Flowering plants - SS2 Biology Lesson Note

In flowering plants, the excretory system is not as prominent or specialized as in animals. Plants have mechanisms to eliminate waste products and maintain homeostasis, but they do not possess dedicated excretory organs like kidneys. Instead, various plant structures and processes contribute to the excretion of waste materials. Here are some key aspects of the excretory system in flowering plants:

1. Stomata:

·         Stomata are small openings primarily found on the leaves, stems, and sometimes other plant parts.

·         These openings allow for gas exchange, including the release of oxygen produced during photosynthesis and the uptake of carbon dioxide.

·         In addition to gas exchange, stomata also play a role in the excretion of water vapor, which is a waste product of plant respiration.

2. Lenticels:

·         Lenticels are small, corky pores found on the stems and woody parts of plants.

·         They allow for gas exchange between the plant's internal tissues and the external environment.

·         Lenticels can also facilitate the release of waste gases, such as carbon dioxide and ethylene.

3. Guttation:

·         Guttation is a process in which liquid droplets are excreted from the tips of leaves or other plant structures.

·         It occurs when there is excess water pressure in the plant's vascular system, causing water to be forced out through specialized structures called hydathodes.

·         Guttation primarily helps in the excretion of excess water and dissolved minerals, but it can also contain small amounts of other waste products.

4. Shedding of Leaves and Bark:

·         Plants often shed old leaves and bark to eliminate waste materials and remove damaged or non-functional tissues.

·         This shedding process allows plants to get rid of waste products and make room for new growth.

5. Storage Structures:

·         Some plants store waste materials and toxins in specialized storage structures, such as vacuoles or trichomes.

·         These structures sequester or isolate waste products, preventing them from affecting vital plant functions.

Overall, while flowering plants lack a dedicated excretory system like animals, they have various mechanisms in place to excrete waste products and maintain proper balance within their tissues. These mechanisms ensure the removal of waste materials while supporting the plant's growth, development, and overall health.