J. Shinkle - Academia.edu (original) (raw)

Papers by J. Shinkle

Research paper thumbnail of Cell Wall Free Space of Cucumis Hypocotyls Contains NAD and a Blue Light-Regulated Peroxidase Activity

PLANT PHYSIOLOGY, 1992

Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativu... more Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativus L.) hypocotyl sections by a low-speed centrifugation technique. The centrifugate contained NAD and peroxidase but no detectable cytoplasmic contamination, as indicated by the absence of the activity of glucose-6phosphate dehydrogenase from the cell wall solution. Peroxidase activity centrifuged from the cell wall of red light-grown cucumber hypocotyl section could be resolved into at least three cathodic isoforms and two anodic isoforms by isoelectric focusing. Treatment of red light-grown cucumber seedlings with a 10-minute pulse of high-intensity blue light increased the level of cell wall peroxidase by about 60% and caused a qualitative change in the anodic isoforms of this enzyme. The increase in peroxidase activity was detectable within 25 minutes after the start of the blue light pulse, was maximal at 35 minutes, and declined to control levels by 45 minutes of irradiation. The inhibitory effect of blue light on hypocotyl elongation was more rapid than the effect of blue light on total wall peroxidase activity, leading to the conclusion that growth and peroxidase activity are not causally related.

Research paper thumbnail of Uncorrelated changes in the distribution of stem elongation, tissue extensibility and cell wall peroxidase activity along hypocotyl axes of Cucumis seedlings exhibiting different patterns of growth

Uncorrelated changes in the distribution of stem elongation, tissue extensibility and cell wall peroxidase activity along hypocotyl axes of Cucumis seedlings exhibiting different patterns of growth

Plant Physiology and Biochemistry, 1993

Elongation rates of hypocotyl regions of cucumber (Cucumis sativum L.) grown in dim-red-light are... more Elongation rates of hypocotyl regions of cucumber (Cucumis sativum L.) grown in dim-red-light are similar along much of the stem axis, while dark-grown seedlings show a marked decline in elongation rate from the apex to the base. In vivo tissue extensibility measurements show that plastic extensibility was highest in the apical region of dark-grown seedlings, lowest in the basal region of dark grown plants, an exhibited similar, intermediate, values in both apical and basal tissue from dim-red-light grown seedlings. Cell wall peroxidase (EC 1.11.1.7) levels were determined in three stem regions for both dark-grown and dim-red-light grown seedlings

Research paper thumbnail of UV radiation in New Zealand: implications for grape quality

Here we report preliminary findings from current research on the effects of ultraviolet (UV) radi... more Here we report preliminary findings from current research on the effects of ultraviolet (UV) radiation on grape chemistry under New Zealand field conditions. Treatments were applied by shielding the fruit zone of Sauvignon Blanc vines from solar UV radiation with plastic filters that had differential transmission spectra. We hypothesised that the differential application of UV treatments will affect grape quality. High performance liquid chromatography was used to examine UV effects on grape quality characteristics. The results showed a number of UV-induced effects in grape berries. While grape morphology was affected mainly by UV-B, levels of UVabsorbing compounds in grape skins increased with decreasing UV wavelengths. This has implications for vineyard management and wine quality.

Research paper thumbnail of 565: UV-B-induced phototropism is mediated by a distinct photoreceptor

565: UV-B-induced phototropism is mediated by a distinct photoreceptor

abstracts.aspb.org

... photoreceptor. Authors: Shinkle, James, R. (A) Atkins, Alaina (A) Koenig, Anna-Lise (A) Barne... more ... photoreceptor. Authors: Shinkle, James, R. (A) Atkins, Alaina (A) Koenig, Anna-Lise (A) Barnes, Paul, W. (B). ... min. When the response to unilateral UV-B for Arabidopsis seedlings carrying the nph (non-phototrophic hypocotyl, Christie et al. ...

Research paper thumbnail of Poster: Education & Outreach

Poster: Education & Outreach

abstracts.aspb.org

As a part of a broader curriculum integration program, science peer-tutors (PTs) assist in lectur... more As a part of a broader curriculum integration program, science peer-tutors (PTs) assist in lecture sections of introductory science and mathematics courses supporting the" biomedical" curriculum. Initial funding was through a grant from the Howard Hughes ...

