8LichtenthalerH K,Babani F,Langsdorf G. Chlorophyll fluorescenceimaging of photosynthetic activity in sun and shade leaves of trees[J]. Photosynthesis Research,2007,93 :235 - 244.
9Krause G H, Weis E. Chlorophyll fluorescence and photosynthesis :the ba8ics[ J]. Annual Review of Plant Physiology and Plant Molec-ular Biology, 1991,42:313 -349.