Crop Science 1

1. PLANT STRUCTURE,
CLASSIFICATION, GROWTH
AND DEVELOPMENT
Chapter II
GROUP 1

2. Importance of Plants
• a primary or vital source of food for human beings & animals
• produces oxygen that refreshes the air in the atmosphere;
so does aquatic plants
• keeps the surroundings cool
• slow down the wind
• prevents soil erosion
• balances the ecosystem;
• serves as building materials and fuels

3. Plants
• living multicellular organism of Kingdom Plantae
• also called as green plants (Viridiplantae)
• obtain their food through photosynthesis in their
chloroplasts, specifically using chlorophyll (green pigment)

4. Weather / Climate
Type IV Climate
• Have equal rain throughout the year

5. Photosynthesis
• the conversion of light energy into chemical energy by a
living organism
• carbon dioxide and water are the raw materials
• sunlight is the energy source
• Glucose and oxygen are the end-products
Overall chemical reaction:
6 CO2 + 6 H2O C6H12O6 + 6 O2

6. Parts of a Plant
Most plants are made up of four basic parts:
1. roots
2. stems
3. leaves and
4. flowers
which later become
5. fruits or seeds
2
5
1
4
3
Tomato plant

7. Root
• a multicellular organ
• anchors a plant in the soil
• absorbs minerals and water
• often stores carbohydrates (e.g. sweet potato & cassava)

8. Root (Taproot/ Dicot)
• composed of one central primary root which gives
rise to lateral roots called branch roots
• usually has deep penetration in the soil where the
ground water is not close to the surface
• stores sugar and starches which plant will
consume during flowering and fruit production

9. Root (Fibrous/ Monocot)
• are thin roots spreading out below the soil suface
• its embryonic roots die and do not give rise to a main root
instead, small roots grow from the stem
• a plant organ that grow in an unusual location is
described to be an adventitious
• usually makes a shallow penetration and hold the top
soil in place

10. Root (Prop root)
• root that grows from the stem of a plant above
the ground

11. Root (Aerial root)
• usually attached on a tree branch
• hangs down in mid-air and absorb water from
rainfall

12. Stem
• Supports the leaves and reproductive structures (flowers &
fruits)
• A pathway for water and minerals from roots to leaves and
leaves to roots

13. Stem (Nodes)
• The points at which leaves are attached

14. Stem
• Axil is the upper angle formed by each leaf and the
stem is an axillary bud, that gives rise to lateral
shoots
• Internodes are the segment between nodes
internode
axillary bud
axil

15. Leaf
• main photosynthetic organ
• absorbing organ for chemicals & micronutrients
(ectodermata)
• a transpiration organ that regulates plant’s body water
through stomata
• it vary in shape and size
• most are flat, some are needlelike (pine tree leaves), others
are cylindrical (onion leaves)
• shape, size and arrangement of leaves helps to identify plant

16. Leaf
• guard cells are the special cells in the leaf skin
• stoma which open and close the pores on the underside
allows the leaf to breathe and transpire, or give off
moisture and exchange gases such as oxygen and carbon
dioxide
• guard cells are crescent-shaped, inner walls are thick

17. Leaf (Arrangement)

18. Leaf (Parts)
• Apex or tip
• Margin is the boundary area
extending along the edge of the
leaf
• Veins consist of vascular tissue,
xylem, and phloem, and connect
the vascular tissue
• Midrib is a thick central vein
that runs from the base of a leaf
to its apex
• Petiole is a stalk that joins a leaf
to a stem
• Stipule is a small leaf like
appendage to a leaf

19. Leaf’s Apex/Tip & Margin

20. Leaf (Difference)
Monocot
- long parallel veins in
narrow leaves
Dicot
- net-like or lots of
branching in broad leaves

21. Flower
• has different size, shape and color but has generally the
same parts
(a complete flower)
1. sepals
2. petals
3. stamens
4. pistils
an incomplete flower may lack of one or more of these parts
like stamens (pistillate or female flwr) or pistil(staminate or
male flwr)

