Dispersal of Arceuthobiumpusillum seeds

1986 ◽  
Vol 16 (1) ◽  
pp. 1-5 ◽  
Author(s):  
F. A. Baker ◽  
D. W. French
Keyword(s):  
Seed Dispersal ◽  
Dwarf Mistletoe ◽  
Fruit Abortion ◽  
The Mean ◽  
Number Of Seeds

Seed dispersal of Arceuthobiumpusillum Peck on Piceamariana (Mill.) B.S.P. was studied at two locations in Minnesota from 1974–1980. Seed dispersal began as early as August 23 and was observed as late as September 27. Most seeds were dispersed in the mornings between 0400 and 0900. The mean annual distance of dispersal ranged from 1.0 to 2.3 m. The density of seeds trapped on the plots ranged from 4.2 to 16.7 seeds/m2. At both locations, the number of seeds trapped outside the stand decreased logarithmically with distance from the source trees. Within stands, seeds were more frequently trapped 1–4 m from source trees than under them. Most seed dispersal occurred 1-3 days after rain. Seeds were dispersed normally on 23 of 30 days when minimum temperatures were less than 0 °C. Fruit abortion was noted on four occasions. Insects were not found to carry dwarf mistletoe seeds.

Dispersal and survival of seed of eastern dwarf mistletoe

1976 ◽  
Vol 6 (3) ◽  
pp. 335-340 ◽  
Author(s):  
George Hudler ◽  
D. W. French
Keyword(s):  
Seed Dispersal ◽  
Black Spruce ◽  
Substantial Reduction ◽  
The Other ◽  
Horizontal Distance ◽  
Dwarf Mistletoe ◽  
Fruit Abortion ◽  
The Mean ◽  
Freezing Temperatures

Seed dispersal of eastern dwarf mistletoe (Arceuthobiumpusillum) parasitizing black spruce (Piceamariana) in the Fond du Lac State Forest, Carlton Co., Minnesota, U.S.A., began in the 1st week of September and continued until the first frost. Most seeds were discharged during the first 3 h after sunrise. Seed expulsion was a function of rising temperature during that time. The mean horizontal distance travelled by discharged seeds was 1.65 m. One seed travelled 13.7 m. Freezing temperatures on August 31, 1970, caused nearly complete fruit abortion in that year of the study and caused a substantial reduction in seed discharge in the other 2 years. Of 3200 seeds placed on the needles of healthy black spruce in September 1971, only 6.5% of the seeds had germinated by August 1972.

scholarly journals Morphological characterization and genetic diversity in lentil (Lens culinaris medikus ssp. Culinaris) germplasm

2014 ◽  
Vol 4 (1) ◽  
pp. 70-76
Author(s):  
KU Ahamed ◽  
B Akhter ◽  
MR Islam ◽  
MR Humaun ◽  
MJ Alam
Keyword(s):  
Seed Weight ◽  
Female Flower ◽  
Morphological Characterization ◽  
Flower Initiation ◽  
Mean Values ◽  
Maximum Value ◽  
Cluster Distance ◽  
The Mean ◽  
100 Seed Weight ◽  
Number Of Seeds

Genetic divergence of 110 lentil germplasm with checks was assessed based on morphological traits using multivariate analysis. Mahalanobis generalized distance (D2) analysis was used to group the lentil genotypes. Significant variations among lentil genotypes were observed in respect of days to 1st flowering, days to 50% flowering, days to maturity, plant height, and number of pods per peduncle, number of pods per plant, number of seeds per plant, 100 seed weight and yield per plant. Considering the mean values, the germplasm were grouped into ten clusters. The highest number of genotypes (17) was in cluster X and lowest (5) both in cluster II and IV. Cluster IV had the highest cluster mean for number of pods per plant (297.08), number of seeds per plant (594.16), 100 seed weight (1.44 g) and yield per plant (8.53 g). Among them, the highest inter-cluster distance was obtained between the cluster IV and I (24.61) followed by IV and III (22.33), while the lowest was between IX and II (1.63). The maximum value of inter-cluster distance indicated that genotypes belonging to cluster IV were far diverged from those of cluster I. The first female flower initiation was earlier in BD-3812 (49 days) in cluster I and cluster IV had highest grain yield per plant (8.53). BD-3807 produced significant maximum number of pods per plant (298.40) in cluster IV. DOI: http://dx.doi.org/10.3329/ijarit.v4i1.21095 Int. J. Agril. Res. Innov. & Tech. 4 (1): 70-76, June, 2014

