scholarly journals Environmental Factors Influencing Germination in Seeded Seashore Paspalum

HortScience ◽  
2006 ◽  
Vol 41 (5) ◽  
pp. 1330-1331 ◽  
Author(s):  
J.S. Shin ◽  
P. Raymer ◽  
W. Kim

Seashore paspalum (Paspalum vaginatum O. Swartz) is a perennial warm-season grass that is rapidly gaining popularity for use on golf courses and athletic fields. The first seeded cultivar of seashore paspalum was recently developed. Seed from the pilot production of this cultivar harvested in Oregon during 2002 by Turf-Seeds, Inc. demonstrated a high level of apparent seed dormancy with a tetrazolium test of 91% but a germination rate of less than 5% at room temperature. This seed was used in laboratory experiments to determine the effect of a number of environmental factors on germination response in this new turf species. Treatment factors are germination media, constant and alternating (night/day) temperatures, and light. A strong and significant effect of temperature on germination was observed. Total germination was increased at higher temperatures. At the same daytime temperature, seed germination under alternating temperature was better than germination at constant temperature. The effect of light on germination was significant at 20, 25, 30, 20/35 °C in water and at 25/35 °C in 0.2% KNO3 germination media. However, the effect of light on germination in KNO3 media was not significant at 35 °C constant and 20/30 °C alternating temperatures. Alternating temperature used in conjunction with KNO3 media reduced the requirement for light. The use of 0.2% KNO3 rather than water as the germination media increased germination in most temperature and light treatments. Based on our results, maximum germination percentage was obtained when seed was germinated at 35 °C constant or 20/35 °C alternating temperature. However, when we consider field application, 25/35 °C with light is more realistic condition in field. Therefore, recommended seed germination test condition is at 25/35 °C with KNO3 treatment.

Weed Science ◽  
2012 ◽  
Vol 60 (4) ◽  
pp. 558-563 ◽  
Author(s):  
Neha Rana ◽  
Barton J. Wilder ◽  
Brent A. Sellers ◽  
Jason A. Ferrell ◽  
Gregory E. MacDonald

Smutgrass is an invasive warm-season perennial bunch-type grass native to tropical Asia. The two varieties of smutgrass prevalent in Florida are small smutgrass and giant smutgrass. Laboratory seed germination experiments were conducted on both smutgrass varieties to determine the effect of various environmental factors on germination and emergence. The average germination rate for both varieties was 88% at 30/20 C day/night temperatures. Seed germination for both varieties was greater under simulated temperature flux than at constant temperatures. Seed of both varieties germinated at four simulated Florida temperature fluxes (22/11, 27/15, 33/24, and 29/19 C day/night), although the germination of small smutgrass and giant smutgrass was reduced at 33/24 and 22/11 C, respectively. Germination of small and giant smutgrass under dark conditions was 27 and 53%, respectively. Both smutgrass varieties germinated over a wide range of pH values. Small and giant smutgrass germination was inhibited at water potentials below −0.2 MPa and when small smutgrass seed was placed below the soil surface. Emergence of giant smutgrass seed did not occur below 3 cm. Both smutgrass varieties germinated over a broad range of environmental conditions, indicating their capability of year-round germination; however, germination is only likely to occur under field conditions during the summer growing season when rainfall is prevalent. These results indicate that both species have the ability to germinate over a wide range of environmental conditions but that germination is inhibited by moisture stress and depth of burial. Considering that giant smutgrass prefers higher temperatures than small smutgrass, the advent of rainfall from June through September is conducive for germination. Practices that focus on the germination pattern of smutgrass could lead to better long-term management of smutgrass in Florida.


Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 190
Author(s):  
Lei Chu ◽  
Yiping Gao ◽  
Lingling Chen ◽  
Patrick E. McCullough ◽  
David Jespersen ◽  
...  

White clover (Trifolium repens L.) is cultivated as a forage crop and planted in various landscapes for soil conservation. There are numerous reports of failed white clover stands each year. A good understanding of the seed germination biology of white clover in relation to environmental factors is essential to achieve successful stand establishment. A series of experiments were conducted to investigate the impacts of light, temperature, planting depth, drought, and salt stress on seed germination and the emergence of white clover. White clover is negatively photoblastic, and seed germination averaged 63 and 66% under light and complete dark conditions 4 weeks after planting (WAP), respectively. Temperature affected the seed germination speed and rate. At 1 WAP, seeds incubated at 15 to 25 °C demonstrated a significantly higher germination rate than the low temperatures at 5 and 10 °C; however, the germination rate did not differ among the temperature treatments at 4 WAP. The results suggest that white clover germination decreases with increasing sowing depths, and the seeds should be sown on the soil surface or shallowly buried at a depth ≤1 cm to achieve an optimal emergence. White clover seeds exhibited high sensitivity to drought and salinity stress. The osmotic potential and NaCl concentration required to inhibit 50% seed germination were −0.19 MPa and 62.4 mM, respectively. Overall, these findings provide quantifiable explanations for inconsistent establishment observed in field conditions. The results obtained in this research can be used to develop effective planting strategies and support the successful establishment of white clover stands.


