Abstract: Under the stress of low temperature (15 ℃) and low light intensity (100μE·m^-2·s^-1) , the photosynthetic light compensation point of cucumber seedlings went up at the beginning of treatment , some parameters of chlorophyll a fluorescence such as Fv/ Fm , qp , ΦPS Ⅱ ( Y) decreased obviously , and the activity of RuBPCase was also reduced. This results indicated that the primary light energy conversion of PS Ⅱ, electron transport and carbon assimilation of cucumber seedlings had been inhibited , thus the capacity of its utilizing low light intensity went down. However , after
the induction of stress , the adaptability of cucumber seedlings increased , and the above parameter reversed the level before stress treatment . The results also showed that the adaptability of greenhouse varieties was higher than that of open field varieties.

Key words: Cucumber, Low temperature, Low light intensity, Chlorophyll a, Fluorescence kinetics, RuBPCase, FBPase