Abstract:In order to evaluate ecophysiological factors and strategies of photoprotection, parameters of photosynthetic physiology and chlorophyll fluorescence were measured in leaves of Fritillaria cirrhosa exposed to different light conditions. The process of the same kind of experiment was introduced in detail.Results illustrate the curve of diurnal changes of photosynthesis in two peaks. Under shade conditions maximum photosynthetic rate (Pmax) increased by 31.1%, internal carbon dioxide concentration (Ci), 10% (p<0.01), comparing with in full light.The numerical value between the light saturated point (LSP) and light compensated point (LCP) also increased 331.5 μmol/(m2·s). At the same time, the apparent quantum yield (AQY) and stomatal conductance (COND) increased markedly.Dark respiratory rate (Rd) and Vapor pressure deficit (Vpdl) decreased remarkably which benefit the accumulation of photosynthetic products.The efficiency of energy harvesting (F′v/F′m)，photochemical quenching of chlorophyll fluorescence (qP)，electron transfer rate (ETR) and Psips2 increased by 14.7% (p<0.01), 8.8% (p<0.01), 10%(p<0.01) and 24.2%(p>0.05) respectively, suggesting good use of available light. Under these conditions photochemical efficiency (Fv/Fm) increased slightly, with minimal damage to photosynthetic structures. This suggests that growth of F. cirrhosa is not seriously affected when cultivated under conditions of full light.When natural light intensity is beyond LSP, photodamage of Fritillaria cirrhosa was avoided by increasing levels of non-photochemical quenching (NPQ) which dissipates heat. Plants under extreme environmental conditions or if more than three years old “shuerzi” are intolerant and their? leaves become reduced in size (becoming narrower) so as to resemble those of two year old plants “yipiye”. It is likely that this adaptive strategy reduces leaf surface area and hence reduces possible damage to photosynthetic structures.