Information

Reason for aquatic plant roots


My question is about why aquatic plants have roots. At first they seem a bit superfluous to me because leaves of the plants could just absorb nutrients directly from the water thereby skipping a need for root function that land plants have to pull nutrients from the soil. I then wonder if nutrient trafficking is the reason for the root system as diffusion may not occur efficiently through thick leaves.


Among terrestrial plants, roots have two major functions - obtaining water (as well as nutrients) and anchoring plants in place. (However, roots may have other important functions as well.) Aquatic plants obviously don't have a problem obtaining water. So roots presumably function primarily as anchors.

There are rootless planktonic plants that float on the surface of water bodies. However, aquatic plants like cattails and water lilies are probably a little more discriminating in their habitat preferences. Imagine a rootless water lily being blown by a hard wind into a patch of water lilies, which block out the sun.


The Planted Tank: Botany: An Introduction to Plant Biology, Part 2: Anatomy of a Plant

Last month I gave a very brief review of botany from a historical perspective. Now that we have an idea of how this field of study developed, let&rsquos look at how we describe plants.

EVOLUTION OF PLANT STRUCTURE

Originally, bacteria known as cyanobacteria or blue-green algae&mdashwhich now sometimes invade our aquariums&mdashdeveloped the ability to photosynthesize. The algae were the next to evolve, and they eventually colonized freshwater environments. The first land plants evolved from freshwater algae (fossils of the spores from these early plants have been used to date this development, believed to have occurred 480 million years ago or more).

Mosses and liverworts, club mosses and horsetails, and ferns&mdashall seedless vascular plants&mdashwere the next to evolve. Seed ferns (plants known by their fossils that may have been the link between the ferns and the seeded plants) and cycads, and the gymnosperms (cone-bearing plants) developed next. About 140 million years ago the first angiosperms appeared these are the vascular, flowering, seeded plants. Their methods of reproduction were far superior to those of the plants that had evolved earlier, and they eventually became the dominant plants that they are now.

Until very recently there was a great deal of debate about the order of evolution and some of the groupings of the angiosperms. The two basic groups of flowering plants are the monocotyledons (monocots) and dicotyledons (dicots). The terms refer to the number of first leaves present (one or two), though there are also other features that distinguish the two. There are some plants, such as the water lilies, that confuse the issue by displaying both monocot and dicot features. Recent evidence from new scientific techniques has helped to clarify the relationships of these plants. It&rsquos now believed that the dicots were in fact the first to develop, and the monocots evolved later from a dicotyledon ancestor.

The different types of plants that have evolved have some similarities and differences in the structure of their growth. The structures of a typical moss, fern, or angiosperm are different, so the various parts of these plants can have different names even if they look similar.

It's much easier to research information on aquatic plants if you're already familiar with the terminology it's an absolute necessity if you're trying to identify a plant using a field guide or dichotomous key. A dichotomous key is a reference that gives a list of numbered paired choices to help you identify a particular organism. You simply choose which statement best describes the organism you're trying to identify, and at the end of that statement will be another number. You go to that number and then are given two more choices. This process repeats until the correct identification is reached.

We see mosses and liverworts in the aquarium quite a bit, and they have both increased in popularity in recent years, with many new mosses and a few new liverworts coming into the hobby. Mosses and liverworts have spores but not the protection of seeds. They&rsquore also non-vascular, which means they don&rsquot have an internal system of vessels to transport water and nutrients. These plants need to be in moist environments to live and reproduce.

Mosses don&rsquot have true roots, though some have rhizoids that look very similar to them. Mosses also don&rsquot have true leaves, though most people (including botanists) call them leaves. The technical term for the leaf-like structures on moss is phyllid. Some liverworts have leaf-like structures, but the liverworts we grow in our aquariums&mdashgenerally Riccia and more recently Pellia&mdashare simpler. These plants don&rsquot really have much in the way of distinctive parts, and their stem and leaf-like structures are called the thallus.

Club mosses, horsetails and ferns are more developed than the mosses and liverworts and have a vascular system. This allows them to grow larger and farther away from their water source. They still have a less developed reproduction system than the seeded plants, though, and they still need water for reproduction.

Water ferns, Java ferns, Bolbitis, Salvinia, and four-leaf clover are some of the common names of the aquatic ferns we grow in our tanks. Ferns have a rhizome and a root. The leaf-like part of a fern is called a frond. Some fronds are specialized to serve different functions for example, what looks like roots hanging down from Salvinia are actually highly modified fronds. The parts of a more typical vegetative frond are: the stipe, which is the lower part of the stem, the rachis, which is the upper part of the stem where the more leafy parts of the fern grow out from, and finally those leafy parts which are called the pinna.