Research paper thumbnail of Auxin Concentration/Growth Relationship for Avena Coleoptile Sections from Seedlings Grown in Complete Darkness

PLANT PHYSIOLOGY, 1984

A biphasic auxin dose-response curve has been obtained for indoleacetic acid (IAA)-stimulated gro... more A biphasic auxin dose-response curve has been obtained for indoleacetic acid (IAA)-stimulated growth of subapical sections of coleoptiles from totally dark-grown oats (Arena sativa L. cv Lodi). The curve for growth at 6 h is composed of a log-linear phase and a modified bellshaped phase separated by a plateau. The curve is log-linear from 0.003 to 0.4 micromolar IAA when sections are incubated in pH 5.9 buffer. The plateau of IAA concentration-neutral growth is seen from 0.4 to 4.0 micromolar UIA. Further increase in growth occurs from 4.0 to 10 micromolar IAA. Changing the pH of the buffer from 5.9 to 5.5 or 6.2 changes the shape of the curve, shifting the plateau to lower IAA concentration, or abolishing it, respectively. The synthetic auxin 2,4dichlorophenoxyacetic acid also shows a biphasic dose-response curve, but the synthetic auxin 1-naphthalene acetic acid does not. The plateau is not affected by the auxin-transport inhibitor 2,3,5-triiodobenzoic acid. The plateau is eliminated by taking sections from coleoptiles grown under continuous dim red light. We advance a model to account for these results based on two modes of auxin uptake into the cell: carrier-mediated uptake and uptake via chemiosmotic diffusion.

Research paper thumbnail of Indole-3-acetic acid sensitization of phytochrome-controlled growth of coleoptile sections

Proceedings of the National Academy of Sciences, 1984

Addition of 6 ,iM indole-3-acetic acid (IAA) to incubation buffer increases the sensitivity of co... more Addition of 6 ,iM indole-3-acetic acid (IAA) to incubation buffer increases the sensitivity of coleoptile sections cut from dark-grown Avena sativa L. cv. Lodi to red light by a factor of 10,000, relative to the response in the absence of added IAA, without changing the maximum amount of lightinduced growth. From 0.03 to 4 IuM IAA sections show at least a 100-fold increase in sensitivity to red light relative to the response in the absence of added IAA. In this IAA concentration range, the light-induced increase in elongation shows two phases of response to red-light fluence, which are separated by a plateau. The biphasic fluence-response curve is also characteristic of the red-light-induced stimulation of coleoptile growth in intact dark-grown seedlings. The effect of IAA on the sensitivity of the phytochrome-mediated growth response appears to be on some step in the transduction of the phytochrome signal, rather than on the growth response itself.

Research paper thumbnail of Phytochrome induces changes in the immunodetectable level of a wall peroxidase that precede growth changes in maize seedlings

Proceedings of the National Academy of Sciences, 1989

The regulatory pigment phytochrome induces rapid and opposite growth changes in different regions... more The regulatory pigment phytochrome induces rapid and opposite growth changes in different regions of etiolated maize seedlings: it stimulates the elongation rate of coleoptiles and inhibits that of mesocotyls. As measured by a quantitative immunoassay, phytochrome also promotes rapid and opposite changes in the extractable content of a Mr 98,000

Research paper thumbnail of Optimization of red light-induced elongation in Avena coleoptile sections and properties of the phytochrome-mediated growth response

Optimization of red light-induced elongation in Avena coleoptile sections and properties of the phytochrome-mediated growth response

Plant, Cell and Environment, 1986

ABSTRACT

Research paper thumbnail of Absence of phyB inhibits hypocotyl elongation in dark-grown Ih cucumber seedlings: an active role for PrB

Absence of phyB inhibits hypocotyl elongation in dark-grown Ih cucumber seedlings: an active role for PrB

Plant, Cell and Environment, 1995

ABSTRACT

Research paper thumbnail of Dim-Red-Light-Induced Increase in Polar Auxin Transport in Cucumber Seedlings . I. Development of Altered Capacity, Velocity, and Response to Inhibitors

PLANT PHYSIOLOGY, 1998

A.M.J.)

