Size dependency of sexual reproduction and of clonal growth in two perennial plants

1995 ◽  
Vol 73 (11) ◽  
pp. 1831-1837 ◽  
Author(s):  
Bernhard Schmid ◽  
Fakhri A. Bazzaz ◽  
Jacob Weiner
Keyword(s):  
Sexual Reproduction ◽  
Clonal Growth ◽  
Vegetative Reproduction ◽  
Solidago Canadensis ◽  
Threshold Size ◽  
Size Dependency ◽  
Allocation Patterns ◽  
Highly Correlated ◽  
Size Threshold ◽  
Sexual Reproductive Allocation

We compared the size dependency of sexual reproduction and clonal growth in two clonal perennials that inhabit old fields, Aster lanceolatus and Solidago canadensis. In both species there was a threshold size required for sexual reproduction to occur, and above that threshold reproductive output increased linearly with vegetative mass. Biomass allocated to clonal growth was also highly correlated with vegetative mass in both species, but there was no evidence of a threshold size for clonal growth. The absence of a clear size threshold for clonal growth emphasizes the similarity between clonal growth (vegetative reproduction) by rhizomes and growth of other vegetative parts, as opposed to sexual reproductive allocation. In both species there were differences in the allocation patterns of plants derived from seeds and those derived from rhizomes. Although seed- and rhizome-derived plants did not differ in phenology and size, the latter allocated more biomass to sexual reproduction and clonal growth in both species. Key words: clonal growth, size dependency, reproduction, Aster lanceolatus, Solidago canadensis, size threshold.

The role of sexual reproduction in maintaining populations of Halophila decipiens: implications for the biodiversity and conservation of tropical seagrass ecosystems

1999 ◽  
Vol 5 (4) ◽  
pp. 260 ◽  
Author(s):  
W. Judson Kenworthy
Keyword(s):  
Life History ◽  
Sexual Reproduction ◽  
Clonal Growth ◽  
World Wide ◽  
Vegetative Reproduction ◽  
Indian River Lagoon ◽  
Sexual Life ◽  
Life History Strategies ◽  
Relative Importance ◽  
Seagrass Ecosystems

In subtropical and tropical communities, seagrass species commonly range over an order of magnitude in size and biomass. This biodiversity corresponds with differences in the relative importance of sexual (seed production) and asexual (clonal growth) life history strategies in the maintenance of seagrass populations. Clonal growth and vegetative reproduction are important in maintaining populations of larger-bodied species. As size of species and degree of clonality decrease, the importance of sexual reproduction increases. World-wide, the smallest species in tropical seagrass ecosystems are represented by the most taxonomically diverse, sexually fecund genus, Halophila. A four-year study of the submarine light regime and seasonal growth cycles of Halophila decipiens and other seagrasses in the Indian River Lagoon, Florida, USA provides a comparative context in which to illustrate the relative importance of different life history strategies in tropical seagrass ecosystems world-wide. While sexual reproduction is critical for maintaining some geographically extensive small-bodied seagrass systems in disturbed and extreme environments, there is also evidence to suggest that the quantitative importance of sexual reproduction may be underestimated for larger, highly clonal species like Thalassia testudinum. Future efforts to conserve tropical seagrass ecosystems necessitates a more comprehensive understanding of the evolutionary consequences of sexual reproduction and a more quantitative evaluation of the population dynamics resulting from the sexual life history strategies of different species.

scholarly journals Inconclusive evidence of sexual reproduction of invasive Halophila stipulacea: a new field guide to encourage investigation of flower and fruit production throughout its invasive range

2020 ◽  
Vol 63 (6) ◽  
pp. 537-540
Author(s):  
Fee O.H. Smulders ◽  
Kelcie L. Chiquillo ◽  
Demian A. Willette ◽  
Paul H. Barber ◽  
Marjolijn J.A. Christianen
Keyword(s):  
Sexual Reproduction ◽  
Clonal Growth ◽  
Large Scale ◽  
Fruit Production ◽  
Morphological Evidence ◽  
Invasive Range ◽  
Reproductive Structures ◽  
Halophila Stipulacea ◽  
The Caribbean ◽  
Low Rate

AbstractThe dioecious seagrass species Halophila stipulacea reproduces mainly through fast clonal growth, underlying its invasive behavior. Here, we provide morphological evidence to show that the first findings of fruits in the Caribbean were misidentified. Consequently, H. stipulacea reproduction is likely still only asexual in the Caribbean. Therefore, we introduce an identification key of H. stipulacea reproductive structures to encourage careful identification and quantification throughout its invasive range. Until large-scale seed production in invaded habitats is reported, the apparent low rate of sexual reproduction needs to be considered in current studies investigating the invasion capacity of this species.

