Diggle Pamela K, Meixner Margaret A, Carroll Amy B, Aschwanden Christie F
Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder 80309-0334, USA.
Ann Bot. 2002 Feb;89(2):145-56. doi: 10.1093/aob/mcf020.
Polygonum viviparum is widely distributed in arctic and alpine regions of the northern hemisphere. Fruit set has never been observed in North American populations and has been reported only very rarely in Europe. Although this species is extremely well studied, the impediments to successful fruit production are unknown. We investigated the sexual reproductive process in P. viviparum growing in the southern Colorado Rocky Mountains. For comparison, we also examined this process in the sympatric congener P. bistortoides, in which reproduction is exclusively sexual. Lack of viable fruit production in P. viviparum has no single developmental explanation; defects occur in each of the processes and structures associated with sexual reproduction studied, yet, these processes and structures also appear to function normally in at least some flowers or individuals. Development is abnormal in many ovules of P. viviparum, however, comparison with P. bistortoides shows that these abnormalities do not contribute to differences in seed production between the two species. The virtual absence of sexual reproduction in P. viviparum appears to be due largely to a low rate of fertilization and to embryo/fruit abortion.
珠芽蓼广泛分布于北半球的北极和高山地区。在北美种群中从未观察到结果现象，在欧洲也仅有极少的报道。尽管对该物种进行了极为深入的研究，但成功结果的阻碍尚不清楚。我们调查了生长在科罗拉多州南部落基山脉的珠芽蓼的有性生殖过程。为作比较，我们还研究了同域分布的近缘种拳参的这一过程，拳参的繁殖完全是有性繁殖。珠芽蓼无法产生可育果实并非由单一的发育问题导致；在所研究的与有性生殖相关的每个过程和结构中都出现了缺陷，然而，这些过程和结构在至少一些花朵或个体中似乎也能正常发挥作用。珠芽蓼的许多胚珠发育异常，不过，与拳参相比表明，这些异常并非导致两个物种种子产量差异的原因。珠芽蓼几乎不存在有性生殖现象，这似乎主要是由于受精率低以及胚胎/果实败育所致。
