摘要
Aims The physiological responses during dormancy removal and multi-phasic germination were investigated in seeds of Paeonia corsica(Paeoniaceae).Methods Seeds of P.corsica were incubated in the light at a range of temperatures(10-25 and 25/10℃),without any pre-treatment,after W(3 months at 25℃),C(3 months at 5℃)and W+C(3 months at 25℃followed by 3 months at 5℃)stratification,and a GA_(3)treatment(250 mg·l^(−1)in the germination substrate).Embryo growth,time from testa to endosperm rupture and radicle emergence were assessed as separate phases.Epicotyl-plumule emergence was evaluated incubating the germinated seeds at 15℃for 2 weeks,at 5 and 25℃for 2 months on agar water before transplanting to the soil substrate at 10,15 and 20℃and at 15℃for 2 months on the surface agar water with GA_(3).Important Findings Embryo growth,testa rupture,endosperm rupture(radicle emergence)and growth of the epicotyl were identified as four sequential steps in seeds of P.corsica.Gibberellic acid alone and warm stratification followed by 15℃promoted embryo growth and subsequent seed germination.Cold stratification induced secondary dormancy,even when applied after warm stratification.After radicle emergence,epicotyl-plumule emergence was delayed for ca.3 months.Mean time of epicotyl-plumule emergence was positively affected by cold stratification(2 months at 5℃)and GA_(3).P.corsica seeds exhibited differential temperature sensitivity for the four sequential steps in the removal of dormancy and germination processes that resulted in the precise and optimal timing of seedling emergence.
基金
Sardinia Regional Government:financial support of Marco Porceddu PhD scholarship(P.O.R.Sardegna F.S.E.Operational Programme of the Autonomous Region of Sardinia,European Social Fund 2007-2013-Axis IV Human Resources,Objective l.3,Line of Activity l.3.1.)
supported by Ente Foreste della Sardegna
The Royal Botanic Gardens,Kew,receives grant in-aid from Defra,UK.
