Iwano Megumi, Entani Tetsuyuki, Shiba Hiroshi, Takayama Seiji, Isogai Akira
Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0101 Japan.
Plant Cell Physiol. 2004 Jan;45(1):40-7. doi: 10.1093/pcp/pch004.
Using an X-ray microanalysis system fitted with variable-pressure scanning electron microscopy, we noted that many calcium crystals accumulated under the stomium in the anther of Petunia. When the anther was dehisced and pollen grains were released from the stomata, the calcium crystals adhered to pollen grains and moved to the stigma together with pollen grains. In contrast, an X-ray microanalysis of the stigma surface before pollination detected no calcium emission on the stigma surface. Furthermore, pollen germination and pollen tube growth in medium without Ca occurred as in complete medium. However, after the pollen grains had been washed with abundant germination medium without calcium, pollen germination in the medium without Ca was inhibited. These results show that the calcium crystals dissolved in the aqueous drop under the exudate on the stigma and supplied calcium ions for pollen germination. In addition, calcium crystals were produced not only in the anther of Petunia but also in Nicotiana, suggesting that calcium crystals supply pollen grains with the calcium ions required for pollen germination and serve to improve reproduction efficiency in Solanaceae.
使用配备可变压力扫描电子显微镜的X射线微分析系统，我们注意到许多钙晶体在矮牵牛花药的气孔下方积累。当花药开裂且花粉粒从气孔释放时，钙晶体附着在花粉粒上并与花粉粒一起移动到柱头上。相比之下，授粉前柱头表面的X射线微分析未检测到柱头表面有钙发射。此外，在无钙培养基中花粉萌发和花粉管生长与在完全培养基中一样发生。然而，在用大量无钙萌发培养基洗涤花粉粒后，无钙培养基中的花粉萌发受到抑制。这些结果表明，钙晶体溶解在柱头渗出物下的水滴中，并为花粉萌发提供钙离子。此外，钙晶体不仅在矮牵牛的花药中产生，在烟草中也产生，这表明钙晶体为花粉粒提供花粉萌发所需的钙离子，并有助于提高茄科植物的繁殖效率。
