Exam 32: Plant Nutrition and Transport

On a trip to the Southwest United States, you and a friend collect some seeds from a piñon, a type of pine tree. Your friend also gathers a small bagful of soil from under the piñon tree. Back home, both of you plant your seeds in commercial sterilized potting soil, but your friend adds a spoonful of the collected dirt to each of her pots. Her seedlings do better than yours. What is the likeliest explanation for your differences?

The loss of water from the leaves of plants is

Where do plants get most of their mass?

Generally speaking, fluids in plants are

Plants are sometimes used for phytoremediation in areas where the soil has been contaminated with heavy metals. Suppose the Acme Remediation Company is proposing to remediate a contaminated area that you wish to restore. Acme presents you with the following data as evidence of their company's ability to remediate soil. -The CEO of Acme Remediation Company is always trying to improve the company's effectiveness by keeping up with current research. Which research topic should have the highest priority for that research?

The corporation Bayer produces an herbicide called Liberty and the LibertyLink soybean, a genetically modified soybean that is resistant to this herbicide. The genetic modification allows soybeans to produce a protein that is able to destroy the Liberty herbicide. Thus, when a farmer sprays the Liberty herbicide on a weed-infested field of LibertyLink soybeans, only susceptible weeds, and not the farmer's soybean crop, die. One weed that farmers would like to get rid of is dodder (Cuscuta pentagona) a plant that uses chemical cues to find other plants such as soybeans. When a soybean plant is found, dodder wraps its leafless stems around the soybean and uses modified roots to tap into the soybean's vascular system. Because of the physical connection between a soybean plant and dodder, scientists hypothesized that dodder could obtain substances from the soybean plant other than nutrients, sugar, and water. They predicted that dodder would be able to gain the protein that destroys the Liberty herbicide. They tested this hypothesis by growing dodder on LibertyLinksoybeans and then applying the Liberty herbicide to see if the dodder would die. Their results are displayed in the table. Concentration of Herbicide (/) Treatment 0 0.36 0.72 3.6 Dodder on LibertyLink soybean Survived Survived Survived Died Dodder on normal soybean Survived Died Died Died Source: Adapted from Jiang, L., Qu, F., Li, Z., & Doohan, D. (2013). Inter‐species protein trafficking endows dodder (Cuscuta pentagona) with a host‐specific herbicide‐tolerant trait. New Phytologist, 198(4), 1017-1022. -Dodder gains nutrients by being a(n)

The pores that facilitate gas exchange in plant leaves are called

-What is true of the guard cells shown in the right-hand panel of this figure?

Which essential nutrient is most likely to leach from the soil?

Which sequence of structures through which water passes into a root is correct?

A gardener planted large, healthy flower bulbs in her garden. When spring arrived, green shoots emerged from the bulbs, and some of them, but not all, produced flowers. She decided to dig up a few bulbs that flowered and a few that didn't to see if she could see what the difference was. She was stunned to find that none of the bulbs looked healthy; they all appeared much smaller. What had happened?

Over the next several decades, world population growth will necessitate as much as a 60% increase in food production, primarily in developing countries. These countries are often the most seriously affected by drought and salinity. Even if irrigation water is available, flooding fields with irrigation water leads to the gradual accumulation of sodium ions and other salts in the soil. To respond to this growing problem, scientists at the University of Connecticut have genetically engineered a plant that can survive in salty soil and withstand extended drought conditions. The new transgenic plant contains a gene for an ion pump. Salt ions are transported from the soil and stored in vacuoles in the cytoplasm. The enhanced uptake of ions into their vacuoles in turn improves water retention in the transgenic plants and their resistance to drought. The concentration of solutes inside and outside plant cells affects the direction of water movement through osmosis. The researchers found that the salt concentration in the cells of the new transgenic plants was significantly higher than in wild plants used as a control. In addition, the transgenic plants survived longer when deprived of water. -The experimental plants were more drought resistant because

Plants are sometimes used for phytoremediation in areas where the soil has been contaminated with heavy metals. Suppose the Acme Remediation Company is proposing to remediate a contaminated area that you wish to restore. Acme presents you with the following data as evidence of their company's ability to remediate soil. -The data provide evidence for which of the following?

Which essential macronutrient for plants is obtained directly from the air?

What is the role of the fungus in a mycorrhizal association?

The water pressure gradient in phloem tubes is formed by the

If a plant is kept in the dark

Why was drip irrigation developed?

Commercial inorganic fertilizers have greatly increased agricultural productivity. What is an advantage of using inorganic rather than organic fertilizers?

What can you conclude from this figure?