油茶叶肿病子房瘿体和叶片瘿体的形态结构特征观察

采用光学显微镜观察了油茶叶肿病子房瘿体和叶片瘿体的形态特征和组织结构特点。结果表明:(1)油茶叶肿病瘿体是油茶的幼嫩子房和幼叶被细丽外担菌感染后所导致的组织增生而成的,细丽外担菌分布于成熟子房瘿体的外表面和叶片瘿体的表面。(2)子房瘿体由受感染的雌蕊子房增殖而来,成熟后表皮层脱落。(3)子房壁分两层,外层子房壁肉质肥厚,主要由大型薄壁细胞构成,是食用的主要部分,内层子房壁为较薄的心皮层,内外两层子房壁之间具有较大的空隙;心皮内有胚珠,胚珠着生在中轴胎座上,胚珠内部中空而没有育性。(4)叶片瘿体为受感染的幼嫩叶片增殖所致,由大型薄壁细胞构成,瘿体表面具表皮层,成熟后表皮脱落。(5)在正常叶片与叶片瘿体的过渡区内有维管束相通,瘿体侧的厚度比正常叶片厚度增加3～4倍,细胞体积增大5～10倍,但瘿体细胞内无叶绿体。

Observation on Morphological and Structural Characteristics of Ovary Gall and Leaf Gall Induced by Exobasidium gracile in Camellia oleifera

The light microscope was employed to observe the morphological and structural characteristics of ovary gall and leaf gall in Camellia oleifera.The results were as follows:(1)The proliferation of tender ovary and leaf infected by a fungus Exobacidium gracile resulted in the formation of hypertrophic fungus galls.The hymenium of E.gracile dispersed on the external surface of mature ovary galls and the surface of leaf galls.(2) Ovary gall developed from infected ovary of C.oleifera,and once reached maturation,the epidermis of ovary gall would exfoliate.(3)It was observed that the ovary gall wall consisted of two layers.The fleshy outer layer was mainly composed of large parenchyma cells,which were actually the main edible parts.The thinner inner layer of ovary wall was carpel containing several ovules attached on the axile placenta,while a large space occurred between the two layers.The ovules were empty and thus infertile.(4)Leaf gall was proliferative tissues of infected tender leaf and was made of large parenchyma cells.The epidermis of leaf gall covered both the upper and lower surfaces of the gall and fallen off when the gall matured.(5)The vascular bundles were found connecting the normal part and the leaf gall in the transition zone.The gall was 3~4 times thicker than normal leaf,and the gall cells were 5~10 times larger than normal leaf cells.No chloroplasts were observed in the gall cells.