摘要:

AbstractThe isolated petioles ofColeusshow a distinct dependence on indoleacetic acid in the development of the epinastic curvature, in aqueous medium. Under the same experimental conditions gibberellic acid shows no effect or an inhibition only.Caffeic acid tested in concentrations between 10−11and 10−3evoked varying responses. In winter‐grown plants the curvaturevs. concentration curve shows two small maxima, which are not evident in the response of summer‐grown plants.The interaction of indoleacetic acid and caffeic acid is tested and discussed in elation with the question of the endogenous auxin in

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1965.tb00194.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractThe original intent of the present study was an inquiry into the architecture of the secondary haustoria of the mistletoesAntidaphne viscoideaandPhthirusa pyrifolia, each representing one of the two subfamilies ofLoranthaceae. In the course of this study it has become clear that there are fundamental similarities uniting the haustoria of the entire order,Santalales. The need for integration of all knowledge of Santalalean haustoria became more pressing as the work proceeded and has culminated in this article in its present form. This work, then, represents an integrated review of the structure and mechanism of Santalalean haustoria, introduced by an account of the haustoria ofPhthirusaandAntidaphne.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1965.tb00195.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractThis article is a modified paper, presented to the 10th International Botanical Congress, Edinburgh 1964. Vernalization is primarily discussed from an eco‐physiological viewpoint, serving as a basis for understanding the mechanism.Eco‐physiological observations point to the part which the substratum plays and also demonstrate the great variability among the requirements for vernalization, both regarding the low temperature treatment in itself and its relation to other factors like day length.The existence of a genetical basis for vernalization shows that DNA has something to do with it, or: that the first step in the vernalization process is a change in the regulation of gene activity.The loci of vernalization are considered to be mitotic cells, so that an important part of the mechanism of vernalization is the influence of low temperature on mitotic cells. This involves a study of nucleic acids.Gibberellins play an important part in vernalization and it may well be that this part will appear to be greater, when more knowledge will be gathered about what can be briefly indicated as: the biosynthesis of gibberell

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1965.tb00196.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractGelation of pectin by plant extracts is due to demethylation by pectin methylesterase; in the presence of Caions Ca‐pectate gels are formed. Pectin methylesterase is inhibited to some extent by 1,2‐dihydroxy‐anthraquinone‐sulphonic acid‐3, 1,4‐dihydroxy‐anthraquinone‐sulphonic acid‐2, and 8‐hydroxy‐quinoline sulphate, but much stronger by m‐digallic acid and tannic acid. A trans‐eliminative breakdown of pectin can interfere with the action of pectin methylesterase.In host‐parasite complexes, the degradation of pectin (either hydrolytically or trans‐eliminatively) can be catalyzed by many different enzymes of plant, fungal or bacterial origin. Various substances, occurring naturally in higher plants, can greatly affect>the activity of these enzymes. Therefore, in order to obtain quantitative data on their respective activities in host‐parasite systems, thorough purification of all pectolytic enzymes fro

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1965.tb00197.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractA revision of the Euphorbiaceous genusMeineckiahas resulted in the recognition of 19 species, with 7 subspecies and 2 varieties (for a total of 25 distinct taxa). Proposed as new are 5 species and 1 subspecies, while new combinations are necessary for 14 species and 6 subspecific taxa. The extraordinary confusion in the taxonomic history of the genus is illustrated by the fact that the 14 previously recognized species have been classified under 6 different generic names:Cluytiandra, Flueggea, Neopeltandra, Peltandra, Phyllanthus, andSecurinega. As revised, the number of species represented in the different regions is as follows: America, 3; Africa and Arabia, 4; Madagascar, 8; India and Ceylon, 4. The genus appears to be of African origin and is probably most closely related toZimmermannia.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1965.tb00198.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

AbstractLongitudinal growth of etiolated pea stem segments has been shown to be strongly stimulated by indoleacetic acid. Lateral growth, on the other hand, was hardly stimulated either by high or low indoleacetic acid concentrations.Addition of sucrose to high indoleacetic acid concentrations (10 μg/ccenhanced lateral growth.Although the 80% ethanol soluble sugar content increased greatly during the growth period, it was only slightly affected by indoleacetic acid.Lateral growth is not, therefore, a result of an increased osmotic value of the cell sap, and the cells consequently do not swell.Not more than 5% of the water absorbed by stem segments during longitudinal and lateral growth is released when the segments are incubated in solutions of high osmotic value.It is concluded that lateral growth of etiolated pea stem segments in solutions of 10 μg/cc IAA and in the presence of sucrose requires, in the first instance, a weakening of the cell wall in a lateral direction and sucrose is somehow needed for this proces

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1965.tb00199.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Book reviewed in this article:D. F. JACKSON, Editor, Algae and Man.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1965.tb00200.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY