蜜柚果实粒化汁胞结构特征解析

Analysis of structure feature of granulated juice sacs in Citrus grandis‘Sanhongmiyou’fruits

汁胞粒化(木质化)是造成三红蜜柚(Citrus grandis‘Sanhongmiyou’)果实品质下降的主要因素。为探究蜜柚果实的不同部位汁胞结构特征、木质化程度差异及其不同组织木质化程度的差异,本研究以福建省平和县9月下旬采收并在室内自然存放1个月的三红蜜柚果实为研究对象,对不同部位汁胞结构特征进行了解析,并评价了不同部位汁胞及汁胞内部不同组织木质化程度。研究发现,蜜柚果实汁胞具有竖直和横向两种排列类型,不同类型汁胞的品质特征及粒化程度不同。通过各部位木质素原位染色和定量分析发现,竖直汁胞(侧面维管束汁胞,靠近果心)易木质化,其木质素浓度是横向汁胞(背面维管束汁胞,靠近白皮层)的(5.11±2.26)倍。对粒化汁胞进行分析后发现,汁胞的简单组织易木质化,其木质素浓度是腔管的(79.95±23.00)倍,并且简单组织中的木质素主要累积在厚壁组织等部位。研究结果为进一步解析蜜柚果实汁胞粒化机制奠定了基础。

Granulation of juice sacs is the main cause for quality decline in pomelo(Citrus grandis)fruits.To investigate the structural feature and differences in the lignification degree of juice sacs in different parts of fruit,and differences in the lignification degree of different tissue,pomelo fruits harvested in Pinghe County,Fujian Province in late September and stored in the room temperature for one month were used as test material to analyze the structure feature of the juice sacs in different parts of fruit and evaluate the lignification degree among juice sacs in different parts of fruit and different internal tissues within juice sacs.The results showed that there were two permutation types for juice sacs in pomelo fruits,including vertical and transversal permutation,which differed in quality characteristics and degree of granulation.Based on the results from both in situ staining and quantitative analysis,it was found that the vertical juice sacs(Jv)were more vulnerable to lignification,whose lignin concentration was 5.11±2.26 times that of transversal juice sacs(Jt).By analyzing the anatomical structure of granulated juice sacs,it was found that the simple tissues in Jv were more vulnerable to lignification with 79.95±23.00 times higher lignin concentration than that of in the lumen,and most of lignin was accumulated in sclerenchyma of simple tissues.The results laid a foundation for further analysis of the mechanism of granulation of juice sac in pomelo fruits.