两种沉水植物对风浪及持续高水位胁迫的适应性研究

以两种沉水植物马来眼子菜(Potamogeton malainus)和狐尾藻(Myriophyllum spicatum)为研究对象,通过原位模拟试验,比较在相同水位变化幅度下不同高水位持续胁迫水平(分别以T0、T1、T2、T3表示恒静止、持续4 d、持续8 d和持续12 d)对沉水植物的生物量、植株伸长、具体形态指标和光合荧光特性的影响,并同步分析滆湖大洪港内两处风浪差异区(湖岸区M1和湖心区M2)两种沉水植物相应的适应性和形态变化的特征.结果表明,马来眼子菜和狐尾藻都表现出了较好的环境适应性,T0时任意两处的两种植物生物量和株高均最大;在风浪扰动较小区域(M2),持续高水位减弱了两种植物的伸长和生长(p0.01),并显著限制其在地上生物量的投资和茎干横向的分支(p0.05).在风浪扰动较大区域(M1),持续高水位对两种沉水植物产生了相同的形态变化,并显著降低各梯度下其Fv/Fm和快速光响应曲线(p0.05),但M1处两种沉水植物的光合能力均显著大于M2处.狐尾藻对风浪扰动和长时间水位胁迫能表现出更强抗弱光性和光合作用能力.因此,持续高水位胁迫下(小于8 d)两种沉水植物对一定程度水动力仍有较好的形态和生长适应性,对特定水文波动特征进行合理应对以保持沉水植物活力和维持湖泊生态系统具有指导作用.

Study on adaptability of two submerged macrophytes for wind-induced wave and high water level stress

The variation of two dominant submerged macrophytes, Potamogeton malainus and Myriophyllum spicatum, were studied in-situ under different time of high water level stress (T0, T1, T2 and T3 respectively referred to the initial static, 4 days, 8 days and 12 days). The biomass, elongation, specific morphological index and photosynthetic fluorescence characteristics of two plants had been compared. The characteristics of two plants'' corresponding adaptations and morphological changes were synchronically researched at two difference wind-induced wave sites (M1,M2 respectively referred to the lake shore and lake center) in Dahonggang of Gehu Lake. The results showed that the high survival rate of Potamogeton malaianus and Myriophyllum spicatum presented their good adaptability to the surrounding, and the biomass and height of two plants were the largest at either place (M1 and M2) in T0 group. Around area where was disturbed by wind-induced wave slightly (M2), continuous high water level weakened plant growth (p < 0.01) and significantly limited their biomass investment on the ground and stem-lateral branching (p < 0.05). Around area where was disturbed by wind-induced wave dramatically (M1), continuous high water level produced the same morphological changes for both two kinds of submerged macrophytes and significantly decreased their F_v/F_m and rapid light response curve values under each depth gradient (p < 0.05). However, the photosynthetic capacity of two plants at M1 was significantly greater than that of M2. Meanwhile, Myriophyllum spicatum presented more strongly low light adaptability and photosynthetic ability. Therefore, two plants under continuous high water level stress (less than 8 days) showed good adaptability of morphology and growth to certain hydrodynamic conditions. It was instructive to make reasonable response to specific hydrological fluctuation characteristics in order to maintain the vitality of submerged macrophytes and the ecosystem of the lake.