Abnormal Stomatal Behavior and Hormonal Imbalance in <i>flacca</i>, a Wilty Mutant of Tomato

Tal, Moshe; Imber, D.; Itai, Chanan

doi:10.1104/pp.46.3.367

Cited by 54 publications

(34 citation statements)

References 23 publications

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“…This suggestion is further supported by the conspicuous curing of the mutant by application of abscisic acid as found by the present authors (5). The possibility of a causal relationship between a lower amount of abscisic acid compounds and higher cytokinin activity (18) and their interaction on the stomatal mechanism is being studied.…”

Section: Discussionsupporting

confidence: 53%

“…This increased activity might contribute to the greater closing ability of the mutant stomata with age, in addition to the decrease of cytokinin activity reported before (18). This suggestion is put forward in view of the data showing that synthetic auxins induce closure of stomata of several plants (1,3,9,19,20) including tomato.…”

Section: Discussionmentioning

confidence: 84%

“…It does not follow the pattern characteristic of the normal plant, namely, inflorescence at every third leaf. It is possible that disturbances of hormone balance, indicated previously for kinetin (18) and in this paper for auxin, are responsible for the delayed and irregular flowering. of labeled leucine into leaf proteins, as stimulated by exogenous auxin (Fig.…”

Section: Rootingmentioning

confidence: 95%

“…While kinetin and, apparently, gibberellic acid stimulate stomatal opening (7,8,10), auxins and abscisic acid induce closure (1,3,9,19, 20 for auxins; 6, 11 for abscisic acid). These studies have been reviewed extensively by Tal et al (18), and only works dealing with auxin and abscisic acid effects on stomata will be discussed here.…”

mentioning

confidence: 99%

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Abnormal Stomatal Behavior and Hormonal Imbalance in flacca, a Wilty Mutant of Tomato

Tal¹,

Imber²

1970

Plant Physiol.

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The wilty tomato mutant, flacca, and the control variety, Rheinlands Ruhm, were compared with regard to the endogenous activity and concentration of auxin-and abscisic acid-like substances during ontogeny. The mutant wilts fast under water deficit because of inability to close its stomata. Symptoms characteristic of excessive auxin are evident in the developing mutant. Among these symptoms are branch and leaf epinasty, excessive rooting along the stem, and increased apical dominance. By using a leucineincorporation assay, spray of whole plants with 2,4-dichlorophenoxyacetic acid, and wheat coleoptile bioassay, indications were found of an excess of activity and concentration of auxin -like substances in shoots of young and mature mutant plants. The wheat coleoptile bioassay also revealed a much lower amount of substances with abscisic acid-like activity in the mutant compared with the normal plant. In contrast to the appearance during ontogeny of morphological symptoms characteristic of auxin excess in the mutant, the absolute amount of auxin-like substances and their activity in incorporation of leucine decreased with age. A parallel decrease of the concentration and activity of auxinlike compounds was also found in the normal plant. The concentration of abscisic acid-like substances increased with age in both genotypes. The disagreement between the increasing morphological symptoms and the decrease of auxin -like activity and concentration is discussed, together with the possibility of a causal relationship between auxinand abscisic acid-like activity and stomatal behavior.Stomatal mechanism is affected by the four groups of plant hormones, namely, kinins, auxins, possibly gibberellin, and abscisic acid. While kinetin and, apparently, gibberellic acid stimulate stomatal opening (7,8,10), auxins and abscisic acid induce closure (1,3,9, 19, 20 These authors also showed that abscisic acid inhibited most of the kinetin-stimulated transpiration.In the present series of studies, dealing with the hormonal imbalance in the wilty tomato mutant, flacca, an attempt has been made to correlate stomatal behavior with endogenous hormonal level. The wilting of theflacca mutant is caused by the abnormal behavior of its stomata. The mutant stomata resist closure in darkness as well as during water deficit (16). Tal et al. (18) suggested that excess kinetin-like activity was responsible for the excessive opening of the mutant stomata. The increased closing ability of the mutant stomata noted in older plants and leaves was explained by the decrease in kinetin-like activity. Tal (16) also indicated that some symptoms of auxin excess were evident in the mutant at maturity. These symptoms consisted of stem swelling and epinasty of branches and leaves, especially on the upper part of the plant. Other symptoms noted later were strong rooting along the stem, and delayed development of side shoots.Application of both the synthetic auxin, 2,4-D (17), and abscisic acid (5) caused stomatal closure in both normal and mutant plants...

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 84%

Section: Rootingmentioning

confidence: 95%

mentioning

confidence: 99%

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Abnormal Stomatal Behavior and Hormonal Imbalance in flacca, a Wilty Mutant of Tomato

Tal¹,

Imber²

1970

Plant Physiol.

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“…It is now well established that leaves of water-stressed plants contain more ABA (Wright, 1969;Milborrow and Noddle, 1970;Zeevart, 1971;Most, 1971) and less cytokinins Vaadia, 1965, 1971). Detailed investigations with the wilty mutant of tomato also indicated that wilting of plants was associated with the increase in cytokinin content and decrease in ABA Imber, 1970, 1971;Tal, Imber and Itai, 1970).…”

Section: Discussionmentioning

confidence: 99%

Reversal of Abscisic Acid Induced Stomatal Closure by Benzyl Adenine

1976

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SUMMARY Benzyl adenine enhanced stomatal opening in isolated epidermal strips of Commelina benghalensis and Tridax procumbens. The stimulation was maximum at a concentration of 5 × 10‐5 M BA. But kinetin had no remarkable effect on stomatal opening. The activity of benzyl adenine was observed over a narrow range of concentrations, from 10‐5 M to 10‐4 M. The increase in stomatal aperture was more pronounced in Commelina than in Tridax. Presence of benzyl adenine in the medium prevented the stomatal closure expected from abscisic acid and could reverse considerably the stomatal closure induced earlier by abscisic acid. It is felt that the balance between abscisic acid and cytokinins can possibly control the stomatal aperture effectively.

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Transpiration and Root Water Uptake

Willigen

Heinen

Kirkham

2005

Encyclopedia of Hydrological Sciences

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Root water uptake is one of the major components of the water balance of a soil. In this article, both the physical as well as the physiological aspects of root water uptake and transpiration are dealt with. The regulation of transpiration by different mechanisms on different levels (e.g. through hormones, adaptation of vessel diameter, root radius, and vertical extension of the root system) is discussed. Attention is paid to the modeling of water uptake by single roots and root systems. The last section deals with the different techniques used to measure root water uptake, for example, lysimeter, sap flow, inverse modeling, and discusses the advantages and disadvantages of the different methods.

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Abnormal Stomatal Behavior and Hormonal Imbalance in flacca, a Wilty Mutant of Tomato

Cited by 54 publications

References 23 publications

Abnormal Stomatal Behavior and Hormonal Imbalance in flacca, a Wilty Mutant of Tomato

Abnormal Stomatal Behavior and Hormonal Imbalance in flacca, a Wilty Mutant of Tomato

Reversal of Abscisic Acid Induced Stomatal Closure by Benzyl Adenine

Transpiration and Root Water Uptake

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