Sesquiterpenes fromCelastrus vulcanicolaas Photosynthetic Inhibitors

2008 ◽  
Vol 71 (8) ◽  
pp. 1331-1335 ◽  
Author(s):  
David Torres-Romero ◽  
Beatriz King-Díaz ◽  
Ignacio A. Jiménez ◽  
Blas Lotina-Hennsen ◽  
Isabel L. Bazzocchi
Keyword(s):  
Photosynthetic Inhibitors

Yellow Nutsedge Control with Soft-Incorporated Herbicides

Weed Science ◽  
1974 ◽  
Vol 22 (4) ◽  
pp. 378-383 ◽  
Author(s):  
P. E. Keeley ◽  
R. J. Thullen
Keyword(s):  
Vegetative Growth ◽  
Cyperus Esculentus ◽  
Yellow Nutsedge ◽  
Greenhouse Experiments ◽  
Storage Organs ◽  
Food Reserves ◽  
Photosynthetic Inhibitors

Two greenhouse experiments were conducted to study the influence of 12 soil-applied herbicides on the sprouting and mortality of yellow nutsedge (Cyperus esculentusL.) tubers. Alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide], butachlor [N-(butoxymethyl)-2-chloro-2′,6′-diethylacetanilide], cycloate (S-ethyl N-ethylthiocyclohexanecarbamate), EPTC (S-ethyl dipropylthiocarbamate), napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide], and U-27267 (3,4,5-tribromo-N,N,α-trimethylpyrazole-1-acetamide) delayed sprouting of tubers and provided 6 to 12 weeks control, but failed to kill tubers. Tubers appeared to escape injury by failing to sprout until activity of the herbicides had substantially dissipated. Herbicides known to interfere with photosynthesis, atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], bromacil (5-bromo-3-sec-butyl-6-methyluracil), methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione], prometryne [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine], San-6706 [4-chloro-5-(dimethylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], and terbacil (3-tert-butyl-5-chloro-6-methyluracil) did not delay sprouting of tubers, but killed shoots after emergence. In addition to controlling vegetative growth, the photosynthetic inhibitors killed tubers by rapidly exhausting the food reserves of these storage organs.

Cotyledon Disc Bioassay for Certain Herbicides

Weed Science ◽  
1976 ◽  
Vol 24 (3) ◽  
pp. 250-252 ◽  
Author(s):  
J. F. Da Silva ◽  
R. O. Fadayomi ◽  
G. F. Warren
Keyword(s):  
Bioassay Method ◽  
Modes Of Action ◽  
Photosynthetic Inhibitors

A rapid cotyledon disc bioassay developed for photosynthetic inhibitors was tested on several herbicides of different modes of action. In addition to being an excellent bioassay method for photosynthetic inhibitors it was found to be useful for the detection of diquat (6,7-dihydrodipyrido[1,2-α:2′,1′-c] pyrazine-diium ion), paraquat (1,1′-dimethyl-4,4′-dipyridinium ion), and dinoseb (2-sec-butyl-4,6-dinitrophenol). Herbicides representing several other modes of action could not be readily detected by this method.

Characterization of Multiple Herbicide-Resistant Italian Ryegrass (Lolium perennessp.multiflorum) Populations from Winter Wheat Fields in Oregon

Weed Science ◽  
2016 ◽  
Vol 64 (2) ◽  
pp. 331-338 ◽  
Author(s):  
Mingyang Liu ◽  
Andrew G. Hulting ◽  
Carol Mallory-Smith
Keyword(s):  
Winter Wheat ◽  
Indirect Evidence ◽  
Acetolactate Synthase ◽  
Italian Ryegrass ◽  
Resistance Mutations ◽  
Herbicide Resistant ◽  
Resistance Patterns ◽  
Photosynthetic Inhibitors ◽  
Two Populations

