番茄果实成熟过程中钙调素含量变化及其与乙烯生成的关系

应用酶联免疫吸附法(ELISA)测定番茄(Lycopersicon esculentum Mill大红品种)果实成熟过程中钙调素(CaM)含量的变化。果实开始成熟(发白期),CaM含量随着呼吸跃变上升,成熟时(粉红期)达到最大,过熟衰老时则下降。果实内部乙烯浓度、ACC含量及其合成酶活性也随跃变而增加,随过熟衰老而降低。GaM含量在果实不同部位中的分布有明显差异,跃变上升期以子房腔组织含量最高,并由中心向外逐渐降低,外周果皮含量最低。此时用外源乙烯催熟处理促进各部位CaM增加。成熟衰老时子房腔组织首先衰老,CaM含量大为降低,但在中柱和果皮中却高于跃变上升期。外源乙烯促进衰老使CaM下降。Ca~(2+)促进番茄圆片CaM含量增高和乙烯产生,CaM抑制剂CPZ,TFP在降低CaM含量的同时也抑制乙烯的产生。

Changes of Calmodulin Content in Tomato Fruits During Ripening and Its Relation to Ethylene Production

The changes of calmodulin (CAM) content in tomato (Lycpersicon esculentum Mill "Dahong") fruits during ripening and senescence were determined by enzyme linked immunosorbent assay (ELISA). It was found that from the onset of climacteric the CaM content increased and reached the maximmum at the full ripe stage (P), then decreased during senescence. Corresponding to the changes of CaM content, the ACC content, the activity of ACC synthase and the internal ethylene concentiation (IEC) also increased with the climacteric rise and reached a maximum at the full ripe stage, then decreased during senescence. (Fig. 2). At the onset of ripening the CaM content in Iocular tissue increased greatly, while in other tissues it decreased from the centre toward the outer part. When the fruit was treated with ethylene at the green mature stage (G), its ripening was accelerated and the CaM in all parts increased (Table 1). At the full ripe stage the contents of CaM in columella and pericarp were much higher than that at the onset of ripening, and were decreased by the ethylene-treatment. However, the locular tissue senesced at that time, and the CaM content in it was lower than that at the onset of ripening and was no longer affected by ethylene-treatment (Table 2). In an experiment with fruit discs it was shown that Ca~(2+) promoted both ethylene production and CaM content increase. The CaM inhibitors, TFP and CPZ, decreased the CaM content in discs and also inhibited ethylene production(Table 3).