Anatomical And Physiological Studies On Pollination And Fertilization Of Ornamental Peach

Peach is a deciduous small tree of the genus Prunus persica.It is divided into fruit peaches and ornamental peaches.The ornamental peaches are favored by people because of its beautiful patterns and auspicious meanings.In this experiment,the pollen of'Fenhua Shanbitao','Hehuan Erse Tao','Mantianhong','Yuanchun'were used as experimental materials,and the suitable storage conditions of pollen of each variety were screened by different drying time and storage temperature.At the same time,three crosses of 'Mantianhong'x'Yuanchun','Mantianhong'x'Baihua Shanbitao','Jiangtao'x'Fenhua Shanbitao'and two self-crossing experiments of'Mantianhong','Jiangtao'were carried out,through regular observation,microscopic observation,physiological measurement and other methods to explore the process of pollination and fertilization,physiological changes,biological characteristics of hybrid fruit set.The main conclusions are as follows:(1)There were differences in the initial viability of pollen under different varieties and different drying time(2h,4h,6h,8h,10h,12h).Among the four varieties,the initial viability of'Hehuan Erse Tao'was the largest,reaching a maximum of 78.19%,followed by'Mantianhong','Fenhua Shanbitao'and'Yuanchun',which were 60.03%,45.70%and 38.57%respectively.There are also differences in the drying time required for different varieties to reach the maximum initial pollen viability.Among them,'Hehuan Erse Tao' and'Mantianhong' have the highest initial viability when dried for 10 hours,while 'Fenhua Shanbitao' had the highest initial pollen viability after 8 hours drying and'Yuanchun' had the highest initial pollen viability after 12 hours drying.(2)There are differences in storage conditions between different varieties of pollen.The lower the storage temperature and the longer the drying time of 'Fenhua Shanbitao',the better the storage effect.It is best at-80? dried 12 hours and the longest can be stored for 250 days.The longer the drying time of 'Hehuan Erse Tao',the better the storage effect,but at the storage temperature,there is a phenomenon that 4? is better than-20? and-60?.It is best at-80? for drying 12 hours,and the viability is 27.18%after 360 days of storage.'Mantianhong' in a lower temperature and is more favorable for storage.It is best at-80? for drying 10 hours,and maintains 52.08%viability when stored for 360 days.'Yuanchun' has a big difference in the best drying time.8 hours is the best at room temperature;12 hours is best at 4? and-20?;10 hours and 12 hours alternate at-60? and-80?,the effect is also good.In the storage temperature of'Yuanchun,the lower the temperature,the longer the storage days,the slower the decline in viability,the optimum storage temperature is-80?,42.56%of the viability is maintained when stored 360 days.(3)There was no significant difference in pollen tube growth among different varieties and storage environments.With the prolongation of storage time,the growth rate of pollen tube decreased,and the slower the growth rate of pollen tube decreased with the decrease of storage temperature.(4)There are differences in pollination and fertilization characteristics of different hybrid combinations.The pollens of three hybrid combinations of 'Mantianhong'×'Yuanchun','Mantianhong'×'Baihua Shanbitao','Jiangtao'×'Fenhua Shanbitao' all germinated on stigma.The initial time of pollen germination was between 0 and 4 hours,the maximum amount of pollen germination was between 24 and 48 hours,and the pollen tube reached ovary between 48 and 72 hours.There were some differences in the number of pollen germination and the growth rate of pollen tube among different cross combinations.The'Yuanchun' pollen had the largest germination number and the fastest growth rate in 'Mantianhong' pistil.(5)During the pollination of ornamental peach,the changes of IAA and GA3 content in pistil were the same,first increased and then decreased,and reached the maximum at lday after pollination.While ZR and ABA content continued to decrease,and the difference between parents was obvious.POD,SOD and CAT increased first and then decreased in 0 to 9 days,and it is the stage of identification,germination and fertilization of pollen in 0 to 3 days,with a high level,but then decreased rapidly and the content was low.(6)There were no obstacles to pollen germination and entry into ovary in three hybrid combinations.Fruit could also expand and grow in the early stage.Pollen entered ovary 2-3 days after pollination.The weight of single ovary of three hybrid combinations and two self-cross combinations increased significantly at 6 days after pollination,suggesting that pollination could significantly promote growth.In terms of nuclear weight,nuclear longitudinal diameter and nuclear transverse diameter,there is a phenomenon of differentiation by maternal parent,that is,maternal difference is significant,otherwise there is no difference.The fruit setting rate is low,the fruit drop is serious,the hybridization is higher than the selfing,and there is may a certain correlation with the hormone level for promoting growth and the low level of antioxidant enzymes.