Abstract：Taking tomato（Lycopersicon esculentum Mill.）variety‘L402’seedling as material, we investigated the effect and physiological mechanism of calcium to methyl jasmonate（MeJA）inducing tomato resistance to gray mold after treated the tomato leaves with MeJA，Ca2+ or inhibitor of Ca2+．The results showed that：（1）Resistance to tomato gray mold was improved significantly after the plant treated with MeJA．Induced resistance was farther enhanced by Ca2+ but restrained badly by chelator as EGTA or the plasmalemma Ca2+ channel blocker as LaCl3．（2）Activities of PAL，PPO and POD also rose after the plant treated with MeJA．The response was generally promoted by exterior Ca2+ and suppressed by the inhibitor of Ca2+ such as EGTA and LaCl3．（3）However，activities of CAT and SOD induced by MeJA were not regulated by Ca2+ or inhibitor of Ca2+．Consequently，modulating of calcium on the induced resistance to tomato gray mold by MeJA may have relations with activities of defensive enzymes such as PAL，PPO and POD in tomato leaves.
