Mandák B, Holmanová S
Institute of Botany, Academy of Sciences of the Czech Republic, 252 43 Průhonice, Czech Republic.
Plant Biol (Stuttg). 2004 Nov;6(6):715-20. doi: 10.1055/s-2004-830384.
Atriplex sagittata is an annual heterocarpic plant that produces three different fruit types (termed A, B, and C). To examine the consequence of heterocarpy on germinability patterns over long time periods, we compared seed germinability of different fruit types that had been stored for up to 8 years. While germinability of non-dormant type C fruits in distilled water was high (up to 100 %) in the first 2 years, it rapidly decreased over time. Dormant fruit types A and B showed increased germinability up to 7 years, though loss of germinability was lower for type B than for type A fruits. Eight-year-old fruits of all types had significantly lower germinability than younger fruits, probably due to loss of viability. Heterocarpy, therefore, ensures that emergence rates for seedlings of A. sagittata will be maintained over relatively long periods, even in years of strong disturbance when all adult plants may be destroyed. The experiment further showed that germinability of all fruit types in high concentrations of salt, as compared with water treatment, changed over the course of 8 years. Whilst dormant types (A and B) of A. sagittata show increased germinability with age of the seed in water treatment, they significantly lose germinability over time with salinity treatment. Type C fruit was not influenced by salt in the first year, but germinability rapidly decreased with time. It follows that the species is able to germinate under high salt concentration in the first year, but this advantage gradually disappears.
箭叶滨藜是一种一年生的异形果植物，会产生三种不同的果实类型（称为A、B和C型）。为了研究异形果对长时间发芽模式的影响，我们比较了储存长达8年的不同果实类型的种子发芽率。虽然在最初两年中，蒸馏水中非休眠的C型果实发芽率很高（高达100%），但随着时间的推移迅速下降。休眠的A和B型果实发芽率在7年内有所增加，不过B型果实发芽率的损失低于A型果实。所有类型的8年生果实发芽率均显著低于较年轻的果实，这可能是由于活力丧失所致。因此，异形果确保了箭叶滨藜幼苗的出苗率在相对较长的时期内得以维持，即使在所有成年植株可能被摧毁的强烈干扰年份也是如此。该实验还表明，与水处理相比，高浓度盐处理下所有果实类型的发芽率在8年中都发生了变化。在水处理中，箭叶滨藜的休眠类型（A和B型）发芽率随种子年龄增加，而在盐处理下，它们的发芽率随时间显著降低。C型果实在第一年不受盐的影响，但发芽率随时间迅速下降。由此可见，该物种在第一年能够在高盐浓度下发芽，但这种优势会逐渐消失。
