悬浮泥沙溶液对金鱼藻快速光响应曲线的影响

Influence of Suspended Sands on Rapid Light Curves of Ceratophyllum demersum in Turbid Solution

用粒径小于100μm的泥沙分别配置浊度为30、60、90 NTU的混浊溶液,将金鱼藻(Ceratophyllum dem er-sum)种植于该溶液中,1个月后测定植株叶片的快速光响应曲线,研究悬浮泥沙对金鱼藻光合荧光特性的影响。结果表明,在60、90 NTU的悬浮泥沙溶液中金鱼藻叶片的荧光产量(Ft)、光适应最大荧光产量(Fm′)和有效荧光产量(ΔFv/Fm)都显著低于对照和30 NTU的植株。与对照相比较,在混浊溶液中植株叶片的光化学淬灭(qP)和非光化学淬灭(qN)随光照强度的增加显著降低,光合能力和热耗散能力显著降低。混浊溶液中,随溶液浊度的增加植株最小饱和光强(Ek)和最大相对电子传递效率(rETRm ax)也显著低于对照植株,光合作用受到显著影响。因而,金鱼藻不适于在高浊度的悬浮泥沙溶液中生长。

Mature CeratophyUum demersum was planted in the turbid solution with different turbidities of 30 NTU ,60 NTU and 90 NTU. The turbidity was caused by suspended substance. For determining the influences of turbidity on the photosynthetic fluorescent characteristics rapid light curves （RLCs） were determined. The experimental results demonstrated that in 60 and 90 NTU turbid solutions fluorescence yield （Ft） ,maximum light-adapted fluorescence yield （F＇m） and AFv/Fm were less significantly than those in the control and 30 NTU solution. Compared with the control plants, photochemical quenching （qP） and non-photochemical quenching （qN） notablely decreased with light exposure of a leaf increasing in turbid solutions. It indicated that photosynthetic capacity and activity of non-photochemical quenching pathways were remarkably reduced. In turbid solutions, the minimum saturating irradiance （Ek ） and maximal relative electron transport rate （rETRmax） responding survive in were less significantly than the control. These proved that their light capacity were reduced notably by suspended sands. So it isn＇ t good for C. demersum to high tubidity of suspended sands solution.