Role of Light Quality and Temperature on Pitted Morningglory (Ipomoea lacunosa) Germination with After-Ripening

Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Marcos J. Oliveira
Keyword(s):  
Red Light ◽  
Thermal Fluctuations ◽  
Ipomoea Lacunosa ◽  
Direct Exposure ◽  
Wide Range ◽  
Thermal Amplitude ◽  
Pitted Morningglory ◽  
Buried Seed ◽  
Time Of Year ◽  
Response To Temperature

Pitted morningglory seed were collected in the fall of 2003 from Blackville, SC, and 2004 from Pendleton, SC, to assess the effect of After-Ripening and burial on light and temperature requirements for germination. Pitted morningglory germination was evaluated over a 12-mo period after maturation. Germination was neither stimulated by red light or inhibited by far-red light, nor was it reversible by red or far-red light. Light was not essential for germination of buried seed. Direct exposure to sunlight prevented germination of recently mature seed, but not once seed had sufficiently after-ripened. Pitted morningglory was capable of germination in darkness over a wide range of constant and fluctuating temperatures immediately after maturation. Germination in response to temperature varied with time of year after maturation, with the population from Pendleton having increased germination in May. Thermal fluctuations increased germination of both populations at suboptimal temperatures. Thermal amplitude regulation of germination varied over time and appeared to play a more important role in germination of after-ripened seed than recently mature ones. The ecological significance of changes in germination requirements with After-Ripening is discussed.

Pitted morningglory (Ipomoea lacunosa) germination and emergence as affected by environmental factors and seeding depth

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 910-916 ◽  
Author(s):  
Marcos J. Oliveira ◽  
Jason K. Norsworthy
Keyword(s):  
Red Light ◽  
Soil Surface ◽  
Moisture Stress ◽  
Hypocotyl Elongation ◽  
Burial Depth ◽  
Hypocotyl Length ◽  
Solution Ph ◽  
Wide Range ◽  
Pitted Morningglory ◽  
Ph Range

Laboratory and greenhouse experiments were conducted to determine the effect of light, temperature, solution pH, solution osmotic potential, and oxygen concentration on pitted morningglory germination and radicle plus hypocotyl elongation, and seeding depth on its subsequent emergence. Daily exposure of seed to natural light resulted in lower germination than in darkness, whereas germination was not influenced by brief exposure to red or far-red light. Germination occurred over a wide range of constant temperatures, from 7.5 to 52.5 C, with optimum germination between 20 and 25 C. Germination occurred at solution pH range of 3 to 10 and was optimal from pH 6 to 8. Radicle plus hypocotyl elongation was influenced by the interaction of temperature and solution pH. A combination of acidic medium (pH 6) and high temperature (30 C) resulted in the greatest radicle plus hypocotyl length of 7.6 cm after a 7-d incubation. Germination and radicle plus hypocotyl elongation, averaged over the 15 and 30 C temperature, decreased with increasing moisture stress, with less than 3% normalized germination at −1.0 MPa. Germination was 29, 40, and 51% at 2, 10, and 20% oxygen, respectively, averaged over 15 and 30 C. Germination of seed lying on the soil surface covered with filter paper or without any cover was similar, averaging 64%. Normalized emergence, relative to germination on the soil surface, decreased with increasing burial depth to 4% emergence at 10 cm, with a mean emergence depth of 4.1 cm, averaged across two soil types.

Longevity of Weed Seeds After 5.5 Years in the Stoneville 50-Year Buried-Seed Study

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 264-270 ◽  
Author(s):  
G. H. Egley ◽  
J. M. Chandler
Keyword(s):  
Abutilon Theophrasti ◽  
Sorghum Halepense ◽  
Burial Depth ◽  
Weed Species ◽  
Original Population ◽  
Ipomoea Lacunosa ◽  
Sesbania Exaltata ◽  
Pitted Morningglory ◽  
Buried Seed ◽  
Anoda Cristata

Seeds of 20 weed species buried at depths of 8, 23, and 38 cm in 1972 and 1973 were exhumed at regular intervals and tested for viability and germination. Burial depth had little to no significant influence on longevity. After 5.5 yr 48% of johnsongrass [Sorghum halepense(L.) Pers.], 36% of velvetleaf (Abutilon theophrastiMedic.), 33% of purple moonflower (Ipomoea turbinataLag.), 30% of spurred anoda [Anoda cristata(L.) Schlecht], 18% of hemp sesbania [Sesbania exaltata(Raf.) Cory], and 13% of pitted morningglory (Ipomoea lacunosaL.) seeds were still viable. No more than 6% of the original population for any other species was viable at 5.5 yr. Hard seeds comprised a high percentage of the longer-lived seeds. Seeds of longest-lived species were losing viability at an average of 26% of the existing population each year from 3.5 to 5.5 yr.

