白梭梭开花及风媒传粉特点

Study on the Flowering and Pollination Characteristics of Haloxylon persicum

对白梭梭的花期物候、开花式样、风媒传粉特点进行了观察 ,对柱头可授性、花粉 -胚珠比 (P/O)做了检测。白梭梭的花部特征有许多适应风媒传粉的特点 :花小、无花冠、具光滑的花粉外壁、指状的柱头突起、较高的花粉 -胚珠比。重力玻片法检测结果表明 ,白梭梭风媒传粉发生在晴朗、昼夜温差大、空气湿度高的 4月中下旬 ;花期持续时间约 14d ,传粉盛期集中在前 3d ,花粉短距离传粉效率较低 ;对荒漠突发不良环境的适应 ,白梭梭具有爆发性的开花传粉机制。

The study area (42°51′N, 89°11′E, -86 m a.s.l.) is located in Turpan Desert Botanical Garden, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences. The soil here is sandy loam, the extremely maximum and minimum temperatures are 47.6 ℃ and 28.0 ℃ respectively, and it belongs to the extremely arid desert climate. The community of Haloxylon persicum growing in the study area forms by introducing Haloxylon persicum from Ganjiahu Nature Reserve of Haloxylon ammodendron in Jinghe County, Xinjiang Uygur Autonomous Region in 1976. Currently, the plant height varies in a range of 5～7 m, and the average crown extent of Haloxylon persicum is 4.0 m×4.0 m.The authors observed the flowering phenology and flowering pattern of Haloxylon persicum, and studied its stigmas and pollen-ovule ratio receptivity.The results show that the flowers of Haloxylon persicum have many anemophily characteristics: the smooth surfaces of pollen grains, finger-shaped papillae and high value of pollen-ovule ratio. The anemophily characteristics are that the pollen quantity decreases rapidly with the increase of distance away from pollen sources. The population of Haloxylon persicum has some anemophily advantages. Pollination of Haloxylon persicum often occurs at fine days in April, when the diurnal-nocturnal temperature difference and the air humidity are high. The duration of flowering is 14 days, the peak pollination occurs at first three days, and the pollens can be transported in a limited distance. In order to enlarge the adaptation range under the severe desert environment, Haloxylon persicum possesses an explosive pollination capability.