I don&rsquot believe there are any live gymnosperms used regularly in the aquarium, though I have heard of people growing cypress seedlings in open-topped tanks, and some folks use cypress wood in their aquascaping. Gymnosperms develop seeds in cones those most common to us are pine, spruce, and fir trees.

When looking at a plant, the parts we see first are the stems and leaves. The places on the stem where leaves and more stems grow is called a node. When cutting stemmed plants to root, this is also the place where new root growth will appear. The part of the stem in between the nodes is called the internode. When a stem grows along the substrate to form a new plant, then the stem is called a stolon. This occurs in plants such as Vallisneria, Sagittaria, and pygmy chain sword.

The leaf itself includes both the leaf stem, which is called a petiole, and the main part of the leaf, which is the blade or lamina. Leaves that don't have a petiole are called sessile, while those with one are petiolate. At the base of the petiole where it attaches to the stem are also one or more small axillary buds which can grow to form a new branch.

Leaves differ greatly in appearance and are a good first step in recognizing a plant, though some plants (particularly those for the aquarium) can have a very different looking leaf depending on the conditions in which the plant is grown.

An important part of the identification of a plant through the leaf is the pattern of its veins. There are three major venation patterns. In the pinnate pattern a main vein runs down the middle length of the lamina and smaller veins form on each side. Pinnate means that it resembles a feather, but I've always thought it looks like the midsection of a fish skeleton. Another type of venation is called palmate, which refers to the hand and the several large veins radiating from the base of the lamina. Think of a maple leaf and how the veins look like the spread fingers of a hand. The third type of venation is parallel, in which many veins run parallel down the length of the lamina. Parallel venation is a major feature of the monocots.

When looking at the shape of the leaf, the main shape, the shape of the tips and bases, and the shape of the edge of the leaf (called the margin) are considered.

Leaf shapes you&rsquoll see often in aquatic-plant literature include lanceolate (long and tapered at the end like a lance), ovate (egg shaped), oblong (long oval shape with long sides parallel), elliptic (long oval shape with rounded long sides), cordate (heart shaped), and linear (very long and narrow).

Leaf shapes and margins are often mentioned together in literature, although sometimes only one is mentioned if it&rsquos the distinguishing feature of a plant. Entire margins are smooth, serrate margins have a jagged teeth-like edge, and undulate margins are wavy. Oak trees (or in the case of aquarium plants, the Mexican oak plant) is a good example of a lobed leaf margin. Feathery leaves are described as pinnate, pinnatifid, or bipinnate. There are many aquarium plants that have developed these kinds of leaves.

COMPOUND LEAVES AND LEAF ARRANGEMENT

Some plants have multiple leaflets that grow on the petiole instead of single leaves. Plants with a single leaf per petiole are called simple leaves. When they have multiple leaflets they're called compound leaves. You can tell the difference between a compound leaf&rsquos leaflet and a simple leaf by checking where the leaf attaches to the stem. If there is no axillary bud, then it's a leaflet and not a leaf. Compound leaves are pinnate when multiple leaflets grow opposite each other along a modified midvein that looks like a stem. This modified vein is called a rachis. When the end of the pinnate leaf ends in two leaflets, it's called even pinnate and when it ends in a single leaflet it's known as odd pinnate. Bipinnate leaves are further divided with leaflets on branches coming out the sides of the rachis. If four or more leaflets grow attached to the end of a petiole, it has a palmate compound leaf. If there are three leaflets, like in clover, it's called trifoliate.

Leaf arrangement is determined by how many leaves are at each node and how they grow. If there is a single leaf at each node the leaf arrangement is alternate. If there are two leaves at each node, they will grow across from each other and form an opposite leaf arrangement. Whorled leaf arrangements consist of three or more leaves at each node. Rosette plants grow leaves in a circular pattern. It looks like all the leaves are coming from the same place, but they actually have very, very close nodes, with almost no internode between them.

Adding a few more botany terms to your vocabulary can help you in making identification faster and easier. Hopefully it will also help you to have a deeper understanding of how complicated the underappreciated world of plants really is.


