Responses of photosynthetic pigments of Spartina alterniflora and Phragmites australis to durative waterlogging

With the invasive plant Spartina alterniflora and indigenous plant Phragmites australis in Chongming Dongtan Nature Reserve of Shanghai as test objects, the responses of their photosynthetic pigments to durative waterlogging were studied during the growth season in 2008. The basic composition and the content of the pigments differed with plant species, and their responses to durative waterlogging also differed. Under durative waterlogging stress, S. alterniflora had the decreased contents of chlorophyll a, b and carotenoid but the increased chlorophyll a/b and carotenoid/chlorophyll ratios, whereas P. australis had the increased pigment contents and rather constant chlorophyll a/b and carotenoid/chlorophyll ratios. After the waterlogging stress relieved, the pigment contents of S. alterniflora increased and its chlorophyll a/b and carotenoid/chlorophyll ratios decreased to the levels of the control, whereas the pigment contents of P. australis were significantly higher than the control. Both S. alterniflora and P. australis showed a compensatory effect after the stress relieved. P. australis could better adapt to the waterlogging stress than S. alterniflora, being able to be used as a substitutive plant for the restoration of coastal wetlands.