Research paper thumbnail of Inhibition of Stem Elongation in Cucumis Seedlings by Blue Light Requires Calcium

PLANT PHYSIOLOGY, 1988

The effects of blue light and calcium on elongation of hypocotyl segments of Cucumber (Cucumis sa... more The effects of blue light and calcium on elongation of hypocotyl segments of Cucumber (Cucumis sativa L. cv Burpee's Pickier) were studied. Cucumber seedlings grown in dim red light showed a rapid decline in the rate of hypocotyl elongation when irradiated with high intensity (100 micromoles per square meter per second) blue light. In intact, 4-day-old seedlings the inhibition began within 2 minutes after the onset of bluelight irradiation and reached a maximum of approximately 55% within 4 minutes. Hypocotyl segments cut from 4-day-old seedlings also showed an inhibition of elongation in response to blue light when segments were floated on aqueous buffer and exposed to blue light for 3 hours. In the presence of 2 micromolar indole-3-acetic acid, blue light caused a 50% inhibition of elongation. Buffering free calcium in the incubation medium with 0.1 millimolar ethylene glycol bis(-aminoethyl ether)-N,N,N',N'tetraacetic acid eliminated the blue-light inhibition of segment elongation. Several experiments confirmed a specific requirement for calcium for the blue-light-induced inhibition of segment elongation. Treating segments with 0.2 micromolar fusicoccin abolished the inhibition of elongation by blue light as did buffering the medium at pH 4. Adding 1 milimolar ascorbate to incubation medium also eliminated the inhibition of segment elongation caused by blue light. Several compounds implicated in cellwall redox reactions alter the magnitude of the blue-light-induced inhibition. The activity of peroxidase isolated from the cell-wall free space of cucumber hypocotyls was inhibited by ascorbate and low pH. The results are consistent with the hypothesis that blue light inhibits elongation by inducing an increase in cell-wall peroxidase activity and implicate calcium ions in the response to blue light.

Research paper thumbnail of Photobiology of Phytochrome-Mediated Growth Responses in Sections of Stem Tissue from Etiolated Oats and Corn

PLANT PHYSIOLOGY, 1986

The far-red reversibility of the phytochrome-controlled stimulation of elongation of coleoptile s... more The far-red reversibility of the phytochrome-controlled stimulation of elongation of coleoptile sections by low fluence red light has been characterized in subapical coleoptile sections from dark-grown Avena sativa L., cv Lodi seedlings. The fluence dependence of the far-red reversal was the same whether or not the very low fluence response is also expressed. The capacity of far-red light to reverse the red lightinduced response began to decline if the far-red light was given more than 90 minutes after the red irradiation. Escape was complete if the far red irradiation was given more than 240 minutes after the red irradiation.

Research paper thumbnail of Ethylene Is Not Involved in the Blue Light-Induced Growth Inhibition of Red Light-Grown Peas

PLANT PHYSIOLOGY, 1992

Although the growth of intact plants is inhibited by irradiation with blue light, the growth rate... more Although the growth of intact plants is inhibited by irradiation with blue light, the growth rate of isolated stem segments is largely unaffected by blue light. We hypothesized that this loss of responsiveness was a result of ethylene production as part of the wounding response. However, we found no interaction between ethylene-and blue light-induced growth inhibition in darkor red light-grown seedlings of pea (Pisum sativum L.). Inhibition of growth begins in dark-grown seedlings exposed to blue light within 3 min of the onset of blue light, as was known for red light-grown seedlings. By contrast, ethylene-induced inhibition of growth occurs only after a lag of 20 to 30 min or more (dark-grown seedlings) or 60 min (red light-grown seedlings). Also, the inhibition response of red light-grown seedlings is the same whether ethylene is present from the onset of continuous blue-light treatment or not. Finally the spatial distribution of inhibition following blue light was different from that following ethylene treatment. 97 50 1 www.plantphysiol.org on July 28, 2016 -Published by www.plantphysiol.org Downloaded from

Research paper thumbnail of Adaptation to Dim-Red Light Leads to a Nongradient Pattern of Stem Elongation in Cucumis Seedlings

PLANT PHYSIOLOGY, 1992

Relative growth rate determinations on 5-millimeter regions of cucumber (Cucumis sativus L.) hypo... more Relative growth rate determinations on 5-millimeter regions of cucumber (Cucumis sativus L.) hypocotyls show that dim-red lightgrown seedlings have an even distribution of growth along the stem axis. This contrasts with the apical to basal graded decline in growth rate seen in dark-grown seedlings, including dark-grown cucumber seedlings used as controls in this study. Dark-grown seedlings convert to the nongradient pattern when transferred to dim-red light. The small amount of light required suggests that the change in developmental pattern may happen in the natural light environment.

