: NO3′and O2: NO2′vary from one experiment to the other and, with the exception of Chlorella cultures reducing nitrite they are higher than the ‘expected’ values of 2.0 and 1.5 respectively.Oxygen evolution accompanying nitrate and nitrite by algae illuminated in the absence of carbon dioxide is completely inhibited by DCMU at concentrations of 4 × 10‐6M. However, nitrite assimilation by both Ankistrodesmus and Chlorella and nitrate assimilation by Ankistrodesmus are less sensitive to the

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb09106.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY