Research On Pollination Biology And Embryology In Artemisia Frigida Willd

Floral dynamic,pollen viability,stigma receptivity, pollination methods, pollination law and embryological characters of Artemisia frigida, which could be discovered in the typical steppe and dertsteppe in Inner Mongolia.Through research showed:(1) Artemisia frigida flowers in inflorescence bloomed from up to down at bloom initial stage. Outer florets bloomed first of all, then middle florets bloomed, middle florets bloomed2-4days latter than the Outer florets.(2)The pollen viability of flowers in inflorescence from the upper stem and middle stem were higher than the others, the pollen viability of Artemisia frigida Willd were46.15%; The pollen viability of afternoon were higher than the morning’s, The pollen viability were lower at initial day, about9.26%.but it were higher on the2nd-3th day after flowering, then reduced evidently; The life-span of pollen were longer, were about20d.(3) The stigma receptivity kept nearly6d,what’s more,reached the highest on the2nd-3th day after blooming.The stigma receptivity of outer female flowers appeared on the first flowering day, what’s more, lasted longer, were highest on the2nd-3th day after flowering. The stigma receptivity of middle flowers appeared latter than the outer female flowers, but its stigma receptivity were achieved the highest on the2nd-3th day after flowering, lasted longer. The best stage of Artemisia frigida stigma receptivity and pollination was on the2nd-3th day after flowering.(4) Pollination methods of Artemisia frigida Willd were anemophilous flower pollination, the pollination efficiency was lower and its maturing rate was also lower, was12%-29%.(5) In horizontal direction,the law of pollen speed was: with the increase of distance, the quantity of pollen speed was less and less, and the bulk of pollens handed down near the plants, the effective spread distance was a bit more than300cm. In vertical direction, the law of pollen speed was:with the increase of height, the pollens which were collected were less and less, the effective spread height was more than100cm.A great quantity of pollens were captured at13:00during24h. Temperature relative humidity and wind speed affected the pollen speed enormously, what’s more, temperature and wind speed were positively correlated to pollen density; relative humidity was negatively correlated to pollen density.(6) The development of anthe:’wall was dicotyledonous and the cytokinesis was successive and the tapetum was metamorphous,The tetrads of microspore were on isoblateral symmetry and tetrahedral arrangement; mature pollen grain was two cell type and there were3colporates in every mature pollen grain. Artemisia frigida embryo sac development was embryo sac of polygonum type. The archesporial cell was from the1layer of cell which was located the nucellus epidermis, was thin nucellus.Tetrad arranged in a line, in end of chalaza was functional macrospore. Mature embryo sac was polygonum. The development of embryo was aster; The development of endosperm was cellular endosperm.