2021 Volume 20 Issue 3 Pages 265-271
The waterlogging tolerance of Actinidia macrosperma, originating from the mid part of China, was compared with that of kiwifruit, and the potential ability of A. macrosperma to serve as waterlogging-tolerant rootstock for kiwifruit was determined. Two-year-old potted vines of own-rooted A. deliciosa ‘Hayward’, A. chinensis [FCM1], and A. macrosperma [Fuchu] were subjected to waterlogging for 14 days in plastic containers. In A. deliciosa and A. chinensis, the photosynthetic rate decreased markedly six days after starting waterlogging, and then leaf necrosis and defoliation occurred. All the leaves fell off by the ninth day of waterlogging. In contrast, a decrease in the photosynthetic rate and leaf disorder were hardly observed in A. macrosperma. In another experiment, three-year-old potted vines of ‘Hayward’ grafted on A. macrosperma [Fuchu] cuttings and A. deliciosa seedlings were waterlogged for 14 days. Leaf necrosis and defoliation occurred only in the ‘Hayward’ plants on the A. deliciosa seedlings, and all the vines defoliated seven days after the treatment completed. In these plants, the photosynthetic rate markedly decreased immediately after starting waterlogging. On the other hand, the photosynthetic rate was maintained at a relatively high level during and after the treatment in ‘Hayward’ on A. macrosperma [Fuchu] rootstock. After submersion for 10 days, the roots’ metabolic activity showed a significant reduction in ‘Hayward’ on the A. deliciosa seedling, but not on A. macrosperma [Fuchu]. These results showed that A. macrosperma is extremely tolerant to waterlogging, and the tolerance appeared in the kiwifruit scion grafted on A. macrosperma.
