不同营养水体对喜旱莲子草化感抗藻的影响

Effect of trophic status of cultivation solutions on allelopathic inhibition of Microcystis aeruginosa by Alternanthera philoxeroides

基于植物化感原理,通过水培实验,模拟在蒸馏水、标准培养液(BG11营养液)和巢湖湖水(富营养化水体)3种不同营养状态的水体下,研究外来入侵植物喜旱莲子草不同培养时期的活体植株和不同腐解时期的残体植株对铜绿微囊藻生长的影响,同时还测定了喜旱莲子草活体植株种植水和残体植株腐解液的pH值和氧化还原电位的变化。结果表明,1)在不同水体营养状态下,喜旱莲子草具有抗藻的潜势,活体植株和残体植株在不同时期均显著抑制迟滞期的铜绿微囊藻(P<0.01),且残体植株抑制作用更强;不同营养水体中喜旱莲子草化感抗藻潜力差异显著(P<0.05),其中活体植株对铜绿微囊藻的抑制效应为:蒸馏水>富营养化湖水>标准BG11营养液,残体植株为:富营养化湖水>标准BG11营养液>蒸馏水。2)两类材料均显示相似的化感抗藻动态,抑制作用先逐渐增强,5d内达到对铜绿微囊藻较高抑制率(活体植株最高抑制率为70.7%;残体植株为91.7%),随后抑制率逐渐趋于稳定。3)喜旱莲子草活体种植水与残体植株腐解液理化性质显著不同(P<0.05),pH值和氧化还原电变化与溶液、时间、材料等因素有关。

Three water solutions with different trophic status （distilled water, BG11 nutrient solution and eutrophic water） were used to study the allelopathic effects of living and dead plants of the invasive species Alter- nanthera philoxeroides at different growth phases on Microcystis aeruginosa in a hydroponics experiment, pH and ORP （oxidation-reduction posed solutions from dead plants of A. philoxeroides. 1） Under different trophic status of culture media, A. philoxeroides had an inhibitory potential and living and dead plants at different stages could significantly inhibit M. aeruginosa at the lag phase. Dead plants had a stronger inhibitory effect on M. aeruginosa than living plants. Living plants had allelopathic effects, in the order, distilled water,eutrophic water）BG11 nutrient so- lution, while for dead plants the order was. eutrophic water）BG11 nutrient solution）distilled water. 2） The two kinds of plant materials gave similar allelopathic inhibition of M. aeruginosa. The inhibitory effect initially increased （for all three trophic water bodies）, and then terminated at a steady state. The highest inhibitory rates of living and dead plants at 70.7G and 91.7%, respectively, were at the 5th day. 3） The physical-chemical properties of exudates from living plants and decomposed dead plants were notably different, and pH values and ORP were related to various factors such as duration and types of solutions and materials. These findings will provide theoretical references for utilization and management of invasive plants and its further application in water-bloom algal control.