同域分布沙拐枣属植物的杂交与迁地保护

The hybridization and taxonomy position between Calligonum L has been controversial. Scholars home and abroad say that there is natural hybridization, but they are lack of corresponding experiment and data support. According the earlier research, Calligonum L exhibits a mixed mating system: self-compatible, rare autonomous selfing, inclined to outcross, no apomixis. Therefore, whether there is hybridization has become the key to the perfection and supplementation of the breeding system. By artificial bagged pollination experiment, pollen tube fluorescence experiment and allele enzyme technology, the present study is aimed at: (1) understanding the process of hybrid pollen's position and the pollen tube's germination and the dynamic process of elongation; explaining whether there is reproductive isolation mechanism; (2) understanding whether there is hybridization within the group of Calligonum L; (3) understanding whether natural habitats with the domain of distribution of mating system has changed, and comparing with ex-situ conservation conditions. By solving the above-mentioned problems, the mating system of the genus is expected to be understood in a deeper and more comprehensive way. The results of this study will provide a strong basis for the fruit morphology variety and classification. Besides, they will also directly serve the ex-situ conservation of Calligonum L.

沙拐枣属植物种杂交问题以及分类地位一直具有争议，国内外学者认为存在天然杂交，但是缺乏相应的实验和数据支持。前期研究表明，该属植物繁育系统为自交亲和，不能主动自交，偏于异交，不存在无融合生殖。因此，该属是否存在杂交成为完善和补充该属繁育系统的关键。本研究拟通过人工套袋授粉实验、花粉管荧光实验以及等位酶技术，目的在于阐述：①杂交花粉的置落、萌发以及花粉管萌发、伸长的动态过程，解释是否存在生殖隔离机制；②该属种间是否存在杂交；③了解自然生境中同域分布种的交配系统是否发生了变化，并与迁地保护条件下的进行比较。通过上述问题的解决，进而对该属植物的交配系统有了更深入和全面的认识。本研究结果将对该属的果实多型现象及分类提供强有力的依据，该结果也将直接服务于该属的迁地保育工作。

中外学者一直认为沙拐枣属植物存在天然杂交，但是没有相应的实验和数据证明。本研究通过对同域分布的沙拐枣属植物的花期物候及繁育系统进行研究，以期为该属是否存在杂交提供有力证明。花期物候观测数据表明，同域分布种间存在花期相遇，不能阻断种间基因交流；利用人工杂交授粉试验和花粉管荧光显微观察表明种间存在杂交的可能性较小；本研究利用SLAF-seq技术测序获得51,015 个 SLAF标签，用SSR Hunter1.3软件设计引物，成功开发出微卫星引物26对，筛选其中多态性最好的9对，对亲本的378个个体进行繁育系统验证，获得数据用软件Cervus3.0处理，结果表明，这9对引物具有很高的多态性（PIC值0.7350-0.9240），其它各项参数为Na：6-18（11.222），Ho：0.1430-0.5160（0.3563）；He：0.6830-0.9510（0.8070），数据表明同域分布的这7种沙拐枣繁育系统以自交为主。综上所述，认为该属植物间不存在杂交。该项研究为该属植物是否存在杂交提供了有力的证据和证明，也为该属的分类研究探索了新的方法。