rhizome
Aquarium Plant Glossary
By Robert Paul Hudson
Adventitious plant
plantlets that develop asexually from a parent plant: a rooted plantlet forming on a part of the mother plant
Alkaline earths
earth metals, calcium, magnesium, barrium, strontium, and their mineral salts
Alternate
single leaves placed alternately on either side of the stalk
Amphibious
able to exist either on land or in the water
Anaerobic
occurring in an environment that lacks oxygen
Angiosperm
a group of plants whose seeds are borne within a matured ovary
Aquatic
growing in water
Asexual reproduction
any form of reproduction that does not require the union of male and female reproductive material
Axil
the junction of the leaf or petiole and the stem
Axillary
arising from the above junction
Biogenic decalcification
When there is a carbon dioxide deficiencey in the water, plants can derive CO2 from the hardening constituents of the carbonate hardness. First they split the hydrogen carbonates into CO2 and carbonates. This causes the pH to rise about one step and the largely insoluable carbonates precipitate and form rough deposits on the leaves and substrate. Some plants such as Vallisneria can even destroy the carbonates and obtain CO2 from them. This raises the pH again by another step. Biogenic decalcification thus causes the water to be 10 to 100 times more alkaline than it was previous. In the dark, the process reverses and the pH drops considerably. Thus these continous large pH swings can pose a significant risk to the well being of fish and animals. The solution is to add enough CO2 to the water and have a significant carbonate level to act as a buffer.
Bipinnate
leaf formed of several leaflets set on either side of the petiole
Bract
specialized scale-like leaf found at the base of a flower
Bullate
blistered, bubbled or puckered in appearance
Bulb
tightly packed fleshy leaves used as a storage organ. Onions and tulips both have bulbs
C
Cation Exchange Capacity (CEC)
Quantifies the ability of media to provide a nutrient reserve for plant uptake. It is the sum of exchangeable cations, or positively charged ions, media can adsorb per unit weight or volume. It is usually measured in milligram equivalents per 100 g or 100 cm3 (meq/100 g or meq/100 cm3, respectively). A high CEC value characterizes media with a high nutrient-holding capacity that can retain nutrients for plant uptake between applications of fertilizer. Media characterized by a high CEC retains nutrients from leaching. In addition, a high CEC provides a buffer from abrupt fluctuations in media salinity and pH. Important cations in the cation exchange complex in order of adsorption strength include calcium (Ca2+) > magnesium (Mg2+) > potassium (K+) > ammonium (NH4+), and sodium (Na+). Micronutrients which also are adsorbed to media particles include iron (Fe2+ and Fe3+), manganese (Mn2+), zinc (Zn2+), and copper (Cu2+). The cations bind loosely to negatively charged sites on media particles until they are released into the liquid phase of the media. Once they are released into the media solution, cations are absorbed by plant roots or exchanged for other cations held on the media particles. Anion exchange capacity Some media retains small quantities of anions, negatively charged ions, in addition to cations. However, anion exchange capacities are usually negligible, allowing anions such as nitrate (NO3-), chloride (Cl-), sulphate (SO4-), and phosphate (H2PO4-) to leach from the media.
Chelators
synthetic organic acids that bind with various trace elements to keep them available in a form that is usable by the plants
Chlorophyll
the pigment that makes plants green. One of the pigments necessary for photosynthesis
Chlorosis
loss of chlorophyll, often a sign of insufficient amounts of iron
Compound leaf
a leaf that is divided into several distinct leaflets
Cordate
heart shaped
Cosmopolitan
found worldwide
Crenate
edged with rounded teeth
Crispate
with wave margins
Cultivar
a man-made (cultivated) variety
Cuticle
the thin skin of the plant. This is thicker and waxy to maintain moisture in emersed growth
Cutting
a fragment of plant material that is capable of growing to become another complete, individual plant
D
Decussate
opposite pairs of shoots set at right angles to the pairs above and below
Denticulate
serrated, edged with small teeth
Distichous
leaves arranged in two rows on either side of the stem
Division
a method of propagation in which the rhizome or vegetative cone is cut into pieces, each of which is capable of becoming a complete new plant
E
Emersed
grown so that the roots and bottom portion of the plant are underwater, rest of the plant grows above the water
Epiphytic
plant that grows on another plant but is not parasitic
Endemic
a species found only in one specific location
Eutrophic
rich in dissolved nutrients, often caused by pollution
F
Filiform
thread like
Frond
the “leaf” of a fern
G
H
Hastate
with two out-turned lobes at the base
Herbivore
plant eater
Hybrid
the offspring of two parents of different species or varieties
Inflorence
flower cluster
Internode
the area between two nodes on a plant stem
J
K
Laminae
broad part of the leaf usually attached to the stalk by the petiole. Also called the blade
Lanceolate
spear shaped
Laterite
an iron-bearing red soil found in tropical areas. Formed by centuries of heat and rain
Leaflet
one part of a compound leaf
Linear
long, narrow, grass-like or strap-like leaf
M
Macronutrients
Nutrients used by plants in relatively large amounts. They are nitrogen (N), phosphorus (P), sulfur (S), calcium (Ca), magnesium (Mg) and potassium (K).
Micronutrients
Nutrients used by plants in small amounts. They are iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), molybdenum (Mo), cobalt (Co), and boron (B).
Monoculture
a large group of a single species of plant
Multipinnate
leaf divided into several sub-groups of leaflets
N
Neotropical
from the tropical areas of the new world (South or Central America)
Node
the point on a plant stem from which the leaves and/or roots appear
O
Offset
young plant growing along a stolon from the parent plant
Oligotrophic
deficient in nutrients needed for plant growth
Ovate
egg shaped
P
Paludal
from a marshy or swampy environment
Pectinate
comb like
Pedicel
the stem of an individual flower
Petiole
the “stalk” attaching the leaf to the stem
Photosynthesis
the conversion of light energy into chemical energy:carbohydrates, (sugar and starch), are produced from carbon dioxide and water through the action of light on the chlorophyll of green plants. Oxgen is released in the process
Pinnate
divided
Plumiform
feather shaped
Polymorphous
having multiple shapes
Q
Raceme
a group of flowers similar to a spike, but with each individual flower on its own stem
Reniform
kidney shaped
Rhizome
creeping stalk from which stalks and roots grow
Rosette
a plant that rises from a distinct crown
S
Sessile
a leaf that is directly attached to the plant stem with no petiole
Shaft
flower-bearing stalk
Spathe
modified leaf surrounding the flower
Spike
a group of flowers arranged closely at the end of a shaft, and attached directly to the shaft
Sporangium
the reproductive organ of primitive plants like ferns and mosses
Spore
the reproductive unit of primitive plants
Stolon
creeping offshoot or “runner” from which young plants arise
Submersed
growing completly underwater
T
Terrestrial
growing on land
Tuber
a swelling of root or underground stalk that functions as a storage organ as in a potato
Tissue culture
the production of new plants from small amounts of plant tissue under carefully controlled laboratory conditions
U
V
Vegetative cone
growing tip of the plant. On a stem plant, it is the tip of the stem. On a rosette plant, it arises from the very center of the rosette
Vegetative reproduction
reproduction via means other than sexual. Unless a mutation occurs, each generation of new plants is identical to the parent plant genetically
W
Whorl
a number of leaves evenly spaced around the stem