Angiosperm Phylogeny Group (2003) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. BotJ Linn Soc 141: 399–436

Arber A (1920) Water Plants: A Study of Aquatic Angiosperms. Cambridge University Press, Cambridge

Campbell R, Drew MC (1983) Electron microscopy of gas space (aerenchyma) formation in adventitious roots of Zeamays L. subjected to oxygen shortage. Planta 157: 350–357

Choi H-K (1985) A Monograph of Vascular Hydrophytes in Korea. Ph.D. thesis, Seoul National University, Seoul

Colmer TD (2003) Long-distance transport of gases in plants: A perspective on internal aeration and radial oxygen loss from roots. Plant Cell Environ 26: 17–36

Colmer TD, Cox MCH, Voesenek CJ (2006) Root aeration in rice(Oryza sativa): Evaluation of oxygen, carbon dioxide, and ethylene as possible regulators of root acclimatizations. New Phytol 170: 767–778

Cook CDK (1996) Aquatic Plant Book, 2 nd ed. SPB Academic Publishing, The Hague

De Bary A (1877) Comparative Anatomy of the Vegetative Organs of the Phanerogams and Ferns. Clarendon Press, Oxford

Evans DE (2004) Aerenchyma formation. New Phytol 161: 35–39

Gunawardena A, Pearce DME, Jackson MB, Hawes CR, Evans DE (2001) Characterization of programmed cell death during aerenchyma formation induced by ethylene or hypoxia in roots of maize (Zea mays L.). Planta 212: 205–214

He CJ, Morgan PW, Drew MC (1996) Transduction of an ethylene signal is required for cell death and lysis in the root cortex of maize during aerenchyma formation induced by hypoxia. Plant Physiol 112:463–472

Hejnowicz Z, Barthlott W (2005) Structural and mechanical peculiarities of the petioles of giant leaves ofAmorphophallus (Araceae). Amer J Bot 92: 391–403

Jackson MB, Armstrong W (1999) Formation of aerenchyma and the processes of plant ventilation in relation to soil flooding and submergence. Plant Biol 1: 274–287

Justin SHFW, Armstrong W (1987) The anatomical characteristics of roots and plant response to soil flooding. New Phytol 106: 465–495

Kaul RB (1971) Diaphragms and aerenchyma inScirpus validus. Amer J Bot 58: 808–816

Kaul RB (1974) Ontogeny of foliar diaphragms inTypha latifolia. Amer J Bot161: 318–323

Kaul RB (1976) Anatomical observations on floating leaves. Aquat Bot 2: 215–234

Kausch AP, Horner HT (1981) The relationship of air space formation and calcium oxalate crystal development in young leaves ofTypha angustifolia L. (Typhaceae). Scan Electron Microsc 3: 263–272

Kawai M, Samarajeewa PK, Barrero RA, Nishiguchi M, Uchimiya H (1998) Cellular dissection of the degradation pattern of cortical cell death during aerenchyma formation of rice roots. Planta 204: 277–287

Lee MO, Hwang JH, Lee DH, Hong CB (2007) Gene expression profile forNicotiana tabacum in the early phase of flooding stress. J Plant Biol 50: 496–503

Les DH, Crawford DJ, Kimball RT, Moody ML, Landolt E (2003) Biogeography of discontinuously distributed hydrophytes: A molecular appraisal of intercontinental disjunctions. Intl J Plant Sci 164: 917–932

Liang F, Shen L-Z, Chen M, Yang Q (2008) Formation of intercellular gas space in the diaphragm during the development of aerenchyma in the leaf petiole ofSagittaria trifolia. Aquat Bot 88: 185–195

Matthews PGD, Seymour RS (2006) Anatomy of the gas canal system ofNelumbo nucifera. Aquat Bot 85: 147–154

Moog PR (1998) Flooding tolerance of Carex species. I. Root structure. Planta 207: 189–198

Pohl RW, Lersten NR (1975) Stem aerenchyma as a character separatingHymenachne andSacciolepis (Gramineae, Panicoideae). Brittonia 27:223–227

Pryer KM, Schuettpelz E, Wolf PG, Schneider H, Smith AR, Cranfill R (2004) Phylogeny and evolution of ferns (Monilophytes) with a focus on the early leptosporangiate divergences Amer J Bot 9: 1582–1598

Ruzin SE (1999) Plant Microtechnique and Microscopy. Oxford University Press, New York

Schenck (1890) Ueber das aërenchym, ein dem kork homologes gewebe bei sumpflanzen. Jahrbücher für Wissenschaftliche Botanik 20: 526–574

Schussler EE, Longstreth DJ (1996) Aerenchyma develops by cell lysis in roots and cell separation in leaf petioles inSagittaria lancifolia (Alismataceae). Amer J Bot 83: 1266–1273

Sculthorpe CD (1967) The Biology of Aquatic Vascular Plants. Edward Arnold Ltd., London