Many Italian ryegrass populations in Oregon are resistant to more than one herbicide; therefore, the resistance patterns of these populations must be determined to identify alternative herbicides for management. Two suspected resistant Italian ryegrass populations (R2 and R4) survived flufenacet plus metribuzin applications under typical winter wheat production conditions. Populations R2 and R4 were resistant to clethodim, pinoxaden, quizalofop, mesosulfuron-methyl, flufenacet, but not to acetochlor, dimethenamid-p, metolachlor, pyroxasulfone, imazapyr, sulfometuron, or glyphosate. R4 was resistant to diuron, but R2 was not. The estimated flufenacet doses required for 50% growth reduction (GR50) were 438 g ai ha−1(R2) and 308 g ai ha−1(R4). Both populations were controlled by pyroxasulfone at rates greater than 15 g ai ha−1. An Asp-2078-Gly substitution in the ACCase gene was found in both populations, while an Ile-2041-Asn was found only in the R4 population. A Ser-264-Gly substitution inpsbA gene was found in the R4 population. These mutations previously have been reported to provide resistance to ACCase and photosynthetic inhibitors, respectively. No resistance mutations were identified in the acetolactate synthase (ALS) gene of either population. The addition of the P450 inhibitor, chlorpyrifos, increased the injury resulting from mesosulfuron-methyl on both resistant populations providing indirect evidence that the ALS resistance may be metabolic. Multiple herbicide-resistant Italian ryegrass populations were identified in this study with both target site and nontarget site based mechanisms likely involved. However, several herbicides were identified including pyroxasulfone, a herbicide in the same group as flufenacet, which could be used to control these two populations.

The crystal structure of the photosynthetic inhibitors DCMU and DTPU

Biopolymers ◽  
1986 ◽  
Vol 25 (9) ◽  
pp. 1615-1621 ◽  
Author(s):  
Chaim Gilon ◽  
Shmuel Cohen ◽  
Yona Siderer
Keyword(s):  
Crystal Structure ◽  
Photosynthetic Inhibitors

scholarly journals Effects of S-Abscisic Acid and (+)-8′-Acetylene Abscisic Acid on Fruit Set and Stomatal Conductance in Apple

HortScience ◽  
2014 ◽  
Vol 49 (6) ◽  
pp. 763-768 ◽  
Author(s):  
Steven J. McArtney ◽  
Suzanne R. Abrams ◽  
Derek D. Woolard ◽  
Peter D. Petracek
Keyword(s):  
Abscisic Acid ◽  
Stomatal Conductance ◽  
Fruit Set ◽  
Apple Fruit ◽  
Leaf Abscission ◽  
Stomatal Limitation ◽  
Cloudy Weather ◽  
Photosynthetic Inhibitors ◽  
Treatment Application ◽  
Fruit Diameter

Fruit set of apple can be reduced by cloudy weather, short-term shade treatments, or application of photosynthetic inhibitors when the young fruit are ≈8 to 15 mm in diameter, indicating that fruit are sensitive to a transient carbohydrate stress during this period. We investigated the potential for S-abscisic acid (ABA) and an ABA analog [(+)-8′-acetylene ABA] to chemically thin apple fruit by causing a stomatal limitation of photosynthesis. Stomatal conductance (gS) of ‘Imperial Gala’/M.7 was reduced by 60% 3 h after application of 250 mg·L−1 ABA or 25 mg·L−1 (+)-8′-acetylene ABA. Stomatal conductance began to recover 4 days after application but did not return to control levels until 19 days after treatment. Application of 250 mg·L−1 ABA combined with 100 mg·L−1 6-benzyladenine (6-BA) when mean fruit diameter was ≈10 mm reduced fruit set of ‘Gala’/M.7 but not ‘Pink Lady™’/M.7 or ‘Morganspur Delicious’/MM.111. Fruit set of ‘Pink Lady™’/M.7 was reduced by application of 20 mg·L−1 (+)-8′-acetylene ABA + 100 mg·L−1 6-BA at full bloom or 10 mg·L−1 (+)-8′-acetylene ABA + 100 mg·L−1 6-BA at the 10-mm fruit diameter stage. Fruit set of ‘Morganspur Delicious’/MM.111 was reduced by application of 25 mg·L−1 (+)-8′-acetylene ABA, either alone or in combination with 75 mg·L−1 6-BA, at the 10-mm fruit diameter stage. ABA and (+)-8′-acetylene ABA triggered leaf abscission at rates above 250 mg·L−1 and 25 mg·L−1, respectively. Fruit set and gS data from the present studies indicate the biological activity of (+)-8′-acetylene ABA is 10-fold higher than ABA. These results suggest that ABA and (+)-8′-acetylene ABA reduced fruit set by causing a stomatal limitation in photosynthesis that resulted in a transient carbohydrate stress. Thinning responses to ABA and (+)-8′-acetylene ABA at the concentrations used in these experiments were reduced compared with standard concentrations of currently available chemical thinning agents. However, increasing the concentration of ABA or (+)-8′-acetylene ABA to levels that would achieve comparable thinning are also likely to result in unacceptable leaf abscission.

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