Cattails can also germinate or root sprout in shallower water during dry periods. When the rain returns, they can then survive in deeper water providing that the shoots can remain above the water level. The cat s tails are actually the flowers of plant. At first glance, these plants appear similar but certain features can be used to easily distinguish them. The cattails have flowers which are brown, cigar-shaped structures on top of the stem whereas the bulrushes have flowers which are loosely clustered into tassels at the very tip of the stem.
Aerobic respiration provides energy much faster than anaerobic respiration.
The energy derived from respiration is utilized in many processes in the roots, a prominent one being the uptake of nutrients across the concentration gradient between the soil and the internal milieu of the root system. Because rooted emergent plants acquire most if not all of their nutrients from the soil, the necessity of supplying oxygen to the roots becomes obvious. The cattails provide an excellent example of how this is accomplished. The transfer of oxygen from the leaves to the roots of the cattail occurs in the lacunae , a system of interconnected, gas-filled chambers that run the length of the leaves and stems. Oxygen gas moves by diffusion down the pressure gradient that is established by the production of oxygen in the leaves during photosynthesis.