Wind-mediated seed dispersal of invasive forage grasses from agricultural grasslands in Hokkaido, Japan

2019 ◽  
Vol 12 (02) ◽  
pp. 133-141
Author(s):  
Chika Egawa ◽  
Atsushi Shoji ◽  
Hiroyuki Shibaike
Keyword(s):  
Seed Dispersal ◽  
Poa Pratensis ◽  
Plant Cover ◽  
Kentucky Bluegrass ◽  
Dispersal Distance ◽  
Phleum Pratense ◽  
Grass Species ◽  
Forage Grass ◽  
Forage Grasses ◽  
Number Of Seeds

AbstractAlthough introduced pasture grasses are essential for forage production in current livestock farming, some species cause serious impacts on native biodiversity when naturalized. Information on the seed dispersal of invasive forage grasses from cultivated settings to surrounding environments can inform management efforts to prevent their naturalization. In this case study, we quantified the wind-mediated seed dispersal distance and amount of dispersed seed of invasive forage grasses from agricultural grasslands in Hokkaido, northern Japan. In total, 200 funnel seed traps were installed around three regularly mown grasslands and one unmown grassland where various forage grass species were grown in mixture. Seeds of each species dispersed outside the grasslands were captured from May to October 2017. Based on the trapped distances of seeds, the 99th percentile dispersal distance from the grasslands was estimated for six species, including timothy (Phleum pratense L.), orchardgrass (Dactylis glomerata L.), and Kentucky bluegrass (Poa pratensis L.). For two dominant species, P. pratense and D. glomerata, the numbers of seeds dispersed outside the field under mown and unmown conditions were determined under various plant cover situations. The estimated dispersal distances ranged from 2.3 m (P. pratense) to 31.5 m (P. pratensis), suggesting that areas within approximately 32 m of the grasslands are exposed to the invasion risk of some forage grass species. For both P. pratense and D. glomerata, the number of seeds dispersed outside the unmown grassland exceeded 100 seeds m−2 under high plant cover situations, while the number of seeds dispersed from the mown grasslands at the same plant cover level was less than one-third of that number. The results suggest that local land managers focus their efforts on frequent mowing of grasslands and monitoring of the areas within approximately 32 m of the grasslands to substantially reduce the naturalization of invasive forage grasses.

Pattern and impact of hornbill seed dispersal at nest trees in a moist evergreen forest in Thailand

2004 ◽  
Vol 20 (5) ◽  
pp. 545-553 ◽  
Author(s):  
Shumpei Kitamura ◽  
Takakazu Yumoto ◽  
Pilai Poonswad ◽  
Naohiko Noma ◽  
Phitaya Chuailua ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Breeding Season ◽  
Seedling Survival ◽  
Evergreen Forest ◽  
Seedling Mortality ◽  
Entire Process ◽  
Nest Sites ◽  
Seed Deposition ◽  
Number Of Seeds

Following the entire process of frugivore seed dispersal, from intake of seeds to seed deposition, is a difficult task. One alternative is to monitor areas of heavy seed rain deposited by animals. We quantified the number of seeds deposited by hornbills and followed the fates of these seedlings for 3 y to evaluate the effectiveness of hornbill seed dispersal at nest trees, on the basis of seedling survival. For 14 mo, fallen fruits and seeds were collected in traps established around four nest trees of each of two hornbill species (Aceros undulatus and Anthracoceros albirostris) and the seedlings were monitored in adjacent quadrats. Seedfall and seedlings of species represented in hornbill diets occurred at significantly higher densities in the traps/quadrats in front of nest cavities than in other traps/quadrats. Fewer seedling species and individuals germinated under nest trees than expected from the composition of the seedfall. Our results suggest that the quality of hornbill seed dispersal might be poor at nest trees due to the highly concentrated seedfall, which results in high seed and seedling mortality. Although seed deposition at nest trees is a useful guide to hornbill diet during the breeding season, it is clearly not of benefit to the plants involved. However, the pattern and consequences of hornbill seed dispersal at nest sites is likely very different from that during the non-breeding season.

