Plant Science Terms - E

Ecology, plant - study of the complex relationships of plants in biological communities

Economic threshold - level at which pest damage justifies the cost of control. In home gardening, the threshold may be aesthetic rather than economic

Ecosystem services - provisioning services such as food and water; regulating services such as flood and disease control; cultural services such as spiritual, recreational, and cultural benefits; and supporting services such as nutrient cycling that maintain the conditions for life on earth

Electrical Conductivity (EC) - a measure of how much salt is in your soil.  High EC can mean that you have a problem from salt water or snow removal.  Soils with very high EC can burn plants.  A low EC means you need to fertilize (fertilizer is essentially make up of different types of salt).  The salts that make up fertilizer are good for your plants but too much can be bad

Elliptical - ellipse-shaped, broadest in the middle, tapering to an acute or rounded apex and base; two or three times longer than wide

Elytra - hardened opaque outer wings of a beetle

Emarginate - a deep notch

Emasculate - to remove a flower’s anthers

Embryo - immature plant within a seed during fertilization. It has two growing points, the radicle (a tiny root) and the plumule (a tiny shoot)

Embryo dormancy - common in seed of woody perennial plants. A physiological condition in the embryo that prevents it from growing. This type of dormancy can be overcome by stratification

Enation - epidermal outgrowths on leaves or stems

End of the Hose Plant - plant that is generally tough, is considered low water usage, and generally needs little maintenance.  End of the hose plants are great for the far corners of the garden where the hose doesn't reach

Endemic - belonging exclusively or confined to a particular place

Endocarp - inner area of the fruit wall. Entomology. The study of insects

Endoskeleton - internal body support found in most animals outside of the insect kingdom

Endosperm - tissue surrounding the embryo of flowering plant seeds that provides nutrition to the developing embryo, or the food-storage area in a seed for the growing embryo

Entire - a smooth edge with no teeth or notches

Enzyme - biological catalyst that aids in conversion of food and other chemical structures from one form to another

Epidemic - widespread and severe outbreak of a disease

Epidermis (leaf) - outer cell layers on the top and bottom of the leaf

Epidermis (root) - cells that protect the root surface. The epidermis contains the root hairs and is responsible for the absorption of water and minerals dissolved in water

Epidermis (stem) - in non-woody plants, the outer single layer of surface cells that protect the stem. As in leaves, this layer is usually cutinized, or waxy, and on young stems it has stomata

Epidermis - outer layer of cells of a herbaceous plant, such as leaves and fruits. These cells are usually covered with a waxy substance, called the cuticle, that minimizes water loss

Epinasty - an abnormal downward-curving growth or movement of a leaf, leaf part, or stem

Erect - cane berries that have arching, self-supporting canes

Espalier - training of tree or shrub to grow flat on a trellis or wall. Espalier patterns may be very precise and formal or more natural and informal

Ethylene - is the only hormone that is a gas. It speeds aging of tissues and enhances fruit ripening

Etioliation - long internodes and pale green color of plants growing under insufficient light or in complete darkness

Evergreen - perennial plant that bears leaves throughout the year and never loses all its foliage at the same time

Evergreen Grass - these grasses are usually plants that look like grasses but aren't actually classified as grasses. Plants like the sedges and carex are grass-like but not grasses

Excise - to remove or extract, as an embryo from a seed or ovule

Excurrent - tree form in which the main trunk remains dominant with small more or less horizontal branches. Fir and sweetgum are examples

Exfoliating - peeling off in shreds or thin layers, as in bark from a tree

Exocarp - outer skin-like region of the fruit wall

Exoskeleton - an insect’s outer body support

Exotic - of foreign origin or character; not native; introduced from abroad, but not fully naturalized

Exposure - the optimum amount of sun or shade each plant needs to thrive


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