The Relationship Between Ca～(2+)-ATPase And Ripening And Senescene In Tomato Fruits

The experiment was performed using 'baoguan'tomato fruits to study the changes of the main physiology-biochemistry characteristics, such as: microsomal membrane and cytoplasmic Ca²⁺-ATPase activity, respiratory rate, ethylene production rate and logcopene content during the fruits maturation and senescence.The effect of the inhibitors of Ca²⁺-ATPase i.e. Na₃VO₄ and EB on Ca²⁺-ATPase activity, respiratory rate, ethylene production rate and logcopene content of the turn stage tomato fruits was also studied during storage period.The main aim of the study is to provide some new information for the further study on the importance of the Ca²⁺-ATPase in the fruits ripening and senescence. The results as the fowllows:1 The respiratory rate and ethylene production rate increased with increasing maturity degree of fruits .The peaks of respiratory rate and ethylene rproduction rate appeared earlier than that in green-mature stage..2 The microsomal membrane and cytoplasmic Ca²⁺-ATPase activity increased with the increasing maturity degee at first, reached the peak at pink stage, and then decreased at full red stage.3 The activity of Ca²⁺-ATPase increased at first and then decreased, which reached the peak at 2nd after harvest.4 Exogenous calcium ion can activate Ca²⁺-ATPase of microsomal membrane in tomato fruits, which the optimum concentration was 2.5mmol/L.The microsomal membrane Ca²⁺-ATPase activity enhanced with the concentration of ATP added, the speed of the enzyme-stimulated reaction reached its peak under 5mmol/L ATP.The appetency of microsomal membrane to ATP was highest at pink stage and then at turn stage ,lest at red stage.The inhibitory effect of the different concentration of Na₃VO₄(200μmol/L, 500μmol/L) and EB(1.0μmol/L, 10μmol/L) on the different maturity degree fruits was also different,the higher concentration of the inhibitors, the more significant were.5 The inhibitors of Ca²⁺-ATPase, i.e.EB,Na₃VO₄ enhanced significantly respiration rate and ethylene production rate and improved the lycopene content of the tomato fruits, but didn' t alter the peak time of the rate of respiration and ethylene production. For example,therespiration rate and ethylene production rate of green maturation fruits were enhanced 24 %, 34.2%;37% ^ 40.3% by 1.0mmol/LNa3VO4, O.lmmol/LEB respectively at green mature stage.but also decreaed the activities of Ca2+-ATPase in the microsomal membrane and cytoplasmic of the tomato fruits.And also the higher concentration of the inhibitor was, the effects were more marked. It showed that Na3VO4 and EB can accelerate the process of fruits ripening and senescence.Thus ,h suggested that Ca -ATPase take part in the process of respiration and ethylene production of tomato fruits,and influenced fruits ripening and senescence.