scholarly journals Outbreeding and inbreeding strategies in herbaceous-shrubby communities in the Venezuelan Gran Sabana Plateau

AoB Plants ◽  
2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Nelson Ramírez ◽  
Omaira Hokche
Keyword(s):  
Plant Species ◽  
Carbon Metabolism ◽  
Life Form ◽  
Sex Expression ◽  
Perennial Herb ◽  
Sexual System ◽  
Dioecious Species ◽  
Successional Stage ◽  
Sexual Systems ◽  
Perennial Herbs

Abstract Breeding system, sexual system, temporal variation in sex expression and herkogamy were evaluated in seven herbaceous-shrubby communities from the Gran Sabana Plateau, Venezuela. This analysis was conducted considering the life form, substrate type, succulence, carbon metabolism, nutritional relation, successional stage, pollination system specificity and endemism of plant species. Of the 348 plant species studied, 73.8 % were hermaphrodite, 16.9 % were monoecious and 9.2 % were dioecious. Plant sexual systems such as dichogamy and herkogamy were associated with life form, nutritional relations, carbon metabolism and pollination systems. Most species were adichogamous, followed by protandrous and protogynous. Protandry was high for perennial herbs, annual herbs and trees, and protogyny was most frequent in perennial herbs. Protandrous and protogynous species were frequently anemophilous. Herkogamy was higher than non-herkogamy. Herkogamy was higher for trees, shrubs and liana; higher in monophilous and lower in anemophilous species. Most of the hermaphrodites were herkogamous and adichogamous species. In contrast, monoecy were commonly perennial herb and dichogamous species and frequently associated with anemophily. Dioecious species were trees and shrubs and with polyphilous pollination. Dioecy was the most frequent sexual system for endemic species. Hermaphrodite species were similarly distributed across plant communities. Monoecy was slightly higher for savanna and fallow than the other communities, and dioecy was higher for shrublands and secondary bushland. Most plant species were non-agamospermous, non-spontaneous self-pollinated and xenogamous. Partially self-incompatible dominated, followed by self-incompatible, partially cross-incompatible and the lowest frequency corresponded to cross-incompatible species. All these results are discussed in the context of evolutionary and ecological trends.

scholarly journals Macrophytes of the lowland wetlands in Morang district, Nepal

2013 ◽  
Vol 1 ◽  
pp. 131-139 ◽  
Author(s):  
Umesh Koirala ◽  
Sasinath Jha
Keyword(s):  
Plant Species ◽  
Rainy Season ◽  
Life Form ◽  
Summer Season ◽  
Rural People

In total, 149 species of macrophytes (angiosperms 138, pteridophytes 7, bryophytes 2, algae 2) were recorded among which 117 species were emergent, 12 floating-leafed, 14 submerged and 6 free-floating on the basis of life form. In general, 68% species had flowering-fruiting during the rainy season, 17% in winter and 15% in the summer season. Many of the plant species were observed to play important role in meeting day to day requirements of the rural people. DOI: http://dx.doi.org/10.3126/njbs.v1i0.7480 Nepalese Journal of Biosciences 1: 131-139 (2011)

Plant diversity of Ghorkhod Protected Area, NE Iran

Phytotaxa ◽  
2016 ◽  
Vol 249 (1) ◽  
pp. 118 ◽  
Author(s):  
FARSHID MEMARIANI ◽  
MOHAMMAD REZA JOHARCHI ◽  
HOSSEIN AKHANI
Keyword(s):  
Plant Species ◽  
Protected Area ◽  
Life Form ◽  
Vascular Plant ◽  
Floristic Composition ◽  
Transitional Zone ◽  
Plant Groups ◽  
Wide Range ◽  
Plant Families ◽  
Ne Iran

