Xitôkinin – Cytokinin

 1. What is cytokinin (Cytokinin)? Cytokinin origin.

Cytokinin is the third group of plant hormones discovered after auxin and gibberellin in plant growth promoters.

Natural citrusin (Cytokinin) in plants was first extracted in 1963 by Letham and Miller in the crystalline form of corn kernels called zeatin, which is 10 to 100 times stronger than kinetin. It was then discovered that cytokinin is found in different plants and is an important group of growth promoters in plants.

Citrinin (Cytokinin) is produced in the root tops and in the growing seed, which is then transported through wood tissue from the roots to the stem.

Cytokinin plays a major role in cell division.

– The effect of cytokinin on cell growth in the tissue culture environment depends on the simultaneous presence of auxin, the ratio of cytokinin (Cytokinin) and auxin is important in determining transformation of new cells.

Cytokinin in plants: Zeatin (major) 2iP – 6 (di – methyl – allyl – amino) purine

Synthetic Cytokinin: Kinetin Benzyl Adenine (BA) Benzyl-Amino-Purine (BAP) Thidiazuron (TDZ)

2. Formulation composition of cytokinin (Cytokinin)

– Cytokinin (Cytokinin) is a derivative of the base of Adenine. There are many different types of cytokinins, most importantly kinetin and zeatin.

                                                                            Some typical cytokinin (cytokinin)

3. The Physiology of Cytokines (Cytokinin)

– Cytokinin stimulates cell division which stimulates cell growth

– The characteristic of cytokinin is the stimulation of strong cell division. So they are considered as cell division promoters, due to the fact that cytokinin strongly activates the synthesis of nucleic acids and proteins leading to cell division.

                                             Experiment on shoot and root distribution in kinetin Benzyl adenine (BA) and auxin NAA

– Citricin (Cytokinin) significantly affects the formation and division of organs of plants, especially the distribution of shoots. It has been shown that the balance between the rate of auxin (cytogenetic) and cytokinin (shoot metabolism) is crucial in morphogenesis of invitro culture tissue as well as in plants. intact. If the rate of auxin is higher than that of cytokinin, it stimulates rooting, while the ratio of cytokinin is higher than that of auxin.

In addition, cytokinin also interacts with auxin, cytokinin weakens the upturned phenomenon, causing the branching of many branches. Cytokinin also affects metabolic processes such as the synthesis of nucleic acids, proteins, cholorophyl and thus affects the physiological processes of the plant.

– In order to increase the multiplication factor, the concentration of cytokinin is increased in culture medium at the bud stage. In the root of the plant is the synthesis of cytokinin (Cytokinin) mainly so that the roots are strong, the formation of many cytokinin (Cytokinin) and stimulate shoots on the ground also formed many.

– Cytokinin slows the aging process of cells, tissues.

The effect of inhibiting aging, prolonging the life of organs can be demonstrated when rootwood is rooted, endogenous cytokinin (Cytokinin) roots and prolongs leaf life. The high content of cyanin (Cytokinin) leaves the leaf green for a long time as it increases the nutrient transport of leafy foliage. On the whole plant, when the root system grows well, it will make the young and grow well. If the roots are damaged, the ground organ will grow old.

– Cytokinin affects the germination of seeds and bulbs

Cytokinin in some cases affects the germination of seeds and bulbs. So if the treatment of cytokinin can break the sleep state of seeds, tubers and sleep buds.

4. Common types of cytokinin (Cytokinin):

Natural cystokines: Today, it is thought that kinetin is not a natural substance that is made up of a reorganization of another substance (Hecht, 1980), with at least one Two types of naturally occurring cytokinins have the same structure as the kinetin structure, which are free compounds or compounds bound to the glucoside or riboside group (Entsch et al., 1980). Two types of cytokinin (Cytokinin) commonly used in tissue culture are:

Zeatin: 4-Hydroxy-3-methyl-trans-2-butenylaminopurine, or 6- (4-hydro-3-methylbut-2-enyl) aminopurine or 2-methyl-4- (1H-purine- -2-buten-1-ol);

2-iP (IPA): N6- (2-isopentyl) adenine or 6- (3-methyl-2-butenylamino) purine.

Dihydrozeatin: 6 – (- hydroxy = 3 = methyl-trans-2-butenyl) aminopurine.

Synthetic cytokinins: Natural cytokines like 2-iP and zeatin are rarely used in experiments because of their high cost. Some synthetic compounds belonging to the cytokinin group commonly used in culture are:

Kinetin: 6-furfurylaminopurine or N-(2-furanylmethyl) -1H-purine-6-amine

+ Properties of some commonly used Cytokinin (Cytokinin)


Substance name Acronym Weight element Solvent Storage temperatures
In powder form Liquid
Adenine ADE 135.1 1.0 HCI 2 – 8oC
6-Benzylaminopurine BAP 225.3 1N NaOH 2 – 8oC
Zeatin ZEA 219.2 1N NaOH 0oC 0oC
6-(3-methyl-2-butenylamino)purine 2-iP 203.2 1N NaOH 0oC 0oC
Kinetin KIN 215.2 1N NaOH 0oC 0oC
1-phenyl-3(1,2,3 thiadiazol-5-yl) TDZ 220.2 DMSO 2 – 8oC
1,3-Diphenylurea DPU 212.3 DMSO 2 – 8oC

5. Application of Cytokinin (Cytokinin) in agricultural production

Use a coconut water solution (natural coconut milk nutrient solution and natural cytokinin) to soak sesame seeds before sowing and spraying on the leaves of the sesame plant (Sesamum indicum L.) to make the growth process. (seed germination rate, leaf area, fresh weight and dry weight), yield (number of fruits/trees, number of seeds/tree, weight of seeds/tree, weight of 1.000 seeds), grain qualities lipid, protein, glutamine content) has been improved.

