JSS 1 Agricultural Science First Term Week 8 and 9
WEEK 8
Plant Forms
Aquatic plants : are plants that have adapted to living in aquatic environments (saltwater or freshwater ). They are also referred to as hydrophytes or macrophytes .
These plants require special adaptations for living submerged in water, or at the water's surface.
The principal factor controlling the distribution of aquatic plants is the depth and duration of flooding.
However, other factors may also control their distribution, abundance, and growth form, including nutrients, disturbance from waves, grazing, and salinity.
One of the largest aquatic plants in the world is the Amazon water lily ; one of the smallest is the minute duckweed .
Many small aquatic animals use plants like duckweed for a home, or for protection from predators, but areas with more vegetation are likely to have more predators. Some other familiar examples of aquatic plants might include floating heart , water lily , lotus , and water hyacinth .
A terrestrial plant: is a plant that grows on or in or from land.
WEEK 9
Classification of crops based on life span
Annual, Perennial, Biennial
Annual plants - Plants that perform their entire life cycle from seed to flower
Annual Plains Coreopsis
to seed within a single growing season. All roots, stems and leaves of the plant die annually. Only the dormant seed bridges the gap between one generation and the next.
Biennial plants - Plants which require two years to complete their life cycle.
Perennial Plants - Plants that persist for many growing seasons. Generally the top portion of the plant dies back each winter and regrows the following spring
Perennial Purple Coneflower
from the same root system (e.g. Purple Coneflower).
Many perennial plants do keep their leaves year round and offer attractive borders and ground cover (e.g. Tickseed, Shasta and Ox-Eyed Daisy).
