Interspecific associations between Hydrilla verticillata and three dominant native genera of submerged macrophytes are taxa dependent

Water level is one of the most important factors affecting the growth of submerged macrophytes in aquatic ecosystems. The rosette plant Vallisneria natans and the erect plant Hydrilla verticillata are two common submerged macrophytes in lakes of the middle and lower reaches of the Yangtze River, China. How water level fluctuations affect their growth and competition is still unknown. In this study, three water depths (50 cm, 150 cm, and 250 cm) were established to explore the responses in growth and competitive patterns of the two plant species to water depth under mixed planting conditions. The results show that, compared with shallow water conditions (50 cm), the growth of both submerged macrophytes was severely suppressed in deep water depth (250 cm), while only V. natans was inhibited under intermediate water depth (150 cm). Moreover, the ratio of biomass of V. natans to H. verticillata gradually increased with increasing water depth, indicating that deep water enhanced the competitive advantage of V. natans over H.verticillata. Morphological adaptation of the two submerged macrophytes to water depth was different. With increasing water depth, H. verticillata increased its height, at the cost of reduced plant numbers to adapt to poor light conditions. A similar strategy was also observed in V. natans, when water depth increased from 50 cm to 150 cm. However, both the plant height and number were reduced at deep water depth (250 cm). Our study suggests that water level reduction in lake restoration efforts could increase the total biomass of submerged macrophytes, but the domination of key plants, such as V. natans, may decrease.

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Megalobrama amblycephala grazes preferentially on Hydrilla verticillata but makes more efficient use of Vallisneria denseserrulata: implications for biological control of submerged macrophytes

Knowledge and Management of Aquatic Ecosystems ◽

10.1051/kmae/2019022 ◽

2019 ◽

pp. 30 ◽

Cited By ~ 1

Author(s):

Chunyu Yin ◽

Zhaoxia Wang ◽

Yu Zhao ◽

Yiming Gao ◽

Wei Zhen ◽

...

Keyword(s):

Submerged Macrophytes ◽

Hydrilla Verticillata ◽

Megalobrama Amblycephala ◽

Food Utilization ◽

Root Weight ◽

Fresh Weight ◽

Blade Width ◽

Negative Effect ◽

Maximum Root Length ◽

Maximum Root

Growth of the meadow-forming macrophyte Vallisneria denseserrulata is often negatively impacted as result of shading by the canopy-forming Hydrilla verticillata. Grazing by the herbivorous cyprinid Megalobrama amblycephala is thought to control H. verticillata. We hypothesized that M. amblycephala would prefer H. verticillata over V. denseserrulata, and that where the latter is grazed, its growth will not be wholly compromised, due in part to the efficiency with which it is metabolized by the grazer. In a pond experiment, macrophytes were planted with monocultures of H. verticillata and V. denseserrulata, and in mixed cultures of the two species, with and without grazing by M. amblycephala. The results showed that in the absence of fish, the growth rate of V. denseserrulata was significantly reduced in the presence of H. verticillata. In the mixture, M. amblycephala had a significant negative effect on the growth of H. verticillata but not on V. denseserrulata. Grazing was associated with reductions in plant height, plant fresh weight and leaf fresh weight but the leaf number, maximum root length, maximum blade width, root weight and stem weight in V. denseserrulata increased. The food utilization ratio of M. amblycephala was significantly higher when grazing solely on V. denseserrulata than when grazing on H. verticillata or the mixture. Our results imply that V. denseserrulata is protected from overgrazing by the ability of M. amblycephala to make more effective metabolic use of ingested material than for H. verticillata. Furthermore, M. amblycephala is beneficial to V. denseserrulata in reducing competition from H. verticillata.

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Ammonium loading drives bacterial community shifts in biofilms attached to the submerged macrophyte Hydrilla verticillata

Aquatic Microbial Ecology ◽

10.3354/ame01942 ◽

2020 ◽

Vol 85 ◽

pp. 59-69

Author(s):

D Lin ◽

L Zhu ◽

C Qiu ◽

X Mu ◽

S Zhang ◽

...

