Fluctuating Temperatures Break Seed Dormancy of Catclaw Mimosa (Mimosa pigra)

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 196-198 ◽  
Author(s):  
Stephen P. Dillon ◽  
Frank Forcella
Keyword(s):  
Environmental Factors ◽  
Seed Dormancy ◽  
Field Conditions ◽  
Optimum Temperature ◽  
Night Temperature ◽  
Mimosa Pigra ◽  
Temperature Ranges ◽  
Fluctuating Temperatures

Because environmental factors facilitating the breaking of dormancy of seed of catclaw mimosa (Mimosa pigra L. ♯ MIMPI) under field conditions were unknown, the effect of constant temperatures (2 to 44 C) on germination of scarified and unscarified seeds, and the effect of diurnally fluctuating temperatures on unscarified seeds were examined. Temperatures fluctuated diurnally by 10 and 20 C in these latter experiments. Germination was less than 10% at all constant temperatures except 44 C, which had 40% germination. Scarification increased germination to 100% at constant temperatures greater than 12 C. Germination of unscarified seed was significantly lower (0 to 23%) when day/night temperature ranges fluctuated by 10 C than when they fluctuated by 20 C. Optimum temperature for germination was 40/20 C, where 93% germination occurred within 4 days.

Environmental Effects on Peppermint (Mentha piperita L.). I. Effect of Daylength, Photon Flux Density, Night Temperature and Day Temperature on the Yield and Composition of Peppermint Oil

1980 ◽  
Vol 7 (6) ◽  
pp. 685 ◽  
Author(s):  
RJ Clark ◽  
RC Menary
Keyword(s):  
Environmental Factors ◽  
Flux Density ◽  
Mentha Piperita ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Peppermint Oil ◽  
Oil Composition ◽  
Night Temperature ◽  
Low Concentrations ◽  
High Concentrations

Long days (16 h light), high photon flux density (1200 �Em-2 s-1.) and high night temperature (20°C) resulted in the highest oil yield. : Daylength, night temperature, day temperature and photon flux density were important interacting factors determining oil composition. The photosynthate model proposed by Burbott and Loomis (Plant Physiol., 1967, <B.42, 20-8) explained the effect of environmental factors with respect to pulegone, menthone and menthofuran. Factors favouring the maintenance of high levels of photosynthate resulted in high concentrations of menthone and low concentrations of pulegone and menthofuran. The photosynthate model does not explain the effect of environmental factors on several other monoterpenes.

Contribution of host and environmental factors to the hyperparasitism of coffee rust under field conditions

2015 ◽  
Vol 44 (6) ◽  
pp. 605-610 ◽  
Author(s):  
S. J. Martins ◽  
A. C. Soares ◽  
F. H. V. Medeiros ◽  
D. B. C. Santos ◽  
E. A. Pozza
Keyword(s):  
Environmental Factors ◽  
Field Conditions ◽  
Coffee Rust

Influence of Environmental Factors on Smallflower Morningglory (Jacquemontia tamnifolia) Germination and Growth

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 519-523 ◽  
Author(s):  
David R. Shaw ◽  
H. Randy Smith ◽  
A. Wayne Cole ◽  
Charles E. Snipes
Keyword(s):  
Environmental Factors ◽  
Optimum Temperature ◽  
Full Sunlight ◽  
Optimum Ph ◽  
Germination And Growth

The optimum pH for germination of smallflower morningglory (Jacquemontia tamnifolia(L.) Griseb. # IAQTA] seed was 8.0. A scarification time of 25 to 60 s using a drum scarifier with medium grit provided the best germination, and the optimum temperature for germination was 35 to 40C. However, the optimum temperature for growth was 25 to 35C, with reductions in growth occurring above or below this range. Emergence after 14 days was 81 and 49% at planting depths of 1.5 and 10 cm, respectively. Shade levels of 30 to 92% reduced smallflower morningglory growth by 38 to 87% compared to plants grown in full sunlight.

