Exam 36: Regulation of Plant Growth

Refer to the figure below, showing the portion of the visible spectrum detected by a particular plant photoreceptor. What is the most likely response of a plant to this portion of the visible spectrum (i.e., 436 nm)?

The advantage of crops that produce more grain per plant is obvious, but the disadvantage is that such a plant is likely to bend over unless the properties of the stem are altered to grow in thickness rather than _______.

A biology class studying plant development is observing the germination of orange seeds.What structure are they most likely to observe emerging from the seed coat?

_______ causes the triple response in seedlings growing underground.

All of the following are plant hormones except

A plant scientist exposes the seeds of a model organism such as Arabidopsis to mutagenic substances.She then treats the resulting seedlings with a specific hormone and looks for individual plants with a unique physiological response.DNA sequencing of these mutants can reveal the underpinning of signal transduction pathways.This type of study is called a(n)

Explain why semi-dwarf varieties of wheat and rice can be more productive than traditional varieties.

Rapid progress in the elucidation of signal transduction pathways in plant hormone action has been made using the model plant, Arabidopsis thaliana.Genetic screens involve the following steps: 1.Mapping and cloning of a gene 2)Selection of a phenotype 3)Exposure of seeds to a chemical mutagen "4)Germination of the seeds and identification of mutants Which of the following shows these steps in their proper sequence?"

Which of the following is not involved in the polar transport of auxin?

Refer to the figure below. The seedless grapes on the right were most likely treated with _______ to make them grow larger.

What happens to auxin after it diffuses into a cell, trapping it in the cell until the auxin can be transported out at the base of the cell?

Genetic screens found two types of gibberellin-insensitive mutant strains: excessively tall plants and dwarf plants.These mutations affected _______ protein(s), a(n) _______ of a transcription factor.In the excessively tall plants, the growth-promoting genes controlled by gibberellin are always switched _______, whereas in dwarf plants they switched _______.

The delicate monocot shoot is protected by a sheath called the

Corn stunt spiroplasma (a bacterium) causes a great reduction in the growth rate of infected corn plants.Diseased plants take on a dwarfed form.Because their appearance is reminiscent of genetically dwarfed corn, you suspect that the bacterium may inhibit the synthesis of gibberellins by corn plants.Describe two experiments you might conduct to test this hypothesis, only one of which should require chemical measurement.

The first step in seed germination is called

To produce roots on a cutting from a fig tree, you would add

You run a genetic screen and find a mutant plant that is dwarf and infertile, with pollen tubes that fail to elongate.You conclude that the mutagen may have altered genes involved in one or more of the _______ hormone pathways.

Which process is not promoted by ethylene?

A botanist compares a wild-type plant to two different mutant plants of the same species.One of the mutants is small and has fewer cells than the wild type.The other has the normal number of cells, though each cell is much smaller than the cells in the wild-type plant.Which hormones are likely to be missing or not functioning properly in these two types of mutants?

Which of the following does not occur during the earliest stages of germination?