Ghorkhod Protected Area (GPA) is located in a transitional zone among different biogeographical units in North Khorassan Province, NE Iran. The study area is mainly a mountainous region in western extensions of Khorassan-Kopet Dagh floristic province. We investigated the floristic composition, life form spectrum and phytogeography of the study area through several random collection efforts and 200 vegetation samples (reléves) in selected vegetation types during 2007–2012. A total of 663 vascular plant species belonging to 367 genera and 81 families are recorded as native and naturalized in GPA. Angiosperms and Dicots are among the most diverse plant groups. The richest plant families are Asteraceae (88 species), Poaceae (78), Lamiaceae (45), Brassicaceae (43), Fabaceae (38), and Caryophyllaceae (32). The genera Allium L. (17 species), Astragalus L. (15) and Cousinia Cass. (12) are the richest ones, however, the majority of the species belongs to oligotypic and monotypic genera. Life form spectrum of the study area is dominated by hemicryptophytes (38.9%) and therophytes (23.4%). Allium transvestiens Vved., Agropyron desertorum Schult., Helictotrichon turcomanicum Czopanov and Piptatherum latifolium (Roshev.) Nevski are recorded as new to Iran. The core flora of the area has the Irano-Turanian origin. However, the wide-range and widespread elements are also well represented in the study area. GPA is inhabited by several endemic, rare and narrow-range plant species, indicating the biodiversity importance of the study area in NE Iran.

scholarly journals Interaction between root exudates and rhizosphere microorganisms facilitates the expansion of poisonous plant species in degraded grassland

2021 ◽  
Author(s):  
Wenyin Wang ◽  
Tianhua Jia ◽  
Tianyun Qi ◽  
Shanshan Li ◽  
Degen A.Allan ◽  
...  
Keyword(s):  
Plant Species ◽  
Soil Nutrients ◽  
Root Exudates ◽  
Carbon Metabolism ◽  
Soil Microbial Communities ◽  
Alpine Grassland ◽  
Poisonous Plant ◽  
Poisonous Plants ◽  
Rhizosphere Microorganisms ◽  
Degraded Grassland

Abstract Background The interaction between rhizosphere microorganisms and rhizosphere exudates is considered a ‘novel weapon’ for poisonous plants’ colonization, but the relationship between them in facilitating the expansion of poisonous plants in degraded or barren land is poorly understood. We examined this relationship in different degradation levels of alpine grasslands on the Tibetan plateau (3,700 m a.s.l) by determining the composition of root exudates, soil physical and chemical properties, rhizosphere microbial diversity and carbon metabolism of the main poisonous and non-poisonous plant species. Results Soil nutrients, including total organic carbon, total nitrogen and available phosphorous, diversity of microorganisms and microbial carbon metabolism were greater in the rhizosphere of poisonous than in non-poisonous plant species (P < 0.05). The distribution of bacteria and root exudates were plant species specific. Soil microbial communities were affected by habitat and plant species in degraded grassland, and more so for bacteria than fungi. The cell growth and death pathway for the poisonous species Ligularia virgaurea was greater than for other poisonous species (P < 0.05), and the difference increased with an increase in grassland degradation and a decrease in soil nutrients (P < 0.05), which could explain how L. virgaurea became the dominant poisonous species in degraded alpine grassland. The roots of L. virgaurea exudated such compounds as alkaloids, lupinic acid, terpenes, artemisinin, and coumarin, which were correlated positively with different bacteria in different habitats. Conclusion It was concluded that poisonous plant species adapted to degraded grassland through the interaction of root exudates and rhizosphere microorganisms, which facilitated their expansion in degraded alpine grassland.

Cryptic dioecy in Actinidia polygama: a test of the pollinator attraction hypothesis

2004 ◽  
Vol 82 (2) ◽  
pp. 214-218 ◽  
Author(s):  
Tetsuhiro Kawagoe ◽  
Nobuhiko Suzuki
Keyword(s):  
Fruit Production ◽  
Sexual System ◽  
Dioecious Species ◽  
Pollinator Attraction ◽  
Cryptic Dioecy ◽  
Actinidia Polygama ◽  
Unisexual Flowers ◽  
Sterile Pollen ◽  
Female Flowers