Seago JL (2002) The root cortex of the Nymphaeaceae, Cabombaceae and Nelumbonaceae. J Torrey Bot Soc 129: 1–9

Seago JL, Peterson CA, Enstone DE (1999) Cortical ontogeny in roots of the aquatic plant,Hydrocharis morsus-ranae L. Can J Bot 77: 113–121

Seago JL, Marsh LC, Stevens KJ, Soukup A, Votrubova O, Enstone DE (2005) A re-examination of the root cortex in wetland flowering plants with respect to aerenchyma. Ann Bot 96: 565–579

Soukup A, Seago JL, Votrubova O (2005) Developmental anatomy of the root cortex of the basal monocotyledon,Acorus calamus (Acorales, Acoraceae). Ann Bot 96: 379–385

Thomas AL, Guerreiro SMC, Sodek L (2005) Aerenchyma formation and recovery from hypoxia of the flooded root system of nodulated soybean. Ann Bot 96: 1191–1198

Tomlinson PB (1982) Anatomy of the Monocotyledons. VII. Helobiae (Alismatidae). Clarendon Press, Oxford

Visser EJW, Bögemann GM, Steeg HMVD, Pierik R, Blom CWPM (2000a) Flooding tolerance of Carex species in relation to field distribution and aerenchyma formation. New Phytol 148: 93–103

Visser EJW, Colmer TD, Blom CWPM, Voesenek LACJ (2000b) Changes in growth, porosity, and radial oxygen loss from adventitious roots of selected mono- and dicotyledonous wetland species with contrasting types of aerenchyma. Plant Cell Environ 23: 1237–1245

Williams WT, Barber DA (1961) The functional significance of aerenchyma in plants. Symp Soc Exp Biol 15: 132–144


Pond plants are a vital part of a balanced aquatic ecosystem

Plants in your pond balance your pond’s ecosystem. Aquatic plants offer food, shelter and environment for fish in ponds.

Michigan has thousands of natural ponds, vernal pools and wetlands where plants perform a specific role in those ecosystems. Understanding the important role of pond plants in Michigan before seeking plant removal management makes dealing with problem s situations easier. Plants are a problem when they interfere with the intended use of the pond. This is particularly true with ponds constructed for a specific purpose such as ponds for sport fishing. Plants play a key part in the natural pond and the constructed pond.

The presence of aquatic plants in ponds are vital to maintaining a balanced ecosystem. Aquatic plants come in a four specialized types in the pond. Forming the base of the food chain for almost all life in the pond, they produce dissolved oxygen in the water and serve as protection for small fish and invertebrates. Their roots hold the soil in place.

The four categories of aquatic plants are:

  1. Submerged: Plants that thrive under water that have roots in the soil at the bottom (pond weed and bladderwort)
  2. Floating: Plants that float at or near the water surface and have either floating roots or roots in the soil at the bottom (duckweed and lily pads)
  3. Emergent: Plants that is rooted in the soil under water, but the larger part of the plant is above water (arrowhead, rushes and cattails)
  4. Shoreline: plants that prefer the shore, but can take being moist and flooded seasonally. (blue flag iris, some shrubs and trees)

Aquatic plants benefits include:

  • Algae control. Plants absorb nutrients in the water from fish waste and reduces nutrient availability slowing algae blooms.
  • Shade and protection for fish. Plants can provide a hiding place for fish from predators both above and below the water. Additionally, plants shade the water reducing the amount of sunlight entering the water helping to slow algae blooms.
  • Food for fish and other wildlife. Fish, turtles, insects, ducks and geese and some mammals feed on aquatic plants.
  • Improved water quality. Many water plants not only absorb nutrients from the water, they also absorb pollutants and heavy metals too.
  • Erosion control. Emergent and shoreline plants often have very large root structures. This enables them to reduce wave action and stabilize the shore creating the most effective erosion control you can get in a pond.
  • Aquatic plants in the pond improves its aesthetics. Many emergent and Shoreland plants offer four seasons of interest at the pond providing attractive flowers, interesting structure, color and depth.

There are many native plants that offer a great variety of choices for managing your natural pond. They range from grasses, rushes and reeds to lily pads, iris, pickerel plant and arrowhead to shoreline shrubs and trees. Careful planning of your pond management including planting will go a long way to ensuring a balanced natural pond system. Avoid introducing non-native and invasive plants into your pond. When managing the plants in your pond, consider the role of the plant before considering its removal. If you have excessive plant growth, there may be a nutrient overloading issue that must be addressed first.

