Pollination, capsule damage, and the production of seeds in Salix setchelliana (Salicaceae), an Alaskan glacial river gravel bar willow

1997 ◽  
Vol 75 (7) ◽  
pp. 1182-1187 ◽  
Author(s):  
D. A. Douglas
Keyword(s):  
Seed Production ◽  
Seed Predation ◽  
Wind Pollination ◽  
River Channels ◽  
Gravel Bars ◽  
Glacial River ◽  
Denali National Park ◽  
Potential Maximum ◽  
Number Of Seeds ◽  
Key Words Alpine

Salix setchelliana, a clonal prostrate willow, is a dominant species of glacial river gravel bars in Denali National Park, Alaska. This habitat, which is located between migrating river channels, is unpredictable in time, patchy in space, and essentially alpine in nature. The species takes advantage of both entomophily and anemophily, thus perhaps improving its success under these conditions. It is dependent primarily on insect pollination, carried out by a variety of species, but wind pollination accounted for 7–25% of seed production. The number of seeds per capsule was much below the potential maximum. Seed prédation, and probably insufficient pollination, influenced seed production. Prédation accounted for a 70% reduction in seed production per capsule in an open pollination treatment (P = 0.005). There were significant differences in number of seeds per capsule between collection sites (P = 0.0022). An inverse relationship was observed between seed predation levels and seed numbers in both insect-damaged and undamaged capsules. Key words: alpine, clonal, pollination, seed prédation.

scholarly journals Seed Production and Seedling Establishment of Parah Trees in Khao Nan National Park, Thailand

2017 ◽  
Vol 15 (3) ◽  
pp. 213-223
Author(s):  
Anun CHAROENSUK ◽  
Mullica JAROENSUTASINEE ◽  
Krisanadej JAROENSUTASINEE
Keyword(s):  
Seed Production ◽  
Seed Size ◽  
Seed Predation ◽  
Seedling Establishment ◽  
Forest Floor ◽  
Seed Weight ◽  
National Park ◽  
Seedling Height ◽  
Main Road ◽  
Number Of Seeds

Parah (Elateriospermum tapos Blume) is a native species of southern Thailand, and is a dominant tree in Khao Nan National Park. There have been few studies of Parah seeds or of seedling establishment. Biotic and abiotic environmental factors interact with seeds and may affect the future of tree populations. This is the first study to determine the factors affecting seeds and seedlings of Parah trees in Khao Nan National Park, Thailand, during 2014 - 2016. We tested 3 factors: (1) parental tree diameter at breast height (DBH), (2) altitude, and (3) distance from the main road. We studied seeds collected from trees, seeds harvested by humans, seed predation, seeds left on the forest floor, and rotten seeds. We measured seed weight, seed size, seedling height, and seedling root collar diameter (RCD). Our results showed that the number of seeds and seedlings per tree, seed weight, seed size, seed harvesting, seed predation, seeds left on the forest floor, rotten seeds, and seedling height varied between the years of study. There was no difference in seeds harvested by humans from 2014 - 2016. The number of seeds per tree and seeds harvested by humans were positively associated with parental tree DBH in 2015 and 2016. The number of seeds left on the forest floor was positively associated with parental tree DBH, and distance from the main road, but was negatively associated with altitude, in 2015, and there was no association in 2016. The number of seeds predated by frugivores was positively associated with altitude in 2016. The number of seedlings per tree was positively associated with distance from the main road. Seedling height was positively associated with distance from the main road, and negatively associated with tree DBH in 2015 and altitude in both years. We found significant results which led to the conclusion that seed production and seeds harvested by humans were positively associated with parental tree size.

Seed germination, seedling demography, and growth of Salix setchelliana on glacial river gravel bars in Alaska

1995 ◽  
Vol 73 (4) ◽  
pp. 673-679 ◽  
Author(s):  
D. A. Douglas
Keyword(s):  
Leaf Area ◽  
Plant Cover ◽  
Summer Precipitation ◽  
Seedling Demography ◽  
Younger Age ◽  
Percent Germination ◽  
Gravel Bars ◽  
Denali National Park ◽  
Seedling Leaf ◽  
Key Words Alpine

