Plants: Nutrition Flashcards
(20 cards)
What must a plant obtain to survive and grow?
inorganic substances
What are essential elements?
those that a plant must obtain to
* complete its life cycle of growth and have reproductive
success
How many macronutrients do pants require in relatively large amounts?
nine
How many micronutrients do plants require in relatively small amounts?
eight
Micronutrients often act as…
cofactors:
* chlorine
* iron
* manganese
* boron
* zinc
* copper
* nickel
* molybdenum
What are fertilizers?
compounds given to plants to promote growth
How can nutrient deficiencies be alleviated?
soil additives: inorganic chemical fertilizers, compost
What are the to most common nutritional problems for plants?
nitrogen and phophorus
Why do we have soil conservation?
Human practices in agriculture have degraded soils
* Irrigation can gradually make soil salty
* Plowed lands are subject to erosion by wind and rain, which
removes topsoil
* Chemical fertilizers are costly and may contaminate
groundwater
What are some soil conservation practices?
*water-conserving irrigation
* erosion control
* prudent use of herbicides and fertilizers
What is eutrophication?
runoff containing excess fertilizer used on nearby land
What are the four main components of soil?
inorganic minerals, organic matter, water, and air
What supplys plants with the nitrogen that they need?
bacteria
Plants cannot absorb nitrogen directly from the air as N2, what must it be converted to?
Ammonium (NH4+) or Nitrate (N03-)
How do soil bacter convert N2 gas from the air into forms usable by plants?
*Nitrogen-fixing bacteria convert atmospheric N2 to ammonia
(NH3 ) in a process called nitrogen fixation
* Ammonifying bacteria add to the supply of ammonium by
decomposing organic matter
* Nitrifying bacteria convert ammonium to nitrates (most
common form taken up by plants)
Plants form mutually beneficial symbioses with fungi (mycorrhizae) what do they do?
- act like extensions of plant roots, increasing the area for absorption
of water and minerals from soil - selectively absorb phosphate and other minerals from the soil
- release growth factors and antibiotics into the soil
- have evolved with plants and were important to plants successfully
invading land
Some plants from symbioses with nitrogen-fixing bacteria such as
- Legumes (peas, beans, alfalfa, and others) form root nodules to
house nitrogen-fixing symbionts in the genus Rhizobium - Other plants, such as alders, form symbioses with other kinds of
nitrogen-fixing bacteria
What are epiphytes (orchids)
*grow anchored on other plants
* absorb water and minerals from rain
What are parasitic plants (mistletoe)
- may not use photosynthesis
- use their roots to tap into the host plant’s vascular
system - absorb sugars and minerals from the host plan
What are carnivores (Venus flytrap)
- capture and digest small animals such as insects
- absorb inorganic elements from prey
- found in nutrient-poor environments
