Physiological responses of cotton at seedling stage to waterlogged stress

In Jianghan plain as well as south China, cotton at seedling stage often encounter waterlogged stress, by which normal growth of cotton plants is affected, the purpose of the study is to analyze the responses to Waterlogging stress. Therefore flooding experiments of cotton in the seedling stage was made and a series of physiological indices were observed such as Chlorophyll Relative value (RC), chlorophyll fluorescence (F0, Fm), Malondialdehyde (MDA), nomadic Proline (Pro), Dissoluble Sugar (DS), Peroxidase (POD) and Superoxide Dismutase (SOD), Analytic results indicated that, after Waterlogging, chlorophyll hydrolysis rate was higher in the first 3 days, the peak value of chlorophyll fluorescence decrease occurred between the 6th to 9th day. It figured that stagnant water on the field should be drained off in 3 days after Waterlogging stress, to avoid the photosynthetic efficiency being strongly inhibited. The balance of normal physiological metabolic process in cotton leaf was broken after Waterlogging, some new negative changes occurred, as MDA content increasing and the activity of SOD decline. Some other positive changes were accompanied, as the increasing of DS and Pro content and the activity of POD, for protecting active tissues. These physiological indices appeared regularly changing characterized by fastslow- fast, which can be simulated in unary cubic regression curve model. © Maxwell Scientific Organization, 2013.