Effects of JA and SA on the growth and development as well as defensive enzyme activity of Rosa rugosa.

In order to study the induced resistance to diseases of Rosa rugosa, by sparying different concentration jasmonic acid ( JA) and salicylic acid ( SA), their influence on the growth and development as well as the activity changes of several defense enzymes in leaves of Rosa rugosa were studied. The results showed that the effects of different concentration JA or SA on the growth and development of R. rugosa were not obvious. Compared with that of control, the differences in plant height and blade area were not obvious after induced by JA or SA. However, the activities of three kinds of protective enzymes, such as phenylalanine ammonia lyase ( PAL), polyphenol oxidase ( PPO) and peroxidase (POD), were obviously affected after being induced by JA or SA. Induced by 0.5, 0.5 and 1郾0 mmol/ L of JA respectively, the activities of PAL, PPO and POD reached their maximal level on the 5th, 3rd and 7th day respectively, and were 1.91, 1.92 and 1.61 times of control, and the differences were significant. Induced by 1.0, 0.5 and 1.0 mmol/ L of SA respectively, the activities of PAL, PPO and POD reached their maximal level on the 3rd, 3rd and 5th day, with their activities were 2.14, 1.63 and 1.81 times of control, and the differences were obvious. The induced activity could last around 7 to 9 days. Spraying JA and SA can stimulate plant defense to environmental stress, such as the encroachments by disease and insect.