Data_Sheet_1_Nanoporous silica gel can compete with the flower stigma in germinating and attracting pollen tubes.PDF

To find nanoporous substrates with hydrodynamic properties useful for pollen hydration and germination, we used the glassy Silica gel and Vycor scales and pollen with different morphological and physiological traits, that of Crocus vernus, and that of Narcissus poeticus. For in vitro tests, the scales were spread on microscope slides, hand pollinated, and incubated. Pollen germination was evaluated with the stereomicroscope and the tube growth was explored with scanning electron microscopy (SEM). The in vivo tests were carried out by sprinkling the stigmas of the Crocus plants with Silica gel scales and immediately after having pollinated them by hand, the plants were incubated. Three hours later, the stigmas were removed and treated for observation with SEM. In vitro the pollen of both species germinated on Silica gel with percentages similar to those of the in vivo and in vitro controls, accumulating fibrillary material at the interface. The tubes grew perpendicular to the surface of the scales, trying to penetrate the scales to the point of flattening with the apex. On Crocus stigmas sprinkled with Silica gel scales, pollen developed tubes that grew to the scales rather than penetrating the papillae. The results underline the close interaction of pollen with nanoporous artificial material, so much so that its pollen tubes are attracted to the Silica scales more than to the stigma papillae that arises from a mechanism of natural selection.

为筛选出具备适用于花粉水合与萌发的流体力学特性的纳米多孔基底（nanoporous substrates），本研究选用了玻璃态硅胶（glassy Silica gel）与Vycor多孔玻片（Vycor scales），以及具备不同形态与生理特征的两种花粉——春番红花（Crocus vernus）与红口水仙（Narcissus poeticus）。
体外实验中，将多孔玻片铺展于载玻片上，进行人工授粉后恒温培养。通过体视显微镜评估花粉萌发情况，并借助扫描电子显微镜（SEM）观察花粉管生长状态。
体内实验的开展方式为：将硅胶玻片撒在春番红花的柱头上，随即进行人工授粉，随后将植株置于恒温培养环境中。3小时后取下柱头，经前处理后用于扫描电子显微镜观察。
体外实验结果显示，两种花粉在硅胶玻片上的萌发率与体内、体外对照组相近，且在界面处积累了纤维状物质。花粉管垂直于玻片表面生长，尝试侵入玻片结构，直至顶端出现扁平形态。
在撒有硅胶玻片的春番红花柱头上，花粉长出的管朝向玻片生长，而非侵入柱头乳突。
本研究结果凸显了花粉与纳米多孔人工材料间的紧密相互作用：花粉管对硅胶玻片的吸引力甚至强于天然柱头乳突，这一现象源于自然选择机制。