Plant Classes and Parts

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Plant Classes and Parts

• Basic Plant Science

AFNR-BAS-13 Explain and demonstrate basic plant
science principles including plant health, growth
and reproduction.
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Uses of Plants

• Plants provide for the three basic human needs
• food fruits, vegetables, grains, nuts, etc.
• clothing cotton, linen, wool, leather (plants
  feed the animals that grow the wool and leather)
• shelter lumber and other wood products

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Uses of Plants

• direct source the plant or plant products are
  used by humans
• fruits, nuts, vegetables, cotton
• indirect source humans use the animal and animal
  products that feed on plants and plant products
• beef, leather, chicken, wool

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Uses of Plants

• Plants are also used by humans for ornamental and
  aesthetic reasons to provide comfort or beauty.
• landscaping (flowers, shrubs, trees, turf)
• ornamental horticulture and floral design (house
  plants, cut flowers
• forestry and outdoor recreation (wildlife
  habitat, hiking, hunting)

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Major Groups of Plants

• gymnosperms
• means naked seed in Greek
• plants that produce seeds not protected by fruit
• examples pines, firs, spruces, redwoods, ginkgo

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Major Groups of Plants

• angiosperms
• in Greek means covered seed or enclosed seed
• plants that flower and produce seeds protected by
  fruit or pods
• examples apples, peaches, pecans, soybeans

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Major Groups of Plants

• There are two classes of angiosperms with
  distinct characteristics.
• cotyledon an embryonic leaf which become the
  seed leaf
• monocotyledons (a.k.a. monocots) mono- - means
  one
• dicotyledons (a.k.a. dicots) di- means two

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Major Groups of Plants

• monocotyledons (a.k.a. monocots)
• seeds have one cotyledon therefore the seedlings
  have one seed leaf
• the vascular bundles are scattered
• the leaves have parallel veins
• flower parts are in multiples of three

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Major Groups of Plants

• dicotyledons (a.k.a. dicots)
• seeds have two cotyledons therefore the seedlings
  have two seed leaves
• the vascular bundles are arranged in a circle
• the leaves have netted veins
• flower parts are in multiples of four or five

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Taxonomy (Naming Plants)

• scientific names are in Latin and printed in
  italics
• common names can be confusing because different
  areas call plants by different names
• binomial nomenclature
• two-name system
• first name is the genus
• second name is the species
• species can be further subdivided into varieties

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Plant Life Cycles

• Annuals plants that complete their life cycle in
  one year (or one season)
• examples marigolds, pansies, petunias, melons,
  beans, squash (and many other flowers, crops, and
  weeds)

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Plant Life Cycles

• Biennials plants that complete their life cycle
  in two growing seasons
• grows vegetative structures (roots, stems,
  leaves) in the first year and then after a period
  of dormancy during cold months, it will produce
  flowers and seeds before dying
• examples carrot, parsley, onion, cabbage,
  hollyhock, Black-eyed Susan

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Plant Life Cycles

• Perennials plants that produce for more than two
  years or growing seasons
• may die back during the winter months and then
  return from their rootstock
• examples azalea, alfalfa, pine trees, maple
  trees, fruit and nut trees, blueberries
• There are two classes of perennials.
• herbaceous plants that have soft stems that are
  killed by frost
• woody plants with hardy stems that can survive
  winter frost

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Plant Processes

• photosynthesis the chemical process converting
  sunlight into energy and food for the plant
• respiration the process of plants using stored
  energy
• transpiration the movement and loss of water
  through evaporation

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Plant Parts

• Roots
• anchor the plant
• absorb water and minerals
• store manufactured food
• primary root the single main root
• secondary roots small roots that branch off the
  main root
• root hairs many tiny roots that increase the
  surface area of the root for absorption
• root cap protects the growing tip of roots

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Plant Parts

• Types of Roots
• tap root root system with one thick main root
• fibrous roots system with many small roots
• adventitious roots grow from the stem or leaf of
  a plant
• example corn has roots above ground to prop up
  the stalk

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Plant Parts

• Stems
• support the leaves, flowers, and fruit
• conduct water, minerals, and food
• store food and water
• produce new stem tissues

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Plant Parts

• Two types of conductive tissues in the stem
• xylem transports water and minerals from the
  roots
• phloem transports food from the leaves
• both are created by the cambium which becomes
  growth rings in trees
• the xylem and phloem are arranged in a ring in
  dicots and scattered in moncots

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Plant Parts

• Leaves
• produce food for the plant through photosynthesis
• epidermis protective layer of cells
• cuticle waxy coating that prevents water loss
• stomata pore-like openings on the underside of
  the leaf that allow gas exchange
• guard cells control the opening and closing of
  the stomata
• mesophyll where photosynthesis takes place made
  up of palisade layer and the spongy layer
• veins contain xylem and phloem and transport
  water and nutrients

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Plant Parts

• Flowers
• purpose of flowers is to reproduce through the
  production of seeds
• sepals the outermost part of a flower (usually
  green) that protects the unopened flower and
  supports the petals when it blooms
• as a whole all the sepals are called the calyx
• petals attract insects and birds for
  pollination usually conspicuously colored

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Plant Parts

• Flowers
• stamen the male part of the flower
• anther produces the pollen which contains the
  male sex cells
• filament supports the anther
• pistil the female part of the flower
• stigma provides a sticky surface to catch pollen
• style supports the stigma
• ovary produces the female sex cells and becomes
  the fruit

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Flower Anatomy
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Plant Parts

• Flowers
• complete flowers flowers that have all the parts
  (sepals, petals, stamen, and pistil)
• incomplete flowers flowers that lack one of the
  four main parts - petals, sepals, pistil, or
  stamen
• male flowers will not have a pistil and female
  flowers will lack stamen
• monoecious plants that have male and female
  flowers on the same plant
• dioecious plants that have male and female
  flowers on separate plants

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Plant Parts

• Fruit
• a mature (fertilized) ovary containing the seed
  or seeds
• may be fleshy or dried
• fleshy fruit are soft and may be consumed by
  humans or animals as food which helps to disperse
  the seeds examples include pumpkin, apple,
  tomato
• dry fruits have hard seeds

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