Seed production and seed germination of Amsinckia hispida

1965 ◽  
Vol 5 (19) ◽  
pp. 495 ◽  
Author(s):  
DJ Connor
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seed Production ◽  
Constant Temperature ◽  
Cold Treatment ◽  
North West ◽  
Seed Maturity ◽  
Germination Behaviour ◽  
Western Victoria ◽  
North Western

Amsinckia hispida is a serious annual weed of cereal culture in north-western Victoria. Individual plants produce seed for up to two months in the spring and this provides a range of seed maturity that is reflected by a gradual build-up of germinability in the following autumn. In addition the seed has an optimum constant temperature for germination of 13�C (48�F) and responds markedly to a period of cold treatment. These three features act together to produce the series of Amsinckia populations which are characteristic of its autumn germination behaviour in north-west Victoria. Seeds which germinate early are responsible for infestations in the pasture phase and those which germinate later are not controlled by pre-sowing cultivation and remain to germinate within crops. The response of Amsinckia to environmental factors is such that these plants which germinate late within wheat crops have an extended rosette period and are highly competitive.

Control of Amsinckia spp. by the pastures of north-western Victoria

1965 ◽  
Vol 5 (19) ◽  
pp. 500
Author(s):  
DJ Connor
Keyword(s):  
Seed Production ◽  
Subterranean Clover ◽  
Barrel Medic ◽  
Limited Application ◽  
One Year ◽  
The One ◽  
Western Victoria ◽  
Establishment Phase ◽  
North Western ◽  
Very High

Amsinckia is a serious weed in the wheat growing areas of north-western Victoria. It is successful in the inter-crop pastures, based upon barrel medic, because it grows faster than barrel medic in the cooler months of May to August. In addition, the rapid growth in height associated with the change from rosette to elongating phases ensures a height advantage over the pasture species when the flush of pasture growth does commence. Seed production by each Amsinckia plant is very high, and for this reason any competitive restriction obtained in one year is not necessarily reflected in the establishment phase of the next. Subterranean clover c.v. Clare is more competitive than barrel medic and was able to eliminate Amsinckia from the sward in two years. However it has only limited application in the pastures of north-western Victoria. A mowing treatment was carried out at the commencement of Amsinckia flowering, for this coincides with the beginning of rapid pasture growth. Regrowth produced a reversal of height relationships within the pasture and enabled barrel medic to shade Amsinckia BJ this treatment growth and seed production of Amsinckia were reduced by 99 per cent within the one season.

A Postfire Chronosequence of Cone, Follicle and Seed Production in Banksia ornata

1986 ◽  
Vol 34 (4) ◽  
pp. 425 ◽  
Author(s):  
AM Gill ◽  
A Mcmahon
Keyword(s):  
Seed Production ◽  
Seedling Establishment ◽  
Quantitative Research ◽  
Weather Conditions ◽  
Fire Intensity ◽  
Stand Age ◽  
Laboratory Conditions ◽  
Western Victoria ◽  
North Western ◽  
Seasonal Weather

The fire-sensitive shrub Banksia ornata relies on seed stored in serotinous 'cones' for its regeneration. Seed release takes place largely as a result of fire but a very small percentage of fruits may open spontaneously. In a chronosequence studied in heaths of the Little Desert of north-western Victoria, we found no seedling establishment in the absence of fire except in the oldest stand, dated at 50+ years since fire. Seed quantity was low in stands 6-7 years old but rose to a peak in the 38-year-old stand. The decline of seed quantity in the 50+ year-old stand was due to dieback and death of bushes. There was no evidence for an increase in the proportion of seeds predated with age of stand. An average of about 70% of the seed was regarded as 'intact' (no sign of damage) and about 80% of these seeds germinated under ideal laboratory conditions. It was estimated that the amount of seed available for regeneration increased with stand age up to 38 years but declined by 50+ years. It was suggested that a period of 16 years without fire could be needed to achieve stand replacement of populations of this species. The age at which full replacement can be achieved will vary, however, according to fire intensity and seasonal weather conditions. Further quantitative research is needed.

scholarly journals 325 Temperature and Gibberellin Acid on Seed Germination of Iris versicolor L.

