混合盐碱胁迫对小白菜种子萌发的影响

用不同浓度的NaCl、Na₂SO₄、NaHCO₃和Na₂CO₃混合液对小白菜(Brassica chinensis L.)种子进行种子萌发试验,观察小白菜种子在不同浓度盐碱胁迫下的发芽率和发芽指数。结果表明,在混合盐碱胁迫下,小白菜种子的发芽率、发芽势、发芽指数和活力指数均随pH值增大和盐浓度的升高呈下降趋势,且各萌发指标与盐浓度的相关系数明显大于pH值,可见小白菜种子发芽受盐浓度的影响更大。低浓度(50mmol·L^-1)盐碱胁迫对小白菜种子萌发影响不大,高浓度(200mmol·L^-1)盐碱胁迫下小白菜的种子萌发受到严重影响。     

Variations in seed germination behavior of Phleum hirsutum subsp. ambiguum and possible applications in semi-natural grassland restoration

Phleum hirsutum Honck. subsp. ambiguum (Ten.) Tzvelev is an important component of the vegetation of some semi-natural grassland habitats of central and southern Italy and especially of those referring to the 6210^* habitat (Directive 92/43/EEC). Seeds of this species are required for the execution of restoration works concerning this habitat. Therefore, the recovery and the study of autochthonous germplasm are needed. This study focused on the intra-specific variations in seed mass and size and in seed germination behavior in this species since the knowledge of these aspects can be very useful in the planning of restoration projects. The present research evidenced significant differences in mean seed mass and size in the populations studied that were correlated to the precipitation values of their collection sites. Studied seeds are able to germinate under a wide range of temperatures. They reached their maximum germination between 5 and 25°C and are capable of germination even at 30°C but with a remarkable reduction in germination percentage. Temperature was found to strongly influence germination, especially in terms of the speed. Light was found to enhance germination in almost all the populations studied while the removal of outer covering structures was found to be of no effect.