トマト果実の鮮度保持とその生理学的研究 (第9報)

Abstract

The present investigation has been carried out to clarify the relationship between the NADP (Nicotinamide Adenine Dinucleotide phosphate) level or the concentration of high energy phosphates and the ripening of tomato fruits.1) When tomato fruits ripened under usual conditions (without being packaged air-tightly), the NADP level of fruits rose with the lapse of time, reached the highest on the stage of ripeness score 3, and thereafter began to lower. This tendency is similar to that of climacteric rise of respiration of fruits.2) When the respiration and maturation of fruits were controlled by being packaged with a polyethylene bag, the NADP level was kept nearly constant or rather slightly lowered during the after-ripening.3) As the results of separative determination of each part of fruits, the NADP level in the jellied pip was found to be higher than that in the flesh part. From the above fact it was deduced that the jellied pip has the more active metabolic rate in which NADP or NADPH are concerned than the flesh part dose, and the metabolic activity of the jellied pip has rather a great influence on the after-ripening of tomato fruits.4) The sum of high energy phosphates increased with the ripening of fruits, reached the maximum, and thereafter decreased. The period when the maximum was reached was later than that of climacteric rise of respiration. The content of ADP in the jellied pip increased with the after-ripening of fruits after harvest. This result obtained concerning ADP seems to support the proposal in which mechanism of climacteric rise of respiration of tomato fruits was explained based on the change of the content of ADP.5) On the other hand, when fruits were packaged with a polyethylene bag, not only total amount of high energy phosphates but also concentration of ADP was controlled and kept lower than those of non-packaged fruits. Previous paper reported that restrained color development in packaged fruits would be caused by the impediment in condensation of IPP after phosphatization of MVA. This deduction has been supported by the present results obtained from the determination of concentration of ATP and ADP in both packaged and non-packaged fruits.