Abstract: The amount and conformation of light-harvesting chlorophyll a/b-protein complex (LHC Ⅱ ) of photosystem II and the expression of a gene encoding for LHC Ⅱ were investigated when maize ( Zea mays L. ) seedlings were exposed to water stress and rewatering. The relative water content (RWC) and water potential in maize leaves decreased markedly after 72 h of water stress; the content of chlorophyll and apoproteins of LHC Ⅱ and the mRNA level of a gene encoding for LHC Ⅱ were reduced pronouncedly, but not recovered after 24 h of rewatering. However, the conformation of LHC Ⅱ in thylakoids was also altered by water stress but could be recovered by 24 h of rewatering. The authors proposed that two ways of dissipating relattive excess excitation energy may be encountered in the photosynthetic membrane. A fast way is by changing the conformation of LHC Ⅱand another relatively slow way is the reduction of components of LHC Ⅱ, through which the reduction of apoproteins of LHC Ⅱ can be regulated partly at the transcript level.

Key words: Zea mays, Water stress, Rewatering, Light-harvesting chlorophyll a/b-protein complex of photosystem Ⅱ