Abstract
Effects of flooding on the growth and physiological changes of seven grape rootstocks, 3309, 3306, 101-14, 5BB, SO⋅4, 110R, and H.F. were examined. The 3-year-old pot grown rootstocks propagated by cutting were flooded to the soil surface for 9 weeks beginning from June 3 in an unheated plastic house. Flooding tolerance judged by the shoot growth and the overall injury symptoms, such as leaf chlorosis and leaf fall, varied greatly among rootstocks. The highest tolerance was observed in 3306 and SO⋅4 rootstocks, followed by 3309, 101-14 and 5BB, while 110R and H.F. were sensitive to flooding. Although the number of aerial roots per plant was larger in H.F. than in 110R and SO⋅4 rootstocks, no significant difference in the emerging time of aerial roots was observed among rootstocks. Regardless of rootstock, the chlorophyll content of leaves and root activity estimated from TTC reduction were decreased by flooding, whereas ethanol content of fine roots was increased, but the relationships between flooding tolerance of rootstocks and these changes were not clear.