For more information about the aquatic plants and invasive species contact Beth Clawson, MSU Extension Educator. To learn more about invasive organisms and invasive aquatic plants contact Michigan State University Extension Natural Resources educators who are working across Michigan to provide aquatic invasive species educational programming and assistance. You can contact an educator through MSU Extension&rsquos &ldquoFind an Expert&rdquo search tool using the keywords &ldquoNatural Resources Water Quality.&rdquo


Reason for aquatic plant roots - Biology

Native to: India (Hydrilla verticillata’s dioecious type originates from southern India. Hydrilla’s monoecious type is probably from Korea)

Hydrilla was introduced into Florida water bodies in 1950-1951. It was thought to have been introduced to the Tampa and Miami areas as an aquarium plant. By the 1970s, it was established throughout Florida waters and in most drainage basins. Hydrilla can grow to the surface of waters as deep as 25ft and form dense mats and can still be found in all types of water bodies.

Species Characteristics

  • Family: Hydrocharitaceae
  • Habit: submersed aquatic, profusely branched, herbaceous perennial with stems up to 20 ft long obligate wetland plant
  • Leaves: small strap-like, pointed whorled, saw-toothed
  • Flowers: (Florida biotype) female flowers only solitary, tiny, white, float on the surface threadlike stalks attached at leaf axils near the stem tips
  • Reproductive parts: turions (“buds” in some of the leaf axils), dark green, cylindrical, to 1/4 in. round. Subterranean turions (“tubers”) yellowish, potato-like, attached to the root tips in the hydrosoil, to 1/2 in. long, 1/2 inch broad readily reproduces by fragments single tuber can grow to produce more than 6,000 new tubers per square m
  • Seeds: Florida biotype does not produce
  • Distribution in Florida: statewide

Impacts

Hydrilla has widescale impacts in Florida waters and is highly adaptable to a variety of growing conditions. It can grow in almost any freshwater system including springs, lakes, marshes, ditches, rivers and tidal zones. Hydrilla can grow in water as shallow as a few inches and up to 20 feet deep. It can grow in as little as 1% of full sunlight.

Hydrilla continues to be sold through aquarium supply dealers and over the internet, despite being a Federal Noxious Weed and a Florida Prohibited Aquatic Plant. Each stem on a Hydrilla plant can grow 1-4 inches per day. Therefore, when hydrilla invades water bodies, ecologically-important native submersed plants such as pondweeds (Potamogeton spp.), tapegrass (Vallisneria americana) and coontail (Ceratophyllum demersum) are shaded out by hydrilla’s thick mats, or are simply outcompeted and eliminated.

Each year in Florida, millions of dollars are spent on herbicides and mechanical harvesters in an effort to place hydrilla under “maintenance control.” Without management, hydrilla slows water flow and clogs irrigation and flood-control canals and interferes with boating (both recreational and commercial) and prevents swimming and fishing. Dense infestations can alter water chemistry and dissolved oxygen levels.

Hydrilla is a prohibited plant and therefore, not recommended by UF/IFAS. Hydrilla is a prohibited plant according to the USDA Noxious Weed List and the Florida Prohibited Plant List. The UF/IFAS Assessment lists Hydrilla as prohibited. It is listed by FLEPPC as a Category l invasive species due to its ability to invade and displace native plant communities.

Control Methods

Avoid introducing hydrilla into water bodies. Use best practices to prevent introduction by cleaning boat trailers, propellors, diver gear and live bait wells. Transporting plant fragments on boats, trailers, and in livewells is the main source of introduction into new lakes and rivers. Do not use hydrilla in aquariums or ornamental ponds. Opt for native submersed aquatic plants such as, sago Pondweed (Potamogeton pectinatus), bladderwort (Utricularia floridana), coontail (Ceratophyllum demersum), fanwort (Cabomba caroliniana) or southern naiad (Najas guadalupensis).

Small infestations of Hydrilla may be removed either manually or using hand tools, such as a rake. In some cases, lake drawdowns may help manage hydrilla by letting the exposed plants die and decompose.

Mechanical harvestors can be used to remove hydrilla from the water and transport it to shore for disposal. One drawback in the use of mechanical harvesters is that cuttings of hydrilla, which are not removed from the water, help to spread this weed.

Currently, four insects and one fish have been released to control hydrilla, but only two of these insects are established, and only one is commonly associated with hydrilla in the southeastern U.S. Click here to learn more.

Several registered aquatic herbicides provide temporary control of hydrilla. See: Efficacy of Herbicide Active Ingredients Against Aquatic Weeds to learn more.


