Definitions: Abscisic acid (ABA) - A plant hormone that slows down growth, often antagonizing actions of growth hormones. Two of its many effects are to promote seed dormancy and facilitate drought tolerance. Seed dormancy is an effect of abscisic acid, in which it has great survival value because it ensures that the seed will germinate only when there are sufficient conditions of light, temperature, and moisture. A second effect of absicisic acid is drought tolerance, which is that ABA is the primary internal signal that enables plants to withstand drought. Abscisic acid is significant not only because of the fact that it slows growth and has many good effects on plants, but because it is the ratio of ABA to one or more growth hormones that determines the final physiological outcome.
Actin - A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells. Actin is responsible for muscle contraction as well as many other kinds of cell movement found in eukaryotic cells. Actin is significant because it is involved in many cellular processes including muscle contraction, cell motility, cell divison, etc. It is also significant because microfilaments are made up of it and microfilaments can form structural networks and allow a new filament to extend as a branch. Cellulose - A structural polysaccharide of cell walls, consisting of glucose monomers joined by B-1, 4-glycosidic linkages. Cellulose is significant because of its role in cell structures. It is a major component of the tough walls that enclose plant cells. Ethylene - The only gaseous plant hormone. Among its many effects are response to mechanical stress, programmed cell death, leaf abscission, and fruit ripening. This is significant becaue plants produce ethylene in response to stresses such as drought, flooding, mechnical pressure, injury, and infection and in turn ethylene has many effects that are good for plants such as enabling the shoot to avoid the obstacle in a triple response. Ethylene also is in involved in several plant processes such as stimulating the release of dormancy, stimulating flower opening, and stimulating fruit ripening. Lignin - A hard material embedded in the cellulose matrix of vascular plant cell walls that functions as an important adaptation for support in terrestrial species. The lignin is significant because is strengthens the walls of water-conducting cells in vascular plants. Meristem - Plant tissue that remains embryonic as long as the plant lives, allowing for indeterminate growth. Mertistems are significant because they allow plants to have growth throughout their life relatively continuously and because they generate cells for new organs for the plant. Ovary - The portion of a carpel in which the egg-containing ovules develop. The ovary contains ovules and if fertilized, an ovule develops into a seed. It will mature into a fruit, either dry and parchmentlike or fleshy, enclosing the seeds. The ovary is significant because it is what allows seeds and fruits to develop and grow.
Phloem - Vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar, amino acids, and other organic nutrients throughout the plant. The phloem is significant because it allows plants to develop and grow big by having sugar, organic nutrients, and food throughout it. Sporophyte - In organisms undergoing alternation of generations, the multicellular diploid form that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generaiton. This is significant because the sporophytes produce spores that develop into gametophytes, and gametophytes produce gametes that unite, forming the zygotes that develop into sporophytes. Sporophytes are one of the two multicellular body forms that alternate in the life cycles of land plants.
Xylem - Vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from roots to the rest of the plant. They contain tracheids, which are tube-shaped cells that carry water and minerals up from the roots. The xylem is significant because it provides water and minerals to the plant all the way from the bottom to throughout the plant. This helps the plant grow and develop in a healthy fashion. Pictures: Angiosperm - A flowering plant, which forms seeds inside a protective chamber called an ovary. Angiosperms are significant because the seeds inside of it mature into fruits, which are benefical for human society.
Conifer leaf - Leaves that are found on coniferous trees such as Pine, Cedar, Fir, and many more. The varied leaves of conifers are attached singly along the stems in a helical pattern or in opposite pairs or trios. They retain their leaves throughout the year and are long, thin, and have a needle-like apperance. The conifer leaf also retains its green color year-round. The significance of the conifer leaf is that the characteristics of the leaves such as their apperance and how they are structured help the tree's survival from severe winter weather and hot summer weather.