scholarly journals Assessing the accuracy of remotely-sensed fire datasets across the Southwestern Mediterranean basin

2020 ◽  
Author(s):  
Luiz Felipe Galizia ◽  
Thomas Curt ◽  
Renaud Barbero ◽  
Marcos Rodrigues
Keyword(s):  
Mediterranean Basin ◽  
Quantitative Estimate ◽  
State Of The Art ◽  
Warm Season ◽  
Burned Area ◽  
Fire Size ◽  
Northern Iberian Peninsula ◽  
Fire Atlas ◽  
Highly Correlated ◽  
Size Threshold

Abstract. Recently, many remote-sensing (RS) based datasets providing features of individual fire events from gridded global burned area products have been released. Although very promising, these datasets still lack a quantitative estimate of their accuracy with respect to historical ground-based fire databases. Here, we compared three state-of-the-art RS datasets (Fire Atlas, FRY and GlobFire) with high-quality ground databases compiled by regional fire agencies (AG) across the Southwestern Mediterranean basin (2005–2015). We assessed the spatial and temporal accuracy in estimated RS burned area (BA) and number of fires (NF) aggregated at monthly and 0.25° resolutions, considering different individual fire size thresholds ranging from 1 to 500 ha. Our results show that RS datasets were highly correlated with AG in terms of monthly BA and NF but severely underestimated both (by 38 % and 96 %, respectively) when considering all fires > 1 ha. Stronger agreement was found when increasing the fire size threshold, with fires > 100 ha denoting higher correlation and much lower error (BA 10 %; NF 35%). The agreement between RS and AG was also the highest during the warm season (May to October) in particular across the regions with greater fire activity such as the Northern Iberian Peninsula. The Fire Atlas displayed a slightly better performance, with a lower relative error, although uncertainty in gridded BA product largely outpaced uncertainties across the RS datasets. Overall, our findings suggest a reasonable agreement between RS and ground-based datasets for fires larger than 100 ha, but care is needed when examining smaller fires at regional scales.

scholarly journals A size threshold governs Caenorhabditis elegans developmental progression

2015 ◽  
Vol 282 (1813) ◽  
pp. 20151283 ◽  
Author(s):  
Sravanti Uppaluri ◽  
Clifford P. Brangwynne
Keyword(s):  
Caenorhabditis Elegans ◽  
Food Availability ◽  
Developmental Stages ◽  
Size Control ◽  
Threshold Size ◽  
Larval Stages ◽  
Developmental Progression ◽  
Order Of Magnitude ◽  
Size Threshold ◽  
The Impact

The growth of organisms from humans to bacteria is affected by environmental conditions. However, mechanisms governing growth and size control are not well understood, particularly in the context of changes in food availability in developing multicellular organisms. Here, we use a novel microfluidic platform to study the impact of diet on the growth and development of the nematode Caenorhabditis elegans . This device allows us to observe individual worms throughout larval development, quantify their growth as well as pinpoint the moulting transitions marking successive developmental stages. Under conditions of low food availability, worms grow very slowly, but do not moult until they have achieved a threshold size. The time spent in larval stages can be extended by over an order of magnitude, in agreement with a simple threshold size model. Thus, a critical worm size appears to trigger developmental progression, and may contribute to prolonged lifespan under dietary restriction.

Niche differentiation between two rhizomatous plant species: Typha latifolia and Typha angustifolia

1982 ◽  
Vol 60 (1) ◽  
pp. 46-57 ◽  
Author(s):  
James B. Grace ◽  
Robert G. Wetzel
Keyword(s):  
Sexual Reproduction ◽  
Shallow Water ◽  
Surface Area ◽  
Leaf Surface ◽  
Vegetative Reproduction ◽  
Typha Latifolia ◽  
Morphological Characteristics ◽  
Niche Differentiation ◽  
Typha Angustifolia ◽  
Leaf Surface Area

Morphological characteristics and biomass allocation were examined for two species of Typha in a small pond. Typha latifolia differed from T. angustifolia in having shorter leaf height, wider leaves, greater leaf surface area, greater allocation to leaves, greater number of smaller rhizomes, greater allocation to vegetative reproduction, smaller allocation to sexual reproduction, and fewer number of flowering plants. For both species, those plants growing in deeper water had taller leaves, a greater allocation to leaves, and a decreased allocation to sexual and vegetative reproduction. Previous studies of these populations have demonstrated that these two species are segregated according to water depth with T. latifolia being competitively superior in shallow water (less than 15 cm) but T. angustifolia having the potential to grow in deeper water than T. latifolia. Results from this study indicate that T. latifolia is competitively superior in shallow water because of its greater leaf surface area but that T. angustifolia's tall, narrow leaves and large rhizome storage permit it to grow in deeper water than T. latifolia. The greater amount of sexual reproduction in T. angustifolia is correlated with its more restricted distribution and fugitive nature.