This study examines the recruitment from seed of Salix setchelliana Ball, a prostrate clonal willow, which grows in the gravel-bar habitat of glacial rivers in Denali National Park, Alaska. Seeds of this species did not exhibit any dormancy. Under laboratory conditions, seeds moistened immediately after collection showed 100% germination, and percent germination decreased with an increase in the length of dry storage. Since summer precipitation is generally frequent in this region, this is probably not a factor limiting recruitment. Most seedlings observed in the field were located on gravel bars with greater plant cover, as opposed to those with sparse plant cover. The survivorship of seedlings over their first winter averaged 11%; in comparison, yearly survivorship in years 1–6 averaged 69%. The most likely cause of mortality was insufficient carbohydrate accumulation. Seedling leaf area differed between years and locations. An inverse relationship was found between leaf area and age-class for seedlings of younger age-classes. Key words: alpine, clonal, recruitment.

Individual crop size increases predispersal predation by beetles in a tropical palm

2020 ◽  
pp. 1-4
Author(s):  
Morgana Maria Arcanjo Bruno ◽  
Klécia Gili Massi ◽  
Alexander V. Christianini ◽  
John du Vall Hay
Keyword(s):  
Seed Predation ◽  
Positive Influence ◽  
Reproductive Phenology ◽  
Individual Plant ◽  
Crop Size ◽  
Seed Predators ◽  
Plant Trait ◽  
Predispersal Seed Predation ◽  
Total Seed ◽  
Number Of Seeds

Abstract Predispersal seed predation is one of the main causes of seed mortality in plant populations, contributing to decreased plant recruitment. Seed loss has previously been found to be related to crop size. Thus, we examined the influence of individual crop size on predispersal seed predation by beetles in the palm Syagrus flexuosa in the Brazilian savanna. The study was carried out in three tropical woodland savanna sites, where we sampled the total seed crop of 46 fruiting palms and checked the presence of beetle larvae inside all seeds per plant. We observed predispersal seed predation of S. flexuosa from all sites and a high variation in the number of seeds preyed on per individual palm. Crop size had a positive influence on the number of seeds lost to predispersal seed predators. Variations in levels of predispersal seed predation may also be accounted for by the reproductive phenology of S. flexuosa. If fruits are not available at the same time, less resource is available for predators and therefore a high proportion of seeds may be preyed on. Thus, our study demonstrates that an individual plant trait, crop size, is an important predictor of beetle seed damage per palm and a driver of the number of seeds lost to predispersal seed predators.

scholarly journals Researches on the Main Characteristics of Red Clover Seedlings and their Influence in

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Marioara GREBENIȘAN ◽  
Doru PAMFIL ◽  
Dorottya Alice DOMOKOS
Keyword(s):  
Plant Breeding ◽  
Seed Production ◽  
Red Clover ◽  
Production Level ◽  
Seed Crop ◽  
Binding Process ◽  
Lower Variability ◽  
Clover Seed ◽  
Number Of Seeds

Concerning the red clover breeding, it is essential to choose as genitors those varieties that possess good characteristics. In order to identify potential genitors, two red clover varieties were studied at Cluj-Napoca: Roxana, diploid variety and Napoca-tetra, tetraploid variety. The analyzed traits comprised the number of capitula/plant, number of seeds/capitulum and the binding process, under the aspect of their contribution to the seed crop and the interaction between those components, in order to provide important clues about di-and tetraploid red clover seed production, for plant breeding. The highest variability (s%=30) presented regarding the number of flowers/capitulum, diploid variety comparatively with a lower variability (s%=26) regarding the number of flowers number/capitulum, tetraploid varieties. Several traits were compared between di-and tetraploid red clover varieties in order to find genitors which can be used for creating new genotypes with high seed production level.

Seed production in Cardiocrium cordatum: effects of nitrogen and dry mass availability of a plant

2006 ◽  
Vol 84 (5) ◽  
pp. 805-812
Author(s):  
Satoki Sakai ◽  
Akiko Sakai ◽  
Kohta Fujioka
Keyword(s):  
Mass Loss ◽  
Seed Production ◽  
Plant Size ◽  
Dry Mass ◽  
Stem Diameter ◽  
N Content ◽  
N Concentration ◽  
The Mean ◽  
Number Of Seeds