2018 ◽  
Vol 36 (0) ◽  
Author(s):  
RC. XIONG ◽  
Y. MA ◽  
HW. WU ◽  
WL. JIANG ◽  
XY. MA

ABSTRACT: Velvetleaf, an annual broadleaf weed, is a common and troublesome weed of cropping systems worldwide. Laboratory and field experiments were conducted to determine the effects of environmental factors on germination and emergence of velvetleaf. Seeds germinated over a range of constant temperatures from 10 to 40 oC regardless of light conditions, but no germination occurred at temperature below 5 oC and beyond 50 oC. Seeds germinated at alternating temperature regimes of 15/5 to 40/30 oC, with maximum germination (>90%) at alternating temperatures of 40/30 oC. Germination was sensitive to water stress, and only 0.4% of the seeds germinated at the osmotic potential of -0.4 MPa. There was no germination at ? 0.6 MPa. Moreover, germination was reduced by saline and alkaline stresses and no germination occurred at ³ 150 mM NaCl or ³ 200 mM NaHCO3 concentrations. However, pH values from 5 to 9 had no effect on seed germination. Seedling emergence was significantly affected by burial depth and maximum emergence (78.1-85.6%) occurred at the 1-4 cm depth. The results of this study have contributed to our understanding of the germination and emergence of velvetleaf and should enhance our ability to improve control strategies in cropping systems in central China.


2019 ◽  
Vol 41 (4) ◽  
Author(s):  
Érica Fernandes Leão-Araújo ◽  
Eli Regina Barboza de Souza ◽  
Nei Peixoto ◽  
Francisco Guilhien Gomes-Júnior

Abstract The cultivation of native fruit species depends on the existence of consistent technical and scientific information on the germination and vigor of seeds for efficient management by seedling producers. The evaluation of the physiological potential of seeds is performed through germination and vigor tests, which must be standardized to ensure the generation of accurate information. For Campomanesia adamantium, information on parameters for conducting physiological tests is scarce. The aims of this work were (i) to evaluate the effect of temperature and seed positioning on the substrate for seed germination and vigor, and (ii) to characterize and describe the essential structures and main types of seedling abnormality. After harvest, fruits were pulped and, after seed extraction, germination tests were carried out for 42 days at three temperatures (20, 25 and 30 °C), with seeds positioned in the germination substrate in two ways (between paper and on paper). Seed vigor was evaluated by means of the first germination count (performed on the 20th day) and the germination rate index. The temperature and substrate interaction did not influence variables under study. The position of seeds on the substrate did not influence the physiological potential results. No differences were observed between seed germination temperatures; however, seeds submitted to germination at 25 °C showed higher vigor compared to the other temperatures. Germination and vigor tests, based on seedling performance, should be performed at constant temperature of 25 °C and seed positioning between paper and on paper may be used. Germination in C. adamantium was characterized as epigeal.


2004 ◽  
Vol 82 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Sabahat Zia ◽  
M Ajmal Khan

Limonium stocksii (Boiss.) Kuntze (Plumbaginaceae) is a perennial, woody shrub distributed at Hawks Bay, Karachi, Pakistan. Experiments were carried out to investigate seed germination responses of L. stocksii at different salinities (0, 100, 200, 300, 400, and 500 mmol/L NaCl) and under different temperature regimes (10:20, 15:25, 20:30, and 25:35 °C), both in a 12 h dark : 12 h light photoperiod and in complete darkness. The highest percentage of germination (about 100%) was obtained at 0, 100, and 200 mmol/L NaCl at 20:30 °C, and a further increase in salinity resulted in a gradual decrease in germination. Less than 5% of seeds germinated at 500 mmol/L NaCl. Germination under salinity treatment at 15:25 °C was slightly more inhibitory than the optimal temperature regime, whereas under both 10:20 and 25:35 °C temperature regimes, seed germination was substantially reduced and few seeds germinated at concentrations higher than 200 mmol/L NaCl. Germination rate was fastest at 20:30 °C and slowest at 10:20 °C. Relatively low seed germination was obtained in the dark in comparison to seeds germinated in a 12-h photoperiod under saline conditions. Recovery experiments showed that exposure of seeds to various salinity and temperature regimes had little effect on viability of seeds.Key words: germination, light, Limonium stocksii, NaCl, recovery, temperature.


