烟草内源细胞分裂素变化与植株形态发育的初步研究

RELATIONSHIP BETWEEN ENDOGENOUS CYTOKININ AND MORPHOLOGICAL DEVELOPMENT IN TRANSGENIC TOBACCO PLANTS

农杆菌介导将异戊烯基转移酶基因(isopentenyl transferase,ipt)导入烟草SD株系的叶肉细胞,经过抗性筛选和鉴定,获得转基因植株.酶联免疫吸附(ELISA)测定叶片内源玉米素核苷(ZR)、异戊烯基腺苷(iPA)和吲哚乙酸(IAA)的质量分数.结果表明:转基因株系的ZR和iPA的质量分数w不同程度地升高,IAA水平随之升高.高水平细胞分裂素导致叶片的气孔密度增加、气孔长度和花型大小减小,以及花粉萌发率降低.当w(iPA+ZR)与w(IAA)的比值大于2时,成年植株上部侧枝茎端生长发育异常,出现丛生状小叶.本文讨论了细胞分裂素水平和细胞分裂素与生长素的比值对转基因烟草生长发育的影响.

Isopentenyl transferase gene （ipt） from Ti plasmid of Agrobacterium tumefaciens was introduced into leaf explant cells of Nicotiana tabacum mediated by A. tumefaciens LBA4404, and several transgenic plant lines are identified. ELISA analysis showed that zeatin riboside （ZR） and isopentenyl adenine （iPA） content in the mesophyll cell of transgenic lines increased, accompanied by elevated IAA levels. In comparison with wide type plants, increased cytokinin level in transgenic plants resulted in increased stomata density, reduced stomata length and flower size, as well as decreased pollen germination rate. Secondary shoots from lateral buds on the top of adult transgenic plants at a ratio （〉2.0） of w（ZR＋Ipa）/w（IAA） grew abnormally with cluster leaflets. Effect of high cytokinin level and cytokinin/IAA ratio on growth and development of ipt transgenets is discussed.