Abstract: Malva rotundifolia grows in oasis-desert ecotone in the Yili Testudo horsfieldi Nature Reserve. In this paper, the quantitative characters and change of organs of M. rotundifolia in different life cycles were researched. The results show that the number and biomass of organs at late fructification stage of M. rotundifolia population were higher than those at vegetative stage. Leaf number at late fructification stage was 1.25 times of that at vegetative stage, root and stem biomasses were over three times, and the ratio of leaf biomass was 2.06. With the increase of leaf number, there was a linear positive correlation among the biomasses of different organs at vegetative stage, but a power function positive correlation after fructification. There was a power function positive correlation between fruit biomass and root and stem biomass after fructification, but a linear positive relationship between fruit number and root and stem biomass. In different life cycles, there were two different phenotypic plasticity patterns of organs of M. rotundifolia population, i.e. the isogony phenotypic plasticity and allometry phenotypic plasticity.

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