How to Use Root Tabs

Because root tabs are water soluble, the key is to insert them into the substrate as quickly and deeply as possible. It’s okay if Easy Root Tabs accidentally pop out or get unearthed by your fish because they won’t harm the water quality, but ultimately, we want the root feeders to have access to more nutrients in the ground. Therefore, use planting tweezers or your fingers to push the whole root tab to the bottom of the substrate. (Do not remove the fertilizer from the capsule or else it will dissolve in the water column.)

Plunge the root tab as deeply as possible into the substrate, preferably underneath the roots of plants.

How many root tabs should you use? Place one tab approximately every 5-6 inches (12-15 cm) in a grid so that they cover the entire substrate. If your fish tank is very densely planted, you may need to add root tabs every 4 inches (10 cm) or closer. Ideally, the root tabs should be inserted directly underneath or near the roots of your plants. In fact, larger plants like Amazon swords may need multiple root tabs placed in a circle around their base to keep them well fed.


Additional Resources

Websites

Center for Aquatic Plants, University of Florida Institute of Food and Agricultural Sciences—http://aquat1.ifas.ufl.edu/

A wide variety of free and for-sale products and services are available including:

Online Newsletter: "Aquaphyte" news of interest to teachers, students and others: http://plants.ifas.ufl.edu/node/498

Online Book: "Identification and Biology of Non-Native Plants in Florida's Natural Areas": http://plants.ifas.ufl.edu/node/646

Additional materials available:

Photographs and Descriptions of Aquatic and Wetland Plants - 12 online: http://plants.ifas.ufl.edu/node/22

Line Drawings of Aquatic and Wetland Plants - 65 online: http://plants.ifas.ufl.edu/linedrawings

Management Methods for Controlling Unwanted Aquatic Plants: http://plants.ifas.ufl.edu/node/673

Online Aquatic and Wetland Plant Database: http://plants.ifas.ufl.edu/APIRS/

Bibliography of Aquatic and Wetland Plant Manuals, Field Guides, and Textbooks: http://plants.ifas.ufl.edu/node/490

University of Florida Herbarium, Florida Museum of Natural History—http://www.flmnh.ufl.edu/natsci/herbarium/

Materials and services available:

Bibliography of literature useful to the study of Florida plants: http://www.flmnh.ufl.edu/herbarium/bib/

Generic Flora of the Southeastern United States project: http://www.flmnh.ufl.edu/herbarium/genflor/

Herbarium Library - Search the books and reprints catalog: http://www.flmnh.ufl.edu/herbarium/lib/

Local Flora: Vascular Plants of North Central Florida: http://www.flmnh.ufl.edu/herbarium/locfl/

Preparation of plant specimens for deposit as herbarium vouchers: http://www.flmnh.ufl.edu/herbarium/voucher.htm

Florida Department of Environmental Protection—http://www.dep.state.fl.us/

The website for the Florida Department of Environmental Protection contains a large amount of useful information for youth and youth leaders interested in environmental education. Online publications about topics specific to aquatic and marine ecosystems include:

Welcome to 4-H2Online—a community for youth to learn about water quality, water conservation and watershed issues. Throughout this site you'll find 4-H's "Exploring Your Environment" Grab-n-Go's and information on how youth nationwide are addressing water issues in their communities. Get started by watching the podcast series "A Day Without Water" to learn more about how you can make an impact in your community!

Florida Sea Grant—Marine education resources—https://www.flseagrant.org/

Florida Sea Grant provides marine education programs to formal and nonformal educators and works closely with the 4-H marine education program. Their website provide links to publications, curricula, lessons, and other educational sites and resources.

Florida Marine Science Educators Association—http://www.fmsea.org/

FMSEA is a professional association of individuals and organizations devoted to the cause of marine education in Florida. They provide workshops and conferences plus a quarterly newsletter that often highlights teaching aids and classroom resource lists.

Careers in Florida's Freshwater Environments

This fast-paced musical DVD and companion booklet introduces middle school students to the many occupations needed to protect and preserve our lakes, rivers and wetlands. Included are introductions to jobs in wildlife, fisheries, plants, water chemistry, recreation, information, and teaching. Some occupations require a high school education, some require college, but emphasis is placed on the fact that all jobs require that students learn what they are studying in school right now. (IFAS Catalog No. DVD 1236)

Aquatic Plant Identification Series

This four-disc DVD set was created for the benefit of aquatic plant managers, regulators, students and the general public, and uses everyday language to identify aquatic plants in Florida. (IFAS Catalog No. DVD 084)

Disc 1: Floating and Floating-leaved Plants󈟬 minutes

Disc 2: Emersed Plants󈠡 minutes

Disc 3: Submersed Plants󈠎 minutes

Disc 4: Grasses, Sedges, and Rushes� minutes

Florida's Aquatic Plant Story

Produced for general public audiences, this consumer-oriented DVD describes the benefits of native aquatic plants and recounts problems caused by some exotics. Introduces the major methods of aquatic plant management. 24 min. (IFAS Catalog No. DVD 1238)

What Makes a Quality Lake?

