Seedling emergence and survival of Warea carteri (Brassicaceae), an endangered annual herb of the Florida Scrub

2007 ◽  
Vol 85 (7) ◽  
pp. 621-628 ◽  
Author(s):  
Carl W. Weekley ◽  
Eric S. Menges ◽  
Pedro F. Quintana-Ascencio
Keyword(s):  
Seedling Survival ◽  
Seedling Emergence ◽  
Annual Plants ◽  
Seedling Density ◽  
Florida Scrub ◽  
Seedling Emergence And Survival ◽  
History Of ◽  
Annual Herb ◽  
Winter Annual ◽  
Persistent Seed Bank

Seedling emergence and survival to flowering are critical processes in the life history of annual plants. We evaluated the importance of year and habitat on seedling emergence and the effects of year, habitat, timing of seedling emergence, and seedling density on survival of Warea carteri Small, an annual mustard endemic to Florida scrub. We tagged 1329 seedlings in 78 permanent 0.25 m2 quadrats in two habitats (scrub and disturbed) between 1999 and 2002 and followed seedlings monthly. Most (>80%) seedling emergence occurred between September and December. Emergence peaked 2 months earlier and was more variable in disturbed sites than in scrub. Seedling survival among years ranged from 3.5% to 12.0%. Seedling density varied from 1 to 75 per 0.25 m2 quadrat, with an overall median of 6.0. Survival was not density dependent. Median age at flowering ranged from 11.7 to 15.2 months, with late season recruits most likely to survive to flowering. Warea carteri recruits like a winter annual but flowers like a summer annual. Its delayed germination and a 12–15 month life span contribute to population cycling. Complete reproductive failure in unfavorable years, high seed production in favorable years, low rates of seed germination, and a persistent seed bank are consistent with predictions for an annual species in a variable habitat.

Seed-bank and seedling dynamics in Hyparrhenia hirta are influenced by herbicide application and mowing management

2012 ◽  
Vol 34 (2) ◽  
pp. 199 ◽  
Author(s):  
V. K. Chejara ◽  
P. Kristiansen ◽  
B. M. Sindel ◽  
R. D. B. Whalley ◽  
C. Nadolny
Keyword(s):  
Seed Bank ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Climatic Conditions ◽  
Control Treatment ◽  
Native Flora ◽  
Seedling Dynamics ◽  
Herbicide Treatments ◽  
Seedling Emergence And Survival

Hyparrhenia hirta (L.) Stapf (Coolatai grass) is a summer-active, C4 perennial tussock grass, native to southern Africa and the Mediterranean region, which has invaded areas of native flora in Australia in recent decades. Understanding its seed and seedling dynamics and how various management treatments (e.g. mowing, herbicide and no management) affect these may assist in identifying the conditions and management strategies required to limit its invasion. The population dynamics of H. hirta have not been comprehensively studied previously. A 2-year field experiment (December 2005–December 2007) was conducted to determine the seed-bank size, pattern of seedling emergence and survival of H. hirta seedlings at three sites in northern New South Wales, Australia, under three treatments: unmanaged (control), mowing and herbicide treatments. The density of H. hirta seeds in the soil at each experimental site under different treatments was measured in December 2005 at the start of the experiment, in December 2006 before the application of the second round of treatments and again at the end of the experiment in December 2007. Hyparrhenia hirta seedlings were assessed at monthly intervals in permanent quadrats (0.5 × 0.5 m) to determine seedling emergence and survival. Seedling emergence occurred on many occasions during the 2-year period of the experiment in each treatment and at all sites but the main seedling flushes were observed from mid summer to early autumn. In 2007, at all sites, seedling emergence declined by more than 90% on the mowing and herbicide treatments compared with the control treatment. Seedling survival was greater in the mowing and herbicide treatments than in the control treatment. The seedling cohorts emerging in winter had a lower survival. This study showed that H. hirta infestations have a large viable seed-bank (~3000 m–2), dependent on the level of infestation and climatic conditions, but that the seed-bank declines rapidly when seed addition is prevented. Some form of direct control of established H. hirta plants in combination with providing appropriate grazing management to encourage competition between grasses will assist in the control of H. hirta.

scholarly journals Seed encrusting with salicylic acid: A novel approach to improve establishment of grass species in ecological restoration

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0242035
Author(s):  
Simone Pedrini ◽  
Jason C. Stevens ◽  
Kingsley W. Dixon
Keyword(s):  
Salicylic Acid ◽  
Seed Germination ◽  
Ecological Restoration ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Field Conditions ◽  
Grass Species ◽  
Seed Coating ◽  
Seedling Density ◽  
Survival And Growth

