Vegetative Reproduction and Aposporous Growths from the Young Sporophyte of Polypodium irioides

1921 ◽  
Vol 48 (7) ◽  
pp. 203 ◽  
Author(s):  
W. N. Steil
Keyword(s):  
Vegetative Reproduction ◽  
Young Sporophyte

scholarly journals POPULATION GENETICS OF ALLOZYME VARIATION IN NEUROSPORA INTERMEDIA

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 785-805
Author(s):  
P T Spieth
Keyword(s):  
Genetic Variation ◽  
Vegetative Reproduction ◽  
Vascular Plant ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Regular Feature ◽  
Local Populations ◽  
Neurospora Intermedia ◽  
Pattern Of Variation ◽  
High Level

ABSTRACT Electrophoretically detectable variation in the fungus Neurospora intermedia has been surveyed among isolates from natural populations in Malaya, Papua, Australia and Florida. The principal result is a pattern of genetic variation within and between populations that is qualitatively no different than the well documented patterns for Drosophila and humans. In particular, there is a high level of genetic variation, the majority of which occurs at the level of local populations. Evidence is presented which argues that N. intermedia has a population structure analogous to that of an annual vascular plant with a high level of vegetative reproduction. Sexual reproduction appears to be a regular feature in the biology of the species. Substantial heterokaryon function seems unlikely in natural populations of N. intermedia. Theoretical considerations concerning the mechanisms underlying the observed pattern of variation most likely should be consistent with haploid selection theory. The implications of this constraint upon the theory are discussed in detail, leading to the presentation of a model based upon the concept of environmental heterogeneity. The essence of the model, which is equally applicable to haploid and diploid situations, is a shifting distribution of multiple adaptive niches among local populations such that a given population has a small net selective pressure in favor of one allele or another, depending upon its particular distribution of niches. Gene flow among neighboring populations with differing net selective pressures is postulated as the principal factor underlying intrapopulational allozyme variation.

scholarly journals Vegetative Reproduction Is More Advantageous Than Sexual Reproduction in a Canopy-Forming Clonal Macroalga under Ocean Warming Accompanied by Oligotrophication and Intensive Herbivory

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1522
Author(s):  
Hikaru Endo ◽  
Toru Sugie ◽  
Yukiko Yonemori ◽  
Yuki Nishikido ◽  
Hikari Moriyama ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Nutrient Availability ◽  
Vegetative Reproduction ◽  
Ocean Warming ◽  
Regeneration Ability ◽  
Combined Effects ◽  
Regeneration Rate ◽  
Fish Herbivory ◽  
C 30

Ocean warming and the associated changes in fish herbivory have caused polarward distributional shifts in the majority of canopy-forming macroalgae that are dominant in temperate Japan, but have little effect on the alga Sargassum fusiforme. The regeneration ability of new shoots from holdfasts in this species may be advantageous in highly grazed environments. However, little is known about the factors regulating this in Sargassum species. Moreover, holdfast tolerance to high-temperature and nutrient-poor conditions during summer has rarely been evaluated. In the present study, S. fusiforme holdfast responses to the combined effects of temperature and nutrient availability were compared to those of sexually reproduced propagules. The combined effects of holdfast fragmentation and irradiance on regeneration were also evaluated. Propagule growth rate values changed from positive to negative under the combination of elevated temperature (20 °C–30 °C) and reduced nutrient availability, whereas holdfasts exhibited a positive growth rate even at 32 °C in nutrient-poor conditions. The regeneration rate increased with holdfast fragmentation (1 mm segments), but was unaffected by decreased irradiance. These results suggest that S. fusiforme holdfasts have a higher tolerance to high-temperature and nutrient-poor conditions during summer than propagules, and regenerate new shoots even if 1-mm segments remain in shaded refuges for fish herbivory avoidance.

scholarly journals Molecular mechanism underlying the effect of maleic hydrazide treatment on starch accumulation in S. polyrrhiza 7498 fronds

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yerong Zhu ◽  
Xiaoxue Li ◽  
Xuan Gao ◽  
Jiqi Sun ◽  
Xiaoyuan Ji ◽  
...  
Keyword(s):  
Plant Growth ◽  
Carbon Fixation ◽  
Maleic Hydrazide ◽  
Starch Content ◽  
Vegetative Reproduction ◽  
Photosynthetic Pigment ◽  
Starch Accumulation ◽  
Chlorophyll Fluorescence Parameters ◽  
Significant Difference ◽  
Starch Production

