Abstract: The effects of different rootstocks on growth and development of apple roots and hormones contents were studied by using 3-year-old Tianhong 2/SH40/Baleng Crabapple and Tianhong 2/SH40. The results showed that the height，diameter，total shoot number，superlong shoots and long shoots number of the interstocks treatments were 21.92%，27.11%，22.48%，78.60% and 156.00% higher than those of the scion-roots. And the short shoots rate was 81.21% in scion-root，which was significantly higher than that of the interstocks（69.58%）. The fine root growth，fine root death，root surface area density and root number density of the interstocks were 58.64%，49.67%，36.88% and 53.33% higher than those of the scion-roots. In 0–60 cm soil layer，four peaks appeared in the annual growth dynamics of the roots in the two treatments，the second and third peak of the interstocks were significantly higher than that of the scion-roots and the third peak was 16 days earlier than that of the scion-roots. The interstocks had two obvious death peaks，while the scion-roots treatments had four death peaks. The rate of（IAA + ZR + GA）/ABA in root of interstocks was significantly higher than that of the scion-root during the tree growth and development.

Key words: apple, dwarf rootstock, root system, endogenous hormone, minirhizotron