Investigation Of Certain Physiological Characteristics In 'Huanghua' And Its Bud Mutant Pear (Pyrus Pyrifolia Nakai)

Fruit color is one of the important agronomic characters,and is also the first sense for consumers to make their purchasing decisions.Now works on pear cultivars with different fruit color to meet consumers' needs are becoming a research focus.In order to reveal the formation mechanism of the browm epidermis of the sand pear,during 6-10 weeks after full blossom and the mature period,the microstructure of the skin was observed continusly.The content of lignin and total phenol compound in skin and pulp were measured by spectrophotometer during 6-10 weeks after full blossom and the mature period in'Huanghua',its bud mutant 'Liihuanghua' and 'Huanghua' bagging,as well as the activities of peroxidase(POD),polyphenol oxidase(PPO),phenylalanine ammonialyase(PAL),4-coumarate:coenzyme A ligase(4CL)and cinnamyl alcohol dehydrogenase(CAD),et al.We also identified and analyzed of the composition of suberin of 'Huanghua',its bud mutant 'Liihuanghua' and 'Huanghua' bagging pear.The major results are as follows:1 The 8 weeks after full blossom is the critical period of skin color changing in'Huanghua',then browning gradually deepened.During this period,the lignin content in skin and pulp were increasing both in 'Huanghua' and its bud mutant 'Luhuanghua',but'Huanghua' has a higher lignin content than that of 'Luhuanghua'.The total phenol compound content has similar trend in skin and pulp of 'Huanghua' and 'Luhuanghua',i.e.they were decreased first,then increased and finally decreased again.The total phenol compound content in skin were higher in 'Huanghua' than that in 'Luhuanghua'.The activities of POD,PAL,4CL and CAD in skin were higher in 'Huanghua' than its bud mutant 'Luhuanghua',and the activities of PPO in skin was close to that in 'Luhuanghua'.2 To explore the reasons for fruit skin color differences between 'Huanghua',its bud mutant 'Liihuanghua' and 'Huanghua' bagging pear,several physiological and biochemical characteristics were measured.The content of lignin and total phenol compound in skin and pulp were measured by spectrophotometer in the mature period,the russult showed that the brightness and purity of skin in 'Huanghua' were less than its bud mutant 'Luhuanghua'and 'Huanghua' bagging,but the yellow degree in 'Huanghua' were more than its bud mutant 'Luhuanghua' and 'Huanghua' bagging.The content of lignin and total phenol compound in 'Huanghua' were higher than 'Huanghua' bagging and its bud mutation'Luhuanghua'.3 To analyse the compositions of suberin of in skin of 'Huanghua','Huanghua'bagging and its bud mutant 'Luhuanghua' pear in the mature period,the suberin compound of perderm of skin were evaluated qualitatively and relative quantitatively using gas chromatography-mass spectrometer(GC-MS).The result showed that the composition of suberin consists of 21 compounds,eicosanol,hexacosanol,octacosanol,hexadecanedioic acid,octadecanedioic acid,9,10-dihydroxyoctadecanedioic acid,16-hydroxyhexadecanoic acid,22-hydroxydocosanoic acid,1-Monopalmitoylglycerol and 18-hydroxyoctdec-9-enoic acid in 'Huanghua' were higher than that in 'Huanghua' bagging and its bud mutant'Luhuanghua'.To analyse the compositions of lignin of skin in 'Huanghua' and'Huanghua' bagging pear in the mature period.The lignin compound of perderm of skin were evaluated qualitatively and relative quantitatively using ultra performance liquid chromatography(UPLC).The result showed that p-hydroxybenzoic acid,vanillic acid,syringic acid and syringaldehyde in 'Huanghua' were higher than 'Huanghua' bagging.