| Pyrus sinkiangensis is an important economic fruit tree in Xinjiang,which is strictly cross-pollinated and fruited.During the pollination of fragrant pear,comprehensive evaluation of pollinated pollen quality,clear temperature and humidity conditions of pollinated pollen storage and transportation,and selection of pollinating nutrient solution with good pollination effect are of great significance for pollination and pollination of fragrant pear.Using P.bretschneideri pollen as pollination material,this paper studied the effects of different storage temperature and humidity on pollination pollen viability,the effects of pollination nutrient solution added chitosan on fruit setting rate and fruit quality of fragrant pear tree,and optimized the pollination nutrient solution of fragrant pear,and obtained the following results:(1)Adding different concentrations of chitosan to the pollinating liquid of fragrant pear showed great differences in pollination pollen viability,fruit setting rate and quality.The concentration of chitosan at 0.25～1.25 m L/L increased pollen germination rate,fruit setting rate and improve fruit quality,while the concentration of chitosan at 2.50～5.00 m L/L decreased pollen germination rate,fruit setting rate and fruit quality.Adding 0.5 m L/L chitosan in pollination solution had the best effect on improving fruit quality.(2)The patented nutrient solution formula(10:1 white granulated sugar +500:1 pollen mate)was optimized.The results showed that the comprehensive effect was the best when the liquid pollination nutrient solution formula was 10:1 white granulated sugar +300:1 pollen mate +2000:1 chitosan +PBO300 times.After pollination,the fruit setting rate of inflorescence was 18.77%,the flower fruit setting rate was 15.97%,and the calyx rate reached 59.81%.The effects of different pollination formulas on the activities of phenylalanine ammoniase(PAL),polyphenol oxidase(PPO),peroxidase(POD)and the content of stone cells in pear fruits were basically the same.Correlation analysis showed that there was a significant positive correlation between PAL,PPO and POD activities and stone cell content.When ripe,stone cell content in all pollinated fruits was lower than that of natural pollination,which inhibited the formation of stone cells in fragrant pear fruits and had a certain improvement effect on fruit quality.(3)Pollen viability at room temperature(25℃)could be maintained for 30 days,pollen at 4℃ lost vitality about 70 days,and pollen viability at-20℃ and-60℃ for a long time(241 days)decreased significantly.After 241 days of storage in liquid nitrogen(-196℃)and-80℃,pollen morphology was still regular and full,pollen vitality was little affected,and the content of nutrients in pollen and the activities of protective enzymes peroxidase(POD),catalase(CAT)and superoxide dismutase(SOD)remained at a high level.Pollen germination rates were 24.39% and 24.76%,soluble sugar contents were 142.87 mg/g and 138.4 mg/g,and soluble protein contents were 24.05 mg/g and 21.73 mg/g,respectively.(4)Under dark and room temperature(25℃)conditions,the higher the relative humidity,the faster the pollen germination rate decreased,the shorter the storage period,and the worse the storage effect.After 15 days of storage with different humidity,0% relative humidity had the best storage effect on pollen,and the pollen germination rate was 2.95%.After 15 days of storage,15% relative humidity had a higher pollen germination rate than other treatments.In conclusion,drying or 15% relative humidity was conducive to short-term pollen storage. |
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