22. Flower (Parts)
• Stamen- makes the male reproductive
part
• Anther-a saclike structure contains
pollen; male sex cell
• Filament- a short stalk
• Pistil- makes the female reproductive
part
• Ovule- female sex cell which pistil
produces, has three main parts: sticky
stigma on top to catch pollen and a
style, a tube that leads to the third
part, the ovary

23. Tissue System
• plant has tissue system
• dermal tissue system serves as the outer protective
covering from physical damage and pathogens
• in non-woody plants, it has epidermis, a single tissue and a
layer of tightly packed cell
• cuticle- a waxy coating of epidermal , helps prevent water
loss
• in woody plants, periderm is its protective tissue

24. Tissue System
• vascular tissue system transports the materials between
the roots and the shoots
(two types)
1. Xylem
-conducts water and dissolved minerals upward
2. Phloem
-transports sugar

25. Tissue System
• stele is the vascular tissue of a root collected
• both xylem and phloem are composed of cells responsible in
the support and transfer system
• Cortex is in the ground tissue that is external to the
vascular tissue; the storage, photosynthesis and support

26. Tissue System

27. Meristems Generate Cells for New
Organ
• intermediate growth is the plant’s growth
• determinate growth is a certain size or limit of a plant
where they will stop from growing
• plants do die

28. Categories of Plant’s Life
• Annual
-completes from germination to flowering to seed
production to death in a single year or less
• Biennial
-requires two general growing seasons to complete
• Perennial
-plants live in many years

29. Meristem
• the embryonic tissue that makes plants capable of growing
throughout life
(has two types)
1. apical meristem
- located at the tip of roots and shoots
2. axillary
- buds of shoots

30. Meristem (Primary growth)
• provides cells that enable the plant to grow and increase in
length
• allows roots to extend or penetrate to the soil and shoots to
increase their exposure to light
• in herbaceous (nonwoody) plants, pg produces all or almost
all, of the plant body

31. Mersitem (Secondary growth)
• woody plants grow in girth in the stem and roots which
results to an increase in thickness and no longer increase in
length

32. Meristem
(Vascular Cambium & Cork Camdium)
• the growth or increase in thickness is caused by the activity
of lateral meristems
• the vascular cambium adds layers of vascular tissue called
secondary xylem (wood) and secondary phloem.
• cork cambium replaces the epidermis with a thicker and
tougher periderm

33. Plant Classification
• classified according to their purpose of identification to
avoid confusion
• may use: scientific names for international level of
identification; by their local names or common names; by
their habitats; types of stem

34. Plant Classification (Habitat)
• Terrestrial- plant that grows on or in or from land
• Aerial- plants have roots above the ground
• Aquatic- plants that have adapted to living in aquatic
environments

35. Plant Classification (Stem- Woody,
Non-Woody)
• Woody- with hard stems and usually brown
• Non-Woody/ Herbaceous- has soft , smooth and usually
green stems

36. Plant Classification (Agronomic/Values)
• according to economic uses and values
• is not based on botanical classification plants

37. Plant Classification (Four Divisions)
1. Thallophytes- lacks true stem and leaves, do no produce
flowers or seeds and consists of one cell
- considered simplest and lowest form of plants
- sub-divided to: algae and fungi
-has no economic importance to farmers

38. Plant Classification (Four Divisions)
1. Bryophytes- lacks true stem and leaves, do no produce
flowers or seeds and consists of one cell but has stem-like
and leaf-like structures
- considered simplest and lowest form of plants
- sub-divided to: algae and fungi
-has no economic importance to farmers

39. Plant Classification (Four Divisions)
• Pteridophytes- known as fern plants
- has no immediate practical importance to farmers

40. Plant Classification (Four Divisions)
• Spermatophytes- are the highest form of plants that exist
on earth
- these are the flowering or seed-bearing plants which
comprise of 135,000 species

41. Plant Classification
• Spermatophytes
1. gymnosperm- seeds are naked
2. angiosperm- plant that has flowers and produces seeds
enclosed within a carpel

42. Plant Classification
• Angiosperm
1. Monocotyledonous- has only one cotyledon or seed leaf
2. Dicotyledonous- has two cotyledons or two seed leaves.

