Influence of Heat on Seed Germination of Cistus Laurifolius and Cistus Ladanifer

1992 ◽  
Vol 2 (1) ◽  
pp. 15 ◽  
Author(s):  
L Valbuena ◽  
R Tarrega ◽  
E Luis

The influence of high temperatures on germination of Cistus laurifolius and Cistus ladanifer seeds was analyzed. Seeds were subjected to different temperatures for different times, afterwards they were sowed in plastic petri dishes and monitored for germinated seeds over two months.The germination rate observed in Cistus ldanifer was greater than in Cistus laurifolius. In both species, heat increased germination percentages. For Cistus laurifolius higher temperatures or longer exposure times were needed. Germination percentages of Cistus ladanifer were lower when heat exposure time was 15 minutes.It must be emphasized that germination occurred when seeds were not treated, while seeds exposed to 150�C for 5 minutes or more did not germinate.

2015 ◽  
Vol 30 (4) ◽  
pp. 243-248
Author(s):  
Marija Saric-Krsmanovic ◽  
Gajic Umiljendic ◽  
Ljiljana Santric ◽  
Ljiljana Radivojevic

The influence of seed storage conditions and different temperatures (5?C, 10?C, 15?C, 20?C, 25?C, 30?C and 26?C/21?C) during germination and seedling development on seed germination, shoot length and germination rate of wild oat (Avena fatua L.) was examined. Germinated seeds were counted daily over a period of ten days and shoot length was measured on the last day, while germination rates were calculated from those measurements. The results showed that seed storage under controlled conditions (T1: temperature 24?1?C, humidity 40-50%; T2: temperature 26?1?C, humidity 70-80% and T3: temperature 4?C) for periods of 3 (t1) and 12 (t2) months had a significant influence on germination of wild oat seeds. The percentage of germinated seeds under all examined temperatures was higher when they were stored for 12 months under controlled temperature and humidity. The results also showed that temperature had a significant effect on the percentage of germination and germination rate of A. fatua seeds. The highest total germination occurred at 15?C temperature (T1: t1 - 41.25%, t2 - 44.37%; T2: t1 - 28.13%, t2 - 34.37%; T3: t1 - 10.63%, t2 - 12.50%). Germination percentage under an alternating day /night photoperiod at 26?C/21?C temperature was higher in all treatment variants (T1: t1 - 8.13%, t2 - 10.00%; T2: t1 - 11.87%, t2 - 13.13%; T3: t1 - 2.42%, t2 - 2.70%) than germination in the dark at 25?C, 30?C and 5?C.


2016 ◽  
Vol 44 (1) ◽  
pp. 291-295 ◽  
Author(s):  
Ljiljana RADIVOJEVIC ◽  
Marija SARIC-KRSMANOVIC ◽  
Jelena GAJIC UMILJENDIC ◽  
Dragana BOZIC ◽  
Ljiljana SANTRIC

The effects of different temperatures (20 °C, 25 °C, 30 °C, 35 °C and photoperiod 26 °C/21 °C), types of soil (sand and loam) and soil herbicides (oxyfluorfen, terbuthylazine and mesotrione) on seed germination percentage, germination rate, as well as seedling length and weight of common milkweed (Asclepias syriaca L.) were examined. Over a period of ten days, germinated seeds were counted daily, and seedling length and weight were measured on the final day and germination rate calculated. The results indicated that temperature was the factor that significantly affected the percentage of germinated seeds of common milkweed, seedling length and germination rate, while it had less influence on seedling weight. The results showed that the alternating day/night temperature of 26 °C/21 °C also had a significant impact as the percentage of germinated seeds was the highest at that temperature on both soil types (sand: 71.3%; loam: 61.3%). Data regarding the herbicides tested (oxyfluorfen, terbuthylazine and mesotrione) showed decreasing germination percentage and seedling length with increasing herbicide concentrations on both soil types. Their effect was weakest on seedling weight. Tested herbicides are usable in control of common milkweed at the stages of germination and early establishment.


2021 ◽  
Vol 1 (01) ◽  
pp. 27-30
Author(s):  
IRANI KHATUN ◽  
RIYAD HOSSEN

Seed germination performance test of Taherpuri onion (a local variety of onion) under six different temperatures (15, 20, 25, 30, 35 and 40°C) was the main goal of this experiment. Germination percentage (GP) was calculated at highest 60.25% at 25°C, and the highest germination rate 20.08 was observed in the same temperature condition. The lowest germination performance (13.25 % germi-nation and 3.32 seeds per day as germination rate) was found at 40°C temperature. Finally, the authors mentioned the temperature 20 to 30°C as optimum range, and suggested the temperature 25°C as best suited for obtaining highest results in case of both germination percentage and germination rate of these seeds. To produce maximum seedlings of the local variety of onion, the mentioned temperature should be followed by the local farmers.


2012 ◽  
Vol 40 (2) ◽  
pp. 220 ◽  
Author(s):  
Rade S. STANISAVLJEVIC ◽  
Savo M. VUCKOVIC ◽  
Aleksandar S. SIMIC ◽  
Jordan P. MARKOVIC ◽  
Zelijco P. LAKIC ◽  
...  