Research paper thumbnail of Physiological Mechanism of the Auxin-Induced Increase in Light Sensitivity of Phytochrome-Mediated Growth Responses in Avena Coleoptile Sections

PLANT PHYSIOLOGY, 1985

The physiology of the auxin-induced 10,000-fold increase in light sensitivity of a phytochrome-me... more The physiology of the auxin-induced 10,000-fold increase in light sensitivity of a phytochrome-mediated growth response (Shinkle and Briggs, 1984 Proc Nati Acad Sci USA 81: 3742-3746) has been characterized in subapical coleoptile sections from dark-grown oat (Avena satita L. cv Lodi) seedlings. Six micromolar indole-3-acetic acid (IAA) must be present for 1 hour before to 2 hour after irradiation in order to confer maximal sensitivity to light. The direct effect of IAA on growth can be separated from its effect on light sensitivity. Several classes of synthetic auxins will substitute for IAA in inducing an increase in sensitivity to light, as will both the phytotoxin fusicoccin and treatment of sections with pH 4.5 buffer. The increase in sensitivity to light induced by 6 micromolar IAA is completely inhibited by buffering the sections at pH 5.9 with 30 millimolar 24N-morpholino)ethanesulfonic acid. These findings suggest that the capacity to respond to very low fluences of light is regulated by extracellular pH.

Research paper thumbnail of Effects of solar ultraviolet radiation and canopy manipulation on the biochemical composition of Sauvignon Blanc grapes

Effects of solar ultraviolet radiation and canopy manipulation on the biochemical composition of Sauvignon Blanc grapes

Australian Journal of Grape and Wine Research, 2012

ABSTRACT Background and Aims: New Zealand is exposed to relatively high solar ultraviolet (UV) ra... more ABSTRACT Background and Aims: New Zealand is exposed to relatively high solar ultraviolet (UV) radiation; such high irradiances of UV radiation having the potential to change the biochemical composition of plants. The aim of this study was to investigate the effects of UV radiation and the role of canopy leaves on berry biochemical composition in Vitis vinifera var. Sauvignon Blanc. Sauvignon Blanc is the major grape variety grown in New Zealand.Methods and Results: Leaves were removed from around the fruiting zones of vines and screens that altered UV radiation exposures were placed over the grape bunches. Samples taken throughout development were analysed for changes in total phenolic compounds (including flavonols), amino acids and methoxypyrazines. Total phenolic compounds increased substantially in response to UV‐B exposure and this was reflected in changes taking place within the skins of the berries. Flavonol levels were determined by UV‐B radiation exposure and accumulated to maximum concentrations at veraison, subsequently declining to harvest. UV radiation did not have a significant effect on the majority of amino acids or methoxypyrazine concentrations. The most noticeable change in amino acid and methoxypyrazine accumulation was caused by the presence of leaves over the fruiting zone, retaining these leaves maintained significantly higher concentrations in the berries at harvest.Conclusions: UV‐B radiation determines the composition of flavonols in the skins of grapes. Amino acid and methoxypyrazine concentrations are not predominantly determined by UV‐B, but retention of leaves over the fruiting zone promotes their accumulation in berries.Significance: Canopy manipulations are routinely used commercially in the vineyard to help control vigour and reduce disease pressure. The findings presented here are important for viticulturists to understand how management of the vine leaf canopy can determine the biochemical composition of the grapes and can therefore, ultimately affect wine quality.

Research paper thumbnail of Cell Wall Free Space of Cucumis Hypocotyls Contains NAD and a Blue Light-Regulated Peroxidase Activity

PLANT PHYSIOLOGY, 1992

Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativu... more Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativus L.) hypocotyl sections by a low-speed centrifugation technique. The centrifugate contained NAD and peroxidase but no detectable cytoplasmic contamination, as indicated by the absence of the activity of glucose-6phosphate dehydrogenase from the cell wall solution. Peroxidase activity centrifuged from the cell wall of red light-grown cucumber hypocotyl section could be resolved into at least three cathodic isoforms and two anodic isoforms by isoelectric focusing. Treatment of red light-grown cucumber seedlings with a 10-minute pulse of high-intensity blue light increased the level of cell wall peroxidase by about 60% and caused a qualitative change in the anodic isoforms of this enzyme. The increase in peroxidase activity was detectable within 25 minutes after the start of the blue light pulse, was maximal at 35 minutes, and declined to control levels by 45 minutes of irradiation. The inhibitory effect of blue light on hypocotyl elongation was more rapid than the effect of blue light on total wall peroxidase activity, leading to the conclusion that growth and peroxidase activity are not causally related.

