Curlyleaf pondweed forms thick monospeciﬁc beds. The dense growth out-competes native aquatic vegetation, degrades lake water quality, and causes problems to navigation and recreation Signiﬁcant time and resources are dedicated every year to the management of curlyleaf pondweed in the Midwest. Problem: management efforts are often applied without taking into account the plant ’s biology and ecology= inefﬁcient or ineffective control.
So going to understand a bit biology! … need to understand the primary energy structure of Curlyleaf Pondweed. The primary structure for energy storage is the turion.--- a vegetative propagule that is its main reproductive means The majority of a turion is comprised of carbohydrates used for germination While the outer casing is designed for protection while in dormancy Turion itself can photosynthesize. Factor ’s of Turion invasiveness… easily dispersed by water currents Turions have a very high germination rate Turions remain viable in sediment for a number of years On top of their main means of reproduction… turions Curlyleaf Pondweed can colonize in deep and shallow water Its strong rhizome anchoring system allows it to grow in a variety of different locales and sediment types Plant can tolerate extreme conditions Extreme conditions: low light and cold temperatures Found growing under 20 inches of snow covered ice Plants will grown from rhizomes of past plants
Understand that The major advantage for P. crispus is its life cycle that produces carbohydrate storage organs known as turions, assisting growth during the winter months Turions sprout as a response to both light and temperature conditions. Germination : Innate dormancy in summer and growth is blocked Dormancy is broken by short days and low temperatures Turions remain dormant in the sediment through summer until cooling water temp triggers germination in the fall Start growing under ice…Sprouted turions can remain dormant under the ice accelerated growth continues with the onset of early spring, when light and temperature conditions are best suitable for growth. By late spring in Minnesota, culrlyleaf is at its maximum phase of growth By mid summer, the warm water conditions cause Curlyleaf to senesce or age, dropping turions to the substrate while the rest of the plant rots. The release of nutrients by senescing Curlyleaf can cause problems with water quality (such as depletion of O2), and may further hinder native macrophyte growth Curlyleaf out competes native Minnesota plants primarily because of its early season maturation ---its at its peak growth when most plants start growing So it is not that P. Crispus produces turions… other plants do that ,,, it is the lifecycle that makes it unique : It is that the turions are a bonus to CPondweed lifecycle
GRAPH B Turion sprouting in and plant growth occurred in mid September 2001 and mid October 2002, followed by little or no growth during ice-covered conditions. Growth resumed in early spring – generally speaking--- peak growth mid May and June. Peak biomass occurred at or near the time of peak turion production and plant senescence and summer dormancy soon followed.
Where to start? At most vulnerable point! this point the plant is the least capable of recovering from stress or disturbance, indicating the point where the success of management efforts will be maximized. Previous studies have shown… In other words… Low points of carbohydrate storage or the seasonal minimum of stored carbohydrates indicate potentially vulnerable periods in the plant ’s life cycle =and may be the ideal time to initiate man- agement and control efforts. Exploiting these low points can lead to improved control of the target species (Madsen 1993a).
2 goals… how herbicides affecting turion viability… Difference between treated and untreated
Turions were randomly collected from Duck Lake and two other non-treated lakes (Ballantyne Lake and West Jefferson)
Plant samples were analyzed for total nonstructural carbo- hydrates (TNC) in herbicide/non-herbicide treated Potomogeton crispus turions using a procedure called “Colorimetric Methods for Determination of Sugars” previously cited by Michel Dubois, K.A. Gilles, J.K. Hamilton, P.A. Rebers and Fred Smith (1955). The dried biomass of turion samplings were separated in to four separate entites Turions from West Jefferson Duck lake treated Duck lake untreated Lake ballentyne
The procedure involves extracting sugars using 80% EtOH from weighted Potomogeton crispus turions, Each of the turions ground and weighed at 25 mg Starch Digestion: hydrolyzing starch to glucose Digestive enzyme mixture a-amlylase + amyloglucosidase) Sugar analysis: measuring glucose hydrolysate (allocated carbohydrate) of each Potomogeton crispus turion. Samples were analyzed using spec at wavelength 450nm. Percent TNC dry weight and standard error were calculated for each plant component. Data combined for each turion sample batch (WJ, BL, DL_U, DL_T). Total TNC storage (g m -2 ) was calculated for turions TNC Data analysis. One- way Anova= Take all samples and tell us if there is a difference or not. Post hoc is going tell us which one is different…and on Sigma Plot..post Hoc is a Dunn ’s method explanation
Explain X and Y axis’ --- GRAPH 333… took from different areas. WJ, BL, DL and then within DL… Untreated and treated areas. Compared all of them based on their average grams of Turion Total Nonstructural Carbohydrates/ m2. What do we see? DT areas are significantly different from areas in two control lakes: WJ and BL, AND other untreated areas within Duck Lake itself. DT turions have significantly less turion TNC … .This tells us that herbicide (endothal) is having some affect on turions in DT area. In DT areas there is a significant decrease in the turions ability to conserve energy for growth. Conseq. treatments of endothall has not allowed new sprouts from existing turions to survive or new turions doesn’t allow new turions to start growing Endothall main job = disturb growth & photosynth of CLP… b/c plant can’t photosynth going to pull more carbohydrates from itS main carbohydrate storage organ= TURION! Although we expect a decrease in CLP’s TNC from the endothall’s killing plant portion (new CLP sprouts)… we see an even greater decrease in DT areas b/c Spraying in Spring effectively takes away CLP’s competitve advantage as an invasive species: It’s Lifecycle!! Endothall and the timing of it’s application takes CLP’s main competitve advantage, it’s lifecycle, and turns it against itself. So what’s going on… Turion is trying to put all energy into growth of new plant- to allocate all it’s carbohydrates to photsynthesis right when ice is off! After Winter…. THERFORE: Hit it w/ herbicide- early Spring after Ice is off- and @ same time turion is putting all energy into growth of new plant--- Herbicide- Endothal= job is to get rid of new sprout… but it indirectly ends up taking carbohydrate reserves of turion that are now being allocated to new sprout Since 2006, the Duck Lake association has been applying endothall in attempts to reduce P. crispus and re-establish native plant communities. Current field research on multiple lakes has observed weak and discolored turions, particularly on lakes treated with herbicide. Zach, grad assitant, when he took samples from duck lake treated areas… noteiced weak and dark colored turions
EXPLAIN AXIS’’’’’ count of number/ m2 WJ increase density because has more CLP …versus BL You’d exped decrease turion density in DT… hurting plant ;;;;; decrease in turions BUT CLP is still producitng turions… just diff. turiions! Think about the lifecycle.. Normally increase in turion carb storage after plant ages… and turion is dropped…. Decreases turion carb storage in winter when ice is one… b/c clp starts to grow. Turion is allocating its carb not storing DT density not changed b/c still producting turions… it’s just that they are weaker… But they can still photosyn. DECREASE in TNC but not in density! We need to base management plant on this change….
