9.1 Nutrition in plants (Book 1B, p. 9-3)
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A
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Plants as autotrophs 自養生物(Book 1B, p. 9-3)
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Ø Since plants are
able to use simple inorganic substances to make the (1) organic substances
(e.g. carbohydrates) they
need, they are known as (2) autotrophs (自養生物).
Their mode of nutrition is
called (3) autotrophic nutrition (自養營養).
Ø The process of making food is called (4) photosynthesis:
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Materials原料 / substrates基質
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n
(5)carbon dioxide in the air.
n
(6) water from the soil.
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Products產物
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Food [in
the form of (7) carbohydrates]
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By-product副產物
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(8) oxygen
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Energy source
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(9)Light energy is trapped by the (10) chlorophyll in green plants.
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Ø Word equation of photosynthesis:
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Light energy
(11) carbon
dioxide + water ---------------------à carbohydrates
+ oxygen
chlorophyll
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Ø Plants absorb (12) minerals (礦物質) from the soil. They are
vital for the synthesis of other materials needed by the plants.
Ø Plants are (13) producers (生產者). They serve as the basic food source for other organisms.
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B
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Mineral requirements
of plants (Book 1B, p. 9-4)
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Ø
For healthy growth, plants need to absorb a variety
of (14) minerals in the form of
(15) ions (離子) from the soil.
Ø
The elements that form these mineral ions can be
divided into two types:
n (16) major elements (大量元素)
n (17) trace elements
(微量元素)
Ø
Examples of major elements and their importance on
plant growth:
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Element
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Main function
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Deficiency symptom
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Nitrogen (N)
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n For the synthesis of (18) proteins
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n Poor growth
n
(19) yellow leaves
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Phosphorus (P)
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n For the synthesis of (20) nucleic acids
n Required in
some enzymatic reactions
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n Poor growth,
particularly of
(21) roots
n
(22) Purple patches on
leaves
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Potassium (K)
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n Promotes photosynthesis and the transport in plants
n Required in
some enzymatic reactions
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n Poor growth
n
Curled-up leaves with dark-coloured edges
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Magnesium (Mg)
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n For the synthesis of (23) chlorophyll
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n Poor growth
n
Yellow leaves
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