Dormancy abscisic acid

Bagni, N., Malucelli, B., and Torrigiani, P., Polyamines, storage substances and abscisic acid-like inhibitors during dormancy and very early activation of Helianthus tuberosus tissue slices, Plant Physiol., 49, 341-345, 1980. 

There are two important classes of allelochemicals synthesized by oxidative cleavages of tetraterpene carotenoids. One is the plant hormone abscisic acid (ABA, 31) that plays important roles in growth and development of plants, especially in seed development and dormancy.17 Dry dormant seeds contain relatively large amounts of ABA, particularly in the seed coats. ABA and phenolic allelochemicals in the seed coats are easily released into the environment when the seeds are imbibed, resulting in inhibition of seed germination and seedling growth of plants in the vicinity. Both ABA and the phenolic compounds are rapidly broken down in the soil, and therefore the inhibition is short-lived. 

Over the intervening 25 years, there have been no mjor developments with respect to the use of abscisic acid, either in the native or derivatized form, in agriculture. The early premise that the oonpound showed for ocntrolling the breaking of dormancy in stored products such as Irish and sweet potatoes, onions, carrots, and other oonmodities, has not materialized. Nether has a use been... 

An interesting effect of Aceria attack on the abscisic acid and ethylene content in the fruits was recorded. This stressor increased the highest values of stimulating phytohormones also. These substances can disturb the dormancy and cause the highest germinability (Fiserova et al., 1999). 

On the basis of genetical and physiological studies it was concluded that plants hormones like abscisic acid and gibberelline play an important role in the regulation of dormancy and germination. They suggested molecular techniques for further investigation related to these two phenomena. 

C. rosicola has been shown to produce the plant hormone abscisic acid (8.19), which is sometimes known as the dormancy hormone. This plant hormone... 

Abscisic acid is a general plant-growth inhibitor. It induces dormancy and prevents seeds from germinating causes abscission of leaves, fruits, and flowers and causes stomata to close. High concentrations of abscisic acid in guard cells during periods of stress induced by drought probably have a role in stomatal closure. 

Growth inhibitors like abscisic acid (dormin) and abscisin II retard growth, promote abscission, and induce dormancy. They were discovered in the 1960s [18]. They directly affect cell division and expansion and induce stomatal closure [8]. 

I 18 The Identification of the Molecular Receptor of the Plant Hormone Abscisic Acid Dormancy Germination... 

K. Hasegawa and T. Hashimoto, Quantitative changes of batatasins and abscisic acid in relation to the development of dormancy in yam bulbils. 

Induction of dormancy during seed development by endogenous Abscisic-Add -studies on Abscisic-Acid deficient genotypes of Arabidopsis thaliana (L.) Heynh. Pknta, Vol.157, No.2, pp. 158-165, ISSN 0032-0935... 

Okamoto, M. Kuwahara, A. Seo, M. Kushiro, T. Asami, T. Hirai, N. Kamiya, Y. Koshiba, T. Nambara, E. (2006). CYP707A1 and CYP707A2, which encode abscisic acid 8 proper control of seed dormancy and germination in Arabidopsis. Plant Physiology, Vol.141, No.l, (May 2006), pp. 97-107, ISSN 0032-0889... 

Finally, another important hormonal factor (but not the last) is the abscisic acid (ABA). This compound is produced mainly in chloroplasts. Its main functions are stomata closure, seed dormancy and the inhibition of axiUaiy buds growth. The addition of ABA to in vitro embryogenic cultures inhibits the early embryo germination and stimulates the coordinated maturation of the somatic embryo. However, prolonged exposition to ABA, this element suppresses growth of the formed in vitro plants (Bozhkov et al., 2002). 

Abscisic acid (44) is involved in a number of hormonal roles in plants (Fig. 26.16) (Milborrow, 1983). This plant growth-regulating compound, probably found in all higher plants, acts as a growth inhibitor and is involved in bud and seed dormancy. (+ )-(5)-Abscisic acid is a potent effector of stomatal closure. Abscisic acid also is linked to water stress resistance in plants. To date, the presence of abscisic acid has not been confirmed in bryophytes (Milborrow and Netting, 1991). 

Dormancy in Cereals — Levels of and Response to Abscisic Acid... 

Lenton JR, Perry VM, Saunders PF (1972) Endogenous abscisic acid in relation to photoperiodically induced bud dormancy. Planta 106 13-22... 

Browning G (1973 a) Flower bud dormancy in Coffea arabica L. 1. Studies of gibberellin in flower buds and xylem sap and of abscisic acid in flower buds in relation to dormancy release. J Hortic Sci 48 29-41... 

Sondheimer E, Tzou DS, Galson EC (1968) Abscisic acid levels and seed dormancy. Plant Physiol (Bethesda) 43 1443-1447... 

Sondheimer E, Galson EC, Tinelli E, Walton DC (1974) The metabolism of hormones during seed germination and dormancy. IV. The metabolism of (S)-2- " C-abscisic acid in ash seed. Plant Physiol (Bethesda) 54 803-808 Steeves TA, Sussex IM (1972) Patterns in plant development. Prentice Hall, Englewood Cliffs... 

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