Studies On Biological Characters Of Sexual Propagation Of Artemisia Frigida

Development of female gamete and male gamete, karyotype, pollen morphologcial characterisrtics,pollination law and seed germination characters of Artemisia frigida , as a good forage,was dstributed in typical steppe and dertsteppe in Inner Mongolia.The results showed: (1)The generation of microspore of Artemisia frigida is from poly archesporial cells; division of cytoplasm of pollen mother cell was consecutive type; tapetum was deformed tapetum; mature androgamete was two cell type. (2)Embryo development of Artemisia frigida was embryo sac of polygonum type.Tetrad arranged in a line, functional macrospore was in end of chalaza. (3)There were both diploid and tetraploid of Artemisia frigida , including Artemisia frigida Willd.and Artemisia frigida Willd. var. atropurpurea Pamp; the chromosome number of diploid was 2n=2x=18; tetraploid was 2n=4x=36. Only accession from Taerlin had satellite. (4)All the pollens were small pollen. Equatorial plane was oval or round; pole plane was three breached round. Germination organ was three hole or ditch type; sculpture on surface was compound sculpture of thorn and grain. The pollen of Artemisia frigida Willd. was oval or long spherical and Artemisia frigida Willd. var. atropurpurea Pamp.was spherical or near spherical. The dimorphism ratio in accessions (varietas, tetralpoid)from Etuoke was the highest, reached 64.5%,P/E=1.07; others was lower than 20%.(5)Flowers in inflorescence bloomed from up to down at initial stage. Outer florets bloomed first, middle florets bloomed 2-4 days latter. In horizontal direction, with the increase of distance, the quantity of pollen speed was less and less, most of pollens remained near plants, the effective spread distance was more than 200 cm. In vertical direction ,the higher, the less the pollens collected, the effective spread height was more than 100 cm .Peak time captured pollens appeared at 9:00 and 13:00 in one day and one night .Temperature and wind speed were positively correlated to pollen density; relative humidity was negatively correlated to pollen density.(6) There were striped sculptures on back of achene of Artemisia frigida and differences in morphology , arrangement , tumour and protuberance of striped sculptures due to the differences of taxonomy position, chromosome ploidy and habitants.(7)1000-seed weights of Artemisia frigida from eight sampling sites were 0.076g-0.124g .Germination rate, germination energy, germination index and vigor index of seeds of Artemisia frigida from Keshiketeng were all the highest, there were differences in seed germination characters compared with others (P<0.05). Seed germination rate began to decline when the moisture content was more than 30% and on the surface of soil was the highest .when the thickness covered with soil was more than 3cm, the seeds can not germinate.