RESULTS: Both species produced diluted nectar with sugar concentrations from 17 to 24%. Analyses of nectar production dynamics showed that as flowers of both species wilted almost all sugar was reabsorbed while the original water was retained in their spurs. We established a nectar sugar concentration gradient for both species, with differences in sugar concentrations at their spur\'s terminus and at their spur\'s entrance (sinus). Sugar concentration gradient levels were 1.1% in H. limprichtii and 2.8% in H. davidii, both decreasing as flowers aged.
CONCLUSIONS: We provided evidence for the reabsorption of sugars but not water occurred in wilted flowers of both Habenaria species. Their sugar concentration gradients vanished as flowers aged suggesting a slow process of sugar diffusion from the nectary at the spur\'s terminus where the nectar gland is located. The processes of nectar secretion/reabsorption in conjunction with the dilution and hydration of sugar rewards for moth pollinators warrant further study.
结果:两种物种都产生了糖浓度为17%至24%的稀释花蜜。对花蜜生产动力学的分析表明,随着这两个物种的花朵枯萎,几乎所有的糖都被重新吸收,而原始的水保留在它们的刺中。我们建立了两个物种的花蜜糖浓度梯度,在他们的骨刺末端和骨刺入口(窦)的糖浓度不同。糖浓度梯度水平在H.limprichtii和H.davidii中分别为1.1%和2.8%。两者都随着花朵的老化而减少。
结论:我们提供了在两种Habenaria物种的枯萎花中重新吸收糖而不是水的证据。随着花朵的老化,它们的糖浓度梯度消失了,这表明糖从蜜腺所在的刺末端的蜜腺扩散过程缓慢。花蜜分泌/再吸收的过程以及对蛾传粉媒介的糖奖励的稀释和水合作用值得进一步研究。