甘蔗和烟草幼叶原生质体的核酸含量与核酸酶活性及其影响因素

与幼叶组织相比，酶法新鲜分离的甘蔗和烟草幼叶原生质体内的ＲＮＡ、ＤＮＡ及总核酸含量均降低。其原因可能是刚游离的原生质体内酸性和碱性ＲＮＡ酶与ＤＮＡ酶等活性提高所致。甘蔗叶原生质体内的核酸降低量和ＲＮＡ酶与ＤＮＡ酶活性的增加程度均高于烟草。随用作渗透压稳定剂的甘露醇浓度增加，甘蔗和烟草叶原生质体的ＲＮＡ酶和ＤＮＡ酶活性均相应提高。其中以甘蔗叶原生质体的核酸酶活性增加水平较明显。在细胞壁降解产物的作用下，除了甘蔗原生质体内的ＲＮＡ酶活性略被促进外，其ＤＮＡ酶和烟草叶原生质体内的核酸酶均不受影响

NUCLEIC ACID CONTENT AND NUCLEASE ACTIVITY IN YOUNG LEAF AND ITS PROTOPLAST OF SUGARCANE AND TOBACCO

As compared with the tissue of young leaf, the contents of RNA, DNA and total nucleic acid in freshly isolated protoplasts from sugarcane (Saccharum officinarum L. ) and tobacco (Nicotiana tabacum L. ) young leaves by using cell wall degrading enzymes were all decreased, resulting probably from the obviously increased activities of RNAase and DNAase in protoplast of both species. The level of nucleic acid decreased and activities of both nucleases increased are markedly greater in sugarcane leaf protoplast than in tobacco one. The activities of both nucleases in leaf protoplasts of both species are correspondingly increased with an increase of the concentration of mannitol used as osmoticum, and the level of activities of both nucleases increased are greater in sugarcane leaf protoplast than in tobacco one in that case. Except that the activity of RNAase in sugarcan leaf protoplast was promoted, the activity of DNAase in it and the activities of both nucleases in tobacco leaf protoplast were not influenced by the cell wall degradation products.