Effects of Drought Stress on Photosynthetic Characteristics and Antioxidant Enzyme Activities of Different Rootstocks and Grafted Apple Variety

PurposeTo study the effects of drought stress on the photosynthetic characteristics and antioxidant enzyme activities of leaves of different rootstocks and grafted apple variety.

MethodsThe apple dwarf rootstock Jizhen No.3 and superior lines 15-1, 1-8, 14-7, 10-1 and 22-46 independently bred by Hebei Agricultural University were used as experimental materials, the changes of photosynthetic parameters and antioxidant enzyme activities in leaves of apple rootstock and its grafted Tianhong No.2 under drought stress were analyzed, and the differences of different intermediate rootstocks to drought stress were analyzed by membership function method.

ResultsUnder drought stress, the photosynthesis of leaves of different rootstocks and stions were affected by different degrees. The initial fluorescence and the ratio of variable fluorescence and maximal fluorescence were significantly or extremely significantly higher than the control group. With the prolongation of drought stress time, the activities of antioxidant enzymes (SOD, POD and CAT) in rootstocks leaves increased at first and then decreased, and the activities of SOD and CAT in grafted varieties increased on the whole. The response of photosynthesis and three antioxidant enzymes in rootstock 14-7 and its grafted Tianhong No.2 leaves to drought stress was relatively weak, while that of rootstock 22-46 and its grafted varieties was strong. Membership analysis showed that the drought resistance of six rootstocks was 14-7>15-1>Jizhen No.3>10-1>1-8>22-46.

ConclusionUnder drought stress, there are differences in photosynthetic characteristics and antioxidant enzyme activities among six different apple rootstocks and grafted apple variety.