To achieve global ambitions in large scale ecological restoration, there is a need for approaches that improve the efficiency of seed-based interventions, particularly in overcoming the bottleneck in the transition from germination to seedling establishment. In this study, we tested a novel seed-based application of the plant stress modulator compound salicylic acid as a means to reduce seedling losses in the seed-to-seedling phase. Seed coating technology (encrusting) was developed as a precursor for optimising field sowing for three grass species commonly used in restoration programs, Austrostipa scabra, Microlaena stipoides, and Rytidosperma geniculatum. Salicylic acid (SA, 0.1mM) was delivered to seeds via imbibition and seed encrusting. The effects of SA on seed germination were examined under controlled water-limited conditions (drought resilience) in laboratory setting and on seed germination, seedling emergence, seedling growth and plant survival in field conditions. Salicylic acid did not impact germination under water stress in controlled laboratory conditions and did not affect seedling emergence in the field. However, seedling survival and growth were improved in plants grown from SA treated seeds (imbibed and encrusted) under field conditions. When SA delivery methods of imbibing and coating were compared, there was no significant difference in survival and growth, showing that seed coating has potential to deliver SA. Effect of intraspecific competition as a result of seedling density was also considered. Seedling survival over the dry summer season was more than double at low seedling density (40 plants/m2) compared to high seedling density (380 plants/m2). Overall, adjustment of seeding rate according to expected emergence combined with the use of salicylic acid via coating could improve seed use efficiency in seed-based restoration.

scholarly journals Giant buttercup (Ranunculus acris L) seedling emergence and survival in Golden Bay dairy pastures

2009 ◽  
Vol 62 ◽  
pp. 222-227 ◽  
Author(s):  
C.S. Lusk ◽  
S.L. Lamoureaux ◽  
G.W. Bourd?t
Keyword(s):  
New Zealand ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Dairy Farms ◽  
Permanent Plots ◽  
Pasture Management ◽  
Seedling Emergence And Survival ◽  
Ranunculus Acris ◽  
Milk Solids ◽  
Autumn And Winter

Giant buttercup (Ranunculus acris L) is an unpalatable weed in New Zealand dairy pastures and is estimated to cost the dairy industry over 150 million annually in lost milk solids revenue In this study the survival of giant buttercup seedlings was determined by following their fates in permanent plots on eight randomly selected dairy farms in the Takaka Valley from November 2004 to August 2008 Seedling emergence occurred yearround but tended to be higher in winter and spring than in summer and autumn Seedling survival was very low with less than 5 of seedlings surviving beyond 12 months Seedlings that germinated in autumn had significantly higher survival at 6 and 12 months (22 and 12 respectively) than seedlings germinating in spring summer and winter (37 and 23 respectively) Good pasture management that prevents overgrazing and pugging in autumn and winter should reduce the autumn flush of seedlings and minimise their survival

Germination of Piptochaetium Napostaense (Speg.) Hackel and Stipa Tenuis Phil. And Seedling Survival Under Field Conditions.

1992 ◽  
Vol 14 (1) ◽  
pp. 49 ◽  
Author(s):  
RA Distel ◽  
DV Pelae ◽  
OA Fernandez
Keyword(s):  
High Temperatures ◽  
Seedling Establishment ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Canopy Cover ◽  
Grass Species ◽  
Plant Canopy ◽  
Seedling Emergence And Survival ◽  
Neighbouring Plant ◽  
High Level

The objectives of this work were to investigate the germination of Piptochaetium napostaense and Stipa tenuis under laboratory conditions and to evaluate the effects of different plant canopy cover on seedling emergence and survival of the two species in the field. Fresh seeds of both species present a high level of dormancy associated with the lemma and palea, preventing seedling emergence immediately after the seeds fall in NovemberPecember. Seventy per cent of the seedlings of both species emerged in autumn. The germination behavior of these grass species may be an ecological adaptation serving to avoid seedling loss through exposure to the high temperatures and drought occurring during summer in the Calden District. Seedling survival was greater in the grazed, low plant canopy cover site, indicating that a certain degree of disturbance to reduce neighbouring plant interference favours seedling establishment in both species.

