Effects of heat and fire on the germination of Acacia sieberiana D.C. and Acacia gerrardii Benth. in Uganda

1996 ◽  
Vol 12 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Patrick Mucunguzi ◽  
Hannington Oryem-Origa
Keyword(s):  
Heat Treatment ◽  
Seed Germination ◽  
Prolonged Exposure ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Short Exposure ◽  
Dry Heat ◽  
Acacia Gerrardii ◽  
Depth Of Burial ◽  
Acacia Sieberiana

ABSTRACTThe effects of heat treatment and fire on seed germination of Acacia sieberiana D.C. and Acacia gerrardii Benth. were studied. Dry heat and fire were studied separately. Seeds treated with dry heat were set to germinate in petri-dishes under laboratory conditions. Other seeds were planted in plots at the Uganda Institute of Ecology, Mweya, which were then burnt, and subsequent seedling emergence was monitored. The effect of heat treatment on seed germination depended on heat intensity and duration of exposure. Higher intensities reduced the germination capacity of Acacia seeds. Short exposure of seeds stimulated germination but prolonged exposure rapidly reduced seed viability. A. sieberiana had a higher heat resistance than A. gerrardii. The survival and germination of seeds after fire increased with depth of burial and A. sieberiana survived better than A. gerrardii. The germinability of seeds of A. gerrardii was not significantly increased by fire.

scholarly journals Effect of dry heat treatment along with some dormancy breaking chemicals on oil palm seed germination

2017 ◽  
Vol 112 ◽  
pp. 489-493
Author(s):  
K.M. Tabi ◽  
G.F. Ngando Ebongue ◽  
G.N. Ntsomboh ◽  
E. Youmbi
Keyword(s):  
Heat Treatment ◽  
Seed Germination ◽  
Oil Palm ◽  
Dormancy Breaking ◽  
Dry Heat ◽  
Dry Heat Treatment

Seed and Germination Biology ofDittrichia graveolens(Stinkwort)

2013 ◽  
Vol 6 (3) ◽  
pp. 371-380 ◽  
Author(s):  
Rachel N. Brownsey ◽  
Guy B. Kyser ◽  
Joseph M. DiTomaso
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Seed Viability ◽  
Base Temperature ◽  
Time Model ◽  
Wide Range ◽  
Total Seed ◽  
Thermal Time Model ◽  
Seed Characteristics

AbstractUnderstanding seed characteristics and seedling establishment patterns is essential for the development of effective management strategies for invasive annual species.Dittrichia graveolens(stinkwort) has increased its range rapidly within California since 1995, yet its biology is not well understood, which has led to poorly timed management. In this study, seed viability, germination, longevity, and dormancy, as well as seedling emergence characteristics ofD. graveolenswere evaluated in field, greenhouse, and laboratory experiments in Davis, CA, over a 2-yr period (fall 2010 to summer 2012). In the laboratory, seed germination ofD. graveolensoccurred at a wide range of constant temperatures (12 to 34 C). Cumulative germination was comparable to total seed viability (80 to 95%) at optimal germination temperatures, indicating that primary (innate) dormancy is likely absent. The base temperature for germination was identified using a thermal time model: 6.5 C and 4 C for 2010 and 2011 seed populations, respectively. In the field, seedlings emerged from fall through spring following precipitation events. A very low percentage of seedlings (2.5%) emerged in the second year after planting. Equivalent seedling emergence was observed over a wide range of light conditions (100, 50, 27, and 9% of available sunlight) in a greenhouse experiment, indicating that seed germination is not limited by high or low light. Results from these seed experiments improve our understanding of the reproductive biology of this rapidly expanding exotic annual and provide valuable information for developing effective timing and longevity of management programs.