Keyword(s):

Submerged Macrophytes ◽

Hydrilla Verticillata ◽

16S Rrna Gene Sequencing ◽

Rrna Gene ◽

Rt Pcr ◽

Copy Numbers ◽

Ammonium N ◽

Microbial Community Structures ◽

Community Shifts ◽

Rrna Gene Sequencing

The effects of ammonium on biofilm attached to submerged macrophytes remain unclear. We studied the microbial communities of epiphytic biofilms on the leaf surface of Hydrilla verticillata under increasing ammonium loadings using 16S rRNA gene sequencing and RT-PCR. The study showed that the microbial community structures were influenced by increased ammonium loadings. N-cycling bacteria including the nitrifier Nitrospira and the denitrifiers Rhodobacter, Hyphomicrobium, and Flavobacterium were found to be predominant. Copy numbers of Ncycling functional genes (including amoA, nxrA, narG, napA, nirK, nirS, qnorB, and nosZ) were stimulated by increased ammonium loadings, showing the high potential of attached biofilms in removing ammonium-N through coupled nitrification-denitrification. Our results indicated that submerged macrophytes facilitated the ammonium removal process not only by providing favorable surface niches for ammonium oxidizers, nitrifiers, and denitrifiers in the attached biofilms but also by mediating dissolved oxygen concentrations and alkalinity condition in the water.

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The promotion effects of silicate mineral maifanite on the growth of submerged macrophytes Hydrilla verticillata

Environmental Pollution ◽

10.1016/j.envpol.2020.115380 ◽

2020 ◽

Vol 267 ◽

pp. 115380

Author(s):

Yunli Liu ◽

Fan Han ◽

Guoliang Bai ◽

Lingwei Kong ◽

Zisen Liu ◽

...

Keyword(s):

Submerged Macrophytes ◽

Hydrilla Verticillata ◽

Silicate Mineral

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Morphological responses to water-level fluctuations of two submerged macrophytes, Myriophyllum spicatum and Hydrilla verticillata

Journal of Plant Ecology ◽

10.1093/jpe/rts009 ◽

2012 ◽

Vol 6 (1) ◽

pp. 64-70 ◽

Cited By ~ 26

Author(s):

X. Zhang ◽

X. Liu ◽

Q. Ding

Keyword(s):

Water Level ◽

Submerged Macrophytes ◽

Myriophyllum Spicatum ◽

Hydrilla Verticillata ◽

Water Level Fluctuations ◽

Morphological Responses

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EFFECTIVENESS OF DIQUAT, BOTH ISOLATED AND ASSOCIATED WITH COPPER SOURCES IN CONTROLLING THE Hydrilla verticillata SUBMERGED MACROPHYTES AND ANKISTRODESMUS Gracilis microphyte

Planta Daninha ◽

10.1590/s0100-83582017350100018 ◽

2017 ◽

Vol 35 (0) ◽

Author(s):

I.C. MALASPINA ◽

C CRUZ ◽

N GARLICH ◽

S BIANCO ◽

R.A PITELLI

Keyword(s):

Submerged Macrophytes ◽

Control Sample ◽

Hydrilla Verticillata ◽

Dry Mass ◽

Copper Oxychloride ◽

Constant Weight ◽

Dry Biomass ◽

Forced Air ◽

Air Circulation ◽

Plant Length

ABSTRACT The goal of this study was to evaluate the effectiveness of diquat, both isolated and associated with copper sources (oxychloride and hydroxide) in controling the H. verticillata submerged macrophyte and the A. gracilis microalgae. For this purpose, 10.0 cm H. verticillata young branches and 300 mL of A. gracilis culture were used. The experiments were performed in laboratory and the tested diquat concentrations were: 0.1; 0.2; 0.4; 0.8; 1.2; and 1.8 mg L-1, either isolated or added with 1.0% copper oxychlorideand hydroxide, as well as a control sample. On day 3, 7, 11, 21 and 30 after application, phytotoxicity signs were evaluated and on day 60 after application, green and dry biomass production and plant length were measured. To obtain dry mass, plants remained in a greenhouse with forced air circulation at 65.0 oC, until constant weight. On day 1, 7, 15, 21, 30, 45 and 60 after application, the concentration of chlorophyll a in the water was assessed. The herbicide diquat used alone or in combination with sources copper oxychloride and hydroxide was effective in the control of H. verticillata and microalgae A. gracilis.

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