– Controlling the number of male flowers, female flowers as you want: If the plant is unity from the seedlings but leaves only, excluding roots, the plant will make 85 – 90% male. On the contrary, if roots develop and remove leaves, most are females. As such, the leaves are capable of expressing males, while the roots express the males. Under medium conditions, there are leaves that are balanced sex. If the embryo is separated and cultured in an artificial medium and only 95% of the GA in the medium is GA. If only Cytokinin (Cytokinin) is 95 – 100% female.

For example: On pumpkin plants such as pumpkin, squash, melon, melon, cucumber, watermelon.

– Fruit and fruitless seed formation: After fertilization, fertilization begins and is quickly established. Fruit growth is due to cell division especially due to rapid cell growth in the gourd. The rapid growth of size and volume of fruit is characteristic of fruit growth.

For example, an apple can grow 6000 times in 20 weeks of growth. Such rapid growth is due to the phyto-hormonal adjustment occurring in the embryo. In that role of cytokinin (Cytokinin) and the growth of the fruit is very large. In newly formed young contains more cytokinin (Cytokinin). Cytokinin stimulates cell division. Therefore, the first stage of citrus fruit production (Cytokinin) plays a very important role. The use of cytokinin (Cytokinin) can also increase the size of fruits such as auxin and GA.For example: apple, lemon, grapefruit …

Controlling aging through cropping and cytokinin use: Fertilizers and water are two important factors in determining the rate of aging of the plant and the plant. Nitrogen and water will cause the plants to grow strong, sprout more and increase the prolonged growth, flowering results slow. Liming and liming will make the tree to grow old, flowering soon because of the shortening time of growth. To control the flowering of flowers, bonsai trees often affect the root system because the roots are the body synthesize cytokinin (Cytokinin) – the hormone children.

– The kitesurfing technique is very familiar to kaleidoscope growers. In order to bloom at the same time and in the Lunar New Year, they are to be flied off the ground with the aim of limiting the growth of the roots – that is, limiting soil nutrients and solids. Particularly limited is the cytokinin source synthesized in the roots. The lack of cytokinin (Cytokinin), the buds stop growing and switch to flower distribution. In order for plants to flower, people often cut roots for the same purpose.

– Slow down the aging of vegetables by combining with some other types: Vegetables after harvesting very quickly broken, qualitative. Chlorophyll and protein content are reduced rapidly. Citricin (Cytokinin) and growth retardants inhibit the aging of vegetables during storage.

+ Cabbage: People sprayed with benzyl adenine (BA) concentration 20 – 40 ppm immediately after harvest can keep the green (chlorophyll content) longer than untreated cabbage. This shelf life may last a few days, even 2 – 3 weeks.

+ Lettuce: Lettuce leaves are yellowed very quickly after harvest. Spraying BA concentration 2.5 – 10 ppm can keep the lettuce leaf fresh and green for 3 – 5 days. It is possible to use CCC and SADH at concentrations of 10 to 50 ppm. It also has the effect of prolonging the storage life of lettuce for 5 – 10 days.

+ Cauliflower: With cauliflower after harvesting the yellowing and leaf loss of leaf quality. In the United States a solution of 10 ppm BA and 50 ppm 2.4 D and stored at 9oC, after 28 days of cauliflower remain blue.

+ Celery: A 10 ppm BA spray can be stored for 22 days. If BA treatment is preserved at 4oC, the duration will be 40 days.

– Restrain the aging of the fruit: ripening of the fruit also manifested the aging process of the fruit. Extending the ripening period of the fruit that inhibits aging is important in preserving fresh fruits as well as favorable for the harvesting season. Growth regulators are the means of prolonging fruit maturation. For example: orange, lemon, pink …

– Extend the life of cut flowers: Flowers after cutting from the tree will be very dying. Speed of aging depends on the cut flowers. Preventing senescence, extending the shelf life of cut flowers is a practical requirement. For example, the dog’s muzzle is using cytokinin and its derivatives are most effective, lasting up to 10 days compared to the untreated control of 4.7 days.

– Use of auxin and cytokinin (Cytokinin) to regulate the growth of organs (roots, buds) in tissue culture:

+ In order to accelerate the invitro, in the first stage need to control the growth of tissue to grow many shoots to increase multiplication. Thus, the concentration of xytokinin in the culture medium was increased.

+ In order to create a complete tree for the soil, the shoots are separated and transplanted into the rooting medium in which the amount of auxin is increased.

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