Pollination in an understorey vine, Smilax rotundifolia, a threatened plant of the Carolinian forests in Canada

1991 ◽  
Vol 69 (11) ◽  
pp. 2555-2559 ◽  
Author(s):  
Peter G. Kevan ◽  
John D. Ambrose ◽  
James R. Kemp
Keyword(s):  
Key Words ◽  
Threatened Species ◽  
Habitat Management ◽  
Seed Set ◽  
Wind Dispersal ◽  
Viscin Threads ◽  
Floral Form ◽  
Fruit And Seed Set ◽  
Management And Conservation ◽  
Key Words Dioecy

Round-leaved greenbrier, Smilax rotundifolia L. (Liliaceae), is an insect-pollinated, dioecious, understorey vine. Its pollen is linked by viscin threads, effectively preventing wind dispersal. In most sites populations are not sexually reproductive, being unisexual, but do not spread vegetatively. Where both sexes occur, fruits and seeds are produced naturally. Artificial cross-pollinations can enhance the level of fruit and seed set. Understanding the biology of this threatened species is important for habitat management and conservation. Key words: dioecy, greenbrier, viscin, floral form, conservation, pollination.

DETERMINATION OF AFTER-RIPENING PERIOD AND HORMONAL RESPONSE OF OROBANCHE SOLMSII C.D. CLARKE SEEDS

1970 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Bista ◽  
G. B. Khattri ◽  
B. D. Acharya ◽  
S. C. Srivastava
Keyword(s):  
Growth Hormone ◽  
Seed Germination ◽  
Key Words ◽  
Incubation Period ◽  
Seed Set ◽  
Summer Season ◽  
Conditioning Period ◽  
Root Parasite ◽  
One Year

To find out the ability of Orobanche seeds to germinate immediately after seed set, seeds were germinated periodically at an interval of three months for one year in GR24. Some Orobanche seeds were capable of germination immediately after seed set but most required about nine months as after ripening or incubation period to be able to germinate. The phenomenon of after ripening in Orobanche seeds could be taken as an ecological measure to dormant over following unfavorable wet summer season. The growth hormone studies on Orobanche seed germination have shown that GA3 at a concentration of 100 ppm substantially enhanced seed germination when applied during pre-conditioning period. NAA showed some stimulatory effect at 0.5 - 1.0 ppm when applied during post-conditioning period but the hormone if applied during pre-conditioning period inhibited the germination. Kinetin failed to stimulate the germination at all the concentrations tested. Key words: Germination, root-parasite, hormone. Ecoprint Vol.11(1) 2004.

scholarly journals Phloem-Feeding Herbivores Affect Floral Development and Reproduction in the Etruscan Honeysuckle (Lonicera etrusca Santi)

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 815
Author(s):  
Sandra V. Rojas-Nossa ◽  
José María Sánchez ◽  
Luis Navarro
Keyword(s):  
Fruit Set ◽  
Floral Development ◽  
Seed Set ◽  
Wild Populations ◽  
Ecological Processes ◽  
Trade Offs ◽  
Complex Landscape ◽  
Fruit And Seed Set ◽  
Phloem Feeding ◽  
Growth And Reproduction

Floral development depends on multifactor processes related to genetic, physiological, and ecological pathways. Plants respond to herbivores by activating mechanisms aimed at tolerating, compensating, or avoiding loss of biomass and nutrients, and thereby survive in a complex landscape of interactions. Thus, plants need to overcome trade-offs between development, growth, and reproduction vs. the initiation of anti-herbivore defences. This study aims to assess the frequency of phloem-feeding herbivores in wild populations of the Etruscan honeysuckle (Lonicera etrusca Santi) and study their effects on floral development and reproduction. The incidence of herbivory by the honeysuckle aphid (Hyadaphis passerinii del Guercio) was assessed in three wild populations of the Iberian Peninsula. The effect of herbivory on floral morphology, micromorphology of stigmas and pollen, floral rewards, pollination, and fruit and seed set were studied. The herbivory by aphids reduces the size of flowers and pollen. Additionally, it stops nectar synthesis and causes malformation in pollen and microstructures of stigmas, affecting pollination. As a consequence, fruit set and seed weight are reduced. This work provides evidence of the changes induced by phloem-feeding herbivores in floral development and functioning that affect the ecological processes necessary to maintain the reproductive success of plants.