Deciduous leaf - Leaves that fall off during the end of the growing season. The growing season is Fall and is an indication that winter is about to start. When fall begins, the leaves turn from green to a different color. The color change differs depending on which type of plant, but usually turns into an orange-reddish/brownish color. The deciduous leaf is signifcant because it better allows the plant/tree to conserve water and to better survive winter weather conditions when it sheds. It's important the plant/tree sheds these leaves in order to prepare for a period of dormancy (hibernation).
Fruit - dry with seed - Fruits are divided into two main caterogies, one of which is dry fruits. Dry fruits can be divided into those in which seeds are contained in a seedpod of some sort which opens to release the seeds (Dehiscent) and those in which there isn't a seedpod which opens (Indehiscent). The ripening of a dry fruit involves the aging and drying out of the fruit tissues. Fruits are significant because they are what plants put their seeds in. Fruits are also significant in a way to humans by providing good nutrition and food to them. Some examples include beans, nuts, and grains. These are especially a major staple food for humans because of the dry, wind-dispersed fruits of grasses, harvested while on the plant. This is a picture of pistachio nuts.
Fruit - fleshy with seed - Fruits are divided into two main caterogies, one of which is fleshy fruits. Fleshy fruits can then be divided again into those who formed from a single flower and those who formed from a group of flowers. They can have one seed or several. Fruits are significant because they are what plants put their seeds in. Fruits are also significant in a way to humans by providing good nutrition and food to them. Some examples include oranges, strawberries, and grapes in which one or more pericarp layers become soft during ripening. This is a picture of strawberries.
Gymnosperm cone - A vascular plant that bears naked seeds---seeds not enclosed in specialized chambers. Their naked condition stands in contrast to the seeds or ovules of flowering plants. Gymnosperm seeds develop either on the surface of of scale or leaf-like appendages of cones, or at the end of short stalks. Gymnosperm cones are significant because the female ones have seeds and the male ones have pollen. This is a picture of a conifer (pine) gymnosperm.
Long-day Plant - A plant that flowers (usually in late spring or early summer) only when the light period is longer than a critical length. These plants are significant because the fact that these plants are long-day ones in which they have a certain photoperiod, shows that they can only grow in certain areas such as in the northern hemisphere and can only flower during certain times of the year, with less darkness. This effects geography, as in where the plants grow and live, and how they survive, with their own clock going on. These plants provide many nutritous foods such as spniach, radish, lettuce, and many cereal varieties to a daily diet. This is a picture of lettuce.
Stem - herbaceous - Plant structures that have been modified to serve the same function as leaves and occur in a number of different plant groups including Cactaceae and Euphorbiaceae. They also have little to no woody tissue. It's a term for the morphological apperance of parts of a plant, typically used when structures look and act like leaves with leaf-like texture and color. The significance of herbaceous stems is that it holds the plant up to get light for photosynthesis and be available for pollination. It also carries water and minerals up the plant and take food down the plant. It also makes the plant look nice. This picture is the stem of a cactus.
Stem - woody - Made up of bark, a woody stem holds up the other structures of the plant such as the leaves and flowers. A woody stem is just one of the types of stems that a plant can have. Woody stems are significant because they hold the plant powerfully enough so that it is able to get light for photosynthesis and be availabe for pollination. It also carries water and minerals up the plant and take food down to the plant. This picture is the stem of a tree.
Thorn of a Plant - A modified branch in the form of a sharp, woody spine. Thorns are significant to plants because they serve as a defense against predators or invaders. They also protect plants from danger other organisms can make.
Bonus:
Character - A heritable feature, such as flower color, that varies among individuals. This could be any observable feature, or trait, of an organism. Characters are signifcant because they are what makes each organism individual and helps tell them apart. The character of this flower is the yellow color.
Day-neutral plants - Unaffected by photoperiod and flower when reaching a certain stage of maturity, regardless of day length. These plants are significant because they are able to grow and flower no matter what, which means that these plants are common and able to grow easily for society. This is a picture of rice.
Pollen - A fine powdery substance, typically yellow, consisiting of microscopic grains discharged from the male part of a flower or from a male cone. Pollen is significant beacause each grain of pollen contains a male gamete that can fertilize the female ovule.
