‘红肉蜜柚’果实汁胞粒化与不同组分POD活性的关系

Relationship Between ‘Hongroumiyou' Fruit of Juicy Sac Granulation and Activity of Different POD

为了研究‘红肉蜜柚’[Citrus grandis(L.)Osbeck.cv.Hongrou miyou]果实汁胞粒化过程中不同结合态过氧化物酶(POD)的变化,以及赤霉素处理对此的影响。以赤霉素处理和未经赤霉素处理的‘红肉蜜柚’果实的近中柱和远中柱汁胞为材料,统计粒化指数后,进行POD提取体系筛选与酶活测定。发现‘红肉蜜柚’果实汁胞粒化指数逐渐上升,有无赤霉素处理无明显变化;可溶性POD最佳提取体系为pH8.0,0.1 mol/L Tris-HCl的缓冲液;离子结合POD的为含0.1%Triton和1 mol/L Na Cl的pH8.0,0.1 mol/L Tris-HCl缓冲液;未检测到共价结合POD活性。此外,可溶性、离子结合POD活性在生长发育过程中整体呈下降趋势,且无论是否经赤霉素处理,近中柱与远中柱汁胞的可溶性POD活性均存在极显著差异(p<0.01),而离子结合POD活性均无显著差异(p>0.05);无论近中柱或远中柱,有无赤霉素处理的可溶性POD均存在极显著差异(p<0.01),而离子结合POD活性仅在远中柱汁胞中有极显著差异(p<0.01)。所以,可溶性POD可能与汁胞粒化关系密切,而离子结合、共价结合POD和赤霉素对汁胞粒化的影响有待进一步研究。

To test the variation of different combined peroxidase（POD） during juice sac granulation in ‘Hongroumiyou＇[Citrus grandis（ L.） Osbeck. cv. Hongrou miyou], and to investigate the influence of gibberellin（ GA） on this process, the fruits of ‘ Hongroumiyou＇ sampled from normal and GA-treated plants were used as the models in this study, which were taken to calculate granulation index, and their juice sac near and away from the vascular cylinder were sampled to determine POD extraction and enzyme activity. The results showed that, the juice sac granulation index of ‘ Hongroumiyou＇ showed a rise. The treatment of GA did not significantly influence such variation pattern. pH8.0, 0.1 mol/L Tris-HCl and pH8.0, 0.1 mol/L Tris-HCl containing 0.1% Triton X-100 and 1mol/L Na Cl were established as the optimal extraction buffer for soluble and ion-bound POD, respectively. But,the covalently-bound POD was not extracted. The whole activities of soluble and ion-bound POD were both falling during growth and development process. The soluble POD activities between juice sacs close to the stele and away from the stele had significant difference（p〈0.01） in normal and GA-treated fruits, and which between normal to GA-treated fruits also had significant difference（p〈0.01） in juice sacs close to the stele and away from the stele,while the ion-bound POD activities had significant difference（p〈0.01） in away from the stele. Therefore, soluble POD was significantly related to the process of juice sac granulation, However, the influence of ion-bound POD,covalently-bound POD and GA on juice sac granulation requires further investigation.