Ethylene may develop inside tissue culture vessels and interfere with the growth of cultivated plantlets. The damaging pattern on in vitro plantlets is not uniform. A study of this damage has been conducted on six fruit species almost equally divided between non-climacteric fruits producing species ( Prunus avium, Vitis vinifera and Fragaria vesca) and climacteric fruits producing species ( Malus communis and Prunus domestica). A probably climacteric producing fruit hybrid (peach×almond GF 677) has also been studied because of its high sensitivity to ethylene. The chlorophyll content appeared to be the best parameter for revealing the size of damage produced by the developing ethylene. In order to draw uniform conclusions, both ethylene and chlorophyll have been calculated as ratios of the dry weight of the plantlet. Their variations, expressed as a percentage of their initial values, have been considered in order to evaluate the trend. A dramatic difference resulted between the climacteric fruits producing species (very sensitive to ethylene) and non-climacteric fruits producing species which were only slightly sensitive to the ethylene. The chlorophyll analysis revealed effects which passed unnoticed to previous observations, lacking such precise analytical tool.