chapter 13 legumes

Question 1

Legume family

Answer 1

• legume (bean) family (Fabaceae)
• five petaled flower
• petals: 2 make up the banner, 2 make up the wings, and 1 makes up the keel
• fruit: legume
• seeds with 2 food-storing cotyledons

Question 2

Legume root nodules

Answer 2

• mutualism between plant and bacteria
• Rhizobium bacteria fixes atmospheric N into ammonia
• ammonia is converted to nitrates and nitrites by bacteria in soil that plants can absorb

Question 3

What are some benefits of genetically engineering nitrogen fixation in other crops?

Answer 3

• Other plants could fix their own N and would not need fertilizer that contains N in it

Question 4

Nitrogen fixation

Answer 4

• many times, is the most limiting factor in soil
• ironic because of its abundance in the atm
• N2 is fixed to ammonia (NH4+)
• ammonia fixed to nitrate (NO3-) and Nitrite (NO2-)
• soil is also negatively charged so they leak out of soil before being absorbed by the plant

Question 5

How is hypoxia in water caused by increased N2?

Answer 5

• oceans are typically low in mineral nutrients
• an increase in N leads to an increase in algae
• these algae eventually die
• this increases the organic matter in the water
• that leads to an increase in decomposing bacteria
• ultimately leading to a decrease in O2 in the water = hypoxia

Question 6

Human nutrition and legumes

Answer 6

• bean protein content: avg 25%

Question 7

Peanuts

Answer 7

• 300 uses of peanuts
• Son of Slave

Question 8

Soybeans

Answer 8

• domesticated in China 3,000 years ago
• little north American interest till 1920s
• phytoestrogens: lower LDL levels