Light Effects on Several Chloroplast Components in Norflurazon-Treated Pea Seedlings

Sagar, Anurag D.; Horwitz, Benjamin A.; Elliott, Robert C.; Thompson, William F.; Briggs, Winslow R.

doi:10.1104/pp.88.2.340

Cited by 53 publications

(51 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Region number Figure 4. RGRs of regions of DG cucumber seedlings transferred to DRL for 30 h. At 3.5 d of age, seedlings were transferred to DRL, and RGRs were determined as described for Figure 1 for the 2-h period beginning at 30 h after transfer (0 Several recent studies have used DRL-grown seedlings to study blue light responses against a background where phytochrome status is unchanged by blue light (13,30) or to study biochemical and molecular aspects of greening under an alternative condition to white light (20). As noted above, the response to a light-to-dark transition is absent in DRLadapted seedlings.…”

Section: Resultsmentioning

confidence: 99%

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

Shinkle

Sooudi²,

Jones³

1992

Plant Physiol.

View full text Add to dashboard Cite

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.A consensus characteristic of stem elongation is a gradient of elongation rates along the stem axis, with high rates of elongation near the apex and a graded decline toward the base. Etiolation is characterized by rapid stem elongation exhibiting a graded pattern (8,9,23,25,28), whereas stem elongation following deetiolation is relatively slow but still exhibits the apical to basal gradient of extension rates (9,10,25). The hypothesis that changes in cell structure and function follow the gradient in growth rate has been tested for several developmental processes (23,25,28).Germinating cucumber (Cucumis sativus L.) seedlings in continuous DRL3 (21) MATERIALS AND METHODSCucumber seedlings (Cucumis sativus L. cv Burpee's pickler) were germinated in moist vermiculite and grown under DRL as described previously (21) or in a similar dark room at 24 ± 10C. Experiments were carried out in growth rooms at two locations (Berkeley, CA, and San Antonio, TX). For both locations, the DRL field in the growth room had fluence rates ranging from 0.3 to 0.5 ,Imol m-2 s-'. The light source for DRL emitted 90% of its total output between 600 and 700 nm, with peaks at 638 and 648 nm (13; data not shown).For determination of RGRs (18, 22), marks (carborundum chips, 100 ,um diameter) were placed at 5-mm intervals along hypocotyls of 3.5-to 4-d-old seedlings for total length of 40 to 60 mm. Seedlings were allowed to recover from handling for 2 h before data were taken. Video images were obtained from a Panasonic WV-1850 video camera (Matsushita Electronics, Seacaucus, NJ) that has a high sensitivity to red and IR light. Images of DRL-grown seedlings were obtained using light available in the DRL growth room. DG seedlings were imaged under photomorphogenetically inactive IR illumination (12). For marking and placement for imaging, DG seedlings were exposed to 1 to 2 min of green work light, which was previously shown not to affect growth in this cultivar (8). The images were processed by a personal computer running video digitizer board (Video-Van-Gough, Tekmatic Systems, Ben Lomond, CA) and programs used previously (18). The digitizer located the marks and recorded their position in x and y coordinates on an arbitrary scale. Region lengths were determined by calculating distances between marks and converting numbers from computer units to millimeters using a conversion factor established by measuring known distances. Marks were tracked for 2 h, ...

show abstract

Section: Resultsmentioning

confidence: 99%

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

Shinkle

Sooudi²,

Jones³

1992

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…This includes genes encoding components of the light-harvesting complexes (Lhcb1), the photosynthetic electron-transfer chain (PetC,PetE,PetH,, the photosystem II oxygenevolving complex (PsbO, PsbP ) and the reductive pentose phosphate pathway (RbcS). Decreased accumulation of transcripts of these genes has been observed by Northern blot hybridization or by translation in vitro of RNA extracted from wild-type plants treated with norflurazon Batschauer et al 1986;Burgess & Taylor 1987;Sagar et al 1988). An example of the effect of norflurazon on transcripts of Lhcb1 and RbcS in 7-day-old tobacco seedlings is shown in figure 1.…”

