关键词: 梭梭, 花, 解剖结构, 石蜡切片, 扫描电镜

Abstract: [Objective] The aim of the study was to explore the adaptation of Haloxylon ammodendron flower to arid environment in the Gurbantunggut desert of China. [Method] The anatomical structures of H. ammodendron flower were observed using paraffin section and scanning electron microscope and its pollen-ovule ratio was also measured. [Results] H. ammodendron flower attached at the new shoots(assimilating branches). The flower was bisexual and small, with a diameter of about 1.0 mm. The flower located at axil solitarily, only with calyx. The base of ovary positioned was within flower disk and the flower had no corolla. The flower had five tepals. The tepal was free, green, papery or scarious. The inner surface of the base was often arachnoid. The flower had five stamens and the stamens were yellow, which belonged to synantherous stamen. The solid style was short with many secretory cells and had no style in the center. The flower had two scaphoid bractlets, outside the cuticula. The bractlet had scarious margins. The ovary had vascular bundle and the connectivum of anther had vascular and the vascular preserves until anther dehiscence. When the flower was mature, the stigma was close to the base of anther. The anther height was slightly higher than that of the fingered stigma, providing a suitable spatial position to self-pollination. The flower had tiny and light but rich pollen grains. The P/O value was 64 815, which was suitable to anemophilous pollination. Based on the observations using scanning electron microscope, we found the pollen grain was nearly spherical with warty ornamentation. The length of polar axis and equatorial axis was 19.08~21.02 μm, 18.59~19.18 μm, respectively. [Conclusion] Our results indicated that H. ammodendron have two pollination ways(self-pollination and cross-pollination). The external feature and anatomical structure showed H. ammodendron flower has strong capacity to adapt to desert environment.

Key words: H. ammodendron, flower, anatomical structure, paraffin section, scanning electron microscope