Phytochrome A Regulates Red-Light Induction of Phototropic Enhancement in Arabidopsis

Parks, Brian M.; Quail, Peter H.; Hangarter, Roger P.

doi:10.1104/pp.110.1.155

Cited by 123 publications

(111 citation statements)

References 35 publications

(40 reference statements)

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“…Within the limits of stability phy-1 is capable of mediating the effect of a FR-reversible induction by R-pulse irradiation. This is similar to recent results obtained with phyAand phyB-deficient Arabidopsis mutants (Parks et al, 1996), although FR reversion of phyA action has not been shown in these experiments. The disappearance of phy-1 exposes the action of the light-stable phy-s, which is either inactive or overcompensated in the presence of phy-I.…”

Section: Interpretation Of Growth and Mt-reorientation Datasupporting

confidence: 82%

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Separation of Photolabile-Phytochrome and Photostable-Phytochrome Actions on Growth and Microtubule Orientation in Maize Coleoptiles (A Physiological Approach)

Fischer

Schöpfer

1997

Plant Physiology

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For separating the physiological actions of photolabile (phy-I) and photostable phytochromes, we compared the effects of red (R) and far-red (FR) light on elongation growth and microtubule reorientation in segments of maize (Zea mays L.) coleoptiles raised either in darkness (phy-l present) or preirradiated with R (phy-l eliminated). In 4.5-d-old dark-grown seedlings R first promoted growth and induced a transverse microtubule orientation. In continuous R the phytochrome action responsible for these responses was replaced by an opposite phytochrome action that produced a stable growth inhibition and longitudinal microtubule orientation. In R-preirradiated segments only the second type of phytochrome action could be observed. Reversion experiments with FR light pulses demonstrated that both types of phytochrome action were dependent on the FRabsorbing form of phytochrome and mirrored the actual phytochrome state after 1 h. We conclude from these and related results that growth promotion and transverse microtubule orientation are mediated by phy-I, whereas growth inhibition and longitudinal microtubule orientation are mediated by photostable phytochrome. The opposite actions of the two phytochromes can be separated by preirradiating the seedlings with R. Photoresponsiveness ascribed to phy-l disappeared after 5 d. phy-1 appears to play a distinct but transitory role in coleoptile development.

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Section: Interpretation Of Growth and Mt-reorientation Datasupporting

confidence: 82%

“…Moreover, there are indications for a response-specificity in the action of the two phytochromes. For instance, the R-induced enhancement of phototropism in Arabidopsis seedlings is specifically mediated by phyA (Parks et al, 1996).…”

Section: A Physiological Approachmentioning

confidence: 99%

Separation of Photolabile-Phytochrome and Photostable-Phytochrome Actions on Growth and Microtubule Orientation in Maize Coleoptiles (A Physiological Approach)

Fischer

Schöpfer

1997

Plant Physiology

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“…In studies of coleoptile phototropism and gravitropism in seedlings grown on clinostats, it was shown that decreased negative gravitropism could lead to increased phototropic curvatures (Shen-Miller & Gordan 1967;Nick & Schafer 1988). Because phytochrome activation by R enhances the development of phototropic curvature and can alter gravitropism, it has been suggested that R-induced enhancement of phototropism might be attributed in part to a change in gravitropism (Parks et al 1996). In Arabidopsis, the effect of R on gravitropism is consistent with this model, but in several other plants that display R-induced enhancement of phototropism, R treattnent resulted in a more robust gravitropic response (Wilkins & Goldstnith 1964;Woitzik & Mohr 1988).…”

Section: Gravitropism and Phototropismmentioning

confidence: 99%

Gravity, light and plant form

Hangarter

1997

Plant Cell & Environment

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Plants have evolved highly sensitive and selective mechanisms that detect and respond to various aspects of their environment. As a plant develops, it integrates the environmental information perceived by all of its sensory systems and adapts its growth to the prevailing environmental conditions. Light is of critical importance because plants depend on it for energy and, thus, survival. The quantity, quality and direction of light are perceived by several different photosensory systems that together regulate nearly all stages of plant development, presumably in order to maintain photosynthetic efficiency. Gravity provides an almost constant stimulus that is the source of critical spatial information about its surroundings and provides important cues for orientating plant growth. Gravity plays a particularly important role during the early stages of seedling growth by stimulating a negative gravitropic response in the primary shoot that orientates it towards the source of light, and a positive gravitropic response in the primary root that causes it to grow down into the soil, providing support and nutrient acquisition. Gravity also influences plant form during later stages of development through its effect on lateral organs and supporting structures. Thus, the final form of a plant depends on the cumulative effects of light, gravity and other environmental sensory inputs on endogenous developmental programs. This article is focused on developmental interactions modulated by light and gravity.

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“…A red-light pulse given prior to the blue-light phototropic stimulus causes a large increase in seedling curvature over the most effective range of blue-light fluences in the wild type but not in ih& phyA null mutants (Pai'ks, Quail & Hangarter 1996).…”

Section: Sensitization To Biue-iight Phototropic Signaismentioning

confidence: 99%