Effects of overstory tree density, site preparation and ground vegetation on natural Scots pine seedling emergence and survival in northern boreal pine forests

2021 ◽  
Author(s):  
Mikko Johannes Kyrö ◽  
Ville Hallikainen ◽  
Sauli Valkonen ◽  
Mikko Hyppönen ◽  
Pasi Puttonen ◽  
...  
Keyword(s):  
Seedling Survival ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Site Preparation ◽  
Ground Vegetation ◽  
Seedling Mortality ◽  
Bottom Part ◽  
High Coverage ◽  
Efficient Treatment ◽  
Seedling Emergence And Survival

Natural regeneration is commonly used forest regeneration method in Northern Finland. It is not known however, what would be the optimal overstory density and ground vegetation composition for seedling emergence and survival, and if site preparation is needed to accompany overstory density manipulation. We studied the effects of overstory density (unthinned control and thinning to 50, 150 and 250 trees ha-1) and ground vegetation removal (mechanical site preparation with disc trenching) on the number of naturally germinated pine seedlings and survival of individual seedlings during 8-11 years. Bare mineral soil was a superior seedbed compared to intact vegetation cover, even though also mortality rate was high on mineral soil. Greater cover of lingonberry, crowberry and slash had a negative effect on seedling number. Seedling mortality was initially high (60% died during the first two years) but decreased throughout the first five years. The mineral soil in the elevated part of disc trencher track showed twice the survival rate in the bottom part of the track. High coverage of small haired mosses was associated with poorer seedling survival. An overstory density of 50-150 trees ha-1 with site preparation seems to be an efficient treatment to promote regeneration under these circumstances.

THE INFLUENCES OF AMOUNTS AND DISTRIBUTION OF IRRIGATION DURING THE HOT AND DRY SEASON ON EMERGENCE AND SURVIVAL OF SOME DESERT WINTER ANNUAL PLANTS IN THE NEGEV DESERT

1994 ◽  
Vol 42 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Yitzchak Gutterman ◽  
Michael Evenari
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
Dry Season ◽  
Negev Desert ◽  
Water Evaporation ◽  
Annual Plants ◽  
Loess Area ◽  
Daily Number ◽  
Daily Water ◽  
Winter Annual

In a flat loess area in the Negev Desert of Israel, different amounts and distribution of irrigation were given to 48 squares of 0.25 m2 on 1 and 30 August, 1977. At this time evaporation rates were high and the range of temperatures near the soil surface between irrigation and seedling emergence was 15–53 °C. Of the species appearing in winter in the Negev, only 22 emerged, and only 3 appeared in substantial numbers. Seedlings of species that emerge during winter after about 10 mm of rain did not emerge after the first irrigation in squares receiving 60 mm of water, a few emerged after 90 and 120 mm, and only 57 after 150 mm. After the second irrigation, when evaporation rates and temperatures were lower, in the same squares, 154,334,534, and763 seedlings emerged after receiving90,120,150, and 200 mm, respectively. The highest number of seedlings emerged, but the lowest percentage survived, when the water was divided into equal daily irrigations during the first 9 days. As the daily water amounts decreased, the number of emerging seedlings also decreased, but the % survival increased. As the daily number of irrigations of 30 or 10 mm increased, the number of emerged seedlings and the % survival increased. However, there were significant differences among the species that emerged. The amounts and distribution of water evaporation rates and temperatures were found to be the important germination regulators in those plants which also inhabit regions receiving summer rains.

scholarly journals Effects of High Soil Surface Temperature on Seedling Survival in Pearl Millet

1993 ◽  
Vol 29 (2) ◽  
pp. 215-225 ◽  
Author(s):  
J. M. Peacock ◽  
P. Soman ◽  
R. Jayachandran ◽  
A. U. Rani ◽  
C. J. Howarth ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Pearl Millet ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Soil Moisture Deficit ◽  
High Soil ◽  
Moisture Deficit ◽  
Seedling Emergence And Survival ◽  
Soil Surface Temperature

SummaryA field technique to screen pearl millet genotypes for their emergence and survival at high soil surface temperatures is described. Genetic variation in seedling emergence and survival is shown and it is argued that this variation is largely due to tolerance of high temperatures rather than tolerance of soil moisture deficit, although some interaction occurred. An index for ‘thermotolerance’ is defined and genotypes are ranked accordingly for this trait, which is shown to be highly heritable. The technique is repeatable and allows a large number of genotypes to be screened at the same time.

scholarly journals Regeneration responses to water and temperature stress drive recruitment success in hemiepiphytic fig species

2020 ◽  
Author(s):  
Huayang Chen ◽  
Nalaka Geekiyanage ◽  
Bin Wen ◽  
Kun-Fang Cao ◽  
Uromi Manage Goodale
Keyword(s):  
Water Stress ◽  
Relative Humidity ◽  
Temperature Stress ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Effect Of Temperature ◽  
Ambient Conditions ◽  
Forest Canopies ◽  
Seedling Emergence And Survival ◽  
Substrate Moisture

