模拟水流流速变化下黑藻生长指标及其差异

Growth Indexes and Their Difference of Hydrilla verticillata under Change of Flow Velocities of Simulated Water Flow

为了研究水流流速对沉水植物黑藻（Hydrilla verticillata）生长指标的作用,采用室内模拟水流流速（设置流速为0 m/s、0.08 m/s、0.16 m/s和0.30 m/s）的方式,对生长中的黑藻进行培养,监测黑藻生长过程中各形态指标的变化和叶片叶绿素的含量。实验结果表明,在0.08 m/s、0.16 m/s和0.30 m/s水流流速下,黑藻的叶长、株高和节间距都显著大于0 m/s下（n=12,p〈0.05）,但水流流速对黑藻的根数和根长无显著作用;在0.08 m/s、0.16 m/s和0.30 m/s水流流速下,黑藻细胞的长宽比显著大于0 m/s下（n=120,p〈0.05）,植物体内叶绿素含量小于0 m/s下;不同生长时期黑藻最大电子传递速率（ETR（max））和光合作用效率都是静止水流下最小;当水流流速为0 m/s、0.08m/s、0.16 m/s和0.30 m/s时,黑藻叶片内叶绿素a＋b平均质量比分别为（2.794±0.727）mg/g、（1.812±0.411）mg/g、（1.627±0.521）mg/g和（1.609±0.748）mg/g。水流会导致水中沉积物营养盐释放和光照强度增加等,能促进黑藻生长,同时水流动的机械拉力是影响黑藻生长的主要因素。

To study the effect of velocity of water flow on the growth of submerged macrophyte Hydrilla verticillata, simulated water flow（velocities were 0 m/s, 0.08 m/s, 0.16 m/s and 0.30 m/s） was used to wash Hydrilla verticillata during its growth period. Changes of morphological index and chlorophyll content were monitored in the growth period of Hydrilla verticillate. The results indicated that leaves length, stem length and distance between leaves of Hydrilla verticillate under water flow velocity of 0.08 m/s, 0.16 m/s and 0.30 m/s were significantly higher than those under 0 m/s（n=12, p〈0.05）. However, water flow velocity has no significant effect on root number and root length（n=12, p〉0.05）. The rate of cell length/width（L/W） of Hydrilla verticillate was significantly higher than that under 0 m/s（n=120,p〈0.05） and chlorophyll content was lower.The maximum electron transfer rate（ETR（max）） and photosynthetic efficiency were higher under water flow velocity of 0.08 m/s, 0.16 m/s and 0.30 m/s than that under 0 m/s. The average chlorophyll a＋b contents were（2.794±0.727） mg/g,（1.812±0.411） mg/g,（1.627±0.521） mg/g and（1.609±0.748） mg/g under the flow velocity of 0 m/s, 0.08 m/s, 0.16 m/s and 0.30 m/s, respectively. Nutrients released from the sediment and light intensity increased under water flow promoted the growth of Hydrilla verticillate. Machine tensile of water was the main reason for the growth of Hydrilla verticillate.