对达乌里秦艽3个自然居群和1个人工栽培居群进行了两年的传粉生态学研究。研究发现:(1)达乌里秦艽套袋花均不结实,说明雌雄异熟和雌雄异位这两种花部机制成功阻止了主动自交,且不存在无融合生殖现象。(2)隔离传粉昆虫导致花寿命明显延长,授粉会导致花冠提前闭合,说明达乌里秦艽的花寿命具有可塑性,可通过延长花寿命确保成功繁殖。(3)在一个自然居群中证明存在花粉限制,且该居群的花寿命显著长于另外两个没有花粉限制的自然居群。(4)在整个雌性持续期柱头都具有一定的可授性,且在第2天可授性最高,随后逐渐降低;开花后期柱头可授性降低,使植物维持花开放资源投入的产出将有可能降低。研究表明,达乌里秦艽在严重缺乏传粉者的情况下,延长花寿命仅能部分弥补传粉者的不足,该物种在部分居群中仍有可能存在花粉限制。
We studied pollination biology of Gentiana dahurica in three natural populations and an artificially cultivated population.Isolated flowers did not set fruit,indicating that both dichogamy and herkogamy together prevented autonomous self-pollination and there is no apomixes in this species.When excluded from floral visitors,female duration of the monitored flowers prolonged distinctly,and any pollination always induced floral closures,which together suggested the plasticity of the floral longevity of this species and their special contributions to ensure reproductive success.Floral longevity of one natural population with pollen limitation was significantly longer than those of the other two natural populations without such pollen limitation,and the difference was mainly caused by the longevity of the female phase.Further experiments suggested that although stigmas were sensitive though the whole female phase,floral fecundity was the highest on the second day and declined afterward.We further found that the overall products of the invests maintaining flowering in the late stage had decreased because of the decreased female fecundity.Therefore,under the scenario without abundant pollinators,the prolonged floral longevity may partly remedy reproductive loss while a few populations still suffer from pollen limitation.