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Konferensabstrakt2007Vetenskapligt granskad

Dormancy cycle in Solanum nigrum seeds

Taab, Alireza; Andersson, Lars

Sammanfattning

Solanum nigrum L. is considered as a weed of many crops in different countries. Increased knowledge regarding the seed dormancy characteristics would facilitate development of effective weed management programs. The objective of this experiment was to characterise the seasonal dormancy cycle in this species. The experiment was carried out 2004 to 2006 in a randomized complete block design with four replicates. Portions of 100 seeds were buried in pots outdoors in November and exposed to natural temperatures. At monthly intervals, samples of the seeds were randomly exhumed and germination was tested in incubators at three different germination conditions including i) high temperature and light (HL) at 25/15 ºC, with 16/8 hours light/darkness, ii) the same temperature regime in complete darkness (HD), and iii) low temperature and light at 18/8 ºC, 16/8 hours light/darkness (LL). The intial level of dormancy was investigated in a germination test of fresh seeds. Germinability was 28.5, 0.5 and 0% in HL, HD and LL, respectively. The results of the burial experiment showed that seeds of S. nigrum have an annual dormancy cycle indicating that cold and warm temperatures basically cause relief and induction of dormancy, respectively. Thus, the species principally behave as a summer annual. After one month of burial, germination was complete or almost complete from December to July when exhumed seeds were tested in HL. High percentages of germination (>90%) were achieved in LL, and HD, after 4 and 5 months of burial, respectively. Surprisingly, germination was reduced with 44 and 57% in May in HD and LL, respectively, in the first year of burial. This was followed by an increase in germination during June and a peak in July. This short-lasting induction of dormancy was repeated in June the second year, but was only observed in HD where germination was reduced with 33.5%.. The main dormancy induction started in July and lasted until September when almost all seeds were dormant. In the first year, breakage of dormancy started in October and in December germination was 97, 75.6, and 71% in HL, HD, and LL, respectively. The second year a reduction in germination was observed when exhumed seed were tested in HD and LL in January and February, respectively. From July to termination of the experiment in November 2006 decrease and increase in germinability of the seeds resembled the pattern of the first year. The present study showed that requirements for germination the first winter decreased as time of burial increased. Under prolonged winter conditions, seeds seem to gain the ability to germinate in both light and darkness. There was a reduced germinability of buried seeds after December 2005 until May 2006 when tested in HD as compared to those tested in HL. This shows that light plays an important role in triggering seed germination during certain periods. Thus, germination in this species is to some extent phytochrome regulated, whereas soil temperature is a key factor regulating seed dormancy cycle. In conclusion, seasonal changes in breakage and induction of dormancy were similar througout the whole period of experiment, suggesting consistency in seed dormancy pattern of S. nigrum. Thus, induction of seed dormancy during summer inhibits late germination and subsequent plant death in autumn

Publicerad i

Titel: 14th EWRS Symposium, Hamar 18-21 June 2007
ISBN: 978-90-809789-2-8Utgivare: European Weed Research Society

Konferens

14th EWRS Symposium

    UKÄ forskningsämne

    Jordbruksvetenskap

    Permanent länk till denna sida (URI)

    https://res.slu.se/id/publ/15020