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CHAPTER I: History, Trends, Issues, and Challenges in Plant Science


CHAPTER I: History, Trends, Issues, and Challenges in Plant Science HISTORY If we were to go back in time 150 million years, we would see many plants very similar to ... – PowerPoint PPT presentation

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Title: CHAPTER I: History, Trends, Issues, and Challenges in Plant Science

CHAPTER I History, Trends, Issues, and
Challenges in Plant Science
  • If we were to go back in time 150 million years,
    we would see many plants very similar to those
    common in our century.
  • During this time, humans had no influence on
    changes in life forms that occurred.
  • 12,000 to 10,000 years ago (perhaps earlier
    according to recent archaeological finds) humans

Plant cultivation
  • Plant cultivation The purposeful growing or
    cultivation of plants to improve the supply of
    materials obtained from these plants.
  • is believed to have started in areas tropical and
    subtropical regions in the Middle East and
    Africa. (By cultivating plants, humans reduced
    the need to travel to follow the food supply).
  • Agronomy is the study of field-grown crops such
    as wheat, soybeans, corn, forages, and those used
    for industrial purposes that require relatively
    low input during the growing part of their life
  • Horticulture is the study of crops include most
    fruits, vegetables, and ornamentals that require
    more intense and constant care, from planting
    through delivery to the consumer.

  • Photosynthesis is the underlying process that
    makes all life on earth dependent on all plants,
    not just the cultivated ones.
  • Embodied Energy
  •  is the sum of all the
  • energy required
  • to produce any goods
  • or services, considered
  • as if that energy was
  • incorporated or
  • 'embodied' in the
  • product itself.

Domestic Trends and Issues give dull view about
green coverage
  • Even though yields continued to increase, income
    per acre declined (Fig. 1-2)

The number of farm workers also continued its
long-term decline (Fig. 1-3).
The area of farmland has also declined (Fig.
Global Trends and Issues
  • Two major trends that will affect crop production
    and the global environment are
  • The increases in human population ? more
  • The increases in energy use.
  • After two centuries of exponential growth, world
    population shows signs of stabilizing at about 9
    billion in 2050 (Fig. 1-5). ????? ?????

Energy use is projected to rise about twice as
fast as population because of economic
development export (Fig. 1-6).
  • China alone represents a major challenge to the
    world's food supply. It has about 20 percent of
    the world's population but less than 7 percent of
    the world's cropland. It had about 0.2 hectares
    per person in 1950 and now has about 0.08.

  • For several centuries, plant scientists studied
    ways to improve crop productivity in a
    cost-effective way?????? ????? ?? ??? ???????
  • They studied abiotic factors light, soil, water,
    and temperature and developed ways of managing or
    monitoring those factors to influence or predict
    plant growth. As Glass houses, improve soil
    characters and water use eff.
  • They studied biotic factors herbs, virus, and
    pests and their management reduced losses to
    those factors. Control of factors.
  • Improved understanding of plant genetics lead to
    breeders developing plants that surely would
    produce more.
  • Modern Plant biotechnology. Genetically modified
    organisms (GMOs). Changes in DNA structure

Organic farming
  • Organic farming has been proposed as a solution
    to many problems related to crop production and
    environmental impact.
  • Organic farming does not allow the use of GMOs
    and certain types of chemicals for pest control
    and fertilization.
  • However, it is not known if organic farming has
    the capability to produce the quantities of crop
    products needed in today's world.

Perfect plant and dependency
  • Maintaining perfect plants almost certainly has
    some degree of negative environmental impact.
  • Although most plants grow very well without human
    intervention, the cultivated grains and grasses,
    fruits, vegetables, and ornamentals have become
    dependent on human intervention to survive.
    Without cultivation, these plants would die out
    after several generations and be replaced by
    hardier species such as wild grasses and
    thistles ???????

Cultivated plants are
1. Cereal crops Wheat, maize (corn), rice, barley, oats, sorghum, rye???????, and millet ??? . (Over half the world's food supply comes from the photosynthetic activity of these crops.)
2. Roots and tubers Potatoes, sweet potatoes, and cassavas.
3. Oil crops Soybeans, corn, peanuts??? ??????, palm,coconuts ??? ???, sunflowers, olive, and safflower.
4. Sugar Sugar cane and sugar beets.
5. Fruit crops Bananas, oranges, apples, pears, and many others.
6. Vegetable crops Tomatoes, lettuce, carrots, melons, asparagus, and so for
  • Over half the world's food supply comes from the
    photosynthetic activity of cereal crops.

Not all of the total production of food materials
becomes available for human consumption
  • Much is lost during harvesting, transportation,
    and marketing, primarily from attacks by insects,
    diseases, birds, and rodents.
  • Some of the production is saved to be used as
    seed for future plantings.
  • Some plants are used to produce human food in the
    form of animal products.

