关键词: 苹果, 砧木, 细根, 周转率, 矮化

Abstract: The dynamics of alive root length density，dead root length density，annual fine root turnover and seasonal fine root turnover in five-year old apple cultivar Fuji grafted on rootstocks or interstems were investigated through four consecutive years observation by using minirhizotrons to analyze the production and turnover of fine root from different apple scion-stock combinations. Results showed that alive root length density，from vigorous scion-stock combinations Fuji/Baleng Crab were the largest，less for dwarfing inter-stem combinations Fuji/M9/Baleng Crab and Fuji/SH40/Baleng Crab，the least for trees on dwarfing rootstocks like Fuji/M9，Fuji/SH40 and Fuji/Malus xiaojinensis. Alive root length density，decreased with tree age increased. The peak of fine root production and death occurred in summer and autumn for all scion-stock combinations. The largest average alive root length density，and dead root length density took place in vigorous scion-rootstock combinations Fuji/Baleng Crab. The annual difference of annual fine root turnover and seasonal fine root turnover was huge，and annual fine root turnover in trees grafted on dwarfing rootstock was higher than that in ones on vigorous rootstock. Alive root length density，from trees on dwarfing rootstock and interstems were lower than those from ones on vigorous rootstock，which were possibly related to dwarfing effect.

Key words: apple, rootstock, fine root, turnover, dwarfing