Research paper thumbnail of Cell Wall Free Space of Cucumis Hypocotyls Contains NAD and a Blue Light-Regulated Peroxidase Activity

PLANT PHYSIOLOGY, 1992

Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativu... more Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativus L.) hypocotyl sections by a low-speed centrifugation technique. The centrifugate contained NAD and peroxidase but no detectable cytoplasmic contamination, as indicated by the absence of the activity of glucose-6phosphate dehydrogenase from the cell wall solution. Peroxidase activity centrifuged from the cell wall of red light-grown cucumber hypocotyl section could be resolved into at least three cathodic isoforms and two anodic isoforms by isoelectric focusing. Treatment of red light-grown cucumber seedlings with a 10-minute pulse of high-intensity blue light increased the level of cell wall peroxidase by about 60% and caused a qualitative change in the anodic isoforms of this enzyme. The increase in peroxidase activity was detectable within 25 minutes after the start of the blue light pulse, was maximal at 35 minutes, and declined to control levels by 45 minutes of irradiation. The inhibitory effect of blue light on hypocotyl elongation was more rapid than the effect of blue light on total wall peroxidase activity, leading to the conclusion that growth and peroxidase activity are not causally related.

Research paper thumbnail of Uncorrelated changes in the distribution of stem elongation, tissue extensibility and cell wall peroxidase activity along hypocotyl axes of Cucumis seedlings exhibiting different patterns of growth

Uncorrelated changes in the distribution of stem elongation, tissue extensibility and cell wall peroxidase activity along hypocotyl axes of Cucumis seedlings exhibiting different patterns of growth

Plant Physiology and Biochemistry, 1993

Elongation rates of hypocotyl regions of cucumber (Cucumis sativum L.) grown in dim-red-light are... more Elongation rates of hypocotyl regions of cucumber (Cucumis sativum L.) grown in dim-red-light are similar along much of the stem axis, while dark-grown seedlings show a marked decline in elongation rate from the apex to the base. In vivo tissue extensibility measurements show that plastic extensibility was highest in the apical region of dark-grown seedlings, lowest in the basal region of dark grown plants, an exhibited similar, intermediate, values in both apical and basal tissue from dim-red-light grown seedlings. Cell wall peroxidase (EC 1.11.1.7) levels were determined in three stem regions for both dark-grown and dim-red-light grown seedlings

Research paper thumbnail of UV radiation in New Zealand: implications for grape quality

Here we report preliminary findings from current research on the effects of ultraviolet (UV) radi... more Here we report preliminary findings from current research on the effects of ultraviolet (UV) radiation on grape chemistry under New Zealand field conditions. Treatments were applied by shielding the fruit zone of Sauvignon Blanc vines from solar UV radiation with plastic filters that had differential transmission spectra. We hypothesised that the differential application of UV treatments will affect grape quality. High performance liquid chromatography was used to examine UV effects on grape quality characteristics. The results showed a number of UV-induced effects in grape berries. While grape morphology was affected mainly by UV-B, levels of UVabsorbing compounds in grape skins increased with decreasing UV wavelengths. This has implications for vineyard management and wine quality.

Research paper thumbnail of 565: UV-B-induced phototropism is mediated by a distinct photoreceptor

565: UV-B-induced phototropism is mediated by a distinct photoreceptor

abstracts.aspb.org

... photoreceptor. Authors: Shinkle, James, R. (A) Atkins, Alaina (A) Koenig, Anna-Lise (A) Barne... more ... photoreceptor. Authors: Shinkle, James, R. (A) Atkins, Alaina (A) Koenig, Anna-Lise (A) Barnes, Paul, W. (B). ... min. When the response to unilateral UV-B for Arabidopsis seedlings carrying the nph (non-phototrophic hypocotyl, Christie et al. ...

Research paper thumbnail of Poster: Education & Outreach

Poster: Education & Outreach

abstracts.aspb.org

As a part of a broader curriculum integration program, science peer-tutors (PTs) assist in lectur... more As a part of a broader curriculum integration program, science peer-tutors (PTs) assist in lecture sections of introductory science and mathematics courses supporting the" biomedical" curriculum. Initial funding was through a grant from the Howard Hughes ...

