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In the embryo, root phloem develops independently in the upper hypocotyl, which lies between the embryonic root, and the cotyledon. [20] In an adult, the phloem originates, and grows outwards from, meristematic cells in the vascular cambium. Phloem is produced in phases. Primary phloem is laid down by the apical meristem and develops from the ...
Connective tissues are made up of cells separated by non-living material, which is called an extracellular matrix. This matrix can be liquid or rigid. For example, blood contains plasma as its matrix and bone's matrix is rigid. Connective tissue gives shape to organs and holds them in place.
In addition to hemocytes, the plasma also contains many chemicals. It is the major tissue type of the open circulatory system characteristic of arthropods (for example, arachnids, crustaceans and insects). [1] [2] In addition, some non-arthropods such as mollusks possess a hemolymphatic circulatory system.
Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue: the vascular cambium and the cork cambium.
JA travels through plants via the phloem, and accumulates in vascular tissue. [6] JA acts as an intracellular signal in order to promote responses in distal tissues. [6] The perception of jasmonate in distal responding leaves is necessary for recognition of the transmissible signal that coordinates responses to wounding stress. [5]
The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immunity or innate resistance against many microorganisms . [ 218 ]
Before the molecular era, the diagnosis of diseases caused by phytoplasma was difficult because the organisms could not be cultured. Thus, classical diagnostic techniques, including symptom observation, were used. Ultrathin sections of phloem tissue from plants with suspected phytoplasma-infections were also studied. [3]
Both these tissues are present in a vascular bundle, which in addition will include supporting and protective tissues. There is also a tissue between xylem and phloem, which is the cambium. The xylem typically lies towards the axis with phloem positioned away from the axis . In a stem or root this means that the xylem is closer to the centre of ...