Germination of White Horehound (Marrubium vulgare) Seeds

Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 266-270 ◽  
Author(s):  
James A. Young ◽  
Raymond A. Evans
Keyword(s):  
Confidence Interval ◽  
Great Basin ◽  
Diurnal Fluctuation ◽  
Optimum Temperature ◽  
Temperature Regimes ◽  
Marrubium Vulgare ◽  
Arid Rangelands ◽  
Temperature Optima ◽  
Fluctuating Temperatures ◽  
Northwestern Nevada

White horehound (Marrubium vulgareL. # MAQVU) is one of the few perennial, herbaceous alien weeds to successfully colonize semiarid to arid rangelands in the Great Basin. Seeds of white horehound, collected from diverse habitats within the Lahontan Basin of northwestern Nevada, were incubated at constant or alternating temperatures ranging from 0 to 40 C. Germination was low and largely limited to alternating temperatures (10 to 25 C alternating with 35 to 40 C). At least a 15-C range in diurnal fluctuation was required for optimum germination (defined as not lower than the maximum observed minus one-half of the confidence interval with 1% probability). Cool-moist stratification at 2 C for 4 to 8 weeks enhanced germination at optimum temperature regimes by as much as 70% and increased overall average germination by 35 to 40%. Cool-moist stratification caused a shift in temperature optima for germination from widely fluctuating temperatures to constant 15 or 20 C. The magnitude of this shift varied among sources of seeds.

scholarly journals Factors Affecting Seed Dormancy and Germination of Greater Bur-Parsley (Turgenia latifolia)

2018 ◽  
Vol 36 ◽  
Author(s):  
M. REZVANI ◽  
S.A. SADATIAN ◽  
H. NIKKHAHKOUCHAKSARAEI
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seed Dormancy ◽  
Seedling Emergence ◽  
Potassium Nitrate ◽  
Germination Percentage ◽  
Dormancy Breaking ◽  
Planting Depth ◽  
Factors Affecting ◽  
Drought And Salt Stresses

ABSTRACT: Our knowledge about seed dormancy breaking and environmental factors affecting seed germination of greater bur-parsley (Turgenia latifolia) is restricted. This study has addressed some seed dormancy breaking techniques, including different concentrations of gibberellic acid (GA3) and potassium nitrate (KNO3), leaching duration, physical scarification as well as some environmental factors effective on seed germination such as salt and drought stresses, pH and seed planting depth. Seed germination was promoted with lower concentrations of KNO3 (0.01 to 0.02 g L-1), while higher concentrations reduced germination percentage. Seed dormancy was declined by low concentrations of GA3 up to 100 ppm. Seeds of greater bur-parsley germinated in a range of pH from 3 to 7. With enhancement of drought and salt stresses, seed germination decreased. Also, there was no seed germination in a high level of stresses. Seedling emergence reduced as planting depth increased. Use of GA3, KNO3, leaching and physical scarification had a positive effect on seed dormancy breaking of greater bur-parsley. The information from the study increases our knowledge about seed dormancy breaking techniques, response of germination to drought and salt stresses and also determination of distribution regions of greater bur-parsley in the future.

scholarly journals Estrategias bioclimáticas para el diseño de edificios vinícolas

2020 ◽  
pp. 7-18
Author(s):  
Verónica Jiménez-López ◽  
Anibal Luna-León ◽  
Stefano Benni ◽  
Gonzalo Bojórquez-Morales
Keyword(s):  
Energy Efficient ◽  
Optimum Temperature ◽  
Indoor Temperature ◽  
Wine Production ◽  
Bioclimatic Design ◽  
Basic Model ◽  
Temperature Ranges ◽  
Hygrothermal Environment ◽  
Design Options ◽  
Correct Design

Greater amount of energy consumed in wineries is used for cooling and humidifying of the interior, for this reason the correct design of energy efficient wineries has become an important issue for winemaking countries. The purpose of the design of buildings that require less or no energy to achieve controlled conditions of the indoor hygrothermal environment for production and aging of wine, allowed to formulate the objective of this work, which was to evaluate six models of wineries with bioclimatic design located in El Valle de Guadalupe, Baja California from data on thermal performance (indoor temperature and relative humidity) and energy consumption (kWh and degrees-hour), obtained by dynamic thermal simulation. The zone of the study was characterized, based on the review of previous studies optimum temperature ranges were defined for aging and wine production. A basic model of a winemaking building was designed to which bioclimatic strategies were applied. The results obtained allowed to suggest the best bioclimatic design options for this type of buildings.

