Zeatin is a
cytokinin
Cytokinins (CK) are a class of plant hormones that promote cell division, or cytokinesis, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and lea ...
derived from
adenine
Adenine () ( symbol A or Ade) is a nucleobase (a purine derivative). It is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The three others are guanine, cytosine and thymine. Its derivati ...
, which occurs in the form of a ''cis''- and a ''trans''-
isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers.
Iso ...
and conjugates. Zeatin was discovered in immature corn kernels from the genus ''
Zea''. It promotes growth of lateral buds and when sprayed on
meristem
The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells conti ...
s stimulates cell division to produce bushier plants.
Occurrence
Zeatin and its derivatives occur in many
plant extract
An extract is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol, oil or water. Extracts may be sold as tinctures, absolutes or in powder form.
The aromatic principles of many spices, nuts, ...
s and are the active ingredient in
coconut milk
Coconut milk is an opaque, milky-white liquid extracted from the grated pulp of mature coconuts. The opacity and rich taste of coconut milk are due to its high oil content, most of which is saturated fat. Coconut milk is a traditional food i ...
, which causes plant growth.
6-(γ,γ-Dimethylallylamino)purine is a zeatin precursor.
Application
Zeatin has a variety of effects including:
# Promotes callus initiation when combined with auxin, concentration 1 ppm.
# Promotes fruit set. Zeatin 100 ppm + GA3 500 ppm + NAA 20 ppm, sprayed at 10th, 25th, 40th day after blossom.
# Retards yellowing for vegetables, 20 ppm, sprayed.
# Causes auxiliary stems to grow and flower.
Zeatin can also be applied to stimulate seed germination and seedling growth.
Zeatin has also been shown to promote the resistance of
tobacco
Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the ...
against the bacterial
pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
''
Pseudomonas syringae
''Pseudomonas syringae'' is a rod-shaped, Gram-negative bacterium with polar flagella. As a plant pathogen, it can infect a wide range of species, and exists as over 50 different pathovars, all of which are available to researchers from internat ...
'', in which ''trans''-zeatin has a more prominent effect than ''cis''-zeatin.
References
{{reflist
External links
Cytokinins
Cytokinins
Purines
Aging-related substances in plants