Study on Flue-cured Tobacco Seedling Culture in Sand-cultured Floating System

For reducing seedling culture cost,tobacco sand-cultured floating system was studied,where sand was the only growing medium.The results showed that:comparing with existing floating system,the sand-cultured system featured higher germination percentage and more uniform seedling size,and the whole seedling stage took about 60 days.The seedlings grew slower until 4 true leaves stage,and it was 2-3 days slower than existing system;afterwards seedlings grew as fast as those growing in the existing system.The characteristics of the seedlings,including stem height and circumstance,area of biggest leaf,dry material accumulation,total root number and vitality of root systems,NR enzyme's activity and chlorophyll content,developed slowly in early growing stage and rapidly in late growing stage.However,the chlorophyll content,NR enzyme's activity and vitality of root systems decreased in late stage of seedling desired to plant.It was concluded that the seedlings cultured in sand-cultured floating system grew vigorously and had well developed root system,moreover,its cost of culture was reduced by 56.58% compared with existing floating system.