Abscisic acid (ABA) - A plant hormone that slows down growth, often antagonizing actions of growth hormones. Two of its many effects are to promote seed dormancy and facilitate drought tolerance. Seed dormancy is an effect of abscisic acid, in which it has great survival value because it ensures that the seed will germinate only when there are sufficient conditions of light, temperature, and moisture. A second effect of absicisic acid is drought tolerance, which is that ABA is the primary internal signal that enables plants to withstand drought. Abscisic acid is significant not only because of the fact that it slows growth and has many good effects on plants, but because it is the ratio of ABA to one or more growth hormones that determines the final physiological outcome.
Actin - A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells. Actin is responsible for muscle contraction as well as many other kinds of cell movement found in eukaryotic cells. Actin is significant because it is involved in many cellular processes including muscle contraction, cell motility, cell divison, etc. It is also significant because microfilaments are made up of it and microfilaments can form structural networks and allow a new filament to extend as a branch.
Cellulose - A structural polysaccharide of cell walls, consisting of glucose monomers joined by B-1, 4-glycosidic linkages. Cellulose is significant because of its role in cell structures. It is a major component of the tough walls that enclose plant cells.
Ethylene - The only gaseous plant hormone. Among its many effects are response to mechanical stress, programmed cell death, leaf abscission, and fruit ripening. This is significant becaue plants produce ethylene in response to stresses such as drought, flooding, mechnical pressure, injury, and infection and in turn ethylene has many effects that are good for plants such as enabling the shoot to avoid the obstacle in a triple response. Ethylene also is in involved in several plant processes such as stimulating the release of dormancy, stimulating flower opening, and stimulating fruit ripening.
Lignin - A hard material embedded in the cellulose matrix of vascular plant cell walls that functions as an important adaptation for support in terrestrial species. The lignin is significant because is strengthens the walls of water-conducting cells in vascular plants.
Meristem - Plant tissue that remains embryonic as long as the plant lives, allowing for indeterminate growth. Mertistems are significant because they allow plants to have growth throughout their life relatively continuously and because they generate cells for new organs for the plant.
Ovary - The portion of a carpel in which the egg-containing ovules develop. The ovary contains ovules and if fertilized, an ovule develops into a seed. It will mature into a fruit, either dry and parchmentlike or fleshy, enclosing the seeds. The ovary is significant because it is what allows seeds and fruits to develop and grow.
Phloem - Vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar, amino acids, and other organic nutrients throughout the plant. The phloem is significant because it allows plants to develop and grow big by having sugar, organic nutrients, and food throughout it.
Sporophyte - In organisms undergoing alternation of generations, the multicellular diploid form that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generaiton. This is significant because the sporophytes produce spores that develop into gametophytes, and gametophytes produce gametes that unite, forming the zygotes that develop into sporophytes. Sporophytes are one of the two multicellular body forms that alternate in the life cycles of land plants.
Xylem - Vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from roots to the rest of the plant. They contain tracheids, which are tube-shaped cells that carry water and minerals up from the roots. The xylem is significant because it provides water and minerals to the plant all the way from the bottom to throughout the plant. This helps the plant grow and develop in a healthy fashion.
Pictures:
Angiosperm - A flowering plant, which forms seeds inside a protective chamber called an ovary. Angiosperms are significant because the seeds inside of it mature into fruits, which are benefical for human society.
Conifer leaf - Leaves that are found on coniferous trees such as Pine, Cedar, Fir, and many more. The varied leaves of conifers are attached singly along the stems in a helical pattern or in opposite pairs or trios. They retain their leaves throughout the year and are long, thin, and have a needle-like apperance. The conifer leaf also retains its green color year-round. The significance of the conifer leaf is that the characteristics of the leaves such as their apperance and how they are structured help the tree's survival from severe winter weather and hot summer weather.
