灵武长枣果实同化物韧皮部卸载和运输途径研究

Studies on Phloem Unloading and Transport Pathway of Photosynthates in Ziziphus jujuba Mill.cv.lingwuchangzao Fruit

韧皮部卸载和韧皮部后运输在调节同化物在果实中的分配和积累方面起着至关重要的作用,而且很大程度上决定着果实的产量和质量。为探讨灵武长枣果实同化物韧皮部卸载和运输途径,以4个时期灵武长枣果实为实验材料,对各个发育时期果实维管束的显微结构进行观察,并综合运用荧光染料活细胞示踪与激光共聚焦扫描显微镜技术实时观察果实内韧皮部同化物卸载路径的变化,为灵武长枣果实同化物积累和品质调控奠定基础。结果显示:(1)膨大前期不仅果实的韧皮部中具有明显的CF绿色荧光,同时在周围薄壁细胞中也分布着CF绿色荧光,筛管伴胞复合体和周围薄壁细胞之间存在着共质体联系。(2)快速膨大期,CF绿色荧光主要局限于果实的韧皮部中,在韧皮部周围薄壁细胞中分布较少,筛管伴胞复合体与周围薄壁细胞之间主要以共质体隔离为主,但也存在着一定的共质体联系。(3)着色期和完熟期,CF绿色荧光局限于果实的韧皮部中,在韧皮部周围薄壁细胞中基本没有CF绿色荧光,果实筛管伴胞复合体与周围薄壁细胞之间是共质体隔离状态,但引入CFDA的同时引入具有质膜通透作用的洋地黄皂苷时,周围薄壁细胞中CF绿色荧光分布明显增加。研究认为,灵武长枣在膨大前期果实韧皮部同化物为共质体卸载途径,快速膨大期果实主要以质外体途径运输同化物,但也通过共质体卸出同化物,着色期和完熟期果实通过质外体途径运输同化物。

Phloem unloading and postphloem transport play pivotal parts in the regulation of the distribution and accumulation of photosynthate in the fruit,and largely determine the yield and quality of the crop.To uncover the phloem unloading and transport pathway of photosynthates in Ziziphus jujuba Mill.cv.lingwuchangzao fruit,the four different developmental periods fruits of Ziziphus jujuba Mill.cv.lingwuchangzao were used as experimental material to observe the microstructure of the vascular bundle of fruit in each development period,the techniques of fluorescent dye tracer in living cell and confocal laser scanning microscopy(CLSM)were used to observe the phloem unloading path of photosynthates in the fruit timely,the research results provide scientific bases of fruit photosynthates accumulation and quality regulation for Ziziphus jujuba Mill cv.lingwuchangzao.The main research results were followed:(1)not only the phloem of the fruit but also the parenchyma cells surrounding the phloem existed evidently the CF green fluorescence,the SE-CC complex and its surrounding cells existed symplastic integration in the early bulking period.(2)The CF green fluorescence was mainly confined to the phloem of the fruit,there is less CF green fluorescence in the parenchyma cells surrounding the phloem,the SE-CC complex and its surrounding cells existed mainly the symplastic isolation but existed few symplastic integration in the rapid enlargement period.(3)The CF green fluorescence was confined to the phloem of the fruit,and there was no CF green fluorescence in the parenchyma cells surrounding the phloem in the coloring period and the maturation period,the SE-CC complex and its surrounding cells existed entirely the symplastic isolation,the CF green fluorescence in the parenchyma cells surrounding the phloem increased significantly while leading in CFDA and Digitonin with penetrating plasma membrane function.Research suggests that the photoassimilates unloading from the phloem was symplast pathway in the early bulking period fruit,the photoassimilates unloading and transport adopted mainly apoplastic pathway in the rapid enlargement period,but existed simultaneously symplast pathway,the photoassimilates unloading and transport adopted apoplastic pathway in the coloring period and the maturation period fruit.