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Variation in seed dormancy and germination among populations of Silybum marianum (Asteraceae)
Author(s) -
Monemizadeh Zahra,
GhaderiFar Farshid,
Sadeghipour Hamid R.,
Siahmarguee Asieh,
Soltani Elias,
Torabi Benjamin,
Baskin Carol C.
Publication year - 2021
Publication title -
plant species biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 36
eISSN - 1442-1984
pISSN - 0913-557X
DOI - 10.1111/1442-1984.12326
Subject(s) - germination , biology , silybum marianum , dormancy , milk thistle , seed dormancy , scarification , darkness , asteraceae , horticulture , botany , agronomy , pharmacology
Milk thistle ( Silybum marianum ) is a medicinal plant; however, lack of consistency in past dormancy studies has hindered propagation of this species from seeds. We tested the germination responses of freshly harvested and after‐ripened (stored for 2 and 7 months; 25°C at 50% relative humidity) seeds from three populations (P1, P2 and P3) in Iran at varying constant or alternating temperatures, with or without GA 3 and in light and continuous darkness. No germination occurred in freshly harvested seeds incubated at any condition without GA 3 application, indicating that all the seeds were dormant. Seeds from P1 and P2, which developed under relatively dry, warm conditions, germinated over a wider range of temperatures after 2 months of dry storage, indicating type 6 of non‐deep physiological dormancy (PD). Seeds from P3, which developed under relatively wet, cool conditions, incubated at constant temperatures (especially on GA 3 ), exhibited an increase in maximum temperature for germination, indicating type 1 of non‐deep PD. Light improved germination of after‐ripened seeds, and GA 3 application substituted for the light requirement for germination. This is the first report that environmental conditions during seed development may be correlated with differences in the type of non‐deep PD. We conclude that milk thistle seeds are positively photoblastic and photodormant and the germination responses of after‐ripened seeds from different populations are different under darkness. Therefore, the impacts of genetic differences and maternal effects on the induction of dormancy during seed development should be considered in attempts to domesticate this medicinal plant.