油樟油细胞和粘液细胞发育的超微结构

利用超薄切片法和透射电镜研究油樟油细胞和粘液细胞发育过程。依据油细胞3层细胞壁的发育将其分为4个阶段。阶段1：仅有初生纤维素壁层，又可分为原始细胞和细胞液泡化二时期。质体内具白色小泡和黑色嗜饿滴，细胞质中有黑色或灰色的嗜饿物质，以及嗜饿物质与液泡的融合。阶段2：栓质化壁层的形成。片层状的栓质叠加在初生纤维素壁内侧。阶段3：内纤维素壁层的形成。较厚而结构松散的内纤维素壁层逐步形成，并叠加在栓质化壁层的内侧，大液泡成为充满嗜饿油脂的油囊。阶段4：油细胞成熟及细胞质解体。杯形构造由内纤维素壁层向细胞腔内突起形成，油囊由液泡包被连接到杯形构造中。解体的细胞质变得电子不透明或呈杂乱状态。粘液细胞发育方式有两种：一种是由内纤维素形成以后的油细胞发育而来，其细胞质中不断产生以同心圆或螺旋线方式排列的多膜结构，并充满整个细胞腔，最后多膜结构解体而成为丝状或颗粒状的粘液；另一种是由已完全成熟的油细胞发育而来，其油囊中的油呈不均匀的状态，并产生局部降解点，逐步扩大，最后油完全降解成颗粒成或丝状的粘液。

DEVELOPMENTAL ULTRASTRUCTURE OF OIL AND MUCILAGE CELLS IN CINNAMOMUM LONGEPANICULATUM

Using ultrathin section and transmission electron microscopy,the developmental process of oil and mucilage cells in Cinnamomum longepaniculatum was observed.According to the development of three wall layers,the process can be divided into 4 stages.In stage 1,the cell wall is consist only of primary (the out) cellulose layer.This stage can also be divided into two periods:one of which is oil cell initial and another is vacuolizing oil cell.During this stage,there are some small electron translucent vesicles and quite different size dark osmiophilic drops in different shaped plastids.Similarly,there also exist dark and gray osmiophilic materials in ground cytoplasm,and their coalescence with vacuoles was observed too.In stage 2,suberized layer is present,and the lamellated suberin layer accumulates inside the primary cellulose layer.In stage 3,the inner cellulose wall layer is formed.Thicker and looser inner cellulose wall layer is piled up gradually inside the suberin layer.In this stage,because of the accumulation of a great quantity of osmiophilic material,the big vacuole becomes into an oil sac filled with osmiophilic lipophilic substances.In stage 4,oil cell matures and the cytoplasm disintegrates.After oil cell maturity,the ground cytoplasm starts to disintegrate,and becomes more electron opaque or exhibits a disordered state.Oil sac is enveloped by plasmalemma and attached to the cupule,which is formed by the protuberance of inner cellulose wall layer into the lumen.Mucilage cells come from parts of oil cells.There are two developmental patterns.One is that mucilage cell comes from oil cell whose inner cellulose layer has already formed.In the ground cytoplasm of such an oil cell,some multimembrane structures whose membrane arranged like concentric circles or like a spiral come out gradually and fill up the whole lumen.Finally,the multimembrane structures disintegrate and become into filiform or granular mucilage.Another pattern is that mucilage cell comes from fully matured oil cell,whose cytoplasm has already disintegrated.In such an oil sac,osmiophilic oil shows an inhomogeneous state.Many local disintegrative sites take place in the different electronic density oil,and these sites expand gradually.Finally,oil disintegrated completely into filiform or granular mucilage.This studies on the developmental ultrastructure of oil and mucilage cells verified that mucilage cell comes from oil cell.