植物的资源分配模式反映了对环境的生态适应对策。2007年整个生长季, 采用生物量法对腾格里沙漠东南缘固沙植被区半灌木油蒿(Artemisia ordosica)地上部分各器官的生长及资源分配格局动态进行了研究。结果表明: 不同时期各器官的生长速率不同, 光合产物在各器官中的分配也不是等量的, 而是按一定的顺序在不同时期有不同的分配中心; 2007年油蒿的营养生长、繁殖输出、生殖枝大小都显著大于年降水量不足其一半的年份, 而繁殖分配和头状花序大小没有差异; 营养器官生物量大的油蒿总的繁殖输出也大, 但生殖期内营养生长和生殖生长既不同时也不等速, 表明资源分配的权衡(Trade-off)是存在的; 固沙植被建立以后, 随着时间延长, 油蒿的当年总生物量、繁殖输出、繁殖器官生物量分配有减小的趋势, 但不显著。

Aims Resource allocation pattern is an important trait of plant ecological adaptive strategy. The composite sub-shrub Artemisia ordosica is widely distributed in the sandy land of northern China and is an important sand-stabilizing plant. However, its growth dynamics and resource allocation patterns are poorly known. Our objectives were to determine: 1) the growth dynamics of vegetative and reproductive organs and the biomass allocation pattern in different growth periods; 2) the relationship between reproductive and vegetative growth and 3) variations of biomass allocation pattern with age of sand-fixing vegetation.
Methods A field experiment was conducted on re-vegetated areas in Shapotou, located at southeastern fringe of Tengger Desert, from April to November 2007. Twenty-five A. ordosicawere sampled monthly in sand-fixing vegetation planted in 1956, 1964, 1981, 1987 and 1991 to measure the number, size and biomass of vegetative organs and reproductive organs such as leaves, vegetative shoots, flowering shoots, capitula and seeds.
Important findings In different growth periods, there were different growth rates and proportion of photosynthate allocation to organs. So the energy accumulation center and growth center vary with growth period. The vegetative growth, reproductive output and size of panicle in 2007 were significantly greater than those in the year when precipitation was less than half that in 2007, while no significant differences were found in reproductive allocation and size of capitula between these years. The individuals with greater vegetative biomass were also characterized by higher reproductive output, but the vegetative and reproductive growth were unsynchronized with different increment speed, which indicated that there was a trade-off between reproduction and vegetative growth. Annual biomass, reproductive output and reproductive allocation showed a trend of decrease with time extension of the sand-fixing project, but no statistically significant differences of the three indices were found among these five vegetation areas with different ages.