Seed Dormancy And Germination Characteristics Of Vicia Angustifolia

Stored and fresh Vicia angustifolia seeds were used to investigate the seed dormancy type, dormancy breaking methods, dormancy mechanism and their ecological significance in present study, the main results are as follows:1. Fresh Vicia angustifolia seeds exhibited combinational dormancy which combines physical and physiological dormancy, and stored seeds exhibited physical dormancy only.2. Seed coat cutting or H2SO4scarification for20min are the most effective methods to break physical dormancy of V. angustifolia compared to the other treatments.3. Effects of different plant growth regulators on seed germination of two seed lots of V. angustifolia were examined, and the results showed that:exogenous fluridone (FL) can significantly promote the germination of fresh seeds, but has no obvious function in promoting the germination of stored seeds; in addition, compared with the stored seeds, fresh seed was more sensitive to exogenous abscisic acid (ABA) inhibitive effect, implies ABA plays a key role in regulating physiological dormancy of V. angustifolia seed. Exogenous GA3can promote fresh seed germination, but exogenous paclobutrazol (PA) showed a slight inhibitive effect on seed germination only, this may suggest that seed endogenous gibberellins content is not the main reason response to seed physiological dormancy.4. Scarified fresh and stored seed were germinated under a series of temperatures ranged from5to30℃at5℃interval, the results showed that stored seed can germinate in a wide temperature (0to30℃), and the ceiling temperature (Tc), the optimal temperature(To) and the base temperature (Tb), are30.67℃,19.86℃and0.33℃, respectively. Compared to stored seed, fresh seed exhibited a relative narrow temperature range (0to20℃); the ceiling temperature (Tc), the optimal temperature(To) and the ceiling temperature (Tc) are21.64℃,9.83℃and-1.50℃, respectively. 5. Scarified fresh and stored seed were germinated under different water potential at10,15,20and25℃, and the hydrotime model were used to analysis germination dynamics at each temperature. The results showed that fresh seeds obtained a significantly higher median water potential [Ψb (50)] than stored seeds, e.g. in the15℃,Ψb of stored seeds and fresh seeds was-1.42MPa and-0.59MPa, respectively. This implies that fresh seed won’t germinate when water availability is limited, and thus explain the phenomenon of soften seeds did not germinate in the winter after disperse in the field.6. Fresh seeds were placed in the soil surface and retrieved every two months to determine seed germination, dormancy and death percentage at20℃. The results showed that as burial duration increased, seed physiological dormancy gradually released, germinated and dead seeds gradually increased. These suggest that the main ecological function of physiological dormancy of V. angustifolia is to hinder rapid germination of soften seeds dispersed in the autumn, and thus avoid the occurrence of seedlings death after germination.