Exam 31: Plant Structure, Growth, and Reproduction

Plants differ from many animals because they undergo indeterminate (continual) growth. Indeterminate growth is common in clonal plants because a single clone can continually produce new clones without undergoing sexual reproduction, even if the plant is capable of doing so. Senescence, an inability to undergo cell division as an organism ages, also occurs in many plants and animals. However, scientists have had a difficult time establishing the occurrence of senescence in cloning plants because of their indeterminate growth patterns. Mutations in somatic cells are common during asexual growth, and these mutations lead to a decrease in sexual fitness. Scientists hypothesize that over time, as these mutations accumulate, they may contribute to senescence in clonal plants. To test this theory, scientists studied a naturally growing population of trembling aspen (Populus tremuloides), a tree species that grows clones from its root system but is capable of sexual reproduction. To determine if trembling aspens senesce, they compared genetic data of estimated tree age with the variable of "diminishing fertility": the amount of pollen released by male aspen trees. Here are the results for this part of the study: Source: Adapted from Ally, D., Ritland, K., & Otto, S. P. (2010). Aging in a long-lived clonal tree. PLoS Biol, 8(8): e1000454. doi:10.1371/journal.pbio.1000454. -What can the scientists conclude from the data?

In general, plant dermal tissues are found

In a flowering plant, the cells that give rise to sperm undergo meiosis in the

Foreign genes can be inserted into a single plant cell that is then cultured to produce

What is a function of a fruit?

What is a characteristic of eudicots?

-Which structure is the result of a generative cell with a thick wall around it?

-Which structure allows sufficient water to enter the leaf?

Flowers bear seeds that develop from ovules housed in protective chambers called

In Utah there is a clone of aspen trees that covers over 100 acres. Such clones can be considered to be a single plant with many stems. It appears that the first stem of this clone originated over 80,000 years ago, even before there were humans in North America. What likely contributes most to the long-term survival (long life span) of aspens?

Sieve-tube elements are food-conducting plant cells that are part of the

A woody plant lives through 5 years of drought, followed by 5 years of good growing conditions. The ring of xylem cells formed during the 5 good years will

Which cells provide flexible support to the growing parts of plants?

Rhizomes that end in enlarged structures that are specialized for storage are called

New growth that increases stem length on a plant arises mainly from

What is the evolutionary advantage of the very long life span of some plants?

-In which structure will meiosis occur?

The three tissue systems of a mature plant root complete their development in the root zone of

Removing the terminal bud of a plant that shows apical dominance will cause

A vascular cambium cell divides to produce an inner and an outer daughter cell. Which outcome represents the probable fate of these cells?