Studies On The Developing Of Apple Fruit External Quality Under The System Of Bagging Cultivation

The research was carried out to find out the structure of fungi population of apple pericarp under bagging microenvironment during different periods and the development process of apple pericarp by using Red Fuji apple as material.And the structure of fungi population of bagging apple pericarp under different weather conditions and the changes of POD,PPO activities in Hanfu apple pericarp were studied. The results indicated that:1.Alternaria after bagging existed all the times in growing season,and Penicillium,Trichoderma and Aspergillus were isolated respectively during different periods in cortical pore,pericarp without cortical pore and inner bag after July;In 'Qianwei' bag which inner bag was black and unwaxed,the population structure of fungi was same with CK,including Alternaria and Penicillium.The population structure of fungi in 'Kobayashi' and 'Tongle' bag included Alternaria,Penicillium,Trichoderma and Aspergillus.It had significant differences in different bags and different periods and had no significant differences in different sites of fruit in the population structure of fungi.2.At the early stage of fruit growth after bagging,the differences among all treatments in temperature and humidity changes were basically coincident.With the time entered into the medium and later stage of fruit growth,the maximum temperature and the time keeping in saturation humidity of bagging apples were higher than CK and Penicillium,Aspergillus as well as Trichoderma were isolated besides Alternaria. Comparing with bagging apples,there were Alternaria and Penicillium isolated in CK.Under high temperature weather condition,Alternaria and Penicillium were isolated among all treatments.But,all the mentioned-above fungi were isolated in bagging apples and Trichoderma and Aspergillus were not found in CK under rainy weather condition.3.The cuticle films of all treatments were symmetry,and there were no significant differences among all treatments in the thickness of cuticle film at the early stage of fruit growth after bagging.The epidermal cells were close and regular in shape,and there were no significant differences in the size of epidermal cells and the thickness of mechanical tissue;while at the medium and later stage of fruit growth after bagging,the cuticle film of 'Qianwei' bag was greatly thicker than 'Kobayashi' bagging treatment and control.In bagging apples,the cuticle films were irregular and unshaped with light V-type concaves in 'Kobayashi' bag and deep V-type concaves in 'Qianwei' bag.However,there were very few light V-type concaves generating in unbagging fruits.In unbagging fruits,a lot of gaps generated in the epidermal cells with loose array,and the size of epidermal cells was greatly smaller than bagging apples.The thickness of mechanical tissue in unbagging apples was greatly thicker than bagging apples and there were no significant differences between 'Qianwei' and 'Kobayashi' bags.4.After bagging,the PPO and POD activities in apple pericarp increased at first and reduced later. However,there were differences between the changes of POD and PPO activities in bagging apples. Comparing with CK,at the early stage of fruit growth,the activity of PPO in bagging apples was higher than CK.But Ck POD activity had a significantly increase and was higher than bagging apples at the medium stage of fruit growth.At the later stage of fruit growth,there was a similar change trend between bagging apples and CK.The POD activity in bagging apples at the early stage of fruit growth was lower than CK slightly.At the medium stage of fruit growth,the activity of POD in bagging apples increased significantly and was higher than CK before harvest.