2014 ◽  
Vol 20 (2) ◽  
pp. 191
Author(s):  
Sofía Basto ◽  
Claudia Ramírez

Tabebuia rosea germination capacity and rate have been examined under light and dark conditions. However, seeds responses to light quality, in particular to short and mid-wavelengths, are not well known. We hypothesized that short wavelengths would have a positive effect on rosea germination. The effects of short, mid and long-wavelengths on germination capacity, rate (germination rate index, germination rate R50, a devised index of germination rate R50´ and peak value), mean daily germination and germination value were evaluated. Light quality had little effect on germination capacity; it was reduced only in darkness. Seeds under short and mid-wavelengths germinated faster (germination rate) than under any other light treatments. We concluded that althoughlt T. rosea seeds respond to all light quality treatments, the short and mid-wavelengths are the cue for increasing germination speed. For synchronizing germination, short and mid-wavelengths transmitted by red cellophane paper can be used as a pre-germinative treatment for restoration and silvicultural purposes.


2004 ◽  
Vol 82 (11) ◽  
pp. 1662-1670 ◽  
Author(s):  
Yuanrun Zheng ◽  
Yong Gao ◽  
Ping An ◽  
Hideyuki Shimizu ◽  
Glyn M Rimmington

Agriophyllum squarrosum (L.) Moq. (Chenopodiaceae), a pioneer species of natural succession in semi-arid regions of China, is widely used for vegetation rehabilitation by air seeding. Experiments were conducted to determine the effects of light intensity and photoperiod, as well as constant and alternating temperatures, on germination to improve the technology of air seeding. Seed of A. squarrosum rarely (<18.5%) germinated at 5/15, 10/20, 15/25, and 20/30 °C (night/day); 39.5% of seeds germinated at 25/35 °C in a 14-h (215 µmol·m–2·s–1) photoperiod. Under dark conditions there was a high final percent seed germination (>90%), except for 71.8% final percent seed germination at 5/15 °C. Constant temperature conditions were associated with lower seed germination (<50%). Less than 13% of seeds germinated at different light intensities (25–400 µmol·m–2·s–1) at 10/20 °C. There was no significant difference in final percent germination when seeds were exposed to 400, 100, or 25 µmol m–2 s–1 for 2 h daily. Final percent germination and germination rate deceased rapidly when the photoperiod was increased under 400 µmol·m–2·s–1. Only 49.2% of seeds germinated after 3 d. Because of the deleterious effect of light on germination, air seeding in late May is recommended.Key words: Agriophyllum squarrosum, air seeding, alternating temperature, constant temperature, light, semi-arid regions.


Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 423-425 ◽  
Author(s):  
Jason C. Fausey ◽  
Karen A. Renner

Controlled environment experiments were completed to determine the effect of temperature on giant foxtail and fall panicum germination, emergence, and growth. Giant foxtail seed germination decreased when exposed to a constant 30 C compared to 20 C. Germination also decreased in the alternating 20/30 C temperature regime when the hours of exposure to 30 C as compared to 20 C increased. Fall panicum required alternating temperatures of 14 C (9 h)/28 C (15 h) to germinate. Giant foxtail seed germination exceeded 60% 4 d after exposure to an alternating temperature of 7 C (9.4 h)/20 C (14.6 h). Conversely, fall panicum seed did not germinate at the 7 C (9.4 h)/20 C (14.6 h) temperature regime and required a minimum of 7 d exposure to alternating temperatures of 13 C (8.7 h)/26 C (15.3 h) for 88% of the seed to germinate. The greatest emergence of giant foxtail and fall panicum was from 1 cm and 1 to 2.5 cm, respectively. Less than 5% of the giant foxtail and fall panicum seed emerged from 7.5 cm. The growth of giant foxtail seedlings was five times greater than that of fall panicum at each temperature regime tested. Incorporation of this information into bioeconomic models could result in accurate predictions of weed germination for effective weed management strategies.


2016 ◽  
Vol 22 (3) ◽  
pp. 259
Author(s):  
Armando Reis Tavares ◽  
Nara Oshiro Santos ◽  
Shoey Kanashiro ◽  
Vanessa Rebouças do Santos

Costus arabicus L. (Costaceae) is a tropical species native from Brazil. The species has ornamental potential as garden and vase plant, and for flower and stem cutting. The aim of this study was to evaluate the seed germination of C. arabicus under different of light and temperature conditions. Seeds subjected to constant temperatures of 20, 25 and 30 °C under photoperiod of 12 h of light or dark. The parameters analyzed were percentage of germination and germination speed index (GSI). The highest germination percentage (70%) was under temperature of 30 °C, both in light or dark. The GSI showed that the germination rate increases as temperature increases, mainly on 30 °C. C. arabicus seeds germinated in the presence or absence of light, thus was considered neutral photoblastic and germination on light under 30 °C was more efficient for seed germination.


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