Biology chapter 36
micronutrients (aka trace elements) are elements that are needed in amounts equal to or less than
0.1g/kg of plant dry mass
macronutrients are elements that are generally required in at least
1g/kg of plant dry mass
water makes up what percentage of plant weight
90%
The concentration of a macronutrient in a plant is typically?
At least 1g/kg dry matter
most plant dry mass originates from
Carbon Dioxide
Soil additions that enhance plant growth by providing essential elements
Fertilizers
water provides what elements for organic compounds
Hydrogen and oxygen
why is humus a beneficial component of soil?
Lessens erosion, binds mineral nutrients to improve fertility, soft consistency fosters root growth
mutualistic associations of fungi and plant roots are called
Mycorrhizae
various soil bacteria transform nitrogen gas in the__________ into ammonia and nitrates
Nitrogen cycle
Plants adapted to shade typically have a ______ mesophyll layer, with ______ air spaces than do sun leaves.
Thinner; more
factors that affect the composition and thickness of soil horizons
Vegetation, climate, history of human impact, and bedrock type
Which nutrient is the source of most of the hydrogen atoms and some of the oxygen atoms in organic compounds?
Water
Since carbon dioxide is not maximized in nature for photosynthesis, it is
a big limiting factor
in plant-Bacteria Symbioses, nitrogen-fixing bacteria provides
a higher supply of fixed nitrogen than a plant could otherwise get from soil
most plants obtain carbon dioxide gas from the atmosphere(NOT SOIL) by
absorption through the stomata (pores that occur in the plant endermis)
Which of the following is a soil feature that enhances plant growth? a.)Compact with few air pockets b.)The presence of humus c.)Tendency to leach minerals d.)High proportion of silt
b.)The presence of humus
Atmospheric carbon dioxide levels: a.) have increased enough that carbon dioxide is not a limiting facot b.) are sometimes high enough to cause stomata to close c.) do not reach levels that saturate plant photosynthesis
c.) do not reach levels that saturate plant photosynthesis
leached elements often end up in natural bodies of water, where they foster(increase) the grown of
cyanobacteria, algae, and aquatic plants
when a plant receives too little of a nutrient, the plant develops
deficiency symptoms
deep lobes are produced by leaves in the sun to
dissipate heat
organic rich soils, containing 8% or so organic matter, are less likely to
erode
the process in which soil is washed away by water or blown away by wind
erosion
chemical elements that are required by plants for survival and play many roles in plant metabolism, often functioning as enzyme cofactors
essential elements
extra layers of palisade are created by leaves in the sun so that
extra light can be absorbed
the dissolution and removal of inorganic ions as water percolates through materials
leaching
heavy rainfall can reduce the fertility of soils by
leaching large amount of nutrients from them
water is split during what cycle of photosynthesis and provides what
light cycle; Electrons
water vacuoles help support plants by
maintaining hydrostatic pressure on the cell wall
In a hydroponics study, scientists observe chlorosis in one of the treatments. This is a sign of:
mineral deficiency
soil organic matter binds what
mineral nutrients
water is the solvent for mineral nutrients and is the main transport medium in plants, allowing the movement of what
minerals and other solutes throughout the plant body via the vascular tissues
excessive application of fertilizers can be detrimental because
minerals not taken up by plant roots are easily washed away
soil organic matter(a.k.a. humus) is largely derived from mostly
plant detritus, the dead and decaying remains of plants; and some from animal wastes and bodies
nitrogen can be a limiting nutrient for plant growth because
plants can't convert nitrogen gas(N2) to an organic form they need
pros and cons of verticle farming
pro: could provide fresh food in the middle of cities, no pesticides, year round, high yeild cons: expensive, high energy needs
in Plant-Bacteria Symbioses, soil bacteria can
produce plant hormones that affect root structure, help tolerate stress, or provide plants with nutrients
plants adapt to shading by
producing thin leaves, and producing more total chlorophyll
layers within a soil profile that are parallel to the soil surface.
soil Horizons
visible layers in the soil are called
soil horizons
limiting factors of plant growth
sunlight, water, carbon dioxide, and essential elements
all photosynthetic plants require light energy for what?
the formation of covalent bonds of organic compounds that make up the plant body
in mycorrhizal associations, soil fungi obtain organic food from
the roots of photosynthetic plant hosts
functions of water in plants
transport of solutes, source of hydrogen for photosynthesis
hydroponic farming-plants suspended over water mineral solution
vertical farming
in mycorrhizal associations, fungi supply the plants with
water and mineral nutrients
the transport of solutes and a major source of hydrogen for photosynthesis are functions of what
water in photosynthesis
physical and chemical breakdown of rock
weathering