Growth

Japanese Bloodgrass

Japanese bloodgrass (Imperata cylindrica), like all species of grass, is a member of the Poaceae family, also known as the Gramineae family. Grass, like most plants, needs three things in order to grow and survive: sunlight, water and nutrients (Harris, 2002).

In order to collect as much water and nutrients as possible, grass’ fibrous roots grow down into the earth, spreading out in different directions like fingers. The wide spread of the root system also helps to keep the grass secured to the ground (Harris, 2002). In the case of the Japanese bloodgrass, as much as 60% of the plant’s biomass consists of the rhizome root systems beneath the soil (Sellers et. al., 2002). This rhizome root system also helps the bloodgrass grow larger. The rhizomes are dense, preventing other plants from taking room in the same area as the grass. They also have sharp tips, which can pierce through the roots of other plants and trees, allowing the root system to continue to grow larger. (Pillion, 2017).

The red colour of the blades gives the bloodgrass its name (image from Wikimedia Commons)

The root systems also help the bloodgrass to thrive after wildfires. The bloodgrass burns far hotter than other plants, causing rapid-spreading wildfires at a temperature which can kill trees and other plants. While the grass above the soil burns, the roots system beneath remain unharmed. After the wildfire the tops of the plants grow back quicker and greenerwhile the roots begin to spread to areas previously occupied by now-destroyed trees and plants, allowing the bloodgrass plant to expand. The destruction of trees is particularly beneficial to the grass, as it exposes it to more sunlight. (Pillion, 2017).


Brewer’s Yeast

Brewer’s yeast (Saccharomyces cerevisiae), like all species of yeast, is a single-celled fungusIn order to grow, yeast must consume carbon-containing compounds. It can consume a wide variety of mono-, di- and trisaccharidesbut shows preference for glucose and fructose over other sugars (Broach, 2012). Yeast digests glucose through the process of fermentation, in both aerobic and anaerobic conditions, producing carbon dioxide and ethanol: 

C₆H₁₂O₆    →     2CO₂     +    2 C₂H₅OH     (+2ATP)

For every molecule of glucose digested, two molecules of ATP are produced. ATP is then converted to ADP through a hydrolysis reaction, releasing which can be used in the yeast’s cellular processes, including growth (Scitable, 2014). 

The carbon dioxide produced through yeast fermentation causes bread to rise (image from Pixabay)

Also required for the growth of yeast is oxygen (Battcock and Azam-Ali1998). Oxygen is not always necessary for the fermentation of sugarssome species of yeast can carry out the process without it—but it is essential for the organism’s growth. 


 

By Emma Bates