Abstract Background Duckweed is considered a promising feedstock for bioethanol production due to its high biomass and starch production. The starch content can be promoted by plant growth regulators after the vegetative reproduction being inhibited. Maleic hydrazide (MH) has been reported to inhibit plant growth, meantime to increase biomass and starch content in some plants. However, the molecular explanation on the mechanism of MH action is still unclear. Results To know the effect and action mode of MH on the growth and starch accumulation in Spirodela polyrrhiza 7498, the plants were treated with different concentrations of MH. Our results showed a substantial inhibition of the growth in both fronds and roots, and increase in starch contents of plants after MH treatment. And with 75 µg/mL MH treatment and on the 8th day of the experiment, starch content was the highest, about 40 mg/g fresh weight, which is about 20-fold higher than the control. The I2-KI staining and TEM results confirmed that 75 µg/mL MH-treated fronds possessed more starch and big starch granules than that of the control. No significant difference for both in the photosynthetic pigment content and the chlorophyll fluorescence parameters of PII was found. Differentially expressed transcripts were analyzed in S. polyrrhiza 7498 after 75 µg/mL MH treatment. The results showed that the expression of some genes related to auxin response reaction was down-regulated; while, expression of some genes involved in carbon fixation, C4 pathway of photosynthesis, starch biosynthesis and ABA signal transduction pathway was up-regulated. Conclusion The results provide novel insights into the underlying mechanisms of growth inhibition and starch accumulation by MH treatment, and provide a selective way for the improvement of starch production in duckweed.

Evolution of the grapevine (Vitis vinifera L.) imprinted by natural and human factorsThis review is one of a selection of papers presented at the symposium on Vitis at the XVII International Botanical Congress held in Vienna, Austria, in 2005.

2007 ◽  
Vol 85 (8) ◽  
pp. 679-690 ◽  
Author(s):  
Roger Bessis
Keyword(s):  
Vegetative Reproduction ◽  
Molecular Characteristics ◽  
Vitis Vinifera L ◽  
Biological Interactions ◽  
Direct Effects ◽  
Parasitic Fungi ◽  
International Botanical ◽  
International Botanical Congress ◽  
Environmental Agents ◽  
Selection Of

This paper is concerned with vegetative reproduction, which is the only mode of propagation in cultivated grapevines. After a brief summary of the systematics of the Vitaceae the question of the nomenclature of cultivated grapevines is discussed. Intra-varietal variability is discussed using morphological and molecular characteristics. The origins of variation are presented: mutations, foreign nucleic acids, and memory of previous environmental conditions. Grapevines provide characteristic products, leading viticulturalists to make selections among the diversity observed in the vineyard, thus decreasing diversity. Grapevines interact with various environmental agents. One example, the natural defence provided by resveratrol, is analysed, showing its direct effects against parasitic fungi and its indirect effects, both metabolic and genetic, on other organisms. Thus, the grapevine, viticulturalists, and their environment form a web of biological interactions.

On the question of vegetative reproduction in apiculate yeasts

1965 ◽  
Vol 10 (6) ◽  
pp. 352-356 ◽  
Author(s):  
Eva Streiblová ◽  
K. Beran
Keyword(s):  
Vegetative Reproduction

CYTOGENETICS OF SOME SPECIES AND NATURAL HYBRIDS IN PROSOPIS (LEGUMINOSAE)

1975 ◽  
Vol 17 (2) ◽  
pp. 253-262 ◽  
Author(s):  
J. H. Hunziker ◽  
L. Poggio ◽  
C. A. Naranjo ◽  
R. A. Palacios ◽  
A. B. Andrada
Keyword(s):  
Chromosome Number ◽  
Interspecific Hybrids ◽  
Vegetative Reproduction ◽  
General Lack ◽  
Cytological Data ◽  
Natural Hybrids ◽  
Regular Meiosis ◽  
Putative Hybrids

Cytological results on 12 species and 4 putative hybrids of Prosopis are presented. Of these, 5 species and 4 hybrids have been hitherto unknown cytologically. The following species proved to be diploid (2n = 28) and constitute new chromosome number determinations for the genus: P. algarobilla Griseb., P. hassleri Harms, P. nigra (Griseb.) Hieron., P. patagonica Speg., P. tamarugo Phil. The diploid nature of some races of P. juliflora (Sw.) DC. is established; apparently under this taxon there are also tetraploid populations. The following putative interspecific hybrids showed regular meiosis with formation of 14 bivalents: P. vinalillo Stuck. (P. ruscifolia × P. alba?), P. alba × P. nigra? and P. hassleri × P. ruscifolia?.So far 28 taxa of the genus have been studied cytologically; 27 of these are diploid. The scarcity of polyploidy in the genus (3.5%) might be a consequence of the almost general lack of means of vegetative reproduction and of the absence of chromosome repatterning in primary speciation. Results of other authors concerning cytological data are also discussed.

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