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 448B-448
Author(s):  
Donglin Zhang ◽  
Diemeng Hu ◽  
John Smagula
Keyword(s):  
Seed Germination ◽  
Constant Temperature ◽  
Significant Influence ◽  
Aquatic Plant ◽  
Germination Rate ◽  
Cold Treatment ◽  
Important Species ◽  
Germination Temperature ◽  
In The Wild ◽  
Petri Dishes

Iris versicolor (blue-flag iris) is a native aquatic plant that grows from Maine to Virginia. It is an important species of wetland regeneration and restoration. Unfortunately, seed germination seldom occurs in the wild. To address this problem, seeds of Iris versicolor were soaked with gibberellin acid (0, 500, 1000, and 1500 ppm) for 24 h after 120 days of cold treatment at 4 °C and then were randomly assigned to three germination temperatures (constant 21 °C; 24 °C/18 °C; 27C/15 °C) and placed in darkness. Germination rates for the three temperature treatments were 54.4% (21 °C), 96.5% (24 °C/18 °C), and 96.0% (27C/15 °C). Oscillating temperature treatments had significantly greater germination rate than constant temperature. Gibberellin acid had significant influence on germination rate; only the constant 21 °C was not favorable for germination. The germination rate was higher at 1000 than at 500 ppm or 1500 ppm or more. Germination occurred within 10 days under germination temperature treatments. All seedlings in petri dishes were successfully transplanted into growing flats.

scholarly journals Seed germination and emergence of Eragrostis tenuifolia (A. Rich.) Hochst. ex Steud. in response to environmental factors

2016 ◽  
Vol 56 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Henrique von Hertwig Bittencourt ◽  
Lisandro Tomas da Silva Bonome ◽  
Fortunato de Bortoli Pagnoncelli ◽  
Marcos Alberto Lana ◽  
Michelangelo Muzell Trezzi
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Constant Temperature ◽  
Cover Crops ◽  
Temperature Regime ◽  
Seedling Emergence ◽  
No Tillage ◽  
Weed Species ◽  
Crop Fields ◽  
Positive Effect

AbstractEragrostis tenuifolia is a weed species that is gaining ground in Brazil. This weed occurs in pastures, grasslands, crop fields, and roadsides. The objective of this study was to examine the effects of different environmental factors on E. tenuifolia seed germination and seedling emergence. The optimum constant temperature for germination was around 35-30°C. It was also found that 85% of seeds germinated under a 30/20°C alternate temperature regime. Light appears to have a positive effect on seed germination. No seedlings emerged when seeds were buried 3 cm or deeper. The results suggested that E. tenuifolia has the potential to spread into pastures and in no-tillage crop systems in Brazil. Measures such as the use of cover crops and/or soil cultivation can be used to limit germination and seedling emergence, respectively.

scholarly journals Temperature fluctuation improves oil palm (Elaeis guineensis) dura × pisifera seed germination

2020 ◽  
Vol 48 (1) ◽  
pp. 49-55 ◽  
Author(s):  
M.G. Norsazwan ◽  
U.R. Sinniah ◽  
A.B. Puteh ◽  
P. Namasivayam ◽  
M. Mohaimi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Seed Germination ◽  
Ambient Temperature ◽  
Seed Production ◽  
Constant Temperature ◽  
Oil Palm ◽  
Temperature Fluctuation ◽  
Daily Maximum ◽  
Seed Processing ◽  
Temperature Amplitude

Oil palm is mainly propagated using dura × pisifera (D × P) hybrid seeds. Among the issues in D × P seed production are relatively poor seed germination and uniformity, despite heat treatment at 40°C to break dormancy. The conditions for germination post-heat-treatment may be a contributing factor. This study aimed to evaluate and compare the effect of constant 30°C or ambient temperature fluctuation at two different locations, Sime Darby Oil Palm Breeding Seed Processing Renggam, Johor and the Seed Production Unit (SPU) Banting, Selangor on oil palm D × P seed germination. At both locations, final mean germination percentage and speed were higher at fluctuating temperatures compared with constant 30°C. Under fluctuating conditions, the Oil Palm Breeding Seed Processing Renggam environment resulted in higher germination (85.8%) compared with SPU Banting (69.8%). Thus, the higher temperature amplitude (difference between daily maximum and minimum temperatures) was an important factor, resulting in higher germination. Therefore, oil palm can be germinated under ambient temperature conditions to obtain higher germination than under constant temperature, avoiding the need for maintaining expensive constant temperature germination rooms. In addition, a sufficiently high temperature amplitude can be beneficial in improving the ability to germinate and the speed of germination.

