甘南地区歪头菜生殖分配对生殖产量的影响

采用现存生殖分配(Standing Reproduction Allocation)的方法研究甘南地区歪头菜(Vicia unijuga)生物量生殖分配。结果表明,不同生长年限植株在整个生长季中,各构件生物量占总生物量的比例随着季节变化表现为营养分配比重不断减少,生殖分配比重不断增加,但营养生物量分配比例占绝对优势,而在蕾期和花期用于有性生殖的生物量(蕾、花生物量)分配比例仅在10%左右;多年生歪头菜种群幼龄时期植株生殖生物量分配仍然随着生长年限的增加而增加,但生殖产量的生物量分配却表现出2年龄5年龄4年龄;2年龄植株蕾－花生物量转换比例和花－荚生物量转换比例分别为1∶1.17和1∶1.36,5年龄植株的分别为1∶0.94和1∶1.31,说明2年龄植株比5年龄植株有较高的生殖利用率,而5年龄植株落花、落荚现象明显。以上结果揭示出,植株对有性繁殖的小比例投资以及生殖转换中产生的生殖损失可能是导致该地区歪头菜种群有性繁殖体种子产量低的重要原因,而影响这一原因的因素可能是生长季过程中的环境干扰和养分竞争等问题。

Reproductive allocation and reproductive yield of Vicia unijuga at Gannan Tibetan region

Biomass allocation of Vicia unijuga at Gannan Tibetan region was studied by the method of Standing Reproductive Allocation. The results showed that vegetative biomass proportion gradually decreased and reproductive biomass gradually increased throughout the growing season although vegetative biomass always had an absolute advantage with less than 10% of reproductive biomass. The reproductive biomass allocation increased with increasing of reproductive age for the young plants of perennial V.unijuga. The reproductive biomass of two-year-age plants was higher. Reproductive conversion ratio from flower buds to flowers and from flowers to pods for two-year-age plants was 1∶1.17 and 1∶1.36, respectively, while that of five-year-age plants was 1∶0.94 and 1∶1.31, respectively. These results indicated that the loss of flowers and pods was obvious for five-year-age plants and reproductive modules utilization was higher for two-year-age plants. The lower seed production of V.unijuga in this area may be resulted from low reproductive investment proportion and the loss in the process of reproductive conversion, which may be influenced by some factors, such as environmental disturbance and nutrient competition.