3. Some plants are used to produce human food in
the form of animal products
  • Loss Energy loss. For example, it takes about 10
    kilograms of grain (which could be consumed by
    humans directly) to produce 1 kilogram of beef.
  • Gain Some of the kinds of feed consumed by
    animal is ordinarily not eaten by humans.
  • Gain Meat, milk, and eggs are important in the
    human diet because they contain proteins of the
    proper quality, as well as some of the necessary
    minerals and vitamins.

TABLE 1 Some Important Food Crops Ranked
According to Calorie and Protein Production per
Unit of Land Area
Rank Calories Produced per Unit Area Protein Produced per Unit Area
1 Sugar cane Soybeans
2 Potato Potato short season ?prod. /unit of area
3 Sugar beets Corn
4 Corn Peanuts
5 Rice Sorghum
6 Sorghum Peas
7 Sweet potato Beans
8 Barley Rice
9 Peanuts Barley
10 Winter wheat Winter wheat
The requirements for continuing increases in the
world's food-producing capability are of
following conditions
  1. The shift in food consumption patterns.
  2. The tremendous increase in world population,
    especially in developing regions (see Fig. 1-7).
  3. Much of the world's best agricultural land is
    already under cultivation, although there is
    still unused productive land awaiting
    development in Argentina, Brazil, Canada, Sudan,
    and Australia.
  4. Agricultural land losses for many reasons such as
    urban expansion and climate changes.

(No Transcript)
Mid-1970s various projections
  • In the mid-1970s various projections implied
    that the world was on the brink of famine or
    ecological disasters due to desperate food needs.
    But this assessment changed in the 1980s by
  • Improved production technology and greater
    incentives to use it.
  • Agricultural research made new cultivars of
    high-yielding wheat, rice, corn, and other crops
    (Cultivar cultivated variety.)

  • Currently, enough food is produced to feed the
    world's population. However, malnutrition and
    starvation exist in both developed and
    undeveloped countries (mostly in the sub-Saharan
    regions of Africa) mostly because social and
    political issues prevent the distribution of food
    to those who need it.

Social and political issues prevent the
distribution of food to those who need it
  • Drought
  • Wars
  • Political instability
  • High human fertility rates
  • Low per capita income?????? ???? ????? ?? ?????
  • Insufficient monetary investment in agricultural
  • Poor distribution of available food since it is
    of costand remain in the hands of rich countries.
  • Solution Produce food crops locally in
    starvation-prone areas.

Meet today's challenges includes the ecological
paradigm????? of agriculture in all scientific
  • A model for this concept was developed that is
    built on four areas of focus
  • Production efficiency,
  • Economic viability,
  • Environmental compatibility?????? ,
  • Social responsibility. Fig. 1-8

  • Plants improve soil properties and prevent its
    erosion because
  • Their decomposing roots, stems, and leaves add to
    the soil's mass, forming a humus material.
  • Their roots act as webs to hold the soil in
  • Their leaves and branches slow the force of the
    falling water.

Wood and Wood Products from Timber Trees
  1. Human shelter.
  2. Source of fuel (Unlike coal, gas, and oil, wood
    is a renewable natural resource).
  3. Construction and other utilitarian uses, such as
    home furnishings.
  4. The ornamental value of trees used for landscape
    and other aesthetic purposes such as carving???
    is nearly inestimable.
  5. The biochemicals found in some wood species
    provide products for industry and medicine.
    Industrial products include latex????, pitch???
    ?????, and resin.
  6. The manufacture of paper.

Textiles from Fiber-Producing Crops
  • Cotton, flax????, and hemp ??? supply much of the
    fabric that clothe us and shelter us.
  • Cotton, hemp, and also jute are used to make
    string ??? , twine?????, rope, and burlap?????.
  • Unfortunately, hemp grown for fiber is the same
    species as marijuana ??? ????. Marijuana plants
    produce the drug tetrahydrocannabinol (THC).

Drugs and Medicines
  • From the earliest history of humans, man used
    herbs to treat diseases and disorders.
  • Much of this wealth???? of plant lore is in
    danger of being lost as indigenous cultures
    ??????? ???????are absorbed into modem
  • Ethanobotany, the study of plant usage by
    indigenous cultures and the preservation of that
    knowledge about plants.

  • Salicylic acid, the pain-relieving component of
    aspirin, is found in the bark of willow?????
    trees (Salix). quinine, which is used to treat
    malaria, and the heart medication, digitalis.
    Morphine, opium ?????, codeine, and heroin are
    all pain-relieving extracts of the opium poppy
    ????? ?????(Papaver somniferum).
  • Cocaine, another painkiller, is derived from the
    coca plant (Erythroxylum coca). However, each of
    these pain-relieving drugs also has addictive
  • One of the newest plants to be recognized for its
    medicinal benefits is a yew ??? ???????(Taxus)
    that produces taxol, a chemical that shows
    promise in the treatment of cancer.
  • Plants also provide latex, pitch, waxes,
    essential oils, perfumes, species, and other

Plants for Ornamental and Recreational Purposes
  1. The appearance and playability of fields is
    vitally important to many sports.
  2. Residential and commercial landscaping is a
    business that generates billions of dollars
    annually in the United States alone.