Abstract:

Exploring the physiological response of Sanchezia oblonga to biotic and abiotic stress,in order to provide a scientific basis for carrying out stress resistance breeding or pest management of garden plants.The study focused on the leaves of S.oblonga under the biotic stress feeding of Achatina fulica and the abiotic stress of leaf cutting.Chlorophyll and tea polyphenol content as well as phenylalanine ammonia lyase activity of the leaves were measured under different growth conditions after leaf cutting and snail feeding stress.The results showed that A.fulica prefer to feed on the leaves of S.oblonga,and their feeding amount is large,which often leads to the leaves being completely consumed,seriously affecting the photosynthesis of S.oblonga.The leaf cutting stimulation and snail feeding stress have significant effects on the chlorophyll content,tea polyphenol content,and phenylalanine ammonia lyase(PAL)activity of the leaves of S.oblonga.At 3,9 and 15 hours after snail feeding and leaf cutting stimulation stress can induce more chlorophyll and tea polyphenols to be synthesized in the leaves of S.oblonga.However,PAL activity decreased rapidly and was significantly lower than that of the control group,suggesting that phenylalanine was accumulating to promote wound repair.The effects of snail feeding on chlorophyll,tea polyphenol content and PAL activity were more rapid than those induced by leaf cutting abiotic stress.In conclusion,the physiological response of S.oblonga after leaf cutting stimulation and snail feeding stress showed that the content of chlorophyll and tea polyphenols increased,and the activity of PAL was inhibited.

Key words: leaf cutting, Achatina fulica, adversity stress, chlorophyll, tea polyphenols, phenylalanine ammonia lyase