Abstract: Lycium barbarum L. is the top choice cash shrub planted on the saline soils in arid areas of China. To study the morphology and biomass allocation of L. barbarum could provide theoretical basis for enhancing the productivity of this shrub and supporting its sustainable use. In this paper, the L. barbarum plants of 4-, 7-, and 11-year old in the Jintai electrical irrigation area of Gansu were selected to study the biomass allocation in their branches, fruits, leaves, and different diameter sizes roots. Little variation was observed in the plant height and canopy diameter among the 4-year-old plants, greater variation was found among the 7-year-old plants (the vigorous growth stage), and little variation was observed again among the 11-year-old plants. Vertically, the total biomass and branch biomass of the 4-, 7-, and 11-year old plants were the greatest at the 50-100 cm layer, the fruit and leaf biomass of the 4-year old plants were the greatest at the 50-100 cm layer, whereas the fruit and leaf biomass of 7-year-old plants were the greatest at the 100-150 cm layer. The biomass of the thick and thin roots of the 4- and 7-yearold plants occupied a greater proportion, while the biomass of the thick roots of the 11-year-old plants occupied over 50% but the biomass of the thin roots only had a small proportion. The biomass allocation to the fruits, leaves, and medium and coarse roots increased with plant age, whereas the biomass allocation to the fine roots was the greatest for the 7-year-old plants, followed by the 11-year-old plants, and then the 4-year-old plants. A quadratic function was developed to describe the relationships between the leaf and root biomass and the plant age.

Key words: Populus euphratica, P. pruinosa, clonal ramet, space distribution pattern.