Identifying germination opportunities for threatened plant species in episodic ecosystems by linking germination profiles with historic rainfall events

2019 ◽  
Vol 67 (3) ◽  
pp. 256 ◽  
Author(s):  
Carole P. Elliott ◽  
Wolfgang Lewandrowski ◽  
Ben P. Miller ◽  
Matthew Barrett ◽  
Shane R. Turner
Keyword(s):  
Threatened Species ◽  
Effective Management ◽  
Environmental Filters ◽  
Rainfall Events ◽  
Upper Limit ◽  
Threatened Plant Species ◽  
Climate Interactions ◽  
Rainfall Patterns ◽  
Management And Conservation

Dynamic processes of seed germination, influenced by niche–climate interactions, underpin successful seedling establishment. For threatened species with niches restricted to specific landforms, such as Banded Ironstone Formations (BIF), understanding germination opportunities in relation to long-term rainfall patterns can be critical for management. We quantified germination profiles (germinating fraction and speed with varying dormancy states) from six taxonomically diverse threatened species that are endemic to BIF in Western Australia, and related this to historic rainfall patterns and events. The upper limit of the germination profiles (i.e. for dormancy-alleviated seed) was 1.2–60 times higher (germinating fraction; Gmax) and 1.1–4 times faster (T10) than the lower profile limit (i.e. dormancy not alleviated) in the physiologically dormant species studied (Tetratheca paynterae Alford subsp. paynterae and T. erubescens J.P.Bull; Ricinocarpos brevis R.J.F.Hend. & Mollemans; Darwinia masonii C.A.Gardner; Lepidosperma gibsonii R.L.Barrett). Seeds of Banksia arborea (C.A.Gardner) A.R.Mast & K.R.Thiele are non-dormant and had a germination profile similar to this upper limit. The minimum period of moisture required for germination was less than eight consecutive days and our simple moisture model, based on historic rainfall patterns for their localities, indicated that these periods have likely occurred 16 times in the last 100 years. We suggest that these BIF species are likely committing to germination during heightened rainfall periods, despite these periods being infrequent and irregular. Understanding the germination profiles of range-restricted species provides important insights into the environmental filters regulating recruitment and supports the development of more effective management and conservation approaches for protecting these species.

The reproductive ecology of island populations of distylous Menyanthes trifoliata (Menyanthaceae)

1998 ◽  
Vol 76 (5) ◽  
pp. 818-828 ◽  
Author(s):  
Faye L Thompson ◽  
Luise A Hermanutz ◽  
David J Innes
Keyword(s):  
Seed Set ◽  
Aquatic Macrophyte ◽  
Pollen Limitation ◽  
Bimodal Distribution ◽  
Stabilizing Selection ◽  
Long Distance ◽  
Anther Length ◽  
Reciprocal Arrangement ◽  
Fruit And Seed Set ◽  
Menyanthes Trifoliata

Menyanthes trifoliata L. is a distylous, clonal aquatic macrophyte found in shallow bogs and river margins throughout the boreal ecosystem, including the island of Newfoundland. A combination of long-distance dispersal and colonization after deglaciation, and pollen limitation resulting from reduced pollinator diversity and abundance documented on islands, predicts the breakdown of heterostyly to favour the establishment of self-compatible homostyles on islands. To test if self-fertilizing homostyles have been selected, variation in floral characters and compatibility relationships were examined in M. trifoliata populations from the Avalon Peninsula of Newfoundland. Morph ratio and its effect on fruit and seed set were examined in nine populations. Of the seven dimorphic populations, morphs occurred in a 1:1 ratio in four populations and deviated significantly from a 1:1 ratio in three populations. The two populations monomorphic for either pin or thrum morphs set few fruits or seeds (<15%). A strictly reciprocal arrangement of stigma height and anther length was not observed between pin and thrum morphs in the majority of populations studied. Stigma-anther separation showed a bimodal distribution with few intermediate "homostylous" flowers, rather than the discreet bimodal distribution typical of distylous species. Fruit and seed set were high (>60%) in equal morph ratio populations and were not significantly correlated to stigma-anther separation, indicating that there was no selective advantage of being homostylous. All three populations tested were highly self-incompatible, confirming that there has not been a breakdown of heterostyly on the island of Newfoundland. A reduced pollinator fauna typical of island environments may have relaxed stabilizing selection for strict herkogamy between floral morphs, resulting in the observed lack of reciprocity.Key words: Menyanthes trifoliata, distyly, homostyle, reciprocal herkogamy, clonal aquatic macrophyte, island of Newfoundland.

