Tissue (biology) parts of the plant. The complex tissue consists of more than one type of cells which work together as a unit. Complex tissues help in the transportation of organic material, water, and minerals up and down the plants. That is why it is also known as conducting and vascular tissue. The common types of complex permanent tissue are: Xylem and phloem together form vascular bundles. Xylem consists of: Xylem serves as a chief conducting tissue of vascular plants. It is responsible for the conduction of water and mineral ions/salt. Xylem tissue is organized in a tube-like fashion along the main
Black bean aphid by the aphid to improve the flow of sap. To obtain enough protein, aphids need to suck large volumes of sap. The excess sugary fluid, honeydew, is secreted by the aphids. It adheres to plants, where it promotes growth of sooty molds. These are unsightly, reduce the surface area of the plant available for photosynthesis and may reduce the value of the crop. These aphids are also the vectors of about 30 plant viruses, mostly of the nonpersistent variety. The aphids may not be the original source of infection, but are instrumental in spreading the virus through the crop. Various