铵胁迫对狐尾藻(Myriophyllum spicatum)和金鱼藻(Ceratophyllum demersum)生物量分配和形态的影响

Changes in biomass allocation and morphology of Myriophyllum spicatum and Ceratophyllum demersum under the ammonium stress

选取了两种常见的沉水植物狐尾藻和金鱼藻,通过测定其单株生物量、株高、根生物量/单株生物量、茎生物量/单株生物量和叶生物量/单株生物量,研究这两种沉水植物在2 mg/L的铵态氮持续处理4 d以及铵态氮胁迫解除后的生长情况.结果表明:铵胁迫阶段,与对照组相比,处理对狐尾藻各测定参数均无显著影响,而使金鱼藻株高显著增加.在铵胁迫解除阶段,与对照组相比,处理组狐尾藻单株生物量增加不显著,而金鱼藻单株生物量显著增加;处理组2种沉水植物株高均显著增加;处理组狐尾藻叶生物量/单株生物量显著增加,而根生物量/单株生物量显著减少,茎生物量/单株生物量保持不变.认为高光照环境下(约400μmol/(m2·s)),水体中铵态氮浓度短时间内(4 d)适当增加对沉水植物生长没有抑制作用;金鱼藻对高铵态氮浓度水体的适应能力较狐尾藻强.

Two submerged macrohphytes, Myriophyllum spicatum and Ceratoph）llum demersum, were selected to investigate their changes in growth, biomass allocation and morphology under ammonium stress of 2 mg/L NH4＋ -N lasting for 4 days and after remo- ving ammonium stress in water column. Individual biomass, shoot height and biomass allocation of three organs （ i. e. , root, stem and leaf） were determined. The results showed that during ammonium stress, shoot height of C. demersum increased compared to the control, while all above parameters of M. spicatum did not change much. When ammonium stress was removed, individual bio- mass of C. demersum increased significantly in comparison to that of the control, while that of M. spicatum kept unchanged. Both species showed significant higher shoot heights in treatment than in the control. Leaf biomass per unit plant weight of M. spicatum increased, while root biomass per unit plant weight decreased relative to the control after removing ammonium stress. This result suggested that ammonium stress in a short term （4 days） would not inhibit the growth of submerged macrophytes in later period in high irradiance （ about 400 μmol/（ m2 · s ） ） , and M. spicatum was more sensitive to ammonium stress than C. demersum.