Flower production in Gerbera: I. Correlations between shoot,leaf and flower formation in seedlings     

L. Leffring 《Scientia Horticulturae》1973,1(3):221-229

Flower production of seedling plants of Gerbera was shown to be positively correlated with the number of lateral shoots and with the number of leaves per flower. The most productive plants were those which formed 2–5 lateral shoots during the first year and had a $\text{leaf}\text{flower}$ ratio of 2–4. The number of lateral shoots at the moment the first flower bud became visible was strongly correlated with the number of lateral shoots after 1 year.There was a positive correlation between the number of lateral shoots and total number of leaves, but hardly at all between total leaf number and flower production, as the $\text{leaf}\text{flower}$ ratio increased with the number of lateral shoots.  相似文献   

Neuroendocrine-immune interactions in fish: a role for interleukin-1   总被引：10，自引：0，他引：10  

Engelsma MY  Huising MO  van Muiswinkel WB  Flik G  Kwang J  Savelkoul HF  Verburg-van Kemenade BM 《Veterinary immunology and immunopathology》2002,87(3-4):467-479

Bi-directional communication between the hypothalamus-pituitary-adrenal (HPA)-axis and the sympathetic nervous system with the immune system is crucial to ensure homeostasis. Shared use of ligands and especially receptors forms a key component of this bi-directional interaction. Glucocorticoids (GC), the major end products of the HPA-axis differentially modulate immune function. Cytokines, especially interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), ensure immune signalling to the neuroendocrine system. In addition, hormones from leukocyte origin such as corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and beta-endorphin, as well as centrally synthesised and secreted cytokines, contribute to the communication network.In teleost fish cortisol is the major product of the hypothalamus-pituitary-interrenal (HPI)-axis which is the teleost equivalent of the HPA-axis. Moderate and substantial increases in cortisol during stressful circumstances negatively affect B-lymphocytes, whereas rescue of neutrophilic granulocytes may support innate immunity. Recent elucidation of lower vertebrate cytokine sequences has facilitated research into neuroendocrine-immune interactions in teleosts and the first evidence for a significant function of interleukin-1 in the bi-directional communication is discussed.  相似文献   

Mutation breeding of Kalanchoë     

C. Broertjes  Miss L. Leffring 《Euphytica》1972,21(3):415-423

Summary Freshly detached leaves of Kalanchoë cv. Annette and Josine were irradiated with X-rays and then planted to root and to produce adventitious plantlets. The age of the leaf, the presence or absence of the petiole as well as the genotype proved to be important factors in the production of adventitious plantlets.In Kalanchoë only solid, non-chimeral mutants were observed which indicates that the apex of the adventitious plantlets may originate from a single cell. This observation agrees with similar results in Achimenes, Saintpaulia, Streptocarpus and other species, where only a very small fraction of the mutants consisted of chimeras.The mutations observed were changes in flower colour and size, time of flowering, type of inflorescence, leaf form, size and colour, plant habit and other directly visible characters.A few promising mutants, selected by commercial plant breeders, are being propagated and will be evaluated.  相似文献   

A comparative study of the black stem fungi on lucerne and red clover and the footrot fungus on pea     

G. H. Boerema  Maria M. J. Dorenbosch  Lidy Leffring 《European journal of plant pathology / European Foundation for Plant Pathology》1965,71(3):79-89

North American (U.S.A., Canada) and Dutch strains of the black stem and footrot organisms were comparedin vitro and some amplifying inoculation experiments were made. It appears that black stem of lucerne is associated in nearly all cases with one relatively uniform pycnidial fungus. From comparison withPhoma herbarum, the type species of the form-genusPhoma, it is concluded that the fungus, although quite different fromP. herbarum, belongs toPhoma and not toAscochyta. The correct name is therefore considered to bePhoma medicaginis Malbr. & Roum. and notAscochyta imperfecta orP. herbarum f.medicaginum. Black stem of red clover is in general caused by a similar pycnidial fungus which, however,in vitro can always be distinguished from the lucerne fungus by its greater variability. This organism, the current name of which isPhoma trifolii, appears to be identical with the well-known footrot fungus of pea:Ascochyta pinodella. It is proposed to designate it asPhoma medicaginis var.pinodella (Jones) Boerema comb. nov. IncidentallyP. medicaginis can be associated with black stem of red clover andP. medicaginis var.pinodella with black stem of lucerne. Inoculation experiments confirmed the pathogenicity of both organisms to lucerne and red clover. On pea only the varietypinodella has been found, although inoculation experiments proved thatP. medicaginis can also attack pea.  相似文献