Female flowers of some dioecious species are known to develop stamens with sterile pollen, a sexual system known as cryptic dioecy. A convincing hypothesis explaining this phenomenon is that stamens in female flowers attract pollinators and so ensure seed production. However, because this hypothesis has rarely been tested experimentally, we tested it in a cryptically dioecious species, Actinidia polygama (Sieb. et Zucc.) Planch. ex Maxim. Our findings show that pollinators do not show a consistent preference based on the sex of the flowers, and that the removal of stamens from female flowers results in a significant reduction in the frequency of insect visits and fruit production. These results strongly support the pollinator attraction hypothesis in A. polygama. Given the evident role of stamens in female flowers in A. polygama reproduction, we discuss why cryptic dioecy is a rare phenomenon.Key words: Actinidia polygama, cryptic dioecy, pseudopollen, pollinator attraction, unisexual flowers.

Effects of salinisation on riparian plant communities in experimental catchments on the Collie River, Western Australia

2003 ◽  
Vol 51 (6) ◽  
pp. 667 ◽  
Author(s):  
A. J. Lymbery ◽  
R. G. Doupé ◽  
N. E. Pettit
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Western Australia ◽  
Soil Salinity ◽  
Riparian Vegetation ◽  
Plant Species Richness ◽  
Perennial Herb ◽  
Groundwater Levels ◽  
Riparian Plant Communities ◽  
Riparian Plant

Although the salinisation of streams has long been recognised as one of Western Australia's most serious environmental and resource problems, there is very little published information on the effects of salinisation on riparian flora and fauna. We studied riparian vegetation in three experimental catchments on the Collie River in Western Australia. The catchments are situated within a 5-km area of state forest and are geologically and botanically similar, but differ in the extent of clearing, groundwater levels and stream salinity. In each catchment, transects were taken perpendicular to the direction of streamflow, and 4-m2 quadrats taken along each transect. Within each quadrat, soil salinity was measured, all plants were identified to species level and percentage cover estimated. The catchments differed significantly in soil salinity, with salinity being greatest in the most extensively cleared catchment and increasing towards the floor of the valley. Plant-species richness, species diversity and species composition were significantly related to soil salinity, both among catchments and among quadrats within the most extensively cleared catchment. Plant-species richness and diversity decreased with increasing soil salinity, an effect that may be partly due to a decline in perennial herb and shrub species. This may have an impact on other components of the riparian ecosystem.

The Vegetation Structure and Floral Changes of 5 Years after Restoration of Cheonggyecheon Stream in Korea

2013 ◽  
Vol 726-731 ◽  
pp. 1548-1554 ◽  
Author(s):  
Bon Hak Koo
Keyword(s):  
Vegetation Structure ◽  
Life Form ◽  
Flood Plains ◽  
The Third ◽  
Introduced Plants ◽  
Flow Channels ◽  
Ecological Changes ◽  
Perennial Herbs ◽  
Concrete Materials ◽  
Straight Flow

The result of 5-years monitoring (2006-2010) in Cheonggyecheon stream, 328 floral species were found in 2006. In 2007, 2008, 2009 and 2010, total 446, 444, 471 and 510 species were found respectively. And among them, 233 introduced species were found in 2006, 312 species in 2007, 308 in 2008, 314 in 2009 and 300 in 2010 were found. Hazard species were found 3-5 species during study period. The rapid increasing in introduced plants was surveyed in the early 1stand 2ndyears. It has shown a relatively stable trend since the third year. By life form, herbaceous plants gradually increased in the early year. And annual and biennial herbs were dominated right after restoration and as time went by perennial herbs ratio increased. By family, flora belongs toCompositaefamily that was found most frequently. By section, 3rdand 4thsections constituted by natural genotypes, such as point bars, wide flood plains, riffles, ponds and marshes, were surveyed more species than 1stand 2ndsections constructed by artificial and non-ecological materials, such as concrete materials and narrow and straight flow channels. As a result, in stream restoration for ecological purpose, naturalized river or ecological river formation and management, rapid ecological changes would appear in the early 1stand 2ndyears, and artificial energy were included to reduce species disturbance. In that time, the stream ecosystem could be stabilized after restoration in the early three years or so.