Effect of Dry Heat, Direct Flame, and Straw Burning on Seed Germination of Weed Species Found in Lowbush Blueberry Fields

2016 ◽  
Vol 30 (1) ◽  
pp. 263-270 ◽  
Author(s):  
Scott N. White ◽  
Nathan S. Boyd
Keyword(s):  
Seed Germination ◽  
Exposure Time ◽  
Heat Exposure ◽  
Seed Viability ◽  
Weed Species ◽  
Dry Heat ◽  
Lowbush Blueberry ◽  
Weed Seeds ◽  
Straw Burning ◽  
Time Required

Experiments were conducted to determine the effects of dry heat, direct flame, and straw burning on germination of several weed species from lowbush blueberry fields. Dry heat experiments were designed as factorial arrangements of temperature (100, 200, and 300 C in experiment 1 and room temperature, 100, 200, and 300 C in experiment 2) and exposure time (0, 5, 10, 20, 40, and 80 s in experiment 1 and 2, 5, 10, and 20 s in experiment 2) to determine the exposure time required to reduce germination for each temperature. Susceptibility to dry heat varied across species tested, but germination of spreading dogbane, meadow salsify, fireweed, and hair fescue seeds collected from lowbush blueberry fields in Nova Scotia, Canada generally declined exponentially as a function of duration of heat exposure at the temperatures tested. Germination decreased more rapidly at higher temperatures in all species, although the duration of heat exposure required to reduce germination by 50 and 90% varied across temperatures and species. Exposure of seeds to direct flame rapidly reduced germination, with less than 1 s of exposure required to reduce seed germination of witchgrass, spreading dogbane, and meadow salsify by > 90%. Straw burning did not consistently reduce germination of hair fescue or winter bentgrass, indicating that a surface burn occurring above weed seeds may not be consistently effective at reducing seed viability. These results provide important estimates of the temperature and exposure times required to reduce viability of weed seeds in lowbush blueberry fields and suggest that thermal technologies that expose weed seeds to direct flame will be the most consistent in reducing seed viability.

scholarly journals 239 Seed Germination and Seedling Characteristics of Cucurbits as Affected by Dry Heat Treatment and Subsequent Handling

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 432C-432
Author(s):  
Hae-Jeen Bang ◽  
Soo-Jung Hwang ◽  
Hyun-Sook Ham ◽  
Jung-Myung Lee
Keyword(s):  
Heat Treatment ◽  
Seed Germination ◽  
Dry Heat ◽  
Seed Moisture ◽  
Heat Treated ◽  
Emergence Rate ◽  
Normal Seed ◽  
Cultivar Susceptibility ◽  
Dry Heat Treatment ◽  
Seedling Characteristics

Dry heat treatment has been commonly used to inactivate some seed-borne pathogens in vegetable seeds. Virtually all the gourd seeds for watermelon rootstock are being treated with dry heat to inactivate cucumber green mottle mosaic virus (CGMMV, a strain of tobamovirus) and Fusarium. Seeds of five gourd and one squash cultivars were treated with dry heat (35 °C for 24 h + 50 °C for 24 h + 75 °C for 72 h) and, immediately after the dry heat treatment, the seeds (moisture content of 1% or lower) were allowed to absorb atmospheric moisture in a moisture saturated chamber until the seed moisture contents reached 2% to 8%. After the equilibrium obtained, the seeds were sealed in air-tight bags and stored for 1 day or 30 days at 20 °C. The seeds were then sown in cell trays and the emergence and seedling characteristics were evaluated. Dry heat treatment caused significant delay in emergence in all tested cultivars, but had little or no influence on the final emergence rate. Moderate to severe injury was observed in seedlings grown from dry heat-treated seeds in three out of six cultivars tested. However, little or no dry heat phytotoxicity was observed in other cultivars, thus suggesting the marked differences in cultivar susceptibility to dry heat treatment. Rapid humidification before sealing also appeared to reduce the early emergence rate in some cultivars, but had no effect on the final emergence rate in most cultivars. Storage of dry heat-treated seeds in sealed bags for 30 days before sowing was highly effective in minimizing the phytotoxicity symptoms in seedlings as compared to the seedlings grown from the seeds sown immediately after the dry heat treatment. This suggests that the reestablishment of metabolic process required for normal seed germination requires a long period after the dry heat treatment. Other characteristics associated with DH treatment will also be presented.

