ent-Kaurene Biosynthesis Is Enhanced by Long Photoperiods in the Long-Day Plants Spinacia oleracea L. and Agrostemma githago L

Zeevaart, Jan A. D.; Gage, Douglas A.

doi:10.1104/pp.101.1.25

Cited by 72 publications

(47 citation statements)

References 13 publications

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“…An example of an LD-induced increase in GA leve1 has been reported in Silene armeria (Talon and Zeevaart, 1992). Stimulation of ent-kaurene biosynthesis by LD conditions has been reported in spinach and in Agrostemma gitkago (Zeevaart and Gage, 1993). Alteration of sensitivity to GA by LD photoperiods has been proposed as a possible regulating mechanism for stem elongation in several species (Jones and Zeevaart, 1980;Metzger, 1985).…”

Section: Discussionmentioning

confidence: 99%

Differential Regulation of Trichome Formation on the Adaxial and Abaxial Leaf Surfaces by Gibberellins and Photoperiod in Arabidopsis thaliana (L.) Heynh

1996

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In wild-type (WT) Columbia and Landsberg erecfa ecotypes of Arabidopsis fhaliana (L.) Heynh., trichomes are present on the adaxial surfaces of all rosette leaves but are absent from the abaxial surfaces of the first-formed leaves. We have determined that both long-day (LD) photoperiod and gibberellin (CA) stimulate trichome formation. WT plants grown in L D conditions produce the first abaxial trichome on earlier leaves than plants grown in short-day (SD) conditions. Photoperiod sensitivity of abaxial trichome formation on WT plants develops gradually over time, reaching the maximum sensitivity about 24 d after germination. Application of gibberellic acid t o WT plants growing in SD conditions accelerates the onset of abaxial trichomes. Conversely, application of 20 to 80 mg LU' paclobutrazol, a CA biosynthesis inhibitor, t o wild-type plants suppresses trichome initiation on the abaxial epidermis. The CAdeficient mutants ga7-5 and ga4-7 and the GA-insensitive mutant g a t l exhibit delayed onset of abaxial trichomes when grown i n L D conditions. l h e null mutant gal-3 produces completely glabrous leaves when grown in SD conditions. Application of gibberellic acid to glabrous ga7-3 plants consistently induces earlier formation of trichomes on the adaxial epidermis than on the abaxial epidermis, demonstrating a difference between the adaxial and abaxial surfaces in their response to CA with regard t o trichome formation.A common feature of the leaves of dicotyledonous species is their dorsiventral asymmetry. If a leaf is cut through its midrib along the long axis of the leaf, the two sides separated by the incision are typically mirror images of each other. However, if the cut is made through the center of the mesophyll layer, parallel to the plane of the leaf surface, the two portions separated by the incision are dorsiventrally asymmetrical. This is because palisade mesophyll occurs immediately below the adaxial epidermis, whereas spongy mesophyll occurs immediately above the abaxial epidermis. Superficial features such as stomata, wax deposition, and trichomes are also often differentially distributed on the two leaf surfaces. Despite the widespread occurrence of dorsiventrality in leaf development, relatively little is known about the genes and the mecha-

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Section: Discussionmentioning

confidence: 99%

Differential Regulation of Trichome Formation on the Adaxial and Abaxial Leaf Surfaces by Gibberellins and Photoperiod in Arabidopsis thaliana (L.) Heynh

1996

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“…It is well known that the application of GAs to many rosette plants, including WT Arabidopsis grown in unfavorable conditions for flowering, promotes stem elongation and flower formation (Zeevaart, 1983;Napp-Zinn, 1985;Bagnall, 1992). LD and vernalization, which also promote bolting and flowering in rosette plants, have been shown to remove specific blocks in the GA biosynthetic pathway in these plants (Metzger, 1987;Hazebroek and Metzger, 1990;Burn et al, 1993;Zeevaart and Gage, 1993).…”