Produced for secondary school students and general public audiences, this program explains the meaning of "Lake Eutrophication." Featuring limnologist Dr. Daniel Canfield, viewers learn about the natural and human factors that help determine a lake's "trophic state". Viewers also learn the differences between oligotrophic, mesotrophic, eutrophic and hypereutrophic lakes in terms of water clarity, algae, higher plants and fish. 1992. 24 min. (IFAS Catalog No. DVD 1237)

This video is an introduction to Florida Lakewatch, an organization of citizen volunteers who monitor the water quality of lakes, rivers and bays. 1993. 12 min. (IFAS Catalog No. VT-438)

Other Resources

Aquatic and Wetland Plant Identification Cards are from the University of Florida Aquatic and Wetland Plant Information Retrieval System (APIRS). A "deck" of 3" x 4" aquatic plant identification cards for in-the-field use. Color photographs and identification information on 67 aquatic and wetland plants is included in the Aquatic Plant Identification Deck. The water resistant laminated cards are held together by a metal post, allowing for quick and easy comparisons between the ID cards and the plants needing identification. List of plants featured in ID Deck. The ID Deck may be purchased for $10.00, plus tax and shipping and handling, from UF/IFAS Publications, PO Box 110011, Gainesville, FL, 32611-0011, 352-392-1764. The UF/IFAS Catalog number of the ID deck is Publication Number SM-50.

Freshwater Plants Poster features 63 aquatic and wetland plants in a typical natural setting. The poster shows the common and scientific names of the plants, is in full-color and is 2 ft. x 3 ft. in size. It is suitable for framing or tacking to the wall. Teachers in Florida may obtain the poster for free. This office has already given away 10,000 copies to teachers, libraries, environmental agency trainers, etc. If you would like to receive a free copy, please contact the APIRS office by e-mail or contact: APIRS, Center for Aquatic Plants, 7922 NW 71 Street, Gainesville, FL, 32653, 352-392-1799. For everyone else, the poster costs $7.00 each plus tax and shipping and handling. To order, contact: UF/IFAS Publications Office, University of Florida, PO Box 110011, Gainesville, FL, 32611-0011, 352-392-1764. The UF/IFAS Catalog number of the poster is Publications Number SM-51.


Tiny aquatic plant offers clues that could enable development of next-generation crops, Salk researchers say

Wolffia, also known as duckweed, is the fastest-growing plant known, but the genetics underlying the strange little plant’s success have long been a mystery to scientists. Now, thanks to advances in genome sequencing, researchers are learning what makes the plant unique and, in the process, are discovering some fundamental principles of plant biology and growth.

An effort led by scientists from the Salk Institute for Biological Studies in La Jolla is providing new findings about the plant’s genome that explain how it’s able to grow so fast.

The research, published in the February issue of Genome Research, will help scientists understand how plants make trade-offs between growth and other functions, such as putting down roots and defending themselves from pests.

The research has implications for designing new plants that are optimized for specific functions, such as increased carbon storage to help address climate change.

“A lot of advancement in science has been made thanks to organisms that are really simple, like yeast, bacteria and worms,” said Todd Michael, first author of the paper and a research professor in Salk’s Plant Molecular and Cellular Biology Laboratory. “The idea here is that we can use an absolutely minimal plant like Wolffia to understand the fundamental workings of what makes a plant a plant.”

Wolffia, which grows in fresh water on every continent except Antarctica, looks like tiny floating green seeds, with each plant the size of a pinhead. It has no roots and only a single fused stem-leaf structure called a frond. It reproduces similar to yeast, when a daughter plant buds off from the mother. With a doubling time of as little as a day, some experts believe Wolffia could become an important source of protein for feeding Earth’s growing population. (It is already eaten in parts of Southeast Asia, where it’s known as khai-nam, which translates as “water eggs.”)

To understand what adaptations in Wolffia’s genome account for its rapid growth, the researchers grew the plants under light/dark cycles, then analyzed them to determine which genes were active at different times of the day. (Most plants’ growth is regulated by the light and dark cycle, with the majority of growth taking place in the morning.)