Storage and hydro-priming treatments to improve the seed quality of two traditional rice varieties; Batapola-el and Suwendal, from Sri Lanka

2020 ◽  
Vol 57 (1) ◽  
pp. 25-35
Author(s):  
MO Galappaththi ◽  
KMGG Jayasuriya ◽  
NS Gama-Arachchige
Keyword(s):  
Sri Lanka ◽  
Seed Germination ◽  
Seed Quality ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Rice Varieties ◽  
Seed Vigour ◽  
Sowing Season ◽  
Traditional Rice

Although the demand for traditional rice varieties has increased, low initial germination and poor storability of these varieties impede its popularization. Thus, the aim of the study was to improve the seed quality using priming treatments and to suggest an effective storage practice of two of the traditional rice varieties; Suwendal and Batapola-el, in Sri Lanka. Seeds were subjected to hydro-priming under various time periods (0, 24, 48 and 72 hours). Seeds were stored in gunny, polysac and polythene bags at room temperature, 25 and 8 °C. Seed quality of primed and stored seeds was evaluated using seed germination, seed vigour (seedling growth and conductivity) and seedling emergence. Hydro-priming for 72 hours has increased the seed germination of the two varieties significantly compared to other priming methods. Further, seeds primed for 72 hours had the highest vigour and highest seedling emergence in both varieties. Storing Suwendal and Batapola-el seeds in polythene bags at 8 °C retained the highest viability and highest vigour for more than six months. Thus, hydro-priming for 72 hours could be recommended to enhancethe seed quality of these two tested varieties and storage at 8 °C in sealed polythene bags could be recommended as an effective storage practice to maintain the seed viability till the next sowing season.

Factors affecting eastern black nightshade (Solanum ptycanthum) seed germination

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 651-656 ◽  
Author(s):  
Jingkai Zhou ◽  
Edward L. Deckard ◽  
Calvin G. Messersmith
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Prolonged Exposure ◽  
Short Exposure ◽  
Cold Stratification ◽  
Light Requirement ◽  
Factors Affecting ◽  
Eastern Black Nightshade ◽  
Solanum Ptycanthum ◽  
Black Nightshade

Effects of environmental factors, especially light, on eastern black nightshade seed germination were studied under growth chamber conditions. Germination occurred only when temperatures were 20 C or higher for 12 to 24 h d−1. Optimum germination occurred within the constant temperature range of 28 to 33 C or with alternating temperatures of 30/25 and 35/30 C. In the dark, eastern black nightshade germination was poor except at high alternating temperatures of 30/25 and 35/30 C. Seed germination was enhanced by light when temperatures were suboptimal. Imbibition was a prerequisite for response of eastern black nightshade seed to light. The light requirement for eastern black nightshade germination was partially overcome by cold stratification, gibberellic acid (GA3), and high or alternating temperatures. Germination of eastern black nightshade seed was promoted by short exposure to sunlight but was inhibited by prolonged exposure, especially when irradiance was high.

scholarly journals EFFECTS OF ENVIRONMENTAL FACTORS ON SEED GERMINATION AND EMERGENCE OF GLYPHOSATE RESISTANT AND SUSCEPTIBLE SOURGRASS

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
J.F. MARTINS ◽  
A.A.M. BARROSO ◽  
P.L.C.A. ALVES
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Environmental Effects ◽  
Water Availability ◽  
Low Temperatures ◽  
Seedling Emergence ◽  
Field Trials ◽  
Allocation Of Resources ◽  
Effects Of Temperature ◽  
Depth Of Burial

