沙坡头人工固沙区油蒿繁殖分配的研究

对沙坡头人工固沙区油蒿 (Artemisia ordosica) 开花结实期的繁殖分配和生殖枝的生长特点进行了研究,结果表明:2006年8—10月,油蒿生殖枝重、头状花序重都显著增加(P<0.05),但繁殖分配均保持在26%左右;油蒿的繁殖分配与个体大小有一定的关系,地径在0.5 cm以上的油蒿个体才能够开始繁殖,繁殖分配大致呈现出在一定范围内随个体增大而上升,然后又随个体继续增大而下降的趋势。对不同建植年代(1956年、1964年、1981年、1987年)样地中油蒿繁殖结构特征和繁殖分配比较发现,1981年样地上油蒿的生殖枝重、单位生殖枝上的头状花序数、繁殖分配都低于其他3个年代,且其他3个年代的样地间无显著差异(P>0.05)。这表明,人工固沙区油蒿种群的繁殖不仅受固沙时间的影响,而且受其他因素的制约。

Reproductive Allocation of Artemisia ordosica in Replanted Area for Sand Fixation in Shapotou Region

A field experiment on the reproductive allocation of sub-shrub Artemisia ordosica was carried out on the re-vegetated areas in Shapotou of Tengger Desert. The results reflected that the weight of flowering shoots and flowers were growing fast, while the reproductive allocation was always approximately at 26% from Aug. to Oct. 2006. It was also found that individuals of Artemisia ordosica began to flower only after it reached a basal diameter of 0.5 cm. The reproductive allocation increased monotonically within a range of basal area sizes only, and a curvilinear, not linear, model could best delineate the relationship between reproductive allocation and plant size (indicated by basal diameter). The reproductive allocations and reproductive units of Artemisia ordosica were different in different re-vegetated areas which established in various time. The reproductive allocation, weight of flowering shoots and quantity of flowers in site re-vegetated in 1981 were significantly lower than the other three sites (1956, 1964, 1987), but the quantity of flowering shoots and size of flowers were almost same in the four sites. These suggested that the reproductive allocation and growth of reproductive units were controlled not only by fixation duration, but also by any other factors.