Research paper thumbnail of Auxin Concentration/Growth Relationship for Avena Coleoptile Sections from Seedlings Grown in Complete Darkness

PLANT PHYSIOLOGY, 1984

A biphasic auxin dose-response curve has been obtained for indoleacetic acid (IAA)-stimulated gro... more A biphasic auxin dose-response curve has been obtained for indoleacetic acid (IAA)-stimulated growth of subapical sections of coleoptiles from totally dark-grown oats (Arena sativa L. cv Lodi). The curve for growth at 6 h is composed of a log-linear phase and a modified bellshaped phase separated by a plateau. The curve is log-linear from 0.003 to 0.4 micromolar IAA when sections are incubated in pH 5.9 buffer. The plateau of IAA concentration-neutral growth is seen from 0.4 to 4.0 micromolar UIA. Further increase in growth occurs from 4.0 to 10 micromolar IAA. Changing the pH of the buffer from 5.9 to 5.5 or 6.2 changes the shape of the curve, shifting the plateau to lower IAA concentration, or abolishing it, respectively. The synthetic auxin 2,4dichlorophenoxyacetic acid also shows a biphasic dose-response curve, but the synthetic auxin 1-naphthalene acetic acid does not. The plateau is not affected by the auxin-transport inhibitor 2,3,5-triiodobenzoic acid. The plateau is eliminated by taking sections from coleoptiles grown under continuous dim red light. We advance a model to account for these results based on two modes of auxin uptake into the cell: carrier-mediated uptake and uptake via chemiosmotic diffusion.

Research paper thumbnail of Indole-3-acetic acid sensitization of phytochrome-controlled growth of coleoptile sections

Proceedings of the National Academy of Sciences, 1984

Addition of 6 ,iM indole-3-acetic acid (IAA) to incubation buffer increases the sensitivity of co... more Addition of 6 ,iM indole-3-acetic acid (IAA) to incubation buffer increases the sensitivity of coleoptile sections cut from dark-grown Avena sativa L. cv. Lodi to red light by a factor of 10,000, relative to the response in the absence of added IAA, without changing the maximum amount of lightinduced growth. From 0.03 to 4 IuM IAA sections show at least a 100-fold increase in sensitivity to red light relative to the response in the absence of added IAA. In this IAA concentration range, the light-induced increase in elongation shows two phases of response to red-light fluence, which are separated by a plateau. The biphasic fluence-response curve is also characteristic of the red-light-induced stimulation of coleoptile growth in intact dark-grown seedlings. The effect of IAA on the sensitivity of the phytochrome-mediated growth response appears to be on some step in the transduction of the phytochrome signal, rather than on the growth response itself.

Research paper thumbnail of Phytochrome induces changes in the immunodetectable level of a wall peroxidase that precede growth changes in maize seedlings

Proceedings of the National Academy of Sciences, 1989

The regulatory pigment phytochrome induces rapid and opposite growth changes in different regions... more The regulatory pigment phytochrome induces rapid and opposite growth changes in different regions of etiolated maize seedlings: it stimulates the elongation rate of coleoptiles and inhibits that of mesocotyls. As measured by a quantitative immunoassay, phytochrome also promotes rapid and opposite changes in the extractable content of a Mr 98,000

Research paper thumbnail of Optimization of red light-induced elongation in Avena coleoptile sections and properties of the phytochrome-mediated growth response

Optimization of red light-induced elongation in Avena coleoptile sections and properties of the phytochrome-mediated growth response

Plant, Cell and Environment, 1986

ABSTRACT

Research paper thumbnail of Absence of phyB inhibits hypocotyl elongation in dark-grown Ih cucumber seedlings: an active role for PrB

Absence of phyB inhibits hypocotyl elongation in dark-grown Ih cucumber seedlings: an active role for PrB

Plant, Cell and Environment, 1995

ABSTRACT

Research paper thumbnail of Dim-Red-Light-Induced Increase in Polar Auxin Transport in Cucumber Seedlings . I. Development of Altered Capacity, Velocity, and Response to Inhibitors

PLANT PHYSIOLOGY, 1998

A.M.J.)