In vitro germination of three Cypripedium species in relation to time of seed collection, media, and cold treatment

1993 ◽  
Vol 71 (6) ◽  
pp. 879-885 ◽  
Author(s):  
M. A. De Pauw ◽  
W. R. Remphrey
Keyword(s):  
Seed Germination ◽  
Cold Treatment ◽  
Subsequent Development ◽  
The Other ◽  
In Vitro Germination ◽  
Optimum Time ◽  
Seed Collection ◽  
Seed Maturity ◽  
Better Than

To maximize the in vitro seed germination of three Cypripedium species, C. candidum Muhl. ex Willd., C. reginae Walt., and C. calceolus var. parviflorum Salisb. Fern., the optimum time of seed collection and the suitability of various media were studied. A cold treatment was investigated for C. candidum. Seed pods were collected at regular intervals after pollination, ranging from green pods at 5 weeks to dry undehisced pods at 12 weeks. Seed was inoculated onto three media, Harvais, Van Waes and Debergh, and a modified Norstog and germination was assessed at 4-week intervals for 20 weeks. Cypripedium reginae germinated better than the other two species. Except for C. candidum in 1989 when germination peaked for seed collected at 6 weeks after pollination, seed collected at 8 weeks after pollination had the highest germination. After 8 weeks, germination decreased sharply in all species, dropping below 1% for C. candidum. There were differences among media but the effects on germination were not consistent and depended on the year, the date of collection, and the species. Subsequent development of protocorms was superior in all cases on the modified Norstog medium. The effect of cold treatment on germination of C. candidum was variable and therefore its importance is questionable. Key words: in vitro, germination, Cypripedium, lady's slippers, seed maturity.

scholarly journals Effect of Environmental Factors on the Germination and Emergence of Drunken Horse Grass (Achnatherum inebrians)

Weed Science ◽  
2020 ◽  
pp. 1-29
Author(s):  
Yonghuan Yue ◽  
Guili Jin ◽  
Weihua Lu ◽  
Ke Gong ◽  
Wanqiang Han ◽  
...  
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Abiotic Factors ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Germination Percentage ◽  
Western China ◽  
Burial Depth ◽  
Achnatherum Inebrians ◽  
Water Ph

Abstract Drunken horse grass [Achnatherum inebrians (Hance) Keng] is a perennial poisonous weed in western China. A comprehensive understanding of the ecological response of A. inebrians germination to environmental factors would facilitate the formulation of better management strategies for this weed. Experiments were conducted under laboratory conditions to assess the effects of various abiotic factors, including temperature, light, water, pH and burial depth, on the seed germination and seedling emergence of A. inebrians. The seeds germinated at constant temperatures of 15, 20, 25, 30, 35°C and in alternating-temperature regimes of 15/5, 20/10, 25/15, 30/20, 35/25, 40/30°C, and the seed germination percentages under constant and alternating temperatures ranged from 51% to 94% and 15% to 93%, respectively. Maximum germination occurred at a constant temperature of 25°C, and germination was prevented at 45/35°C. Light did not appear to affect seed germination. The germination percentage of seeds was more than 75% in the pH range of 5 to 10, with the highest germination percentage at pH 6. The seeds germinated at osmotic potentials of 0 MPa to -1.0 MPa, but decreasing osmotic potential inhibited germination, with no germination at -1.2MPa. After 21 d of low osmotic stress, the seeds that did not germinate after rehydration had not lost their vitality. The seedling emergence percentage was highest (90%) when seeds were buried at 1 cm but declined with increasing burial depth and no emergence at 9 cm. Deep tillage may be effective in limiting the seed germination and emergence of this species. The results of this study provide useful information on the conditions necessary for A. inebrians germination and provide a theoretical basis for science-based prediction, prevention and control of this species.

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