Study On The Breeding System Of The Endangered Plant Prunus Mongolica Maxim

Prunus mongolica Maxim is the specific xerophilous and deciduous shrub of the gobi desert region. It is landscape and soil-conserving plant of desert region and desert steppe,also be an important woody yushina plant. It is determined as the plant of the third-class protection.This article investigated and analyzed the Quantitative characteristics, flowering biology, Flowering penology and Breeding system of Prunus mongolica Maxim in the middle of Yin Mounte and uses plant reproductive ecology as the research method, The results were shown as follows:1.The average number of reproductive genet of Prunus mongolica Maxim in the experimental fields (of four different altitudes) was 2.32; the most number of the reproductive genet in Altitude II was 3.43; and in Altitude I, the least number was 1.71. There was no significant difference between altitudes (ρ> 0.05). Frequency analysis found that the frequency of Altitude II was minimum, Altitude III was maximum.2.The flowering stage of the population was the similar more than 20 days. The petal color of Prunus mongolica Maxim. changed along with the flower opening, from pink to white pink and finally pale pink. At the same time, the position of its petal changed gradually from closed to extension The stigma also changed from yellow to brown. The bisexual flower's life was generally 11-13 days. Most of its morphological parameters in each altitude (p> 0.05) did not differ significantly, only the stamen exist big differences (p <0.05).3. The flower biomass of Prunus mongolica Maxim. reduced when the altitude turned higher, and the differences become apparent among different altitudes(p<0.05). Besides, the flower biomass was correlated positively with the plant height and the crown size, negatively with different altitudes.4. The pollen of Prunus mongolica Maxim. became alive an hour before the blooming. when blooming at 1 d, the pollen viability was significantly higher; when in full bloom at 2 d, the pollen viability in four altitudes were all reached the highest about 60%. With the altitude increased the activity of the pollen increased. After blooming at 4 d, the pollen viability has fallen rapidly. When at 5 d, it still falls gradually. More than half of the pollen was still dynamic when their petals were shed.The stigma receptivity of Prunus mongolica Maxim in each altitude had receptivity an hour before blooming, had the stronger receptivity from the secondday to the fifth day after blooming . The stigma receptivity was different between four altitudes. At low altitudes(Altitude I & II) stigma receptivity was 6 d, at high altitudes(Altitude IV) lasted about 10 d. The period of the pollination at low altitudes last shorter than at high altitudes. Stigmas secreted mucus 1d after shedding pollens, Stigmas have maximum secretions from the secondday to the fifth day after shedding pollens.The amount and time of secretions increases with the height of altitude. so the best pollinating stage of peony was at second day after flowering and the best pollinated stage of stigma overlaps with the stage of high vitality of pollen for a longer time about 2～3days.5. Based on the results of hand outcross pollination ,OCI and the breeding system of Prunus mongolica Maxim was outcross and not self-compatible,not apomixes in hermaphroditicy and insect pollination.6. The best distance of wind-pollination for Prunus mongolica Maxim. at high altitudes(Altitude III & IV) was about 5m, but when at low altitudes(Altitude I & II) it was about 3m. Wind-pollination of Prunus mongolica Maxim. in south planting line direction acted similar to west planting line direction. At the same time, the concentration of wind-pollination within the optimal distance to the tested pollen source increased along with the increasing of the distance. But the concentration reduced when beyond it. For the wind-pollination of Prunus mongolica Maxim. at different altitudes, the nearest distance of pollen capture rate was no more than 50% The intensity of Prunus mongolica Maxim. pollen at three different time may exist the following relationship: in the morning>in the afternoon>in the evening.7.From the results,We concluded that part abortive pollen and lack of pollinator might be the major factor leading to the endangered status of Prunus mongolica Maxim Breeding bees and artifieial xenogamy could improve fruiting and the yield of seeds in Praetiee.