Effect of prolonged vegetative reproduction of olive tree cultivars (Olea europaea L.) in mitochondrial homoplasmy and heteroplasmy

Genome ◽  
2003 ◽  
Vol 46 (3) ◽  
pp. 377-381 ◽  
Author(s):  
Angel García-Díaz ◽  
Ricardo Oya ◽  
Antonio Sánchez ◽  
Francisco Luque
Keyword(s):  
Mitochondrial Genome ◽  
Sexual Reproduction ◽  
Olea Europaea ◽  
Vegetative Reproduction ◽  
Intergenic Spacer Region ◽  
Olea Europaea L ◽  
Chloroplast Genomes ◽  
Mitochondrial Region ◽  
Olive Trees ◽  
Olea Europaéa

The inheritance of mitochondrial and chloroplast genomes does not follow Mendelian laws, but proceeds by vegetative segregation. Most organisms show organelle homoplasmy, which is probably produced and maintained during sexual reproduction. We have tested the effect of prolonged vegetative multiplication in the maintenance of mitochondrial homoplasmy and the generation of heteroplasmy in cultivated olive trees, Olea europaea L. Seven trees, each representing a different variety of olive, were analysed by the study of an intergenic spacer region of the mitochondrial genome. A very high level of heteroplasmy was detected in all cases. We found multiple genome variants of the sequence analysed. The frequency of genomes with no changes in the spacer region was 11.5%. This means that 88.5% of genomes contain at least one change. The same spacer mitochondrial region was sequenced in several clones from four olive trees of a second generation of sexually reproduced trees. In these trees, many clones were identical and had no changes, which represents a clear reduction of the heteroplasmy (p < 0.001). Therefore, this work supports the relevance of the role of sexual reproduction in the maintenance of mitochondrial homoplasmy and also shows that mutations accumulate in a non-coding sequence of the mitochondrial genome when vegetative propagation is maintained for a long period of time.Key words: mitochondrial genome, homoplasmy, heteroplasmy, olive trees, vegetative reproduction, sexual reproduction.

Reproduction of salal (Gaultheriashallon) under forest canopy

1990 ◽  
Vol 20 (1) ◽  
pp. 91-100 ◽  
Author(s):  
F. L. Bunnell
Keyword(s):  
Sexual Reproduction ◽  
Forest Canopy ◽  
Vegetative Reproduction ◽  
Resource Limitation ◽  
Shoot Density ◽  
Physiological Integration ◽  
Forest Canopies ◽  
Plant Persistence ◽  
Crown Closure ◽  
Optimality Models

Sexual and vegetative reproduction of salal (Gaultheriashallon Pursh) was measured under forest canopies of different closure. Sexual reproduction occurred only at ≤33% closure; vegetative reproduction occurred under sparse and dense closure. Crown closure influenced sexual reproduction primarily through interception of radiation and associated reductions in salal vigour. Irradiance had a greater influence on the mode of reproduction than did shoot density, and allocation of total reproductive effort (sexual plus vegetative) was contrary to optimality models, but consistent with resource limitation. No shoot <5 years old flowered; shared costs of flowering indicated physiological integration among salal shoots. Vegetative reproduction was negatively associated with age (r2 = 0.95), and 85% of the space occupied after 9 years of growth was occupied during the first 3 years. Under canopy the spatial pattern of salal shoots was better adapted to maintain plant persistence than to colonize new areas. Implications of salal's rates and modes of reproduction to forest and wildlife management are noted.

Clonal growth and sexual reproduction: tradeoffs and environmental constraints

Oikos ◽  
2014 ◽  
Vol 124 (4) ◽  
pp. 469-476 ◽  
Author(s):  
Tomáš Herben ◽  
Božena Šerá ◽  
Jitka Klimešová
Keyword(s):  
Sexual Reproduction ◽  
Clonal Growth ◽  
Environmental Constraints
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