cashwell_wikireader_edits

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Overview
Botany is the science of plant life and a branch of
biology. The term "botany" comes from the Ancient
Greek word βοτάνη (botanē) meaning "pasture,"
"grass," or "fodder.” Traditionally, botany has also
included the study of fungi and algae by mycologists
and phycologists respectively. Today, botanists study
approximately 410,000 species of land plants. Botany
originated in prehistory as herbalism with the efforts
of early humans to identify - and later cultivate - edible,
medicinal and poisonous plants, making it one of
the oldest branches of science. In the 19th and 20th
centuries, new techniques were developed for the
study of plants, including methods of optical microscopy
and live cell imaging, electron microscopy, etc.
Modern botany is a broad, multidisciplinary
subject with inputs from most other areas of
science and technology.
Importance
The study of plants is vital because they underpin
almost all animal life on Earth by generating a large
proportion of the oxygen and food that provide
humans and other organisms with aerobic respiration
with the chemical energy they need to exist. Plants
are crucial to the future of human society as they
provide food, oxygen, medicine, and products for
people, as well as creating and preserving soil. Botanists
examine both the internal functions and processes
within plant organelles, cells, tissues, whole plants,
plant populations and plant communities. Virtually
all staple foods come either directly from primary
production by plants, or indirectly from animals that
eat them.Plants and other photosynthetic organisms
are at the base of most food chains because they use
the energy from the sun and nutrients from the soil
and atmosphere, converting them into a form that
can be used by animals. Botanists study how plants
produce food and how to increase yields.
Caffeine
Botany
Overview
Caffeine is a central nervous system (CNS) stimulant
of the methylxanthine class. It is the world's most widely
consumed psychoactive drug. Unlike many other
psychoactive substances, it is legal and unregulated
in nearly all parts of the world. There are several
known mechanisms of action to explain the effects
of caffeine. The most prominent is that it reversibly
blocks the action of adenosine on its receptors and
consequently prevents the onset of drowsiness induced
by adenosine. Caffeine also stimulates certain portions
of the autonomic nervous system. Caffeine is found
in the seeds, nuts, or leaves of a number of plants
native to Africa, East Asia and South America, and
helps to protect them against predator insects and to
prevent germination of nearby seeds. The most
well-known source of caffeine is the coffee bean.
People may drink beverages containing caffeine to
relieve or prevent drowsiness and to improve
cognitive performance.
Natural Occurance
Around thirty plant species are known to contain
caffeine. Common sources are the “beans” (seeds) of
the two cultivated coffee plants, Coffea arabica and
Coffea canephora. Along with the cocoa plant,
Theobroma cacao; the leaves of the tea plant; and
kola nuts. Caffeine in plants acts as a natural pesticide:
it can paralyze and kill predator insects feeding on
the plant. High caffeine levels are found in coffee
seedlings when they are developing foliage and lack
mechanical protection. Caffeine is stored in tea leaves
in two places. Firstly, in the cell vacuoles where it is
complexed with polyphenols. This caffeine probably
is released into the mouths of insects, to discourage
herbivory. Secondly, around the vascular bundles,
where it probably inhibits pathogenic fungi from
entering and colonizing the vascular bundles. Caffeine
in nectar may improve the reproductive success of
the pollen producing plants by enhancing the reward
memory of pollinators such as honey bees.
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