Growth Response and Carbohydrate Status of Gibberellin-treated Spectral Filter-grown Chrysanthemum Plants

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 522c-522
Author(s):  
Anuradha Tatineni ◽  
Sonja L. Maki ◽  
Nihal C. Rajapakse
Keyword(s):  
Plant Height ◽  
Growth Regulation ◽  
Red Light ◽  
Sucrose Phosphate Synthase ◽  
Spectral Filter ◽  
Spectral Filters ◽  
Wide Range ◽  
Ornamental Crops ◽  
Carbohydrate Levels ◽  
Carbohydrate Status

Interest in the use of non- (or less) chemical methods to reduce the height of ornamental crops has increased tremendously. Manipulation of greenhouse light quality is one alternative for plant growth regulation. We have shown that eliminating far-red light from the greenhouse environment with liquid CuSO4 spectral filters is effective in reducing the height of a wide range of plants though plant carbohydrate status is also altered under CuSO4 filter. In previous studies, application of GA3 reversed both the reduction of plant height and carbohydrate status of CuSO4 spectral filter grown plants. It has been proposed that GAs enhance the activity of the enzyme sucrose phosphate synthase to regulate carbohydrate levels. In the present study the role of exogenously applied GA19, GA1, and GA3 in overcoming the reduction of plant height and carbohydrate levels was investigated. Chrysanthemum plants were treated weekly for 4 weeks with saturating doses of GA19, GA1 and GA3 (25 μg) or the growth retardants paclobutrazol and prohexadione. GA1 was also applied with paclobutrazol and prohexadione to assess whether response to GAs is altered under CuSO4 filter. GA1 and GA3 promoted growth similarly under control or CuSO4 filter. GA19 was least effective in promoting growth under CuSO4 filter. In summary, these results suggest that gibberellin physiology is altered under spectral filters with the conversion of GA19 a possible point of regulation. The correlation between the carbohydrate status and the growth of the plants will be discussed.

Seed germination response of a noxious agricultural weed Echium plantagineum to temperature, light, pH, drought stress, salinity, heat and smoke

2018 ◽  
Vol 69 (3) ◽  
pp. 326 ◽  
Author(s):  
Singarayer Florentine ◽  
Sandra Weller ◽  
Alannah King ◽  
Arunthathy Florentine ◽  
Kim Dowling ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Drought Stress ◽  
Invasive Weed ◽  
Germination Response ◽  
Elevated Salinity ◽  
Wide Range ◽  
Agricultural Weed ◽  
Soil Seedbank ◽  
Response To Temperature ◽  
Salinity Management

Echium plantagineum is a significant pasture weed in the Mediterranean climatic zone of several countries, including Australia. This invasive weed, introduced as an ornamental into Australia (where it is known as Paterson’s curse), quickly became established and is now a significant weed of agriculture. Although E. plantagineum is a well-established, highly competitive weed that thrives under disturbance and is tolerant of a wide variety of conditions, including varying soil moisture and drought, and some aspects of its ecology remain unknown. This study investigated germination response to temperature and light, pH, soil moisture, salinity, and pre-germination exposure of seed to heat and smoke. Temperature was found to be more influential on germination than light and the species is tolerant to a wide range of pH. However, available moisture may limit germination, as may elevated salinity. Management of this weed requires approaches that minimise soil seedbank input or prevent germination of soil seedbanks.

scholarly journals Woody species do not differ in dormancy progression: differences in time to budbreak due to forcing and cold hardiness

2021 ◽  
Author(s):  
Al Kovaleski
Keyword(s):  
Maximum Rate ◽  
Path Length ◽  
Cold Hardiness ◽  
Woody Species ◽  
Two Dimensions ◽  
Spring Phenology ◽  
Wide Range ◽  
The Difference ◽  
Response To Temperature ◽  
Phenological Phases

