关键词: 苹果, 砧木, 根系, Ca²⁺, 吸收动力学, 温度, 代谢抑制剂

Abstract: The experiment were carried using apple seedlings(Malus hupenensis Rehder)and pot—cultured three—year old apple tree(Fuji/Malus hupenensis Rehder)．It was studied that the kinetics of Ca²⁺ uptake and the effect of temperature and metabolic inhibitor 2，4-Dinitrophend(2，4-DNP)on Ca²⁺ uptake rate. The result show that the relation of Ca²⁺ uptake rate and Ca²⁺ concentration fits into Michaelis-Menten model under low concentlation of Ca²⁺ (0.02—0.5 mmol·L^-1)．The Ca²⁺ uptake rate rise linearlv with the increase of Ca²⁺ concentration in both intact roots and excised roots and the rate of Ca²⁺ uptake in intact roots exceeds in excised roots under high concentration of Ca²⁺ (0.5-5.0 mmol·L^-1)．The rates of Ca²⁺ uptake were inhibited by 2，4-DNP both in intact roots and excised roots．The inhibition rate was bigger under low concentration than high concentration and in excised roots than in intact roots. Under low concentration,the rate of Ca²⁺ uptake Was influenced markedly by temperature．The α value and Ca²⁺ uptake rate in excised roots were the highest under 15—20 ℃．Under high concentration,the rate of Ca²⁺uptake did not afected markedly by temperature．The Ca²⁺ uptake rate in absorbing roots was similar to extensive roots according to roots surface area．The α value in
ligneous roots was 54% to absorbing roots and extensive roots．

Key words: Apple, Rootstock, Roots, Kinetics of Ca²⁺ uptake, Temperature, Metabolic inhibitor