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).
Like other organisms, plant cells are grouped together into various tissues. These tissues can be simple, consisting of a single cell type, or complex, consisting of more than one cell type. Above and beyond tissues, plants also have a higher level of structure called plant tissue systems.ylem and phloem throughout the plant make up the vascular tissue system. They allow water and other nutrients to be transported throughout the plant. Xylem is consists of two types of cells known as tracheids and vessel elements.