Nutrition

 

Like all members of Kingdom Plantae, P. pungens is autotrophic, meaning it can create its own energy; it is unnecessary for it to consume other species. This organism is more specifically known as being photosynthetic. Photosynthesis is the process by which plants use energy from the sun to produce sugar. The reaction uses water (H₂O), carbon dioxide (CO₂) and sunlight to produce sugar (C₆H₁₂O₆) and oxygen (O₂) seen here:

Sunlight + 6H₂O + 6CO₂ à C₆H₁₂O₆ + O₂

The tree gets the necessary water from the ground, which it absorbs through its roots. Carbon dioxide is taken from the atmosphere by its leaves. Even more specifically, the CO₂ gas is transported across the cell wall by the stomata (or stomatal lines). Finally the energy required for the reaction comes from the sun in the form of solar power. To take in light from the sun, plants use chloroplasts with specialized green pigments called chlorophyll to convert unusable energy from the sun into chemical energy that they can use to fuel the photosynthesis reaction. This produces oxygen (what we breathe) and glucose (sugar) for the plant. Plants take this sugar and through cellular respiration generate energy (ATP). All plants, including the Blue Spruce store their food as starch.

Specialized structures within the spruce’s trunk allow for transport of this sugar, glucose, as well as water and many other substances. Vascular tissues called xylem and phloem (or click here), usually found together, help move sugars, water and other nutrients up, down, and to every part of the tree. To generalize the structures of each, the xylem moves water and nutrients up the trunk to the top of the tree and everywhere else necessary. The phloem moves sugars down to the roots and places in between. Moving water up, against the force of gravity is not an easy task. Here are a few properties of water that are vital to the UPWARD transport through the tree: water moves from an area of high water potential (low concentration) to low water potential (high concentration), water molecules are highly polarized and have a tendency to attach to one another (cohesion), and water molecules have a high affinity for other polar molecules (adhesion). Now, the question is, how does water get to the tops of trees? Water evaporating from leaves (transpiration) creates a lowered water potential of the mesophyll cells of the leaf. Due to the increased concentration of ions in the leaves, water from the high potential xylem moves into the low potential mesophyll cells. This reduces pressure in the xylem, which in turn draws water into the vessels. Adhesion and cohesion keep the chain from breaking and do not allow water molecules to detach from one another as they move up the trunk. Roots soak up water from the soil using this very same idea of water potential.

The Colorado Blue Spruce is quite tolerant to adverse conditions. It prefers moist, acidic soils, but can withstand dry soil, variant pH, and even winter salt spray, which makes it desirable for growth in colder climates.