Section: Gibberellin Mutantsmentioning

confidence: 99%

Physiological Signals That Induce Flowering.

et al. 1993

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INTRODUCTIONThe timing of the transition from vegetative growth to flowering is of paramount importance in agriculture, horticulture, and plant breeding because flowering is the first step of sexual reproduction. Studies to understand how this transition is controlled have occupied countless physiologists during the past half century and have produced an almost unmanageably large amount of information (Bernier et al., 1981a; Halevy, 1985 Halevy, -1989Bernier, 1988;Kinet, 1993).A majority of plants use environmental cues to regulate the transition to flowering because all individuals of a species must flower synchronously for successful outcrossing and because all species must complete their sexual reproduction under favorable externa1 conditions. Any environmental variables exhibiting regular seasonal changes are potential factors that control the transition to flowering. The major factors are photoperiod, temperature, and water availability. Plants that do not require a particular photoperiod or temperature to flower, i.e., the so-called "autonomous-flowering" plants, are usually sensitive to irradiance. The environmental factors are perceived by different parts of the plant. Photoperiod and irradiance are perceived mainly by mature leaves in intact plants. Temperature is perceived by all plant parts, although low temperature (vernalization) is often perceived mainly by the shoot apex. Water availability is perceived by the root system.There are strong interactions between these different factors, so that each factor can change the threshold value for the effectiveness of the others. Plants, as opportunists, will thus make use of a different critical factor in different environments. Melilotus officinalis, for example, is a biennial with a vernalization requirement in temperate zones and an annual long-day (LD) plant with no cold requirement in arctic regions. In photoperiodic species, such as the short-day (SD) plant Pharbitis nil and the LD plant Silene armeria, flowering in unfavorable photoperiods can be caused by changing temperature, irradiance, or nutrition or by removing the roots. Similarly, in some late-flowering mutants of Arabidopsis, vernalization and an increase in the proportion of far-red light in the light source can substitute for one another in promoting the transition to flowering (Martínez-Zapater and Somerville, 1990; Bagnall, 1992). Clearly, there are alternate pathways to flowering in most, ifTo whom correspondence should be addressed. not all, plants. Because the different flowering-promoting factors are perceived by different parts of the plant, this implies that these parts interact and that the fate of the apical meristem-remaining vegetative or becoming reproductive-is controlled by an array of long-distance signals from the entire plant.The ability of subsets of plant parts to control flowering is also underscored by the fact that some plants may flower almost normally after complete defoliation (Hyoscyamus niger, red Perilla, Chenopodium amaranticolor) or derooting (Perilla, Loli...

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“…Moreover, in GA-deficient dwarf varieties of several species, exogenously applied GAs can promote stem elongation, proving that they are required for these responses (Ross, 1994). Induction of flowering by long days in rosette plants has been correlated with increased GA levels (Talon et al, 1991;Zeevaart and Gage, 1993). GA-deficient (ga) mutants of Arabidopsis flower late in long days and fail to flower at a11 in short days (Wilson et al, 1992).…”

Section: Arabidopsis Thaliana Has Five Genes Encoding Phytochrome Apomentioning

confidence: 99%

Phytochrome B Affects Responsiveness to Gibberellins in Arabidopsis

et al. 1996

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ent-Kaurene Biosynthesis Is Enhanced by Long Photoperiods in the Long-Day Plants Spinacia oleracea L. and Agrostemma githago L

Cited by 72 publications

References 13 publications

Differential Regulation of Trichome Formation on the Adaxial and Abaxial Leaf Surfaces by Gibberellins and Photoperiod in Arabidopsis thaliana (L.) Heynh

Differential Regulation of Trichome Formation on the Adaxial and Abaxial Leaf Surfaces by Gibberellins and Photoperiod in Arabidopsis thaliana (L.) Heynh

Physiological Signals That Induce Flowering.

Phytochrome B Affects Responsiveness to Gibberellins in Arabidopsis

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