烤烟种子萌发阶段若干特性动态变化分析

A Study on the Germinating Rates,Isoperoxidases and Their Activities Flue—Cured Tobacco Cultivar Seed in various Stages

以10个主栽烤烟品种为材料，对种子阶段萌发进行观察研究，并对其中5个品种种子萌发阶段的过氧化物酶、鲜重进行测定。结果表明：发芽同步指数为0．77～0．93，平均值为0．82，说明烤烟种子萌发具有高度集中时期；所有品种发芽率累积函数都符合Logistic生长曲线；过氧化物酶谱带随萌发阶段而发生变化，其谱带数、颜色深浅的变化与该谱总活力变化一致，即不断上升直至第7天左右开始降低；种子萌发集中性、Logistic曲线陡度和拐点、过氧化物酶谱带及活力、鲜重等性状，品种间都存在差异；阶段萌发率的遗传变异系数以集中萌发早期（136～144时）为最高，集中萌发阶段表现出的遗传变异可以作为遗传改良的基础。烤烟主栽品种种子萌发的有关特性对指导育苗和进行遗传改良具有一定参考价值。

The germinating rates and isoperoxidases of 10 and 5 flue-cured varieties respectively were investigated at various stages of germination. The indexes of synchronous germination. Which ranged from 0. 77 to 0. 93, showed that tobacco seeds germinated in highly concentrated phases. A Logistic curve was fitted to the cumulative rates of germination for all 10 tobacco cultivars tested. The numbers, colour degree and activities of isoperoxidases depended on germinating stages for flue-cured cultivars, increasing during the first 7 days and decreasing after this. There were different changes among cultivars for the following characteristics: accumulative rate of germination, inflection point and gradients of Logistic curve, numbers and activities of isoperoxidases. The highest genetic coefficient of variation (GCV) of the germination rate was observed at the beginning of the middle stages with 13. 81. The results above mentioned may be valuable for seedling cultivation and genetic improvement of seed germinating characteristics in flue-cured tobacco.