条斑紫菜自由丝状体的形态结构观察

以光镜和电镜观察条斑紫菜（Porphyra yezoensis）自由丝状体生长过程中，从营养藻丝、壳孢子囊枝到成熟的壳孢子囊枝细胞形态结构的变化，结果表明，光镜下自由丝状体在生长过程中细胞外部形态、色素体位置和颜色均发生变化；电镜观察显示了3个不同时期细胞的超微结构，主要包括细胞壁、细胞核、色素体、类囊体、内质网、蛋白核、线粒体、液泡、红藻淀粉和质体小球等。在自由丝状体的生长过程中细胞超微结构的主要变化为细胞壁增厚并产生脊突；色素体数量减少、分布位置从连续排列在细胞两侧到分散排列在细胞边缘，并且在类囊体膜之间出现空隙；红藻淀粉量增多并充满细胞间质。对这些变化与自由丝状体生长环境水温、光照强度和光照时间发生变化之间的关系进行探讨，综合分析认为，条斑紫菜自由丝状体在生长过程中，生长环境经由夏季高温、光照时间长、光照强度高到秋季温度下降、光照时间缩短、光照强度下降的变化，丝状体细胞发生细胞壁增厚、疏松，色素体数量减少，内质网面积增加，液泡、线粒体数量增多，红藻淀粉量大大增加等结构的变化。

Observation on free-living conchocelis of Porphyra yezoensis

The changes among three different stages of conchocelis in Porphyra yezoensis(conchocelis filament,conchosporangial branch and mature conchosporangial cell) were observed with light microscope and transmission electron microscope.The results showed that under light microscope cell shape,chloroplasts' position and colour changed during the growth of free-living conchocelis and at the same time under transmission electron microscope the ultrastructure of free-living conchocelis were observed.The results showed that the main structures of free-living conchocelis included cell wall,nucleus,chloroplasts,thylakoids,endoplasmic reticulation,pyrenoid,mitochondria,vacuoles,floridean starch and lipid body.With the development of free-living conchocelis of Porphyra yezoensis,the changes of cells mainly showed cell wall's thickness increased and external wall became irregular;the number of chloroplasts decreased,besides,their positions became discontinuous at the brim of cells in stead of successive arrayment along the vertical sides of cells in former stage and in some mature conchosporangial cells lacunas appeared between thylakoids.The amount of floridean starch increased greatly.All these phenomena may have relationship with the changes of water temperature,light intensity and persistence of sunlight which have been discussed in this paper.In conclusion,the above comprehensive analysis showed the changes,which happened during the development of free-living conchocelis from high termperature,long day time and intensive sunlight in summer to low temperature,short day time and less intensive sunlight in fall,caused free-living conchocelis cell to have serial of transformations,for example,cell wall thickening and loosening,chloroplast becoming smaller,area of endoplasmic reticulation expanding,the amount of vacuole,mitochondria and floridean starch increasing greatly.