逆境下培養菸草細胞的核仁微細構造

Abstract

以Actinomycin D(AMD)或熱來處理，指數中期(mid-log)的栽培菸草(Nicotiana tabacum L。cv Wisconsin 38)懸浮培養細胞，藉著銀染色方法和超薄切片技術觀察。對照組細胞的核仁相當繳密(compact)，主要由濃的細絲成分(dense fibrillar component)、顆粒狀成分(granular component)、細絲中心(fibrillar center)和核仁染色質(nucleolusassociated chromatin)等四部分組成。銀顆粒分佈在細絲成分、顆粒成分、細絲中心，核質中的染色質。細胞經熱處理後，核仁發生分離(segregation)，顆粒部分消失(degranulation)以及泡化(vacuolation)，銀顆粒分佈在細絲成分、顆粒成分，而核仁空泡(nucleolar vacuoles)沒有銀顆粒的存在。AMD亦造成核仁分離，銀顆粒在細絲成分、顆粒成分皆有，然而，核仁空泡中沒有銀的出現。逆境處理，對總蛋白質量，過氧化氫?(peroxidase)活性，以及胞器，皆有影響。

Suspension culture cells of tobacco (Nicotiana tobacum L. cv N38) in mid-log phase were collected and treated with heat or AMD, and then observed by silver staining and ultrathin section methods. Normal nucleolus is contact and consists of four components, i. e., dense fibrillar compnent, granular component, fibrillar center and nucleolus-associated chromatin; silver grains dispersed in fibrillar component, granular component, fibrillar center and chromatin of nuoleoplasm, Cells treated with heat stress showed the nucleolar segregation, degranulation and vacuolation; silver grains dispersed in fibrillar component, granular component and scarcely in nucleolar vacuole. Nucleolar segregation was also observed in AMD treatments; silver grains were found in fibrillan and granular components except nucleolar vacuole. Noreover, stress have also effects on protein contents, peroxidase activity and structure of cell organelles.