The consequences of mixed pollination on seed set in Vaccinium corymbosum

1991 ◽  
Vol 69 (11) ◽  
pp. 2448-2454 ◽  
Author(s):  
S. P. Vander Kloet
Keyword(s):  
Key Words ◽  
Seed Set ◽  
Vaccinium Corymbosum ◽  
Viable Seed ◽  
Maturation Time ◽  
Embryo Abortion ◽  
Berry Ripening ◽  
Time Required ◽  
Compatible Pollen ◽  
Berry Maturation

Self pollen of Vaccinium corymbosum germinates as well as outcross (compatible) pollen from the same population and more rapidly than compatible pollen from more distant populations. When a mixture of self and compatible pollen, either from the same or incontiguous populations, is applied to the stigma, the time required for berry ripening is significantly reduced compared with compatible pollen alone, although seed set also decreases significantly. Adding compatible pollen from different pollen donors significantly increased seed set but also increased the time for berry maturation by 5 days. Self pollen in conjunction with compatible pollen resulted in a 50% loss of viable seed production and an 8% gain in berry maturation time. Self-pollination resulted in embryo abortion in V. corymbosum. Key words: pollination, Vaccinium, seed set, outcrossing.

The importance of aquatic and terrestrial habitat for the European pond turtle (Emys orbicularis): implications for conservation planning and management

2004 ◽  
Vol 82 (11) ◽  
pp. 1704-1712 ◽  
Author(s):  
G F Ficetola ◽  
E Padoa-Schioppa ◽  
A Monti ◽  
R Massa ◽  
F De Bernardi ◽  
...  
Keyword(s):  
Habitat Management ◽  
Terrestrial Habitat ◽  
Po River ◽  
Emys Orbicularis ◽  
Point Counts ◽  
Pond Turtle ◽  
Life History Stages ◽  
Conservation Plans ◽  
Management And Conservation ◽  
Water Eutrophication

The European pond turtle, Emys orbicularis (L., 1758), is threatened throughout its distribution, prompting management of habitats and populations for conservation. Quantitative data on habitat requirements for this species are needed to better evaluate which areas are the most suitable, or what actions can improve habitat suitability. We studied relationships between the distribution and abundance of E. orbicularis and the environment by analysing water quality and features of 39 wetland and upland habitats in the Po River delta of northern Italy; visual transects and point counts were used to determine turtle presence and relative abundance. Emys orbicularis occurs more frequently and abundantly in permanent wetlands surrounded by woodlands, and its presence does not appear to be related to water eutrophication. Woodlands strongly influence adjacent wetland features and may be important for turtles' terrestrial activities such as nesting and dispersal. Habitat management and conservation plans for E. orbicularis should include protection of extensive terrestrial woodland habitat containing diverse wetland systems, to support turtle survival at different life-history stages. The requirements for wetlands and natural terrestrial habitat are difficult to meet in the currently human-dominated European lowlands; nevertheless, conservation plans for this species should take a broad-scale approach.

scholarly journals Genetic Variability in Flower Attractiveness to Honeybees (Apis mellifera L.) within the Genus Citrullus

HortScience ◽  
1999 ◽  
Vol 34 (5) ◽  
pp. 860-863 ◽  
Author(s):  
S. Wolf ◽  
Y. Lensky ◽  
N. Paldi
Keyword(s):  
Genetic Variability ◽  
Positive Relationship ◽  
Seed Set ◽  
Pollen Grains ◽  
Vegetable Crops ◽  
Total Sugars ◽  
Nectar Volume ◽  
Limiting Step ◽  
Nectar Sugar ◽  
Fruit And Seed Set