To clarify how seed production depends on the relative N and dry mass availability, we examined the number and size of seeds, and the loss of dry mass in Cardiocrium cordatum (Thunb.) Makaino plants that differed naturally in overall size and stem N content. After adjusting for plant size (basal stem diameter was used as a criterion of plant size), the amount of dry mass lost because of respiration in a plant decreased with an increase in the stem N content of the plant, whereas the total dry mass of seeds of a plant increased with an increase in the stem N content. Plants with a high stem N content relative to dry mass status used dry mass resources more efficiently in seed production by reducing the loss of dry mass. Plants with a higher stem N content produced a greater number of seeds, and the amount of dry mass lost decreased with an increase in the number of seeds of the plant, possibly because the resources allocated to seed production are consumed rapidly, if numerous seeds simultaneously absorb those resources. However, the stem N content of a plant had no influence on the mean seed dry mass, seed N content, and the seed N concentration, and the latter three parameters did not affect respiration loss of dry mass. We concluded that plants undergoing seed production reduce dry mass loss if their relative N to dry mass availability is high, through an increase in the numbers of seeds they produce.

The effect of defoliation on seed production by capeweed (Arctotheca calendula)

1973 ◽  
Vol 13 (65) ◽  
pp. 676 ◽  
Author(s):  
JG McIvor ◽  
DF Smith
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Yield Components ◽  
Seed Weight ◽  
Leaf Removal ◽  
Late Flowering ◽  
Individual Seed ◽  
Number Of Seeds

Two experiments were done in pots to assess the effect of defoliation at different times on the seed yield of capeweed (Arctotheca calendula). Yield components measured were: number of seedheads per plant, number of seeds per seedhead, number of seeds per plant, and weight of individual seeds. Of the components of yield, number of florets per seedhead and individual seed weight were maintained under all treatments; number of seedheads and number of seeds per seedhead were more affected by defoliation. Whether grown as spaced plants or in swards, leaf removal did not significantly reduce the number of seeds produced unless combined with bud and flower removal at late flowering only. The results are discussed in relation to the growth and persistence of capeweed in pastures.

AEC Glacier alpine bluegrass

2002 ◽  
Vol 82 (1) ◽  
pp. 95-98 ◽  
Author(s):  
B. A. Darroch ◽  
S. N. Acharya ◽  
J. Woosaree
Keyword(s):  
Key Words ◽  
Seed Production ◽  
Rapid Growth ◽  
Cultivar Description ◽  
High Elevations ◽  
Key Words Alpine

AEC Glacier alpine bluegrass, Poa alpina L., is a reclamation cultivar developed for use in reclaiming and revegetating disturbed sites at high elevations. It is the second alpine bluegrass cultivar released by the Alberta Environmental Centre, Vegreville, AB. This cultivar is expected to complement a prior release, AEC Blueridge alpine bluegrass. AEC Glacier is adapted to high elevations where it is capable of rapid growth and seed production. Key words: Alpine bluegrass, Poa alpina, cultivar description, reclamation

What determines the number of seed produced in a flowering event? A case study of Calyptrogyne ghiesbreghtiana (Arecaceae)

2000 ◽  
Vol 48 (5) ◽  
pp. 659 ◽  
Author(s):  
Saul A. Cunningham
Keyword(s):  
Resource Allocation ◽  
Seed Production ◽  
Natural Variation ◽  
Seed Set ◽  
Plant Seed ◽  
Flower Production ◽  
Number Of Seeds ◽  
Female Flowers

Calyptrogyne ghiesbreghtiana Linden ex. H. Wendl. is an understorey palm that occurs at La Selva Biological Station, Costa Rica. In this paper I combine analysis of natural variation and results of experimental manipulations to ask (1) what limits seed production? and (2) what processes cause variation in seed production by C. ghiesbreghtiana? The number of seed produced per inflorescence ofC. ghiesbreghtiana was limited substantially by the loss of female flowers to floral herbivores. Much variation in the number of seed produced perinflorescence of C. ghiesbreghtiana was due to losses of developing fruits to predators. Together these phenomena illustrate the influential role of natural enemies in the reproductive success of this plant. Seed-set efficiency (number of seeds/number of female flowers) was highly variable in this species, and such high levels of variation appear to be common in other species. For species with highly variable seed-set efficiency, the role of resource allocation to flower production in determining differences in seed production among individual plants is likely to be relatively small.

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