Based on the forecasted warming scenarios by IPCC, we studied the impacts of warming (increased by 2.0 and 3.5 ℃) on seed reproduction of two lakeside dominant species (Schoeno-plectus tabernaemontani and Sparganium stoloniferum) in a typical plateau wetland (Napahai) in Northwestern Yunnan, by using "open-top chamber" technique. The results showed that warming had significant effects on the seed setting rate of both species, though with interspecific variation. The seed setting rate of S. tabernaemontani was significantly increased under two warming treatments, while that of S. stoloniferum was significantly decreased under the 2.0 ℃ warming treatment and had no variation under the 3.5 ℃ warming treatment. Warming promoted the spike growth of both species. For S. tabernaemontani, under the warming of 2.0 and 3.5 ℃ treatments, the spike length was increased by 82.9% and 89.0%, the spikelet number was increased by 133.3% and 150.0%, the biomass of each individual was increased by 10.1% and 89.6%, and the rate between biomass of per plant panicle and total biomass was increased by 79.5% and 409.3%, respectively. For S. stoloniferum, under the warming of 2.0 and 3.5 ℃ treatments, the spike length was increased by 66.1% and 95.2%, and the rate between biomass of per plant panicle and total biomass was increased by 878.8% and 1052.6%, respectively. Warming significantly increased seed yield of both species. Under the warming of 2.0 and 3.5 ℃ treatments, the seed yield per panicle of S. tabernaemontani was increased by 33.7% and 58.3%, respectively. For S. stoloniferum, the seed yield was increased by 3.4% and 69.5%, respectively. Under the warming of 2.0 and 3.5 ℃ treatments, the seed length of S. tabernaemontani was increased by 5.4% and 6.9%, and the seed length/width was increased by 9.1% and 5.3%, respectively. Warming had no significant effects on the seed shape of S. stoloniferum. The maximum and minimum temperatures were dominant factors affecting seed reproductions of both species. The advance of growing season, the prolonging of nutrition growing period, and accumulation of organic matter induced by warming would provide sufficient nutrient and energy accumulation for the reproduction and development of plants, which would promote seed reproduction capability of both species under the warming conditions.
基于IPCC对未来大气增温的预测,采用开顶式生长室(OTC)增温技术,以不增温为对照,研究滇西北高原典型湿地纳帕海湖滨带优势植物水葱和黑三棱在大气增温2.0和3.5 ℃处理下种子的繁殖特征.结果表明: 大气增温对植物结实率影响显著,但存在种间差异.其中,增温对水葱的结实率有促进作用;黑三棱结实率在增温2.0 ℃处理下显著下降,但在增温3.5 ℃处理下又恢复到对照水平.增温促进了2种植物穗的生长,在增温2.0、3.5 ℃处理下水葱的穗长分别增加82.9%、89.0%,小穗数分别增加133.3%、150.0%,每株穗生物量分别增加了10.1%、89.6%,每株穗生物量占总生物量的比例分别增加79.5%、409.3%;在增温2.0、3.5 ℃处理下,黑三棱穗长分别增加66.1%、95.2%,每株穗生物量占总生物量的比例分别增加878.8%、1052.6%.增温显著增加了水葱和黑三棱每穗种子产量,在增温2.0、3.5 ℃处理下,水葱每穗种子产量分别增加33.7%、58.3%,黑三棱每穗种子产量分别显著增加3.4%、69.5%.在增温2.0、3.5 ℃处理下水葱种子长分别增加5.4%、6.9%,种子长宽比分别增大9.1%、5.3%;而增温对黑三棱的种子形态无显著影响.最高温和最低温是影响2种植物种子繁殖的主要温度因子.温度增高引起的生长季提前、营养生长期延长以及有机物积累量增加,为植物繁殖扩散提供了充足的物质和能量积累,可能是2种植物在增温条件下繁殖能力提高的原因.
Keywords: Napahai wetland; Northwestern Yunnan Plateau; adaptation; atmospheric warming; seed reproduction.