Research paper thumbnail of Inhibition of Stem Elongation in Cucumis Seedlings by Blue Light Requires Calcium

PLANT PHYSIOLOGY, 1988

The effects of blue light and calcium on elongation of hypocotyl segments of Cucumber (Cucumis sa... more The effects of blue light and calcium on elongation of hypocotyl segments of Cucumber (Cucumis sativa L. cv Burpee's Pickier) were studied. Cucumber seedlings grown in dim red light showed a rapid decline in the rate of hypocotyl elongation when irradiated with high intensity (100 micromoles per square meter per second) blue light. In intact, 4-day-old seedlings the inhibition began within 2 minutes after the onset of bluelight irradiation and reached a maximum of approximately 55% within 4 minutes. Hypocotyl segments cut from 4-day-old seedlings also showed an inhibition of elongation in response to blue light when segments were floated on aqueous buffer and exposed to blue light for 3 hours. In the presence of 2 micromolar indole-3-acetic acid, blue light caused a 50% inhibition of elongation. Buffering free calcium in the incubation medium with 0.1 millimolar ethylene glycol bis(-aminoethyl ether)-N,N,N',N'tetraacetic acid eliminated the blue-light inhibition of segment elongation. Several experiments confirmed a specific requirement for calcium for the blue-light-induced inhibition of segment elongation. Treating segments with 0.2 micromolar fusicoccin abolished the inhibition of elongation by blue light as did buffering the medium at pH 4. Adding 1 milimolar ascorbate to incubation medium also eliminated the inhibition of segment elongation caused by blue light. Several compounds implicated in cellwall redox reactions alter the magnitude of the blue-light-induced inhibition. The activity of peroxidase isolated from the cell-wall free space of cucumber hypocotyls was inhibited by ascorbate and low pH. The results are consistent with the hypothesis that blue light inhibits elongation by inducing an increase in cell-wall peroxidase activity and implicate calcium ions in the response to blue light.

Research paper thumbnail of Photobiology of Phytochrome-Mediated Growth Responses in Sections of Stem Tissue from Etiolated Oats and Corn

PLANT PHYSIOLOGY, 1986

The far-red reversibility of the phytochrome-controlled stimulation of elongation of coleoptile s... more The far-red reversibility of the phytochrome-controlled stimulation of elongation of coleoptile sections by low fluence red light has been characterized in subapical coleoptile sections from dark-grown Avena sativa L., cv Lodi seedlings. The fluence dependence of the far-red reversal was the same whether or not the very low fluence response is also expressed. The capacity of far-red light to reverse the red lightinduced response began to decline if the far-red light was given more than 90 minutes after the red irradiation. Escape was complete if the far red irradiation was given more than 240 minutes after the red irradiation.

Research paper thumbnail of Ethylene Is Not Involved in the Blue Light-Induced Growth Inhibition of Red Light-Grown Peas

PLANT PHYSIOLOGY, 1992

Although the growth of intact plants is inhibited by irradiation with blue light, the growth rate... more Although the growth of intact plants is inhibited by irradiation with blue light, the growth rate of isolated stem segments is largely unaffected by blue light. We hypothesized that this loss of responsiveness was a result of ethylene production as part of the wounding response. However, we found no interaction between ethylene-and blue light-induced growth inhibition in darkor red light-grown seedlings of pea (Pisum sativum L.). Inhibition of growth begins in dark-grown seedlings exposed to blue light within 3 min of the onset of blue light, as was known for red light-grown seedlings. By contrast, ethylene-induced inhibition of growth occurs only after a lag of 20 to 30 min or more (dark-grown seedlings) or 60 min (red light-grown seedlings). Also, the inhibition response of red light-grown seedlings is the same whether ethylene is present from the onset of continuous blue-light treatment or not. Finally the spatial distribution of inhibition following blue light was different from that following ethylene treatment. 97 50 1 www.plantphysiol.org on July 28, 2016 -Published by www.plantphysiol.org Downloaded from

Research paper thumbnail of Adaptation to Dim-Red Light Leads to a Nongradient Pattern of Stem Elongation in Cucumis Seedlings

PLANT PHYSIOLOGY, 1992

Relative growth rate determinations on 5-millimeter regions of cucumber (Cucumis sativus L.) hypo... more Relative growth rate determinations on 5-millimeter regions of cucumber (Cucumis sativus L.) hypocotyls show that dim-red lightgrown seedlings have an even distribution of growth along the stem axis. This contrasts with the apical to basal graded decline in growth rate seen in dark-grown seedlings, including dark-grown cucumber seedlings used as controls in this study. Dark-grown seedlings convert to the nongradient pattern when transferred to dim-red light. The small amount of light required suggests that the change in developmental pattern may happen in the natural light environment.