AbstractBudbreak is one of the most observed and studied phenological phases in perennial plants. Two dimensions of exposure to temperature are generally used to model budbreak: accumulation of time spent at low temperatures (chilling); and accumulation of heat units (forcing). These two effects have a well-established negative correlation: the more chilling, the less forcing required for budbreak. Furthermore, temperate plant species are assumed to vary in amount of chilling required to complete endodormancy and begin the transition to breaking bud. Still, prediction of budbreak remains a challenge. The present work demonstrates across a wide range of species how bud cold hardiness must be accounted for to study dormancy and accurately predict time to budbreak. Cold hardiness defines the path length to budbreak, meaning the difference between the cold hardiness buds attain during the winter, and the cold hardiness at which deacclimated buds are predicted to open. This distance varies among species and throughout winter within a species. Increases in rate of cold hardiness loss (deacclimation) measured throughout winter show that chilling controls deacclimation potential – the proportion of the maximum rate response attained at high chill accumulation – which has a sigmoid relationship to chilling accumulation. For forcing, rates of deacclimation increase non-linearly in response to temperature. Comparisons of deacclimation potential show a dormancy progresses similarly for all species. This observation suggests that comparisons of physiologic and genetic control of dormancy requires an understanding of cold hardiness dynamics and the necessity for an update of the framework for studying dormancy and its effects on spring phenology.

The influence of the seasons: how the agricultural calendar impacts farmer perceptions of cover crops

2021 ◽  
pp. 1-11
Author(s):  
Margaret Beetstra ◽  
Robyn Wilson ◽  
Eric Toman
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Conservation Practice ◽  
Individual Level ◽  
Practice Adoption ◽  
Wide Range ◽  
Research Findings ◽  
Time Of Year ◽  
Conducting Research ◽  
Conservation Practice Adoption

Abstract Across the Midwest, substantial funding and personnel time have been allocated to encourage farmers to adopt a wide range of conservation practices but adoption rates for many of these practices remain low. Prior research focuses largely on the influence of individual-level factors (e.g., beliefs, attitudes) on conservation practice adoption rather than on contextual factors (e.g., seasons) that might also play a role. In the present study, we considered seasonal variation and its potential influence on farmer cover crop decision-making. We first established how farmer temporal and financial resources fluctuate across the year and then compared the annual agricultural decision and cover crop decision calendars. We also considered farmer cover crop perceptions and likely behaviors. To study this, we surveyed the same Midwestern farmers in the spring, summer and winter within a 12-month period. Results indicated that farmers were generally the least busy and the most financially comfortable in the winter months. Moreover, farmers perceived the benefits of cover crops differently throughout the year. These results indicate that seasonality can be a confounding factor which should be considered when designing and conducting research and farmer engagement. As researchers, it is our responsibility to understand the specific calendar experienced by our sample and how that may influence responses so we can examine theory-supported factors of interest rather than seasonality as a driver of farmer responses. As practitioners, it is important to use research findings to engage with farmers about conservation in a way that prioritizes communicating about the most salient aspects of the practice at the time of year when farmers will be most receptive.

Temperature-induced pupil movements in insect superposition eyes

2000 ◽  
Vol 203 (4) ◽  
pp. 685-692 ◽  
Author(s):  
P. Nordstrom ◽  
E.J. Warrant
Keyword(s):  
High Temperatures ◽  
Cydia Pomonella ◽  
Codling Moth ◽  
Light Level ◽  
Agrotis Segetum ◽  
Effect Of Temperature ◽  
Activation Temperature ◽  
Ambient Light Level ◽  
Wide Range ◽  
Response To Temperature

In this paper, we describe the hitherto largely overlooked effect of temperature on the pupil of insect compound eyes. In the turnip moth Agrotis segetum and in two other nocturnal insects with superposition eyes, the lacewing Euroleon nostras and the codling moth Cydia pomonella, the pupil not only opens and closes with changes in the ambient light level, as expected, but also with changes in temperature in the absence of light. In complete darkness, the pupil of A. segetum responds over a wide range of temperatures, with the pupillary pigments migrating to a light-adapted position when the animal is exposed to either low or high temperatures. At temperatures between 21.0 and 22.7 C, the pigments migrate to the fully dark-adapted position, resulting in an open pupil and maximal eye glow. Pupil closure at high temperatures shows two distinct thresholds: the first at 23.8+/−0.7 C and a second some degrees higher at 25.7+/−1.2 C (means +/− s.d., N=10). Temperatures exceeding the first threshold (the activation temperature, T(a)) initiate a closure of the pupil that is completed when the temperature exceeds the second threshold (the closure temperature, T(c)), which causes rapid and complete migration of pigment to the light-adapted position. All temperatures above T(a) affect the pupil, but only temperatures exceeding T(c) result in complete closure. Temperatures between T(a) and T(c) cause a slow, partial and rather unpredictable closure. The lacewing and the codling moth both show very similar responses to those of A. segetum, suggesting that this response to temperature is widespread in superposition eyes. The possibility that the ambient temperature could be used to pre-adapt the eye to different light intensities is discussed.