scholarly journals Influence of different methods for breaking seed dormancy of Ambrosia artemisiifolia, Abutilon theophrasti and Xanthium strumarium on emergence in field conditions

2021 ◽  
Vol 30 (1) ◽  
pp. 29-37
Author(s):  
Jovana Krstić ◽  
Goran Malidža ◽  
Miloš Rajković ◽  
Miloš Krstić
Keyword(s):  
Seed Dormancy ◽  
Block Design ◽  
Ambrosia Artemisiifolia ◽  
Abutilon Theophrasti ◽  
Field Conditions ◽  
Practical Significance ◽  
Xanthium Strumarium ◽  
Weed Species ◽  
Invasive Weed ◽  
Breaking Seed Dormancy

Seed dormancy is an important trait that contributes to the survival rate of weeds, helps to avoid the effects of herbicides and protects them against adverse environmental conditions. In order to determine which methods are effective in breaking seed dormancy of invasive weed species (Ambrosia artemisiifolia, Abutilon theophrasti, Xanthium strumarium), an experiment was set up in 2019 in a randomized block design, with three replications in the experimental field of the Institute of Field and Vegetable Crops (Novi Sad). The collected seeds of one population of A. artemisiifolia and A. theophrasti, were cleaned and stored in cold storage at 4°C until testing, while X. strumarium was stored at room temperature. Seed propagation was done in a weed science laboratory, using nine different methods for breaking seed dormancy. The seeds were exposed to different conditions of temperature, light and humidity over a certain period of time (24h or 48h). The dynamics of weed emergence were monitored daily, for a period of 31 days and expressed cumulatively in percentages. Based on the obtained results, the highest percentage of sprouted plants was determined in treatments where the seeds were propagated under light conditions, in water. An appropriate method of propagation can influence the breaking of seed dormancy and emergence in field conditions, which can have practical significance in the research of competitive relations between crops and tested weed species.

scholarly journals Different strategies for breaking physical seed dormancy in field conditions in two fruit morphs of Vachellia caven (Fabaceae)

2018 ◽  
Vol 28 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Ana E. Ferreras ◽  
Paula I. Marcora ◽  
M. Paula Venier ◽  
Guillermo Funes
Keyword(s):  
Seed Dormancy ◽  
Environmental Conditions ◽  
Environmental Variables ◽  
Environmental Heterogeneity ◽  
Environmental Changes ◽  
Gradual Increase ◽  
Field Conditions ◽  
Fruit Morphology ◽  
Physical Dormancy ◽  
And Coping

AbstractDifferences in fruit morphology among or within species might indicate differences in other regenerative traits, such as seed dormancy and germination. In species with physical dormancy (PY), environmental conditions are suggested to be responsible for dormancy break in field. Seeds of Vachellia caven have PY. This species exhibits two fruit morphs highly represented in Córdoba forests, Argentina: one is dehiscent and the other is indehiscent. In this study we performed a burial experiment with the aim to determine if the differences in V. caven fruit morphology were related to different patterns of PY break of their seeds in field conditions. We related these patterns to (1) environmental conditions that could influence the loss of PY, and (2) histological features of the lens zone. Seeds of both morphs exhibited dormancy break within 14 months of the start of the experiment, but with different patterns. The dehiscent morph showed an abrupt percentage of seeds that broke dormancy 14 months after the beginning of the experiment, probably after undergoing environmental changes similar to those suggested by the two-stage softening model. The indehiscent morph showed a gradual increase in seeds that broke dormancy, not clearly related to any of the environmental variables studied. No differences in seed coat structure of the lens zone were observed between morphs. The existence of both morphs could confer the species with higher possibilities of establishing and coping with environmental heterogeneity. Those characteristics contribute to the understanding of the success of this species in open and disturbed environments.

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