关键词: 辣椒, 弱光, 气体交换, 叶绿素荧光

Abstract: The effects of low light (75 - 100μmol·m^-2 ·s^-1 ) on photosynthetic gas exchange, chlo
rophyll fluorescence and chlorophyll contents in seedlings of different Capsicum were studied. The results
showed that under low light, net photosynthetic rate ( Pn) , dark resp iration rate, night resp iration rate, actual
photochemical efficiency of PS Ⅱ in the light ( ФPS Ⅱ) , electron transport rate ( ETR ) , photochemical
quenching ( qP) and excitation energy to PSⅡphotochemistry decreased, whereas the heat dissipation in
creased and no significant changes in maximal photochemical efficiency of PSⅡ in the dark ( Fv/Fm). From
the response curve of ФPSⅡ to light intensity, itwas seen thatwith the increase of light intensity, there was a
faster decrease in ФPSⅡ. The response curve of ETR to light intensity indicated that Capsicum grown under
low light had lower saturate electron transport rate light and saturation point of electron transport rate, as com
pared with those grown under normal light. The SPAD value of leaves in Capsicum decreased which mean that
the synthesis of chlorophyllwas inhibited under low light. Capsicum with lower net photosynthesis decreasing,
higher Fv/Fm and ETR may possess potential low light-tolerance.

Key words: Capsicum, Low light, Photosynthetic gas exchange, Chlorophyll fluorescence