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