Germination of Aristida armata Under Constant and Alternating Temperatures and Its Analysis With the Cumulative Weibull Distribution as a Model

1987 ◽  
Vol 35 (5) ◽  
pp. 581 ◽  
Author(s):  
RF Brown
Keyword(s):  
Weibull Distribution ◽  
Shape Parameter ◽  
Germination Rate ◽  
Coefficient Of Determination ◽  
Its Analysis ◽  
Minimal Distortion ◽  
Different Temperatures ◽  
Fitted Function ◽  
Extremes Of Temperature

Germination of Aristida armata was compared at different temperatures on a thermogradient plate. Temperatures ranged from 10°C to 50°C with day/night differentials of 0, 5, 10 and 15°C. Alternating temperatures improved overall germination, particularly at the extremes of temperature. Average temperatures of 35°C and higher were fatal to many seeds. Day temperatures of 17.5°C and lower inhibited germination but did not prevent subsequent germination under warmer conditions. There was little variation in the rate of germination with incubation under constant temperatures. Under alternating temperatures, maximum germination occurred at lower temperatures than those under which germination rate was greatest. A four-parameter cumulative Weibull distribution was used to summarise cumulative germination. The distribution has the general form: Y = M(1-exp[- {k(t - I)}c]), where Y is the total germination at time t, M is the final total germination, k is germination rate, I is the interval between the start of incubation and the start of germination, and c is a shape parameter. In nearly all cases, the fitted function had a coefficient of determination greater than 0.98. The Weibull distribution allows reconstruction of the original germination data with minimal distortion and its use is recommended for both the analysis and modelling of germination responses.

scholarly journals Investigation of Feller-Buncher Performance Using Weibull Distribution

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 284
Author(s):  
Ebru Bilici
Keyword(s):  
Weibull Distribution ◽  
Shape Parameter ◽  
B Value ◽  
Productivity Analysis ◽  
Volume Data ◽  
Estimation Model ◽  
Distribution Method ◽  
Timber Volume ◽  
C Value ◽  
The Right

With the advancement of technology in forestry, the utilization of advanced machines in forest operations has been increasing in the last decades. Due to their high operating costs, it is crucial to select the right machinery, which is mostly done by using productivity analysis. In this study, a productivity estimation model was developed in order to determine the timber volume cut per unit time for a feller-buncher. The Weibull distribution method was used to develop the productivity model. In the study, the model of the theoretical (estimated) volume distributions obtained with the Weibull probability density function was generated. It was found that the c value was 1.96 and the b value was 0.58 (i.e., b is the scale parameter, and c is the shape parameter). The model indicated that the frequency of the volume data had moved away from 0 as the shape parameter of the Weibull distribution increased. Thus, it was revealed that the shape parameter gives preliminary information about the distribution of the volume frequency. The consistency of the measured timber volume with the estimated timber volume strongly indicated that this approach can be effectively used by decision makers as a key tool to predict the productivity of a feller-buncher used in harvesting operations.

Study on Sequential Compliance Method Influenced by Shape Parameter of Weibull Distribution

2011 ◽  
Vol 189-193 ◽  
pp. 4361-4364 ◽  
Author(s):  
Hong Liang Lou ◽  
Xing Lin Li ◽  
Xian Zhao Xu ◽  
Yang Ping Zhang ◽  
Zhong Hua Yu
Keyword(s):  
Weibull Distribution ◽  
Shape Parameter ◽  
Weibull Distributions ◽  
Simulation Test ◽  
Consumer’S Risk ◽  
Producer’S Risk ◽  
Rejection Probability

When sequential compliance method is used for Weibull distributions, the shape parameter is usually considered to be fixed. However, because of the life of products are determined by many factors, the shape parameter is variational in practice, that is to say, the shape parameter in the criterions is different from that in the practice. In this paper, the changes of acceptance and rejection probability are researched by the influence of shape parameter changes. Finally, by means of simulation test, changes on the shape parameter affecting on the probability of acceptance and rejection are quantitatively analyzed. As a result, the larger the gap on the shape parameter in the criterions and in the practice is, the larger the gap on the producer’s risk and the consumer’s risk.

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
Keyword(s):  
Seed Germination ◽  
High Temperatures ◽  
Exposure Time ◽  
Germination Rate ◽  
Heat Exposure ◽  
Cistus Ladanifer ◽  
Different Temperatures ◽  
Petri Dishes ◽  
Germinated Seeds

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.

Temperature Effect on Seed Germination Performance of a Local Variety of Onion in Bangladesh

2021 ◽  
Vol 1 (01) ◽  
pp. 27-30
Author(s):  
IRANI KHATUN ◽  
RIYAD HOSSEN
Keyword(s):  
Seed Germination ◽  
Temperature Effect ◽  
Performance Test ◽  
Germination Rate ◽  
Germination Percentage ◽  
Optimum Range ◽  
Local Variety ◽  
Different Temperatures ◽  
Local Farmers

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.

scholarly journals Acid and Temperature Treatments Result in Increased Germination of Seeds of Three Fescue Species

2012 ◽  
Vol 40 (2) ◽  
pp. 220 ◽  
Author(s):  
Rade S. STANISAVLJEVIC ◽  
Savo M. VUCKOVIC ◽  
Aleksandar S. SIMIC ◽  
Jordan P. MARKOVIC ◽  
Zelijco P. LAKIC ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Seed Germination ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Germination Rate ◽  
Festuca Rubra ◽  
Time Intervals ◽  
Different Temperatures ◽  
Successful Establishment ◽  
Seed Collecting

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.

scholarly journals Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Germination Rate ◽  
Seed Viability ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Viability Test ◽  
Physiological Dormancy ◽  
Different Temperatures ◽  
Germination Requirements

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.

scholarly journals ELECTRICAL CONDUCTIVITY AND QUALITY OF DIFFERENT UMBEL ORDER CARROT SEEDS

2020 ◽  
Vol 9 (04) ◽  
pp. 75-81
Author(s):  
Luana de Souza Marinke ◽  
Hugo César Rodrigues Moreira Catão ◽  
Gabrielly Fernanda Francisco ◽  
Ítala Menegon Castilho ◽  
Letícia Rodrigues de Oliveira ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Germination Rate ◽  
Statistical Design ◽  
Germination Test ◽  
Aerial Portion ◽  
Initial Characterization ◽  
Different Temperatures ◽  
Physiological Quality ◽  
Final Score

Carrot seeds exhibit irregular vigor due to the wide blooming period of the crop. Results from germination tests are insufficient to evaluate the physiological potential. Thus, vigor tests are used in combination with germination tests. The objective of this work was to evaluate the quality of carrot seeds from different umbel order and the electrical conductivity under different temperatures and imbibing periods. Carrot seeds from cultivar Brasilia were used to perform the experiments. Content of water, the first and the final score of the germination test, index of germination rate, and length of roots and of the aerial portion were determined in the initial characterization. The electrical conductivity test was completed with replicates containing 50 seeds, in 25 mL deionized water at 20, 25 and 30oC. Evaluations were performed with 2, 4, 6, 8, 12 and 24 hours of imbibing period. The experiment was accomplished under a completely random statistical design. The quality of carrot seeds varied according to the umbel order. Seeds of secondary umbels showed better physiological quality. The electrical conductivity test is efficient to evaluate the vigor of carrot seeds with 8 hours of imbibing period at 25°C.

Sign in / Sign up

Export Citation Format

Share Document