Deciduous leaf - Leaves that fall off during the end of the growing season. The growing season is Fall and is an indication that winter is about to start. When fall begins, the leaves turn from green to a different color. The color change differs depending on which type of plant, but usually turns into an orange-reddish/brownish color. The deciduous leaf is signifcant because it better allows the plant/tree to conserve water and to better survive winter weather conditions when it sheds. It's important the plant/tree sheds these leaves in order to prepare for a period of dormancy (hibernation).
Fruit - dry with seed - Fruits are divided into two main caterogies, one of which is dry fruits. Dry fruits can be divided into those in which seeds are contained in a seedpod of some sort which opens to release the seeds (Dehiscent) and those in which there isn't a seedpod which opens (Indehiscent). The ripening of a dry fruit involves the aging and drying out of the fruit tissues. Fruits are significant because they are what plants put their seeds in. Fruits are also significant in a way to humans by providing good nutrition and food to them. Some examples include beans, nuts, and grains. These are especially a major staple food for humans because of the dry, wind-dispersed fruits of grasses, harvested while on the plant. This is a picture of pistachio nuts.
Fruit - fleshy with seed - Fruits are divided into two main caterogies, one of which is fleshy fruits. Fleshy fruits can then be divided again into those who formed from a single flower and those who formed from a group of flowers. They can have one seed or several. Fruits are significant because they are what plants put their seeds in. Fruits are also significant in a way to humans by providing good nutrition and food to them. Some examples include oranges, strawberries, and grapes in which one or more pericarp layers become soft during ripening. This is a picture of strawberries.
Gymnosperm cone - A vascular plant that bears naked seeds---seeds not enclosed in specialized chambers. Their naked condition stands in contrast to the seeds or ovules of flowering plants. Gymnosperm seeds develop either on the surface of of scale or leaf-like appendages of cones, or at the end of short stalks. Gymnosperm cones are significant because the female ones have seeds and the male ones have pollen. This is a picture of a conifer (pine) gymnosperm.
Long-day Plant - A plant that flowers (usually in late spring or early summer) only when the light period is longer than a critical length. These plants are significant because the fact that these plants are long-day ones in which they have a certain photoperiod, shows that they can only grow in certain areas such as in the northern hemisphere and can only flower during certain times of the year, with less darkness. This effects geography, as in where the plants grow and live, and how they survive, with their own clock going on. These plants provide many nutritous foods such as spniach, radish, lettuce, and many cereal varieties to a daily diet. This is a picture of lettuce.
Stem - herbaceous - Plant structures that have been modified to serve the same function as leaves and occur in a number of different plant groups including Cactaceae and Euphorbiaceae. They also have little to no woody tissue. It's a term for the morphological apperance of parts of a plant, typically used when structures look and act like leaves with leaf-like texture and color. The significance of herbaceous stems is that it holds the plant up to get light for photosynthesis and be available for pollination. It also carries water and minerals up the plant and take food down the plant. It also makes the plant look nice. This picture is the stem of a cactus.
Stem - woody - Made up of bark, a woody stem holds up the other structures of the plant such as the leaves and flowers. A woody stem is just one of the types of stems that a plant can have. Woody stems are significant because they hold the plant powerfully enough so that it is able to get light for photosynthesis and be availabe for pollination. It also carries water and minerals up the plant and take food down to the plant. This picture is the stem of a tree.
Thorn of a Plant - A modified branch in the form of a sharp, woody spine. Thorns are significant to plants because they serve as a defense against predators or invaders. They also protect plants from danger other organisms can make.
Bonus:
Character - A heritable feature, such as flower color, that varies among individuals. This could be any observable feature, or trait, of an organism. Characters are signifcant because they are what makes each organism individual and helps tell them apart. The character of this flower is the yellow color.
Day-neutral plants - Unaffected by photoperiod and flower when reaching a certain stage of maturity, regardless of day length. These plants are significant because they are able to grow and flower no matter what, which means that these plants are common and able to grow easily for society. This is a picture of rice.
Pollen - A fine powdery substance, typically yellow, consisiting of microscopic grains discharged from the male part of a flower or from a male cone. Pollen is significant beacause each grain of pollen contains a male gamete that can fertilize the female ovule.