Research paper thumbnail of Physiological Mechanism of the Auxin-Induced Increase in Light Sensitivity of Phytochrome-Mediated Growth Responses in Avena Coleoptile Sections

PLANT PHYSIOLOGY, 1985

The physiology of the auxin-induced 10,000-fold increase in light sensitivity of a phytochrome-me... more The physiology of the auxin-induced 10,000-fold increase in light sensitivity of a phytochrome-mediated growth response (Shinkle and Briggs, 1984 Proc Nati Acad Sci USA 81: 3742-3746) has been characterized in subapical coleoptile sections from dark-grown oat (Avena satita L. cv Lodi) seedlings. Six micromolar indole-3-acetic acid (IAA) must be present for 1 hour before to 2 hour after irradiation in order to confer maximal sensitivity to light. The direct effect of IAA on growth can be separated from its effect on light sensitivity. Several classes of synthetic auxins will substitute for IAA in inducing an increase in sensitivity to light, as will both the phytotoxin fusicoccin and treatment of sections with pH 4.5 buffer. The increase in sensitivity to light induced by 6 micromolar IAA is completely inhibited by buffering the sections at pH 5.9 with 30 millimolar 24N-morpholino)ethanesulfonic acid. These findings suggest that the capacity to respond to very low fluences of light is regulated by extracellular pH.

Research paper thumbnail of Effects of solar ultraviolet radiation and canopy manipulation on the biochemical composition of Sauvignon Blanc grapes

Effects of solar ultraviolet radiation and canopy manipulation on the biochemical composition of Sauvignon Blanc grapes

Australian Journal of Grape and Wine Research, 2012

ABSTRACT Background and Aims: New Zealand is exposed to relatively high solar ultraviolet (UV) ra... more ABSTRACT Background and Aims: New Zealand is exposed to relatively high solar ultraviolet (UV) radiation; such high irradiances of UV radiation having the potential to change the biochemical composition of plants. The aim of this study was to investigate the effects of UV radiation and the role of canopy leaves on berry biochemical composition in Vitis vinifera var. Sauvignon Blanc. Sauvignon Blanc is the major grape variety grown in New Zealand.Methods and Results: Leaves were removed from around the fruiting zones of vines and screens that altered UV radiation exposures were placed over the grape bunches. Samples taken throughout development were analysed for changes in total phenolic compounds (including flavonols), amino acids and methoxypyrazines. Total phenolic compounds increased substantially in response to UV‐B exposure and this was reflected in changes taking place within the skins of the berries. Flavonol levels were determined by UV‐B radiation exposure and accumulated to maximum concentrations at veraison, subsequently declining to harvest. UV radiation did not have a significant effect on the majority of amino acids or methoxypyrazine concentrations. The most noticeable change in amino acid and methoxypyrazine accumulation was caused by the presence of leaves over the fruiting zone, retaining these leaves maintained significantly higher concentrations in the berries at harvest.Conclusions: UV‐B radiation determines the composition of flavonols in the skins of grapes. Amino acid and methoxypyrazine concentrations are not predominantly determined by UV‐B, but retention of leaves over the fruiting zone promotes their accumulation in berries.Significance: Canopy manipulations are routinely used commercially in the vineyard to help control vigour and reduce disease pressure. The findings presented here are important for viticulturists to understand how management of the vine leaf canopy can determine the biochemical composition of the grapes and can therefore, ultimately affect wine quality.

Research paper thumbnail of Cell Wall Free Space of Cucumis Hypocotyls Contains NAD and a Blue Light-Regulated Peroxidase Activity

PLANT PHYSIOLOGY, 1992

Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativu... more Solutions were obtained from the cell wall free space of red light-grown cucumber (Cucumis sativus L.) hypocotyl sections by a low-speed centrifugation technique. The centrifugate contained NAD and peroxidase but no detectable cytoplasmic contamination, as indicated by the absence of the activity of glucose-6phosphate dehydrogenase from the cell wall solution. Peroxidase activity centrifuged from the cell wall of red light-grown cucumber hypocotyl section could be resolved into at least three cathodic isoforms and two anodic isoforms by isoelectric focusing. Treatment of red light-grown cucumber seedlings with a 10-minute pulse of high-intensity blue light increased the level of cell wall peroxidase by about 60% and caused a qualitative change in the anodic isoforms of this enzyme. The increase in peroxidase activity was detectable within 25 minutes after the start of the blue light pulse, was maximal at 35 minutes, and declined to control levels by 45 minutes of irradiation. The inhibitory effect of blue light on hypocotyl elongation was more rapid than the effect of blue light on total wall peroxidase activity, leading to the conclusion that growth and peroxidase activity are not causally related.