Question

Trichomes are hairlike outgrowths of the epidermis of plants that are thought to provide protection against being eaten by herbivores (herbivory). In a certain plant species, stem trichome density is genetically determined. To investigate variation in stem trichome density within the plant species, a student counted the number of trichomes on the stems of six plants in each of three different populations. The student used the data to calculate the mean trichome density (number of hairs per square centimeter) for each population. The results are provided in the table below.

TRICHOME DENSITY IN THREE PLANT POPULATIONS (number of trichomes/cm2)

Population Plant 1 Plant 2 Plant 3 Plant 4 Plant 5 Plant 6 Sample Mean Standard Error of the Mean (SEM)
I 8 11 9 10 8 6 9 1
II 12 6 15 9 13 8 11 1
III 13 17 9 14 12 16 14 1
(a) On the axes provided, create an appropriately labeled graph to illustrate the sample means of the three populations to within 95 percent confidence (i.e., sample mean ± 2 SEM).

Answer 1

Trichomes are hair-like epidermal structures on plants that help reduce water loss, reflect solar radiation, and store defensive compounds against herbivores. A waxy cuticle also minimizes water loss, and some plants have multiple epidermal layers for added protection.

Step-by-step explanation:

Trichomes are specialized hair-like structures that exist on the epidermal surface of plants. They serve multiple functions, such as reducing transpiration by affecting the air flow over the leaf surface, increasing solar reflectance, and providing defense mechanisms against herbivores by storing substances that are toxic or unpleasant to them. Plants like xerophytes and epiphytes may have a thick covering of trichomes to further reduce water loss and protect against excessive transpiration.

In addition to reducing water loss through transpiration, a waxy layer called the cuticle covers the plant leaves to minimize water loss. This is especially important for plants that live in extreme temperature conditions. The combination of these structures, along with multiple epidermal layers in certain plant species, helps to protect plants from various environmental stresses.