Abstract Mechanisms for surviving water and temperature stress in epiphytes are essential adaptations for successful regeneration in forest canopies. Hemiepiphytes start their life cycle as epiphytes, eventually establishing areal root connections to the ground. This strategy allows for greater light capture, while benefitting from minimized risk of fire, flooding, and damage by terrestrial herbivores, but exposes the vulnerable seedling stage to heat and drought stress. However, the response to temperature and water stress during early regeneration in hemiepiphytes is not known. In this study, we tested the effect of temperature (15/5°C, 25/15°C, 35/25°C; day/night diurnal variation) and water availability, as substrate moisture (0.00 MPa, −0.20 MPa, −0.35 MPa) and water vapor (18.5% to 99.5% relative humidity), on seed germination, seedling emergence, and survival in six hemiepiphytic and nine non-hemiepiphytic Ficus species. Under high temperature conditions (35/25°C), hemiepiphytes had higher gemination and seedling survival, achieved peak germination slower and extended germination. Greater water stress (−0.35 MPa) in the growth substrate resulted in higher germination of non-hemiepiphytes; hemiepiphytes, in contrast, took a shorter time to complete germination, but had higher seedling emergence and survival. Hemiepiphytes germinated at 99.5% relative humidity more readily compared to non-hemiepiphytes. These findings provide the first comprehensive evidence that hemiepiphytic Ficus species are better adapted to drier and warmer conditions during the critical transition from seed to seedling. Through greater flexibility in achieving peak germination and duration of regeneration activity, hemiepiphytes modulate their recruitment process to be more resilient under abiotic stressors. This may allow them to be more successful in regenerating in forest canopies under ambient conditions that are transient. These results support previous work showing greater drought tolerance of hemiepiphytic Ficus species in larger size classes, and extend this finding to show that physiological adaptations for drought and heat tolerance start from the early seedling emergence stage.

scholarly journals Soil-borne fungi influence seed germination and mortality, with implications for coexistence of desert winter annual plants

PLoS ONE ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. e0224417 ◽  
Author(s):  
Yue M. Li ◽  
Justin P. Shaffer ◽  
Brenna Hall ◽  
Hongseok Ko
Keyword(s):  
Seed Germination ◽  
Annual Plants ◽  
Winter Annual ◽  
Soil Borne Fungi

Henbit (Lamium amplexicaule), Common Chickweed (Stellaria media), Shepherd's-Purse (Capsella bursa-pastoris), and Field Pennycress (Thlaspi arvense): Fecundity, Seed Dispersal, Dormancy, and Emergence

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Erin C. Hill ◽  
Karen A. Renner ◽  
Christy L. Sprague
Keyword(s):  
Seed Production ◽  
Seedling Emergence ◽  
Crop Productivity ◽  
Seed Fate ◽  
Stellaria Media ◽  
Thlaspi Arvense ◽  
Emergence Patterns ◽  
Field Pennycress ◽  
Winter Annuals ◽  
Winter Annual

Winter annual weeds protect the soil from erosion and retain nutrients during the winter; however, they can also act as a host for crop pests and pathogens and impede planting. Increased knowledge of the reproductive biology and the seed fate of winter annuals would be useful to improve management and crop productivity. The objectives of this research were to determine the recruitment biology of shepherd's-purse, henbit, common chickweed, and field pennycress, including seed production, dispersal, dormancy, and seedling emergence, based on growing degree days (GDD). Henbit was the least prolific of the four weeds studied, producing 800 to 40,000 seeds m−2at naturally occurring densities; shepherd's-purse was the most prolific, producing 11,000 to 400,000 seeds m−2with 40 to 230 plants m−2. Fifty percent seed rain occurred for henbit, common chickweed, shepherd's-purse, and field pennycress at 620, 790, 880, and 1300 GDDBase,0C, respectively. Overall, seeds were dormant for all species at the time of dispersal. In 2 of 3 yr, dormancy of later-dispersed common chickweed decreased after 6 mo of storage at natural, fluctuating temperatures in the absence of water. The emergence patterns of the four species followed the Gompertz equation and were indicative of facultative winter annuals. The emergence patterns by rate were similar between henbit and common chickweed and between shepherd's-purse and field pennycress. Seed production, dispersal, dormancy, and seedling emergence were influenced by moisture; therefore, including a precipitation or soil moisture component into a GDD model (such as the use of hydrothermal time) would improve the accuracy of predicting winter annual reproduction, seed fate, and emergence.

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