Characterisation of naturalised strains of Trifolium subterraneum var. brachycalycinum cv. Clare in northern New South Wales

1994 ◽  
Vol 34 (1) ◽  
pp. 33 ◽  
Author(s):  
GM Lodge
Keyword(s):  
Seed Weight ◽  
New South ◽  
New South Wales ◽  
Trifolium Subterraneum ◽  
Summer Rainfall ◽  
Median Number ◽  
South Wales ◽  
The Mean ◽  
Floral Characters ◽  
Number Of Seeds

Burrs were collected from paddocks on 3 properties in northern New South Wales where the age of the Trifolium subterraneum var. brachycalycinum cv. Clare swards varied from 19 to 28 years. At 1 site burrs were also sampled from swards sown 2 and 10 years previously. Twenty seedlings from these burrs and 20 plants of certified cv. Clare were grown as spaced plants in a nursery. These were assessed for vegetative and floral characters, flowering time, number of seeds per burr, seed weight, and percentage hardseed after storage at 25/25�C for 6 months and 25/45�C for a further 6 months. For most plants the mean number of days from sowing to first flower was similar to that of Clare. Compared with the naturalised strains, Clare had the lowest (P<0.05) mean number of seeds per burr: about 25% below the mean of the strains (2.7 seeds per burr). While the lowest mean seed weights of the strains were not significantly different from those of Clare, the seed weights of plants from 3 sites were higher (P<0.05) than those of Clare. After storage for either 6 or 12 months, hardseed levels were also lowest (P<0.05) for Clare. Plants from the 2-year-old sward had the same median number of seeds per burr (2.0) as Clare. As sward age increased, the median number of seeds per burr increased to 2.8. Hardseed percentages were lowest for plants of Clare and for those from the 2-year-old sward after 6 months, and for Clare after 12 months. These studies indicated the presence of divergent strains in old swards of Clare in a summer rainfall environment. Natural selection among variability within Clare is the most likely reason for the development of these strains in an environment marginal for the long-term persistence of this softseeded cultivar. Although strains had the same vegetative and floral markings as Clare, differences in ecologically important characters such as number of seeds per burr, seed weight, and hardseededness may result in plants that are better adapted to the environment in which they evolved. From these studies 23 plants of T. subterraneum var. brachycalycinum were selected for further evaluation.

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.

scholarly journals Consequences of intraspecific variation in seed dispersal for plant demography, communities, evolution and global change

AoB Plants ◽  
2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Rebecca S Snell ◽  
Noelle G Beckman ◽  
Evan Fricke ◽  
Bette A Loiselle ◽  
Carolina S Carvalho ◽  
...  
Keyword(s):  
Global Change ◽  
Seed Dispersal ◽  
Intraspecific Variation ◽  
Individual Variation ◽  
Temporal Dynamics ◽  
Biodiversity Loss ◽  
Mean Value ◽  
Plant Fitness ◽  
Spatial And Temporal Dynamics ◽  
The Mean

AbstractAs the single opportunity for plants to move, seed dispersal has an important impact on plant fitness, species distributions and patterns of biodiversity. However, models that predict dynamics such as risk of extinction, range shifts and biodiversity loss tend to rely on the mean value of parameters and rarely incorporate realistic dispersal mechanisms. By focusing on the mean population value, variation among individuals or variability caused by complex spatial and temporal dynamics is ignored. This calls for increased efforts to understand individual variation in dispersal and integrate it more explicitly into population and community models involving dispersal. However, the sources, magnitude and outcomes of intraspecific variation in dispersal are poorly characterized, limiting our understanding of the role of dispersal in mediating the dynamics of communities and their response to global change. In this manuscript, we synthesize recent research that examines the sources of individual variation in dispersal and emphasize its implications for plant fitness, populations and communities. We argue that this intraspecific variation in seed dispersal does not simply add noise to systems, but, in fact, alters dispersal processes and patterns with consequences for demography, communities, evolution and response to anthropogenic changes. We conclude with recommendations for moving this field of research forward.

Reproductive schedule of Medicago lupulina (Leguminosae) in a patchy environment

1985 ◽  
Vol 63 (11) ◽  
pp. 2044-2048 ◽  
Author(s):  
L. V. Pavone ◽  
R. J. Reader
Keyword(s):  
Drought Stress ◽  
Habitat Type ◽  
Ground Cover ◽  
Growing Season ◽  
Patchy Environment ◽  
Risk Of Death ◽  
Medicago Lupulina ◽  
The Mean ◽  
First Time ◽  
Number Of Seeds