Turions give up most of their energy (carbohydrates) to sprout after after Winter ice is off of lakes. Endothall when in contact with new Culyleaf Pondweed sprouts takes up most of turion energy (carbohydrates) at it’s peak carbohydrate allocation time--- after Winter. Turion carbohydrate storage reserves are indirectly depleted when endothal, a contact herbicide, is applied to and depletes new Curlyleaf Pondweed turion sprouting at the end of Winter/early Spring. It is possible that endothall effectively counterattacks Curlyleaf Pondweed’s lifecycle, which is it’s competitve advantage. Pic of turion being formed.. Apical meristem– vegetatvie bud
Carbohydrate Allocation Patterns in SouthernMinnesotaHerbicide (endothal) treated CurlyleafPondweed(Potomogeton crispus)PopulationsErika Magnusson, Zach Gutknechtand Dr. Christopher Ruhland, PhDBiology DepartmentMinnesota State University, Mankato
PlantWise et al 2013Frank Koshere et al. nd.•Curlyleaf pondweed is the most widely-dispersed nuisance-formingnon-native submersed aquatic plant in the state of Minnesota.•Native to Europe and Asia, curlyleaf pondweed is now thoroughlynaturalized in North America.
P. crispus Turion Biology• Ridged organs that provide:– Protection against frost– Store carbohydrates used for germination– Can photosynthesizePeterson, M. et al 2003Crow Wing Lakes Association et al. 2010
• Ideal time to initiate management and control efforts• Carbohydrate Low Points• Carbohydrate utilization from storage exceedscarbohydrate productionPlant Life Cycle Vulnerable Periods
My research is attempting to assess if endothallcan effectively control P. crispus turions bydecreasing carbohydrate concentrations.Purpose of Study
1. To analyze the effect of endothal on turionviability by measuring turion Total NonstructuralCarbohydrate concentrations (g/ m^2)1. Analyze the difference:• Between treated and untreated areas withinDuck Lake and untreated areas of WestJefferson Lake, and Lake BallantyneGoals of This Study
Ballantyne LakeDuck LakeWest Jefferson LakeStudy Lakes
“Colorimetric Methods for Determination of Sugars”previously cited by Michel Dubois, K.A. Gilles, J.K.Hamilton, P.A. Rebers and Fred Smith (1955).• West Jefferson• Duck Lake treated• Duck Lake untreated• Lake BallantyneProcedure
Method Procedure1. Extraction: Ethanol (EtOH) method2. Starch Digestion: a amlyase- amyloglucosidasemethod3. Sugar analysis with a peroxidase-glucoseoxidase/odianisidine reagent (PGO)• One-way Anova and the Post-Hoc is a Dunn’s method
Conclusions• It is possible that endothal is affective at decreasing CurlyleafPondweed turion TNC• Future Research: Endothal affect on Curlyleaf Pondweed turionitself and not just the plant portion.– Noticed that turions collected had less ridigity (were softer) in DuckLake treated areas than DU, WJ and BL– Does endothal prevent nutrient sources from forming in Turions?
Bibliography• Crow Wing Lakes Association. (2010, April 29). Curly Leaf Pondweed. In TheWebsite of the 10th and 11th Crow Wing Lakes Association. Retrieved April14, 2013, from crowwing11.org• Koshere, F. (Photographer). Potamogeton crispus curly pondweed growing inBone Lake, Wisconsin. [Image of photograph]. Retrieved April 14, 2013, fromhttp://bioweb.uwlax.edu• Peterson, M. (2003, May). Mature turions (seeds) that washed to shore. InCurly Leaf Identification. Retrieved April 14, 2013, fromhttp://www.lakeorono.org/CurlyleafID.pdf• Wolf, T. E., & Madsen, J. D. (2003). Seasonal biomass and carbohydrateallocation patterns in Southern Minnesota curlyleaf pondweed populations. J.Aquat. Plant Manage, 41, 113-118.• (2013). Europe; CABI. Retrieved April 14, 2013, fromhttp://www.plantwise.org/
Acknowledgements• Zachrie Gutknecht• Christopher Ruhland, PhD• Undergraduate Research Center-MinnesotaState University, Mankato