44. Growth Stages of Plants (Four Stages)
1. Vegetative- from seed germination where the young plant
embryo absorbs moisture and nutrients from the stored
food inside the seed
- seed swells and breaks the seed coat
- the root tip comes out and elongates downward
- the shoot will become the main stem
- leaves unfold and roots continue to grow and spread
- the plant is capable to process photosynthesis
- this will continue until roots, stem and leaves developed

45. Growth Stages of Plants (Four Stages)
2. Reproductive- starts with the formation of flower until
flower’s fully open and undergoes pollination followed by fruit
development
- the development of fruit will be affected according by
nutrition, light and temperature
- fertility for nutrition, light for photoperiodism and
temperature for development of flower

46. Growth Stages of Plants (Four Stages)
3. Ripening- when fruit reaches the period of maturity and
undergoes some characteristics qualitative changes
- includes softening of the flesh of the fruit and changes
in color and flavor

47. Growth Stages of Plants (Four Stages)
4. Senescence- start of full maturity of the plant which ends
in death
- classifies into: partial, the deterioration and death of
some parts of the plant; over-all senescence, the aging
and death of the entire plant

48. Internal Factors
• Genetic makeup is a specific characteristics or traits of a
plant that affects the factor of plant growth and
development
-various crops have observable differences inherited form
the parent plant; may be similar but not identical
- for the gene to develop the characteristics or traits it
must be subjected to a favorable environmental condition

49. Internal Factors
Physiological factors derived from functional process at the
cellular level in plants
• Organic chemical compounds produced in one part of the
plant and transported to another part commonly known as
hormone also affects the plant growth and development
• Auxin is the hormone that affects the cell elongation,
tropism, apical dominance and fruit development
• Giberellin is also involved during the stem elongation,
flowering and seed germination

50. Internal Factors
• Abscisic acid is responsible when stomatal is in closure, bud
and seed dormancy
• Ethylene is involved when the fruit undergoes ripening
period, leaf abscission and senescene
• Cytokinin is the hormone that promotes cell division and
elongation

51. Internal Factors
• Today, farmers consider the genetic makeup or
characteristics of the plant they intend to grow, examples:
resistance to pests and diseases, high yielding capacity or
production performance of the plant , and the growth
duration period of the crop

52. External Environment
• environmental factors that affect plant growth and
development is very important
• ensures the appropriate technologies in crop production and
productivity in terms of yield of the crops grown

53. External Environment
Plant Growths and Development
• temperature is very useful during photosynthesis,
transpiration and respiration
• high temperatures causes increase in respiration sometimes
above the rate of photosynthesis
• for growth to be occur:
photosynthesis must be greater than respiration

54. External Environment
• high temperature for warm-season crops can cause pollen to
become not viable during flowering stage (pepper or tomato)
• cool season crops are: cabbage, broccoli and celery
• also a warm-seasoned crops are: rice, corn and beans

55. Temp. Req. of Common Crops
Temperature Range
(Celsius)
Crops
7-13
(Low Temperature)
Asparagus, Cabbage, Cauliflower, Celery,
Garlic, Potato, Spinach, Lettuce
13-18
(Moderately High Temp.)
Snap beans, Sweet pepper, Carrot, Bunching
onion
18-30
(High Temperature)
Rice, Corn, Sweet potato, Taro. Winged bean,
Eggplant, Okra

56. Light
• Sun is the main source of light
• Although artificial light can also source of light ; basically,
plants derive physical energy from the sunlight which is very
important in the process of photosynthesis
• Plants vary in the amount of light they require to achieve
normal growth
• Some plants prefer full sunlight (corn & rice), other require
varying degrees of shade (broccoli, cabbage, lettuce)

