底质类型与正反扦插对轮叶黑藻生长生理的影响

底质是沉水植物扎根生长并稳定繁衍的基本条件,不同类型底质物化特性存在差异。为了探究沉水植物大规模引植过程中产生形态学顶端颠倒现象对其恢复生长的影响,通过室内水族缸模拟实验和杭州西湖茅家埠湖区原位盆栽实验,研究不同类型底质(湖泥、湖泥+沙子、沙子、黄土)和正反向扦插对轮叶黑藻(Hydrilla verticillata)生长形态及生理指标的影响。结果显示,不同底质类型对黑藻生物量积累、分蘖数等形态指标影响显著(P<0.05),湖泥中黑藻生长最佳,其增加生物量(6.27 g)、分蘖数(19.8枝)在4种底质中最大;其次为黄土(5.14 g和18.8枝),其能促进植株和根系伸长;叶绿素、蛋白含量、超氧化物歧化酶活性及丙二醛测定结果进一步印证以上结果。各种底质中,反向扦插处理的黑藻分蘖数和根数较正向扦插均有显著减少,尤其是黄土底质中,反向比正向扦插分别减少10.2枝和22.8根,生物量降低2.961 g,但不影响最终形态学上端的形成。西湖茅家埠原位实验表明,在含水率和营养较低的底质中,盆栽黑藻长势相对优于含水率和营养较高底质中的黑藻,且同一底质盆栽于原位时比异位时更有利于生物量积累。建议恢复沉水植被时可以适当改良底质,尤其是物理特性,种植时需区分植物形态学的上下端。研究结果可为不同类型底质的浅水湖泊沉水植物群落恢复提供参考。

Effects of Sediment Type and Positive/Negative Cutting on Growth and Physiology of Hydrilla verticillata

In this study, the effects of sediment types and positive/reverse cutting on the growth morphology and physiological indexes of Hydrilla verticillata were studied through laboratory aquarium simulation experiment and lake in-situ potted experiment. The results indicated that different sediment types had significant influence on the biomass accumulation, number of tillers and other morphological indicators of the H. verticillata (P < 0.05). The H. verticillata grew best in the lake mud, and its biomass and number of tillers were the largest in the four sediments (lake mud, lake mud + sand, sand and clay). The biomass and tillers number in the clay sediment was following, butthe clay could promote the extension of H. verticillata plant height and root system. The measure results of chlorophyll, protein content, superoxide dismutase activity and malondialdehyde further confirmed the above findings. The number of tillers and roots, and the biomass of the H. verticillata were significantly reduced by the reverse cutting, but the formation of the upper end of morphology was not affected. In the potted experiment of Maojiabu, Hangzhou West Lake, comparatively, the biomass, plant number and plant height of H. verticillata potted in the relatively barren sediment with low moisture content were all superior to that in the relatively fertile sediment with high moisture content. And the biomass accumulation of H. verticillata is better when the sediment being potted in situ than when it is heterotopic. It is suggested that the sediment, especially its physical characteristics, can be improved before the submerged vegetation restoration. In addition, it is necessary to distinguish the upper and down ends of plant morphology when planted.