On the conflicting generic delineation in the Onopordum group (Compositae, Cardueae - Carduinae): a combined nuclear and plastid molecular approach

2008 ◽  
Vol 21 (4) ◽  
pp. 301 ◽  
Author(s):  
Núria Garcia-Jacas ◽  
Mercè Galbany-Casals ◽  
Kostyantyn Romashchenko ◽  
Alfonso Susanna
Keyword(s):  
Dna Sequences ◽  
Second Life ◽  
Life Form ◽  
Plastid Dna ◽  
Life Forms ◽  
Morphological Characters ◽  
Central Asian ◽  
Perennial Herbs ◽  
Natural Groups ◽  
Sectional Rank

The limits of the genera that compose the Onopordum group of the Cardueae–Carduinae are difficult to establish. There are two main life forms; one is exemplified in the genus Onopordum, which includes only biennial colonisers in the Mediterranean region and temperate Eurasia; the second life form is exemplified in the group of perennial herbs of the genera Alfredia, Ancathia, Lamyropappus, Olgaea, Synurus, Syreitschikovia and Xanthopappus, all of them growing in the mountains of central Asia. We explored relationships among the genera of the complex by using Bayesian and parsimony analyses of a combined dataset of nuclear and plastid DNA sequences. Our results confirmed that the group is natural and the two life forms correspond to well defined entities. Generic limits within the eight central Asian genera are, however, very difficult to establish. Our results suggested that the present genus circumscription is artificial, especially for the largest genus, Olgaea, which appears paraphyletic. Some solutions are suggested. The most preferable might be lumping all small genera together in a broadly redefined genus Alfredia, and assigning sectional rank to the natural groups that result from correlating morphology with our molecular results. However, none of the possible solutions is free of problems because morphological characters and molecular phylogeny are not fully congruent. Some considerations on the origin and peculiar adaptations for becoming a successful coloniser shown by Onopordum are also offered, finding parallels to these adaptations in other examples of biennial colonisers within subtribe Carduinae.

Priming effects on seed germination of two perennial herb species in a disturbed lava field in central Mexico

2018 ◽  
Vol 28 (1) ◽  
pp. 63-71
Author(s):  
Jafet Belmont ◽  
María E. Sánchez-Coronado ◽  
Helia R. Osuna-Fernández ◽  
Alma Orozco-Segovia ◽  
Irene Pisanty
Keyword(s):  
Seed Germination ◽  
Perennial Herb ◽  
Germination Capacity ◽  
Short Term ◽  
Potential Applications ◽  
Successional Species ◽  
Cultivated Species ◽  
Perennial Herbs ◽  
Herb Species ◽  
Seed Coats

AbstractPriming has proved to enhance seed germination, but most of the research dealing with this topic has been carried out with cultivated species. The potential applications that this process has on wild species, which can be useful for restoration, are usually overlooked. This study analyses the germination response after natural priming and hydropriming of Penstemon roseus and Castilleja tenuiflora, two perennial herbs growing in a protected area known as ‘Parque Ecológico de la Ciudad de México’. Photoblastism was evaluated for both species. Seeds were exposed to a hydration/dehydration cycle and then placed in germination chambers to determine responses to hydropriming. To identify the effects of natural priming, seeds were buried in natural conditions and then recovered every two months and placed in germination chambers. Germination percentages and rates were then quantified. Both species proved to have permeable seed coats. Penstemon roseus seeds are positive photoblastic whereas C. tenuiflora seeds are indifferent to light. Priming methods increased C. tenuiflora germination rates, but they did not affect germination capacity. For P. roseus, priming methods did not improve germination rates, and germination capacity of recovered seeds decreased after the rainy season, suggesting that P. roseus forms a short-term, transient, seed bank. The germination strategies of these two species allow them to occupy suitable microsites for germination and establishment. These responses can be helpful in developing restoration programmes based on the accelerated establishment of native and characteristic successional species.

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