57. Light
• Plants requires duration of exposure to sunlight which varies
from seasons and locations
• Photoperiodism is the response of plants to light duration
• Light affects flower development and maturity
• Plants tend to grow longer when influenced by photoperiodic
• The knowledge of photoperiodic reaction guides the farmers
to make proper schedule of planting

58. Light
• Example:
the winged bean is a short day plant. It flowers when the day
length is less then 11hours. So farmers should plant in the
month of August so that the flowering period will fall under
short day period. Planting in then long day period ( April &
May) is not on time because it will only flower during the
short days month (November)

59. Light
• The duration of light and dark periods also influences the
formation of storage organ of certain plants
• Long days hasten bulbing in onion;
• Short days hasten tuber formation in potato, root
enlargement in sweet potato and corn formation in taro
• In cucurbits, long day coupled with low temperature
produces male flower, short days with low temperature
produces female flower

60. Light
• It varies on the different intensities of light on how will the
crop react whether the crop is a shade or sun plant
• Shade plant are capable of lower photosynthesis rate than
sun plants, but respiration rate is correspondingly low
• So net photosynthetic rate is high at low light intensity
• Sun plants have higher light requirement than shade plants
• The amount of light higher in sun plants in which
photosynthesis is equal to respiration

61. Light
• It is important therefore that a farmer knows how each of
these characteristics of light affects crop production, so
they can adjust their agricultural practices

62. Light Level Crops
High Rice, Corn, Cucurbits, Eggplant,
Legumes, Potato, Tomato, Sweet Potato
Medium Allium, Asparagus, Carrot, Celery,
Brassica, Lettuce, Spinach, Taro
Low to Total
Darkness
Ginger, Bamboo shoots, Mushroom

63. Weather / Climate
• Weather plays a major role in determining the success of
agricultural pursuits
• Most field crops are dependent solely upon weather to
provide life‐sustaining water and energy
• Occasionally, adverse weather conditions can cause
production losses, especially if experienced during critical
stages of growth
• Weather changes each day and assumes a certain pattern
which repeats itself year after year
• Climate is the pattern of that particular location

64. Weather / Climate
• Each drop has a certain climatic requirement to attain
normal growth and development
• The growth and yield potential of the crop will greatly be
affected if there is no favorable climate
• Having also the knowledge on the prevailing climatic
condition in a particular place will help you in preparing
certain crops to be planted in the period or time of planting

65. Weather / Climate
Type I Climate
• Dry season from November to April
• Rainy season from May to October
• This type of climate can be found in Western Luzon,
Mindoro, Negros and Palawan.
• high mountains serves a protection from rain coming from
northwest so these places are free from strong typhoon

66. Weather / Climate
Type II Climate
• No distinct dry season but with pronounced strong rains
from November to January
• Can be found in Catanduanes,Sorsgogon, Eastern part of
Albay, Eastern and Western part of Camarines Norte and
Camarines Sur, greater part of eastern Quezon, Samar,
Leyte and Mindanao.
• Has no protection against thunder storm and rain

67. Weather / Climate
Type III Climate
• No pronounced season
• Dry season from November to April
• Rainy season for the rest of the months
• No pronounced thunder rain and short dry season only lasts
for 3mos
• Western part of Cagayan, Isabela, Nueva Vizcaya, eastern
part of Mountain Province, Northern Quezon, Masbate,
Romblon, s.Panay, e.Negros, Central and Northern Cebu,
southern part of Mindanao & almost e. Palawan

68. Weather / Climate
• The said places were said to have protection from thunder
storm but affected by typhoon coming from northeast.

69. Weather / Climate
Type IV Climate
• Have equal rain throughout the year

70. Diseases & Insects
• Leads to reduction in yield which is determined on how
severe the damage is and the percentage of plant part that
is damaged or infected
• The damages on plant leaf will reduce the amount of good
manufactured in the process of photosynthesis
• Some may be prevented by planting disease resistant
varieties of plants and by applying agricultural practices like
integrated pests management

71. “Plant life is vital as a source of food.”