These nematodes, sold under the names of Scanmask and Nemasys, are microscopic, wormlike creatures that will destroy the fungus gnats but are not harmful to people, pets, plants, or earthworms. These products can be used whenever the soil is not frozen and will keep working for many months.
Vegetative structures. There are three levels of integrated organization in the vegetative plant body: organ, tissue system, and tissue. The organs of the plantâthe roots, stems, and leavesâare composed of tissue systems (dermal tissue, ground tissue, and vascular tissue; see below Tissue systems).
Wikijunior:Biology/Tissues - Tissues. 1  Organisms are made of tissues. 2  When two or more tissues work together to do one thing they make up organs. 3  In plants, there are two types of tissues... 4  Meristematic tissue: This has actively dividing cells. 5  Permanent tissue: This type of tissue has developed cells.