“Surprisingly, Wolffia only has half the number of genes that are regulated by light/dark cycles compared to other plants,” Michael said. “We think this is why it grows so fast. It doesn’t have the regulations that limit when it can grow.”

The researchers also found that genes associated with other important elements of behavior in plants, such as defense mechanisms and root growth, are not present. “This plant has shed most of the genes that it doesn’t need,” Michael said. “It seems to have evolved to focus only on uncontrolled, fast growth.”

Joseph Ecker, a co-author of the paper who is an investigator with the Maryland-based Howard Hughes Medical Institute and director of Salk’s Genomic Analysis Laboratory, said: “Data about the Wolffia genome can provide important insight into the interplay between how plants develop their body plan and how they grow. This plant holds promise for becoming a new lab model for studying the central characteristics of plant behavior, including how genes contribute to different biological activities.”

One focus of Michael’s lab is learning how to develop new plants from the ground up so they can be optimized for certain behaviors. The current study expands knowledge of basic plant biology as well as offers the potential for improving crops and agriculture.

By making plants better able to store carbon from the atmosphere in their roots — an approach pioneered by Salk’s Harnessing Plants Initiative — scientists can optimize plants to help address the threat of climate change.

Michael plans to continue studying Wolffia to learn more about the genomic architecture of plant development. ◆

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Reason for aquatic plant roots - Biology

Origin: Brazil, Argentina, Paraguay

Introduction to Florida: 1840s (Ornamental)

The family Anacardiaceae contains poison ivy, poison oak, poison sumac, and Schinus terebinthifolius, or Brazilian peppertree. People sensitive to poison ivy, oak or sumac may also be allergic to Brazilian pepper tree because it also has the potential to cause dermatitis to those with sensitive skin. Some people have also expressed respiratory problems associated with the bloom period of pepper tree.

Species Characteristics

Brazilian peppertree is a shrub or small tree that reaches over 30 feet in height, typically with a short trunk hidden in a thicket of branches. Some trees can live over 30 years. The leaves are alternately arranged with 1-2 inch long, elliptic, and finely toothed leaflets. The leaves are also reddish, often possessing a reddish mid-rib. The flower clusters are white and 2-3 inches long with male and female flowers that look very similar. The glossy fruits are borne in clusters that are initially green, becoming bright red when ripe. Seeds are dark brown and 0.3 mm in diameter. Flowering occurs from September through November and fruits are usually mature by December.

Impacts

This shrub/tree is one of the most aggressive and wide-spread of the invasive non-indigenous exotic pest plants in the State of Florida. There are over 700,000 acres in Florida infested with Brazilian peppertree. Brazilian peppertree produces a dense canopy that shades out all other plants and provides a very poor habitat for native species. This species invades aquatic as well as terrestrial habitats, greatly reducing the quality of native biotic communities in the state.

Control Methods

The public should be notified to avoid cultivating, transplanting, or promote proliferation of Brazilian pepper. Care should also be exercised to avoid seed spread through disposal of cut trees. Due to its invasive nature, it is placed by the Florida Department of Environmental Protection under section 62C-52.011 as a Class I -“Prohibited Aquatic Plant.” This law prohibits sale and or movement of this species.

A well established native cover or plant community is a way to suppress Brazilian peppertree. However, the rapid growth and high germination rates make Brazilian pepper-tree difficult to suppress from a cultural weed management standpoint.

When utilizing aggressive mechanical methods, the entire plant, particularly the root system, should be removed. Roots ¼ inch in diameter and larger are able to resprout and produce new plants, so follow-up from this type of control method will be necessary. Pepper-tree seeds cannot tolerate heat and will not germinate following a fire, but the plant has the potential to resprout after a fire from roots.

Two biological control agents are currently approved for use for Brazilian peppertree control in Florida, Pseudophilothrips ichini (Brazilian peppertree thrips) and Calophya latiforceps (Yellow Brazilian peppertree leaf galler). Both insects attack the growing shoots of Brazilian peppertree and can impact the growth of the plant. Research has shown that these insects are specific to Brazilian peppertree and are safe to use in Florida to control this invasive weed. Releases of the Brazilian peppertree thrips is ongoing in Florida and releases of the yellow Brazilian peppertree leaf galler are planned for the future.

Chemical methods for Brazilian peppertree control can be separated into soil residual, foliar and basal bark/cut stump treatments. Each of these will be discussed in detail in the following sections.