Efficient germination of fescue seeds is essential for successful establishment of meadows and pastures. This research was conducted to ascertain the effects of various acid and temperature treatments on seed germination in three fescue species: Festuca rubra, F. ovina, and F. pratensis. Seeds from different cultivars, populations, or lots were exposed either to four concentrations of sulfuric acid at three different time intervals (12 treatments) or six different temperatures at three different time intervals (18 treatments). Despite all belonging to the genus Festuca, the seed from different species responded differently to the treatments. The three optimum treatments for F. rubra seed involved soaking in a 75% solution of sulfuric acid for 20 minutes (improved the germination rate by 19%), soaking in a 50% solution of sulfuric acid for 30 minutes (improved the germination rate by 18%) and exposure to either 60°C or 70°C for 90 minutes (improved the germination rate by 17%). For F. ovina seed, optimal treatments included soaking seeds for either 10 or 20 minutes in a 50% sulfuric acid solution (both treatments improved germination rates by 13%) or exposing seeds for 30 minutes in a 25% sulfuric acid solution and 80°C for 60 minutes (improved germination rate by 12%). Two optimal treatments were identified for F. pratensis seed. Whereas the first involved soaking the seeds in a 75% sulfuric acid solution for 30 minutes (improved germination rates by 22%), the second involved either exposing the seeds to 90°C for 90 or 60 minutes, or exposing the seeds to 80°C for 90 minutes (improved germination rate by 21%). Our findings indicate that if fescue seed is to be sown during the autumn (two to three months after seed collecting), treating it with acid and temperature can significantly enhance its germination.


Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.


Weed Science ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 505-510 ◽  
Author(s):  
R. Ghorbani ◽  
W. Seel ◽  
C. Leifert

Detailed knowledge about the environmental conditions required for weed seed germination and establishment in soil is an important prerequisite for the development of integrated and biological weed control strategies. Germination and establishmentof Amaranthus retroflexuswere studied at different temperatures, planting depths, soil types, nitrogen supply, and water potentials. The minimum temperature for seed germination was > 5 C; maximum germination occurred between 35 and 40 C. At temperatures between 25 and 35 C, an additive effect on germination rate was observed when temperature and water availability were increased. For all soils tested, the percentage emergence of seeds placed on the soil surface and 4 cm deep was significantly lower than seeds placed between 0.5 and 3 cm. Emergence in the four sandy soils was generally greater than in the two heavier soils included in the study. There was a highly significant interaction between seed depth and soil type. Plant growth was also greatest in the lighter soils. Plant height, number of leaves, leaf area, fresh and dry weight, and nitrogen and carbon percentage in plant tissues ofA. retroflexusincreased significantly with increasing soil nitrogen supply.


2016 ◽  
Vol 30 (1) ◽  
pp. 263-270 ◽  
Author(s):  
Scott N. White ◽  
Nathan S. Boyd

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.


2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Yongji Wang

To explore the optimum temperature, light intensityand water conditions for seed germination of Siphonostegia chinensis Benth.,seed germination experiment were carried out under different temperatures(5/15, 10/20, 15/25, 20/30℃), different light intensity(14h light/10h darkness, complete darkness)and different concentrations(0%, 5%, 10%, 15%, 20%)of PEG-6000 solution. In terms of concentration, 5% PEG was regarded as the low level, 10% and 15% as the medium level, and 20% as the high level. The results showed that (1) Germination rate, germination potential, and germination index were increased with the rise of temperature. In addition, seed germination was significantly higher under the dark conditions than that with the 14h light/10h darkness. (2) No seed germination occurred when the temperature was below 10/20 ºC at 14h light/10h darkness. (3) Under 14h light/10h darkness, the germination rate, germination potential and germination index first increased and then decreased with the increase of PEG concentration. The low concentration was more beneficial to the seed germination. (4) Under the condition of complete darkness, the germination rate, germination potential and germination index decline with fluctuation with the increase of PEG concentration. Seed germination of Siphonostegia chinensis Benth. was inhibited in high concentration of PEG.


HortScience ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 100-103
Author(s):  
Ahmet Korkmaz ◽  
Wallace G. Pill ◽  
Bruce B. Cobb

The effect of seed germination rate, or of seedling emergence rate, was studied in relation to subsequent plant growth of `Cortina' lettuce (Lactuca sativa L.). Seedling growth response to selection by time of germination was assessed by imbibing seeds at 5 °C to increase the time range for germination. Germinated seeds were removed daily and transferred to “slants” (germination paper held at 20° from vertical) at 15 °C. Five days after each transfer, root and hypocotyl lengths were measured. As days required for germination increased, root lengths decreased and hypocotyl lengths increased, resulting in no change in total seedling length. The relation between rate of seedling emergence from raw or pelleted seeds of the same lot and shoot fresh weight was examined using commercially practiced hydroponic techniques. Shoot fresh weight at 10 and 21 days after planting was related inversely and linearly to the day of emergence for both seed treatments. In the same study, the coefficient of variation of shoot fresh weight was positively related to time of seedling emergence only at 10 days. Germinated seeds were selected after 1 and 2 days of imbibition; subsequent seedling emergence rate and shoot fresh weight at 25 days were recorded. First-day germinated seeds had faster and more synchronous emergence, and produced heavier and more uniform shoots. Discarding slow-to-germinate seeds should enhance seedling emergence and growth.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 899C-899
Author(s):  
Moo R. Huh ◽  
Beyoung H. Kwack ◽  
Leonard P. Perry

In this experiment, the effects of salinity from 0.0%, 0.5%, 1.0%, and 5.0 % NaCl on Hibiscus syriacus L. and Hibiscus hamabo Sieb. & Zucc. seed germination with various temperature and Ca treatments was investigated in petri dishes with 10 ml of distilled water or with the appropriate saline solution. At 11 days after treatment, the highest germination rate was obtained at 20C with H. syriacus and 25C with H. hamabo without NaCl and Ca treatments. At 25C, only H. hamabo seeds germinated with 1% NaCl, with dry and fresh weight increasing as Ca concentration increased. With 0.5% NaCl treatment, the germination rate of H. hamabo and H. syriacus increased as Ca concentrations (0.0, 13.35, and 133.5 mM) increased. Without NaCl treatments, hypocotyl and leaf length and width of H. syriacus were longer than those of H. hamabo; with NaCl treatments, the inverse was true.


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