Theme E: La croissance des plantes

Adaptation - a feature or characteristic of an organism that makes it better sited to its environment.

Anther - the male part of the flower that consists of a long stalk and a bulb on the tip end. The bulb produces pollen grains which carry the sperm nuclei needed to fertilize the eggs.

Biennial - continuing or lasting for two years, growing vegatively during the first year and fruiting and dying during the second year.

Bulb - an enlarged underground section of a stem (like a large bud) that will grow into a new plant when planted.

Chlorophyll - the green pigment in plant leaves and stems that is able to trap energy from the sun for the process of photosynthesis.

Cotyledons - the two halves of a seed like those in a bean. They give rise to two stubby rounded leaf-like structures on the stem of the emerging plant when the seed germinates. Some seeds like those of corn have only one cotyledon that emerges as the seed germinates.

Cutting - a section of a plant capable of developing into a new plant.

Deciduous - a kind of tree or shrub that loses its leaves every autumn. In general, broadleaf trees and shrubs are deciduous. One local conifer (cone bearing tree) that drops its needles in the fall is the tamarack or larch.

Dispersal- to spread out; seeds are spread out away from the parent plant by wind, water, catapult seed pods, and by animals.

Dormant - to remain inactive when conditions are not suitable. Seeds are often dormant until conditions are right for germination.

Embryo Plant - the tiny plant within a seed.

Erosion - the wearing away by the action of water, wind or glacial ice.

Evergreen - a kind of plant that does not lose its leaves every autumn but, instead, remains green all year long. Conifers such as spruce and pine are evergreens.

Flower - the part of the plant that produces the seeds. Flowers are often very colourful and can be fragrant in smell to attract insects for pollination.

Fruit - the fleshy, often sweet part of a plant that holds the seeds. Apples, oranges and tomatoes are fruit.

Germination - the initial growth of a seed to produce a new plant. Germination does not need light or soil nutrients because the embryo plant draws on the stored food in the cotyledons during the stage of growth.

Leaves - the green needle-shaped or broad flat structures on the branches of plants which manufacture most of the plant's food by photosynthesis.

Life Cycle - the sequence of stages that organisms go through from egg to adult.

Nutrient - a substance that provides nourishment.

Phloem - the tissue in plants through which food is transported from one part of the plant to another. In woody stems phloem is found along the inside edge of the bark.

Photosynthesis - the process or making food (sugars) in green plants or organisms that contains chlorophyll. The source of energy for photosynthesis is light and the raw materials are carbon dioxide and water molecules.

Pistil - the female part of the flower containing the egg or eggs in its swollen base near the bottom of the petals. The tip end is sticky and traps the pollen grains.

Pollination - the transfer of pollen from the male part (anther) of a flower to the female part (pistil). Pollination is done by insects or can be done by wind or water. The pollen carries the male sperm cell that must fertilize the egg before it can grow into an embryo plant.

Propagation - to cause to continue or increase by sexual or asexual reproduction.

Roots - the network of tubules and fibers that grow from the base of the plant stem extending outward underground. Roots absorb mineral nutrients and water.

Runner - the outgrowth of stems that extend along the ground which give rise to new plants at various points along its length.

Seed - a structure containing a tiny embryo plant and stored food which can give rise to a new plant under suitable conditions.

Stem - the main body of the plant above ground that supports the branches and leaves.

Tuber - a short, fleshy, underground stem bearing minuscule leaves each with a bud potentially able to produce a new plant. The underground stem of a plant where starch is stored.

Xylem - tiny tubules in plants through which water and dissolved minerals are transported from the roots to other parts of the plant.