Plant diversity has important functions in ecosystem productivity overyielding and community stability. Little is known about the mechanism causing productivity overyielding and stability under harsh conditions. This study investigated the photosynthetic response and subcellular distribution of uni- and co-cultured duckweeds (Lemna aequinoctialis and Spirodela polyrhiza) under excess copper (1.0 mg/L) and low temperature (5 °C) conditions. The results showed that the growth of uni-cultured L. aequinoctialis was not different from that of uni-cultured S. polyrhiza across copper treatments at control temperature (25 °C). The growth rate of L. aequinoctialis increased by 55.5 % under excess copper concentration when it coexisted with S. polyrhiza, compared with uni-culture. Subcellular distributions of copper were predominantly distributed in cell walls. S. polyrhiza accumulated more copper in cell walls than L. aequinoctialis under uni-cultured condintion at excess copper concentration. Co-cultured S. polyrhiza increased copper accumulation in cell walls of co-cultured L. aequinoctialis to decrease toxicity at excess copper concentration, compared with L. aequinoctialis. Low temperature increased copper toxicity, with duckweeds having lower growth rate and photosynthetic activities (Fv/Fm). The L. aequinoctialis growth rate in co-culture was higher than in uni-culture under excess copper concentration and low temperature conditions, indicating that S. polyrhiza decreased the copper toxicity for L. aequinoctialis. The photosynthetic activity (Fv/Fm) of co-cultured L. aequinoctialis was higher than that of uni-cultured L. aequinoctialis exposed to excess copper concentration at low temperature. The community that formed by co-culturing S. polyrhiza and L. aequinoctialis produced more biomass by avoiding the toxicity of excess copper through heavy metal compartmentalization and photosynthetic activities.

植物多样性在生态系统生产力过剩和社区稳定中具有重要作用。对于在恶劣条件下导致生产率过高和稳定性的机理知之甚少。这项研究调查了在过量铜（1.0 mg / L）和低温（5°C）下单培养和共培养的浮萍（Lemna aequinoctialis和Spirodela polyrhiza）的光合作用响应和亚细胞分布。结果表明，单培养L的生长。在控制温度（25°C）的情况下，铜处理过程中的aequinoctialis与单培养的S. polyrhiza没什么不同。L的增长率。水痘与单培养相比，在过量铜与S. polyrhiza共存的情况下，铜的含量增加了55.5％。铜的亚细胞分布主要分布在细胞壁中。S.萍在细胞壁积累更多的铜比L. aequinoctialis下单培养condintion在过量的铜浓度。共培养S.萍在细胞壁增加铜积累共培养L. aequinoctialis在过量的铜浓度降低的毒性，比较了L. aequinoctialis。低温会增加铜的毒性，而浮萍的生长速度和光合活性（Fv / Fm）会降低。的在过量铜浓度和低温条件下，共培养的金合欢菌的生长速率高于单培养的生长速率，这表明多枝链霉菌降低了铜对L的毒性。水母。低温暴露于过量铜的条件下，共培养的金合欢乳杆菌的光合作用活性（Fv / Fm）要高于单培养的金合欢乳杆菌的光合作用活性。由S. polyrhiza和L. aequinoctialis共同培养形成的群落通过避免多余的铜通过重金属区分开和光合作用而产生的毒性，产生了更多的生物量。