Exam 29: Plant Structure and Function: Moving Photosynthesis Onto Land

You are studying two closely related tree species, one growing in a well-watered environment and one in a drier environment. You find that both species have similar photosynthetic rates and keep their stomata open for the same amount of time over the growing season, yet the species from the drier environment does not grow in height as quickly. A reasonable hypothesis for its slower growth might be that in the drier environment:

Guard cells can actively increase their volume and, therefore, size by:

Grapes growing on a vine are observed to shrink slightly during the day, only gaining in size at night. You decide to do an experiment where you sever the phloem, but not the xylem, of the stem that supplies a cluster of grapes. You expect to see that for the grapes in the experimental cluster:

Root activities are all passive, requiring no additional energy.

A wheat farmer is concerned that his land has been depleted of nitrogen. What steps can he take to make sure his wheat crops have enough nitrogen for the next season?

Which of the following is false regarding CAM?

A researcher determines that her favorite plant has a symbiotic relationship with fungi. Upon closer examination, she notices that fungal cells form a sheath enclosing the root tip, but no arbuscules are present. Of what type of mycorrhizae is this an example?

You are growing C₃ and C₄ plants in normal (21%) and low (1%) O₂ air, under both warm, well-lit conditions and cool, shady conditions. You find that, in general, the C₃ plants have a photosynthetic advantage over C₄ plants in:

At the "source" end of the phloem, sugar loaded into the phloem draws water into the sieve tubes by osmosis, raising the pressure. What happens to the water at the sink end?

Why would a farmer allow a field to be taken over by weedy, non-crop members of the bean family?

Although plants expend metabolic energy to move both water and carbohydrates between leaves and roots, the transportation of water requires slightly more energy.

A sieve element does NOT contain which of the following?

Which of the following groups contain vessels as their primary form of water transport?

You are evaluating novel varieties of C₃ rice that express PEP carboxylase and rubisco in both mesophyll and bundle-sheath cells for a project to develop rice plants that are capable of C₄ photosynthesis. Your MOST promising candidates are those for which the enzyme levels of:

Tracheids are shorter and typically narrower than vessels.

How do bryophytes avoid damage to their tissues from a dry environment?

Under what circumstances are leaves "sinks" for carbohydrates delivered by phloem?

One of the earliest evolutionary adaptations that helps plants to retain water in a terrestrial environment is the:

The waxy substance on leaf surfaces is the: