Phytol – A biosurfactant from the aquatic weed Hydrilla verticillata

2019 ◽  
Vol 17 ◽  
pp. 736-742 ◽  
Author(s):  
S. Pandi Prabha ◽  
C. Karthik ◽  
S. Hema Chandrika
Keyword(s):  
Hydrilla Verticillata ◽  
Aquatic Weed

Mutations in Phytoene Desaturase Gene in Fluridone-Resistant Hydrilla (Hydrilla verticillata) Biotypes in Florida

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 412-420 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
Fredy Altpeter ◽  
William T. Haller
Keyword(s):  
Herbicide Resistance ◽  
Single Point ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Phytoene Desaturase ◽  
Day Length ◽  
Single Point Mutation ◽  
Aquatic Weed ◽  
Systemic Control

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. One susceptible and five fluridone-resistant biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Because fluridone is an inhibitor of the enzyme phytoene desaturase (PDS), the gene for PDS (pds) was cloned from fluridone-susceptible and -resistant hydrilla biotypes. Somatic mutations in amino acid 304 of hydrilla PDS are known to confer herbicide resistance. We determinedpdssequence from these hydrilla biotypes at planting and 12-mo after planting. Two independent mutations at the arginine 304 codon ofpdswere found in the resistant hydrilla plants. The codon usage for arginine 304 is CGT, and a single point mutation yielding either serine (AGT) or histidine (CAT) was identified in different resistant hydrilla biotypes. There were no differences at codon 304 in the PDS protein of any hydrilla biotype 12-mo after planting. Several other mutations were also found in resistantpdsalleles, though their possible role in herbicide resistance is unclear.

scholarly journals Plectosporium tabacinum, a Pathogen of the Invasive Aquatic Weed Hydrilla verticillata in Florida

Plant Disease ◽  
1999 ◽  
Vol 83 (1) ◽  
pp. 24-28 ◽  
Author(s):  
M. L. Smither-Kopperl ◽  
R. Charudattan ◽  
R. D. Berger
Keyword(s):  
Aquatic Plant ◽  
Tap Water ◽  
Water Pressure ◽  
Plant Cells ◽  
Hydrilla Verticillata ◽  
Spring Water ◽  
Aquatic Weed ◽  
Acid Fuchsin ◽  
Inoculum Concentration ◽  
Submerged Aquatic Plant

Plectosporium tabacinum, the anamorph of Plectosphaerella cucumerina, was isolated in 1996 from Hydrilla verticillata (hydrilla), an invasive aquatic weed in Florida. P. tabacinum, applied as a suspension of conidia, was pathogenic to hydrilla shoots maintained in aqueous solutions in test tubes. Koch's postulates were fulfilled in several repeated experiments. Infected shoots became slightly chlorotic within 24 h after inoculation. Infected leaves remained intact and were supported by water pressure but collapsed upon removal from water. Histological studies of leaves stained with malachite green and acid fuchsin revealed fungal hyphae within plant cells. The disease developed over a range of temperatures from 15 to 30°C. At 25°C, symptoms were most severe in 5% Hoagland's solution, followed by river water, deionized water, 0.5% Hoagland's, tap water, and spring water. Disease severity increased as inoculum concentration was increased from 105 to 107 conidia ml-1. This is the first report of P. tabacinum as a pathogen of hydrilla, a fully submerged aquatic plant species.

scholarly journals Combate biológico de Hydrilla verticillata Vahl con carpa herbívora (Ctenopharyngodon idella Vía).

2016 ◽  
Vol 7 (2) ◽  
pp. 1
Author(s):  
Manuel Rojas ◽  
Renán Agüero A.
Keyword(s):  
Costa Rica ◽  
Equilibrium Point ◽  
Water Flow ◽  
Grass Carp ◽  
Hydrilla Verticillata ◽  
Production Costs ◽  
The Other ◽  
Ctenopharyngodon Idella ◽  
Aquatic Weed ◽  
The Third

Hydrilla verticillata has become an important aquatic weed of irrigation canals at some rice farms of Guanacaste, Costa Rica. This species slows water flow, often causing flooding in adjacent roads, its control increases overall production costs. To evaluate efficiency of the grass carp in controlling Hydrilla three trials were conducted, with varying densities of the fish. In the preliminary trial, 987 kg/ha of grass carp reduced Hydrilla biomass in nearly 62 m3 in 21 days. During the second trial, treatments with 1264 and 2042 kg/ha of the fish completely eliminated the weed after 30 days. However, during the third trial, 1000 kg/ha of the carp only reduced Hydrilla volume in 19 m3, after 66 days. The ratio kg of carp/initial volume of Hydrilla proved to be more important than just the kg/ha of the carp. It was observed that when such ratio was lower than 0.02, the carp did not provide a satisfactory control of Hydrilla; on the other hand, a ratio higher than 0.05 significantly reduced the weed's biomass. The equilibrium point between weed regrowth and biomass consumed by the carp occurred at a ratio close to 0.03.

scholarly journals Effects of Topramezone and Bispyribac-sodium in Irrigation Water on Warm-season Turfgrasses

2017 ◽  
Vol 27 (5) ◽  
pp. 599-606
Author(s):  
William T. Haller ◽  
Lyn A. Gettys ◽  
Taizo Uchida
Keyword(s):  
Weed Control ◽  
Cynodon Dactylon ◽  
Southeastern United States ◽  
Warm Season ◽  
Hydrilla Verticillata ◽  
Paspalum Notatum ◽  
Aquatic Weed ◽  
Primary Target ◽  
Low Concentrations ◽  
Herbicide Concentration