Section: Norflurazon and Carotenoid-deficient Plantsmentioning

confidence: 99%

Coordination of plastid and nuclear gene expression

Gray

Sullivan

Wang

et al. 2003

Phil. Trans. R. Soc. Lond. B

180

178

View full text Add to dashboard Cite

The coordinated expression of genes distributed between the nuclear and plastid genomes is essential for the assembly of functional chloroplasts. Although the nucleus has a pre-eminent role in controlling chloroplast biogenesis, there is considerable evidence that the expression of nuclear genes encoding photosynthesis-related proteins is regulated by signals from plastids. Perturbation of several plastid-located processes, by inhibitors or in mutants, leads to decreased transcription of a set of nuclear photosynthesisrelated genes. Characterization of arabidopsis gun (genomes uncoupled) mutants, which express nuclear genes in the presence of norflurazon or lincomycin, has provided evidence for two separate signalling pathways, one involving tetrapyrrole biosynthesis intermediates and the other requiring plastid protein synthesis. In addition, perturbation of photosynthetic electron transfer produces at least two different redox signals, as part of the acclimation to altered light conditions. The recognition of multiple plastid signals requires a reconsideration of the mechanisms of regulation of transcription of nuclear genes encoding photosynthesis-related proteins.

show abstract

“…These results are characteristic of NF-treated plants grown under white light (11,36). The lack of carotenoids in NFtreated plants is thought to ultimately result in the formation of triplet Chl which leads to the photooxidation of various plastid components, including Chl, membranes, and proteins (33).…”

Section: Enzyme Assaysmentioning

confidence: 84%

Chloroplastic Regulation of Apoplastic α-Amylase Activity in Pea Seedlings

Saeed

Duke²

1990

Plant Physiol.

View full text Add to dashboard Cite

Photobleaching of pea (Pisum sativum L.) seedling leaves by treatment with norflurazon (San 9789) and 7 days of continuous white light caused a 76-to 85-fold increase in the activity of the primary a-amylase, a largely apoplastic enzyme, over normally greening seedlings. Levels of chlorophyll were near zero and levels of plastid marker enzyme activities were very low in norflurazon-treated seedlings, indicating severe photooxidative damage to plastids. As levels of norflurazon or fluence rates were lowered, decreasing photobleaching of tissues, a-amylase activity decreased. Levels of leaf ji-amylase and starch debranching enzyme changed very little in norflurazon-treated seedlings. Infiltration extraction of leaves of norflurazon-treated and normally greening seedlings indicated that at least 57 and 62%, respectively, of a-amylase activity was in the apoplast. a-Amylase activity recovered from the apoplast of photobleached leaves of norflurazon-treated seedlings was 18-fold higher than that for green leaves. Inhibitors of photosynthesis (DCMU and atrazine) and an inhibitor of chlorophyll accumulation that does not cause photooxidation of plastid components (tentoxin) had little effect on levels of a-amylase activity, indicating norflurazon-caused loss of chlorophyll and lack of photosynthesis did not cause the large induction in a-amylase activity. An inhibitor of both abscisic acid and gibberellin synthesis (paclobutrazol [PP333]) and an analog of norflurazon which inhibits photosynthesis but not carotenoid synthesis (San 9785) caused only moderate (about fivefold) increases in a-amylase activity. Lincomycin and chloramphenicol increased a-amylase activity in light grown seedlings to the same magnitude as norflurazon, indicating that the effect of norflurazon is probably through the destruction of plastid ribosomes. It is proposed that chloroplasts produce a negative signal for the regulation of the apoplastic a-amylase in pea.In photosynthetic tissues, normal gene expression involves the interplay of nuclear and chloroplast genomes. There is a significant body of evidence supporting the hypothesis that plastids produce a positive signal, yet unidentified, which regulates nuclear genes of proteins destined for both chloroplasts and extrachloroplastic sites (for reviews cf 33,40). Photooxidation of plastid constituents in carotenoid deficient plastids has been found to reduce or prevent the expression '

show abstract

Light Effects on Several Chloroplast Components in Norflurazon-Treated Pea Seedlings

Cited by 53 publications

References 26 publications

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

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

Coordination of plastid and nuclear gene expression

Chloroplastic Regulation of Apoplastic α-Amylase Activity in Pea Seedlings

Contact Info

Product

Resources

About