低温对桂花万点金叶肉细胞超微结构的影响

Effects of low temperature on mesophyll cell ultrastructure of Osmanthus fragrans ‘Wandian Jin’

为探讨桂花万点金Osmanthus fragrans‘Wandian Jin’在低温胁迫下叶肉细胞溶酶体等细胞器超微结构的变化规律,以3年桂花品种万点金为试材,模拟自然降温过程胁迫桂花植株,经取样制片后,用透射电子显微镜拍照。结果表明:常温条件下,叶绿体线粒体结构正常;溶酶体数量较少。5℃低温处理时,部分叶绿体较之常温发生肿胀;嗜锇体和线粒体数量较之常温有增多现象;初级溶酶体和次级溶酶体并存,数量增多。0℃低温胁迫时,叶绿体膨胀加剧,部分呈椭球形;嗜锇体较多;淀粉粒有肿胀变大的现象;线粒体数量增多;次级溶酶体结构复杂多样,大小不一。-5℃低温胁迫处理时,叶绿体较前期的低温胁迫肿胀更加剧烈,部分叶绿体向细胞中央游离;线粒体增多;初级溶酶体和次级溶酶体数量增多,形态多样;叶肉细胞有胞内结冰和胞间结冰现象。

To understand the effects of low temperature stress on lysosomes or another organella in the mesophyll cell of Osmanthus fragrants‘Wandian Jin’,we chose three years old O. fragrans‘Wandian Jin’as the test material. The intelligent artificial climate chamber was applied to simulate the natural cooling process for O. fragrans. After sampling and making slices,the mesophyll cell of O. fragrans was used for investigation with the transmission electron microscope. The results showed that the chloroplast and mitochondrion′s structures did not display abnormal,however,the number of lysosomes decreased. Under the treatment of the low temperature at 5 ℃,some chloroplasts occurred a degree of swelling compared with that at the normal temperature;the number of osmiophilic granules and mitochondrions was increased;primary lysosome was found to coexist with secondary lysosome and their numbers grew. At low temperatures 0 ℃,chloroplast was more and more expand,some chloroplasts showed a spheroidicity shape;the amount of osmiophilic granule was significant;starch grain swelled and enlarged;the number of mitochondrion was increased;the structure of secondary lysosome was complicated and varying in size. At low temperatures-5 ℃, chloroplast swelled more strongerly than in the early,parts of the chloroplast were dissociated in the center of cells;the number of the mitochondrion, the primary lysosome and secondary lysosome was increased, and the shapes of lysosome varied. In addition,the mesophyll cells showed to ice intracellularly ice and freeze intercellularly.