Terrariums

**You will need to keep the plants alive throughout the semester so you can describe and document their progress for lab points. Follow directions below carefully.

Plant Terrariums

(this exercise is adapted from Zooinverse / MicroPlants Team: Botanical Collections at the Field Museum https://static.zooniverse.org/microplants.fieldmuseum.org/pdfs/MossLiverwortTerrarium.pdf)

Background

The bryophytes are lycophytes comprise a collection of some of the first plants to diverge from other terrestrial plants.

• Bryophytes: This group includes both mosses and liverworts. These groups have in common that they are land plants that lack well-developed, specialized tissue for conducting water and nutrients.This tissue is called vascular tissue - because bryophytes lack it, they are called non-vascular plants.
• Lycophytes: Unlike bryophytes, lycophytes have vascular tissue. This makes lycophytes vascular plants. However lycophyte leaves each have only a single vein. This trait differs from all other vascular plants, which have multiple branching veins in each leaf. Confusingly, spikemosses, despite their common name, are actually a kind of lycophyte (not a moss). Spikemosses may resemble true mosses, which accounts for their misleading common name, but they have vascular tissue and other traits (which we will discuss later in the semester) that differentiate them from bryophytes.

As we will discuss later in the semester, bryophytes have several traits that confine them to living in moist environments. Additionally, many are well adapted for shady environments. Some club mosses are also adapted for moist, shady environments. Moist, shady environments can be achieved creating terrariums, enclosed clear containers with plants and sometimes other organisms.

Goals

We will investigate effects of light levels on the absolute and relative growth rates of a bryophyte, a moss, and a clubmoss. Each of us will create two similar terrariums, one of which will be covered with a screen to reduce light levels. We will compare the growth of the three plants in each environment to see whether each fares better in high or low light and whether the patterns are similar or different between them.

Example of a terrarium in a glass jar. Licensed CC 2.0 by Luis Perez.

Provided supplies

4 clear plastic bowls (2 with holes, 2 without holes)

Bag of gravel

Bag of potting soil (with high peat concentration)

3 cups with plants

liverwort

moss

spikemoss (sometimes referred to as clubmoss below)

Ruler, Permanent marker, and stickers (from bag marked 'General')

Directions

(adapted from Zooinverse / MicroPlants Team: Botanical Collections at the Field Museum https://static.zooniverse.org/microplants.fieldmuseum.org/pdfs/MossLiverwortTerrarium.pdf)

• To the 2 bowls provided that do not have holes, add the provided gravel to the bottom . This will create a space for excess water that drains through the potting soil.
• Layer on top of the pebbles approximately 3.5 cm of moistened potting soil (or as much as you have if you have less). Do not pack the soil to the bottom of your container, but rather leave it loose and let it settle to the bottom naturally.
• On the top edge of the bowls, label one as "light" and one as "shade" so the labels can be seen in your photo. There should be a black permanent marker in your bag marked 'General' to accomplish this. Also put one of your identifying stickers (from the supplies bag labeled "general" on one of the dishes so I can tell that the photograph is yours).
• In both bowls, plant a liverwort thallus (marked L on side of packaging), a section of moss (marked M), and a section of spikemoss (marked C/S) at equal distances from one another, giving each plant plenty of space to flourish. The liverwort and moss should sit on the surface of the soil - press them gently against the soil to ensure contact. The spikemoss has roots that should be shallowly buried.
• Use tap water to water both dishes similarly. Drip water in until the soil looks uniformly brown. The internal environment should be moist, but not soggy, and it should not require frequent watering. It should be remoistened frequently - spraying with water daily is best, but it's fine to drip water across the surface every one - two days.
• Put the "shade" terrarium on the left and "light" terrarium on the right. Photograph the pair of dishes together in the same photograph with their lids off. and upload it on the Padlet terrarium page. Will will compare the photographs at the beginning of the semester to ones at the end to monitor changes over the next several weeks.

• After photographing, place one dish in an area with bright, but indirect light, such as near a window. Place the other dish in a shadier area, such as several feet way from a window. Alternatively, place one directly beneath a desk lamp (use the timer provided and set it for 12 hours of light and 12 hours of dark). Place the other near the edge of the area illuminated by the desk lamp. Cover both terrariums with with tops that have holes for ventilation.
• You should keep both dishes moist over the next several weeks, and we will appraise the growth the plants in both dishes periodically over this period. Finally, we will rephotograph the plants in both containers at the end of the semester.

Note to instructors:

Students place one terrarium in a brighter/ sunnier location & one in a shadier location. They submit initial photos to Padlet,, and they submit follow-up photos intermittently throughout the semester to the same Padlet (I organize the Padlet into columns, and each student gets their own column; it helps for instructor to pre-label columns with student names so they are in same order as gradebook.)

There is no consistent difference between light and shade terrariums across students, probably because of differences in watering and what they consider to be bright or more shaded. However, the replicate terrariums in different locations helps to ensure that one terrarium at least survives the semester.

I buy white pebble/gravel and potting soil from a garden store. I buy plastic disposable bowls from Amazon (not sure this is the same brand, but something like this linked bowl. I drill ~ 8 holes ~ 1/4" diameter in the "lid" bowls using a drill - before I started doing this, there were problems with fungus/mold.