Plant Form and Function

• Roots anchors the plant, and absorb and conduct water and minerals it has two types: taproot system (dicots), and fibrous root system (monocots)
• The very first root that forms is called a radicle. This is a part of the embryo that is responsible for the growth of the root.
• The root cap protects the young root tip as it further protrudes into the soil
• these are the areas of the roots. name each area.

  A) Area of Maturation

  B) area of elongation

  C) area of cell division

  D) root cap

  
• apoplastic route - water is absorbed through the cell wall of the plant
• symplastic route - through the cytoplasm and plasmodesmata
• it is in the symplastic route where water filtration occurs
• modified roots
• modified roots

  • storage roots
  • buttress roots
  • climbing roots
  • pneumatophores
  • prop roots
  • root nodules
  • strangling roots
• storage roots - store food, e.g., carrots, potatoes, turnips
• buttress roots stabilize the tree against wind and gravity forces. they are large, wide roots that help keep shallow-rooted forest trees from toppling over. 
• climbing roots are the adventitious roots that arise from the nodes or internodes in plants having weak stems.
• pneumatophores are specialized for gas exchanged. they are typically submerged under water which is why they breathe through their roots
• prop roots are the roots that grow upwards from the ground and are used for support and anchorage or extra support
• root nodules have a symbiotic relationship between legumes and leguminous bacteria. examples of these are beans, peas, soybeans, etc.
• strangling roots grow in a circular pattern, gradually strangling and killing the trunk
• modified stems have 7 types:

  1. rhizome
  2. runners
  3. tuber
  4. bulb
  5. corm
  6. cladophylls
  7. tendrils
• rhizomes are fleshy underground stems. the adventitious roots grow from the rhizome. Ginger is an example of this
• runners or stolon are horizontal stem that runs along the ground. examples are grass and strawberries
• tubers are similar to that of rhizomes, however, they have eyes or nodes that can form new shoots. potatoes are an example
• bulb is a shortened underground storage stem with fleshy leaves. they produce smaller lateral buds that later can be separated
• corms are swollen underground stems covered with dry scale leaves. an example of this is taro or gabi
• cladophylls resemble leaves, hence they are photosynthetic. these are flattened leaf-like stems that function for storage and photosynthesis
• tendrils are a stem or leaf modification of climbing plants. the stem tendrils arise for the axillary bud. the leaf tendrils on the other hand, arise for the leaf or a part of it.
• axillary buds have the ability to make new shoots
• flowers are specialized shoot that can have up to four rings of modified leaves

  1. sepals
  2. petals
  3. stamens
  4. pistil
• sepals are the small, leaf-shaped, green-colored outer parts of the flower. they look like they hold the flower itself.
• petals are what we see - they attract insects for pollination and protect the flower's reproductive organs
• stamens are the pollen producing part of the flower
• the pistil is the female reproductive organ and produces a seed-bearing fruit
• parts of a flower

  A) petal

  B) sepal

  C) stamens

  D) anther

  E) ovary

  F) stigma

  G) ovule

  
• fruit is the seed-bearing structure in flowering plants formed from the ovary after flowering
• the fruit has an exocarp, mesocarp, and endocarp
• the exocarp is the generally tough outer part of the fruit that protects the seeds
• the mesocarp is the middle part of the fruit. this is the edible part, provides shade for humans, and food and crops
• endocarp is for seed protection. it also sustains and communicates with developing seeds
• fruits have three types

  1. simple
  2. aggregate
  3. multiple
• simple fruits are derived from one ovary
• aggregate fruits are derived from ovaries of a single flower
• multiple fruit is derived from ovaries from multiple flowers