Absorption, Translocation, and Metabolism of Imazaquin in Pitted (Ipomoea lacunosa) and Entireleaf (Ipomoea hederaceavar.integriuscula) Morningglory

Weed Science ◽  
1992 ◽  
Vol 40 (4) ◽  
pp. 503-506 ◽  
Author(s):  
Mark A. Risley ◽  
Lawrence R. Oliver
Keyword(s):  
Ipomoea Lacunosa ◽  
Pitted Morningglory ◽  
Treated Leaf

Pitted morningglory and entireleaf morningglory treated with14C-imazaquin translocated14C to areas above and below the treated leaf. Pitted morningglory absorbed and translocated more14C from14C-imazaquin than entireleaf morningglory. Translocation of14C from root-supplied14C-imazaquin was similar in both species 1 d after treatment, with14C moving rapidly to the shoots. Entireleaf morningglory metabolized slightly more imazaquin than pitted morningglory in treated leaves. Greater tolerance of entireleaf morningglory than pitted morningglory to postemergence applications of imazaquin is attributed to reduced absorption and translocation and increased metabolism of the herbicide in the entireleaf morningglory.

Response of Two Arctic Amphipods, Gammarus zaddachi and Boeckosimus (Onisimus) affinis, to Variations in Temperature and Salinity

1975 ◽  
Vol 32 (12) ◽  
pp. 2564-2568 ◽  
Author(s):  
M. Busdosh ◽  
Ronald M. Atlas
Keyword(s):  
Respiration Rate ◽  
Ecological Distribution ◽  
Temperature Changes ◽  
Gammarus Zaddachi ◽  
Wide Range ◽  
Abrupt Changes ◽  
Response To Temperature

Two arctic amphipods were found to be capable of tolerating a wide range of temperatures and salinities. They were tolerant to both abrupt changes, as would occur in crossing a thermocline, and to gradual changes, as would occur seasonally.Gammarus zaddachi could survive lower salinities and higher temperatures than Boeckosimus (Onisimus) affinis. Salinity had a statistically significant effect on rates of respiration for both organisms, but only Gammarus zaddachi showed significant changes in respiration rate in response to temperature changes. The ecological distribution of these amphipods appears to be in part determined by their ability to tolerate fluctuations in salinity and temperature.

Drivers' Perceptions of Unsafe Driving Behaviors and Their Countermeasures: A Study in Saudi Arabia

2014 ◽  
Vol 70 (4) ◽  
Author(s):  
Tanweer Hasan ◽  
Ishtiaque Ahmed ◽  
Hamid O. Al-Bar
Keyword(s):  
Saudi Arabia ◽  
Police Officers ◽  
Time Pressure ◽  
Red Light ◽  
The United States ◽  
Aggressive Driving ◽  
Road Rage ◽  
Driving Behaviors ◽  
Wide Range

There is an increased public concern about the role of aggressive driving and "road rage" in crashes and traffic fatalities. There is no general agreement as to what constitutes aggressive driving. Consequently, the objective of the study was to survey of the perceptions on the specific unsafe driving acts. Perceptions and beliefs of drivers about unsafe and aggressive driving actions and their countermeasures are presented in this paper. The study primarily looked at the wide range of driver attitudes about speeding and other forms of unsafe driving behavior. The study was conducted in Jeddah, the second largest city of Saudi Arabia by interviewing a sample of 300 drivers. The results indicated that the drivers, in general, prefer to drive at higher speeds and could be considered as more aggressive compared to the drivers in the United States. The most dangerous reported driving act was "drive thru red light", followed by "racing another driver". Only 23% of the drivers thought that it was dangerous to drive over 30 km of the legal speed limits. The most often seen unsafe driving action was "speeding (70%), followed by "driving too closely (57%), "failing to use turn signals (53%), "drive inattentively (50%)", and "running red lights (43%)". The main causes of unsafe driving behaviors were "being in a hurry/time pressure (66%)", "aggressive behavior of others (52%)", and "refusing traffic rules (51%)". The countermeasure that was viewed to be the most effective in reducing unsafe driving behaviors was assigning more traffic police officers (66%). The study revealed that, more than half the drivers believed that more frequent ticketing (60%), doubling or tripling fines (54%), and doubling the length of imprisonment (53%) would be effective in reducing unsafe driving behaviors.

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