Topramezone and bispyribac-sodium were registered for aquatic weed control in the last decade. A primary target for these products is fluridone-resistant hydrilla (Hydrilla verticillata), which is one of the most invasive submersed weeds in the southeastern United States. Both products have water use restrictions that prohibit irrigation of turfgrasses with treated waters until the herbicides have degraded to very low concentrations. The objective of these studies was to identify the concentrations of topramezone and bispyribac-sodium that are phytotoxic to turfgrasses that are commonly planted in Florida. Three species of turfgrass were irrigated twice weekly with 0.5 inch of treated water for 4 weeks (eight irrigations total). Cumulative EC10 values (the herbicide concentration that caused a 10% reduction in biomass compared with untreated control plants) after eight irrigations with water containing topramezone were 3.5, 4.3, and 17 ppb for ‘Palmetto’ st. augustinegrass (Stenotaphrum secundatum), ‘Pensacola’ bahiagrass (Paspalum notatum), and ‘Tifway 419’ hybrid bermudagrass (Cynodon dactylon × C. transvaalensis), respectively. Bispyribac-sodium was less toxic to all turfgrasses evaluated, with EC10 values of 56, 16, and >800 ppb for ‘Palmetto’ st. augustinegrass, ‘Pensacola’ bahiagrass, and ‘Tifway 419’ hybrid bermudagrass, respectively. These results support label instructions and highlight the need to comply with irrigation restrictions because the typical use concentrations for submersed weed control with topramezone and bispyribac-sodium are in the 20–40-ppb range.

Structure of seeds and developing seedlings of Hydrilla verticillata

1993 ◽  
Vol 51 ◽  
pp. 350-351
Author(s):  
D. L. Holmberg ◽  
F. J. Ryan
Keyword(s):  
Electron Microscopy ◽  
Research Laboratory ◽  
Light And Electron Microscopy ◽  
Hydrilla Verticillata ◽  
Aquatic Weed ◽  
Viable Seed ◽  
Dioecious Plant ◽  
Fresh Material ◽  
Viable Seeds ◽  
Scanning Electron

Until recently, it was believed that Hydrilla verticillata, a widespread aquatic weed, did not generally produce seeds. There were reports that the monoecious biotype from the U. S. was sometimes capable of producing viable seeds, although these were not described in any detail. Recent work at the USDA ARS Aquatic Weed Research Laboratory, Ft. Lauderdale, FL, identified a monoecious biotype of H. verticillata from Penang Island (Malaysia) that is self-fertile and reliably produces viable seed. This biotype may also be crossed with other biotypes including the female dioecious plant from Florida. This work was undertaken to describe the anatomical characteristics of seeds and developing seedlings, using light and electron microscopy.Seeds and seedlings of the Penang Island biotype and Florida X Penang Island cross were processed for light and scanning electron microscopy (SEM). Fixed and fresh material was used. Seeds and seedlings were fixed in 2% paraformaldehyde and 0.1% gluteraldehyde in 0.1M phosphate buffer, pH 7.0. and dehydrated to 100% ethanol.

Growth and Reproductive Physiology of Fluridone-Susceptible and -resistant Hydrilla (Hydrilla verticillata) Biotypes

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 441-445 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
William T. Haller ◽  
Megh Singh
Keyword(s):  
United States ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Reproductive Physiology ◽  
Day Length ◽  
Aquatic Weed ◽  
Environment Protection ◽  
Economic Problems ◽  
Systemic Control

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Several biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Phenotypic measurements were performed during this 1-yr period to monitor differences in growth and reproductive physiology. All fluridone-resistant biotypes (except R3) were growing at the same rate or greater than the susceptible hydrilla. These data suggested that there are no deleterious effects on growth and reproductive physiology because of development of fluridone resistance. Aggressive spread of fluridone-resistant dioecious hydrilla in aquatic ecosystems can severely affect hydrilla management and, consequently, cause substantial and long-lasting ecological and economic problems throughout the southern United States.

scholarly journals Hydrilla verticillata (hydrilla).

2020 ◽  
Author(s):  
Julissa Rojas-Sandoval
Keyword(s):  
Native Plants ◽  
Hydrilla Verticillata ◽  
Aquatic Weed ◽  
Survival Strategy ◽  
Aquatic Habitats ◽  
The World ◽  
Undisturbed Sediment ◽  
The Usa ◽  
Noxious Weed ◽  
Zooplankton Communities

Abstract H. verticillata is a submerged fast-growing aquatic herb. It has a highly effective survival strategy that makes it one of the most troublesome aquatic weeds of water bodies in the world. It has the potential to alter fishery populations, cause shifts in zooplankton communities and affect water chemistry. It forms dense masses, outcompeting native plants and interfering with many uses of waterways. It is readily dispersed by movement of plant fragments and can produce up to 6,000 tubers per m2. Tubers can remain viable for several days out of water or for over 4 years in undisturbed sediment. They are not impacted by most management activities, and a small percentage can sprout throughout the year making the species very difficult to manage or eradicate. It can be spread by water flow, waterfowl and recreational activities and is sold as an aquarium plant. Currently, this species is considered as one of the most aggressive invasive species in aquatic habitats. In the USA it has been listed as a Federal Noxious Weed since 1976, and is regarded as one of the worst invasive aquatic weed problems in Florida and much of the country. Its import is prohibited in Western Australia and Tasmania, and it is on the EPPO alert list.

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