Fruit and seed set in insect-pollinated agricultural crops rely primarily on honeybees because of their ease of management and transportation. In many fruit and vegetable crops, the number of bee visitations can be the limiting step in obtaining optimal yield. Increasing the attractiveness of flowers to honeybees could, therefore, provide a useful means of improving fruit yield and seed production. Genetic variability in attractiveness to honeybees was found within the genus Citrullus. The number of daily visits per flower ranged from six to 12 among cultivars. Moreover, most of the visits to the more attractive cultivars occurred in the first hour of bee activity, whereas visits to the less attractive cultivars started later in the morning. A positive relationship was found between the frequency of bee visitations and seed number per fruit. Analyses of floral attributes indicated no genetic variability in flower size, amount of pollen grains, or nectar volume; however, differences were observed in the concentration of sucrose and total sugars in the nectar. A positive relationship was found between attractiveness to bees and nectar sugar concentration, suggesting that this characteristic is one of the parameters responsible for variability in attractiveness to honeybees.

scholarly journals Comparative reproduction mechanisms of three species of Ocimum L. (Lamiaceae)

2016 ◽  
Vol 69 (1) ◽  
Author(s):  
Matthew Oziegbe ◽  
Temitope Olatayo Kehinde ◽  
Joshua Olumide Matthew
Keyword(s):  
Reproductive System ◽  
Seed Set ◽  
Ocimum Basilicum ◽  
The Self ◽  
Self Pollination ◽  
Insect Visitation ◽  
Open Treatment ◽  
Fruit And Seed Set

<em>Ocimum</em> species have a combination of reproductive system which varies with the locality and cultivar. We have studied here the reproductive mechanisms of five variants of three <em>Ocimum</em> species in Nigeria, namely: <em>Ocimum canum</em> Sims., <em>O. basilicum</em> L., and <em>O. americanum</em> L. Flowers from each variant were subjected to open and bagged pollination treatments of hand self-pollination, spontaneous self-pollination and emasculation. All open treatments of the five <em>Ocimum</em> variants produced more fruit and seed than the corresponding bagged treatments. The two <em>O. canum</em> variants and <em>O. basilicum</em> ‘b<span><sub>1</sub></span>’ produced high fruit and seed set in the open and bagged treatments of spontaneous self-pollination. <em>Ocimum basilicum</em> ‘b<span><sub>2</sub></span>’ and <em>O. americanum</em> produced higher fruit and seed set in the self-pollination open treatment but significantly lower fruit and seed set in the bagged treatment. Fewer fruit and seeds were produced in the emasculated open treatments but none in the emasculated bagged treatments of the five <em>Ocimum</em> variants. The floral foragers comprising of bees, wasps and butterflies visited the <em>Ocimum</em> species to collect pollen or nectar in the open treatments. The two <em>O. canum</em> variants and <em>O. basilicum</em> ‘b<span><sub>1</sub></span>’ variant reproduced mainly through autogamy but <em>O. basilicum</em> ‘b<span><sub>2</sub></span>’ and <em>O. americanum</em> showed mixed reproduction of autogamy and outcrosssing. Insect visitation to the flowers enhanced pollination resulting in higher fruit and seed set in all the <em>Ocimum</em> species studied.

A Symposium on the Dingo. Edited by Chris Dickman and Daniel Lunney. A Review by Peter Thomson.

2001 ◽  
Vol 23 (2) ◽  
pp. 189
Author(s):  
P Thomson
Keyword(s):  
Threatened Species ◽  
Canis Lupus ◽  
New South ◽  
New South Wales ◽  
Species Conservation ◽  
Vulnerable Species ◽  
South Wales ◽  
Legislative Changes ◽  
Management And Conservation

A symposium on the dingo (Canis lupus dingo) was held in Sydney in May 1999 to discuss issues surrounding the conflicting views of the dingo: seen both as a potentially threatened species, and as a species that needs to be controlled because of its predation on livestock. The Symposium was particularly relevant to New South Wales (NSW) because of consideration being given to place the dingo on the schedule of NSW vulnerable species, under the NSW Threatened Species Conservation Act 1995. The potential for conflict was exacerbated by concurrent legislative changes in NSW (Rural Lands Protection Act 1998) requiring the Crown to control pest animals declared under the Act. Despite the obvious focus on the NSW situation, many of the issues discussed have wider relevance to the management and conservation of dingoes across Australia.

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