ABSTRACT Sourgrass is one of the most problematic weeds of Brazil. It is an aggressive species in the allocation of resources from the environment and reported to be glyphosate resistant in several states of the country. This work has aimed to verify environmental effects on seed germination and seedling emergence of sourgrass. Laboratory and field trials were conducted to determine the effects of temperature, light, photoperiod, water availability and depth of burial in germination and emergence of seeds. The maximum germination was greater than 80% for seed originated from resistant plants between 15 and 30 oC. For the susceptible ones, the maximum germination occurred only at 30 oC. Germination occurred for both biotypes independent of the presence of light. The best photoperiod for germination of both biotypes was between 8 and 14 hours. Seeds originated from resistant plants showed higher germination levels at low temperatures in the presence of light and in less water availability. There was no germination from -0,8 MPa for both biotypes. The emergence for both biotypes was low, indicating that seed burial could be used in the management of the species. Seeds from resistant plants showed higher and larger germination in temperatures, water content and depth of burial ranges than from originated from susceptible plants.

scholarly journals Effect of dry heat on seed germination of Desmodium and Stylosanthes species

2020 ◽  
Vol 48 (3) ◽  
pp. 419-437
Author(s):  
Daniel E. Salazar ◽  
Luis Guillermo Santos ◽  
Peter Wenzl ◽  
Fiona R. Hay
Keyword(s):  
Heat Treatment ◽  
Seed Germination ◽  
Physical Dormancy ◽  
Dry Heat ◽  
Tropical Grasslands ◽  
Equivalent Effect ◽  
High Germination ◽  
Ecological Relationship ◽  
Feasible Alternative ◽  
Dry Heat Treatment

Mechanical scarification with a scalpel is the best treatment to break physical dormancy and reach high germination percentages in many legumes. However, it is highly time-consuming. Given the ecological relationship between the presence of physical dormancy and high temperatures in tropical grasslands, dry heat treatment could also promote breaking of physical dormancy in Desmodium and Stylosanthes species. This study assessed seed germination of several accessions of nine species of Desmodium and Stylosanthes. Seeds were treated with dry heat (80°C for 30 minutes) and scarified with a scalpel to determine whether dry heat is a reliable alternative treatment to overcome physical dormancy. Mechanical scarification with a scalpel was effective and resulted in high germination for all species. In S. guianensis, both treatments had an equivalent effect, making dry heat a feasible alternative. Dry heat could also be a reliable alternative in D. heterocarpon, D. velutinum, S. hamata, and S. scabra, but tetrazolium tests may be necessary to confirm viability. For D. barbatum and D. scorpiurus, dry heat could be an alternative but further research is needed to confirm this, while in S. capitata and S. viscosa dry heat is not a reliable alternative.

Seed Biology and Ecology of Natalgrass (Melinis repens)

Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 527-532 ◽  
Author(s):  
Courtney A. Stokes ◽  
Gregory E. MacDonald ◽  
Carrie Reinhardt Adams ◽  
Kenneth A. Langeland ◽  
Deborah L. Miller
Keyword(s):  
Water Stress ◽  
Seed Germination ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Field Conditions ◽  
Tropical Regions ◽  
Seed Biology ◽  
The World ◽  
Depth Of Burial ◽  
Osmotic Potentials

Natalgrass is an invasive species that has become increasingly problematic in natural areas in Florida and other subtropical and tropical regions around the world. Natalgrass is a prolific seed producer, but little information is available regarding its seed biology and ecology. Research was conducted to determine levels of seed dormancy and to examine the effects of light, temperature, pH, water stress, and depth of burial on natalgrass seed germination. In addition, seed persistence under field conditions was examined both on the soil surface and while buried. Seeds appeared to undergo afterripening. Seed germination was not light dependent and occurred from 15 to 35 C, with optimum germination occurring at 20 to 35 C. Germination occurred at pH levels of 6 and 8 and was affected by water stress; no germination was observed at osmotic potentials less than −0.2 MPa. Seeds emerged from depths of at least 5 cm. Under field conditions, germination was reduced after burial; however, burial lengths of 3 to 15 mo did not result in differences in germination levels. Seedling numbers from seed deposits on the soil surface were greatly reduced after 1 mo, and no seedling emergence was observed after 4 mo.

Sign in / Sign up

Export Citation Format

Share Document