Abstract:In this experiment,chloroplast thylakoid membrane proteins were isolated from poplar reciprocal hybrids (Poplus siminii×P.pyramidalis;P.pyramidalis×P.simonii) and willow hybrids (Salix babylonica×S.fragilis),as well as their parents,and also several poplar representive species including female and male plants.The polypeptides were separated by SDSPAGE.The polypeptide patterns obtained were analysed and compared between hybrids and their parents,female and male plants,and among the representive species.Results obtained are as follows: 1.poplar thylakoid membrane proteins were separated into more than 40 polypeptides varied with different species.According to this difference.these tested species of Poplus can be divided into three groups:Aigeiros (P.deltoides Bartr CL.‘Lux‘ and P.deltoides Bard CL ‘Harvard‘) and Tacamahaca (P.simonii Carr) possessing 50kd,and 27kd polypeptides,are in the same group,Leuce (P.alba L.) which has no these two polypeptides belongs to the second group.The third group is Leucoides (P.lasiocarpa Oliv.) in which,50kd and 27kd bands are very faint. 2.One 44kd polypeptide band was observed in the hybrid poplar when it is possessed in their female parent but not in their male parent.It means that 44kd polypeptide may be maternal inheritance and be used as a genetic marker in poplar breeding. 3.The patterns of thylakoid membrane polypeptides of willow hybrids were coincided with its parents in morphological characters.Therefore,we can deduce that there are some relations between thylakoid membrene polypeptides and morphological characters. 4.There were no common pattern of thylakoid membrane polypeptides between female and male and male plants in all tested species,But the male plant of P.simonii Carr.has one more polypeptide band than female plant.This band is very stable and good repeatability in our experiment and can be used as a marker to distinguish the male plant of P.simonii Carr.in poplar breeding.