Effects of waterlogging and increased soil nutrients on growth and reproduction of Polygonum hydropiper in the hydro-fluctuation belt of the Three Gorges Reservoir Region
Effects of waterlogging and increased soil nutrients on growth and reproduction of Polygonum hydropiper in the hydro-fluctuation belt of the Three Gorges Reservoir Region
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DOI：
10.17521/cjpe.2020.0159
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发表时间：
2020-11-01
影响因子：
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通讯作者：
Yu Fei-Hai
中科院分区：
文献类型：
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作者：
Chen Yu-Han;Luo Yi-Fu;Yu Fei-Hai
水淹和土壤养分是影响三峡库区消落带植物生长的主要环境因子。消落带不同高程的河岸植物所经历的淹水强度和土壤养分浓度不同;因此，我们假设同一种植物在不同海拔对淹水和土壤养分增加的反应也不同。方法以河岸植物水蓼（Polygonum hydropiper）为材料，其种子是从自然居群中采集的。采用普通园温室试验，研究了涝渍和土壤养分对高海拔和低海拔地区水蓼生长和繁殖性状的影响，结果表明：涝渍显著或极显著地降低了水蓼的功能叶长、功能叶宽、总分支数、叶生物量、花生物量和植株总生物量;低养分处理显著或极显著降低了总节数、总分支数、根生物量、花生物量和植株总生物量，说明淹水和低养分均抑制了水蓼的生长和繁殖。此外，淹水与土壤养分的交互作用显著影响了根系生物量，淹水后土壤养分水平越高，根系生物量积累越多。高高程植株的根生物量和叶生物量显著或趋于显著高于低高程植株, 而低高程植株的始花时间早于高高程植株, 且繁殖分配也显著高于高高程植株, 表明高低高程水蓼植株对资源的分配策略不同。该研究结果表明水蓼的生长和繁殖特性受根部水淹和土壤养分共同限制, 但对根部水淹条件下高土壤养分生境具有较好的适应性; 同时, 低高程植株可以通过调整其生长和繁殖特性以提高对所处生境胁迫的适应性。
Aims Flooding and soil nutrients are the main environmental factors that affect plant growth in the hydro-fluctuation belt of the Three Gorges Reservoir Region (TGRR). Flooding intensity and concentration of soil nutrients experienced by riparian plants at different elevations of the hydro-fluctuation belt are different; therefore, we hypothesized that growth and reproductive responses of plants of the same species from different elevations to waterlogging and increased soil nutrients are also different.Methods In this study, the riparian species Polygonum hydropiper, which is widely distributed at low and high elevations of the hydro-fluctuation belt of the TGRR, was selected and its seeds were collected from natural populations. Effects of waterlogging and soil nutrients on growth and reproductive traits of P. hydropiper from high- and low-elevation areas were studied in a common-garden greenhouse experiment.Important findings Waterlogging significantly, or with marginal significance, decreased length and width of functional leaves, total branch number, leaf biomass, flower biomass, and total biomass of plants; low nutrient treatment significantly or marginal significantly decreased total node number, total branch number, root biomass, flower biomass, and total biomass of plants, indicating that both waterlogging and low soil nutrients inhibited growth and reproduction of P. hydropiper. Moreover, the interaction between waterlogging and soil nutrients significantly affected root biomass, showing higher root biomass accumulation at high soil nutrient conditions upon waterlogging. The high-elevation plants had significantly or marginal significantly higher leaf and root biomass than those from low elevation; however, flowering time of the low-elevation plants was significantly earlier, and reproduction allocation was higher than the high-elevation plants, indicating that resource allocation strategy was different between the high- and the low-elevation plants. The results indicate that growth and reproduction of P. hydropiper are inhibited by both waterlogging and soil nutrients, and this species has high adaptability at high soil nutrient conditions to waterlogging; meanwhile, low-elevation plants can adjust their growth and reproductive characteristics to improve their fitness under environmental stress.