Reproductive schedules for cohorts of Medicago lupulina seedlings were compared in adjacent habitats, distinguished by the presence or absence of a ground cover of mosses. The objective of the study was to determine how the reproductive schedule of a single taxon changes in a patchy environment (i.e., where risk of death changes with habitat type). The mortality rate was higher where mosses were absent, probably because of increased drought stress. In both habitats some plants reproduced for the first time in their second growing season, but the percentage reproducing for the first time in their third or fourth growing season was greater at moss-covered sites (15%) than at moss-free sites (4%). Fewer plants reproduced either once or repeatedly in the moss-free habitat (10% once, 1% repeatedly) than in the moss-covered habitat (18% once, 7% repeatedly). However, the mean number of seeds produced per plant was greater at moss-free sites (0–93) than at moss-covered sites (0–27). These results indicate that the timing, frequency, and amount of reproduction will all change where a species experiences different microhabitats within a patchy environment.

scholarly journals Pollination Efficiency of Amegilla calens (Hymenoptera: Apidae) on Gossypium hirsutum L. (Malvaceae) Variety L457 Flowers at Meskine (Maroua, Cameroon)

2021 ◽  
Author(s):  
Issaya Kodji issaya ◽  
Beaudelaine Stephanie Kengni ◽  
Tope Sidonie Fameni ◽  
Fohouo Fernand-Nestor Tchuenguem
Keyword(s):  
Foraging Behaviour ◽  
Seed Quality ◽  
Pollination Efficiency ◽  
Gossypium Hirsutum L ◽  
Flower Visit ◽  
Single Flower ◽  
The Mean ◽  
Seed Yields ◽  
The Impact ◽  
Number Of Seeds

This study was carried out to evaluate the impact of Amegilla calens bee on fruit and seed yields of G. hirsutum in an experimental field, in September 2018 and 2019. The experiments were carried out on 540 flowers divided in four treatments: 120 flowers accessible to all visitors; 120 flowers bagged to avoid all visits; 200 flowers protected and uncovered when they were opened, to allow A. calens visits; 100 flowers bagged then uncovered and rebagged without the visit of insects or any other organism. Bees daily rhythm of activity, its foraging behaviour on flowers, its pollination efficiency, the fruiting rate, the number of seeds per fruit and the percentage of normal seeds were evaluated. Results indicate that among 11 insect species recorded on flowers, X. olivacea ranked second and harvested nectar. Throughout the pollination efficiency of a single flower visit, X. olivacea provoked a significant increase of the podding rate, the mean number of seeds per pod, the percentage of normal seeds and the mean weight of a seed by 39.48 %, 18.19 %, 49.62 % and 31.53 % respectively. The conservation and installation of X. olivacea nests close to P. vulgaris fields is recommended to improve its pod production and seed quality.

scholarly journals Internal seed dispersal by parrots: an overview of a neglected mutualism

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1688 ◽  
Author(s):  
Guillermo Blanco ◽  
Carolina Bravo ◽  
Erica C. Pacifico ◽  
Daniel Chamorro ◽  
Karina L. Speziale ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Plant Species ◽  
Fruit Size ◽  
Food Plants ◽  
Size Difference ◽  
Population Declines ◽  
Columnar Cacti ◽  
Parrot Species ◽  
The Mean ◽  
Germination Experiments

Despite the fact that parrots (Psitacifformes) are generalist apex frugivores, they have largely been considered plant antagonists and thus neglected as seed dispersers of their food plants. Internal dispersal was investigated by searching for seeds in faeces opportunistically collected at communal roosts, foraging sites and nests of eleven parrot species in different habitats and biomes in the Neotropics. Multiple intact seeds of seven plant species of five families were found in a variable proportion of faeces from four parrot species. The mean number of seeds of each plant species per dropping ranged between one and about sixty, with a maximum of almost five hundred seeds from the cactiPilosocereus pachycladusin a single dropping of Lear’s Macaw (Anodorhynchus leari). All seeds retrieved were small (<3 mm) and corresponded to herbs and relatively large, multiple-seeded fleshy berries and infrutescences from shrubs, trees and columnar cacti, often also dispersed by stomatochory. An overview of the potential constraints driving seed dispersal suggest that, despite the obvious size difference between seeds dispersed by endozoochory and stomatochory, there is no clear difference in fruit size depending on the dispersal mode. Regardless of the enhanced or limited germination capability after gut transit, a relatively large proportion of cacti seeds frequently found in the faeces of two parrot species were viable according to the tetrazolium test and germination experiments. The conservative results of our exploratory sampling and a literature review clearly indicate that the importance of parrots as endozoochorous dispersers has been largely under-appreciated due to the lack of research systematically searching for seeds in their faeces. We encourage the evaluation of seed dispersal and other mutualistic interactions mediated by parrots before their generalized population declines contribute to the collapse of key ecosystem processes.

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