Effect of plant growth regulators on ethylene production, 1-aminocyclopropane-1-carboxylic acid oxidase activity, and initiation of inflorescence development of pineapple

1996 ◽  
Vol 15 (3) ◽  
pp. 121-128 ◽  
Author(s):  
X.-j. Min ◽  
D. P. Bartholomew
HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 704-706 ◽  
Author(s):  
Edward W. Bush ◽  
Wayne C. Porter ◽  
Dennis P. Shepard ◽  
James N. McCrimmon

Field studies were performed on established carpetgrass (Axonopus affinis Chase) in 1994 and 1995 to evaluate plant growth regulators (PGRs) and application rates. Trinexapac-ethyl (0.48 kg·ha-1) improved turf quality and reduced cumulative vegetative growth (CVG) of unmowed and mowed plots by 38% and 46%, respectively, in 1995, and suppressed seedhead height in unmowed turf by >31% 6 weeks after treatment (WAT) both years. Mefluidide (0.14 and 0.28 kg·ha-1) had little effect on carpetgrass. Sulfometuron resulted in unacceptable phytotoxicity (>20%) 2 WAT in 1994 and 18% phytotoxicity in 1995. In 1995, sulfometuron reduced mowed carpetgrass CVG 21%, seedhead number 47%, seedhead height 36%, clipping yield 24%, and reduced the number of mowings required. It also improved unmowed carpetgrass quality at 6 WAT. Sethoxydim (0.11 kg·ha-1) suppressed seedhead formation by 60% and seedhead height by 20%, and caused moderate phytotoxicity (13%) in 1995. Sethoxydim (0.22 kg·ha-1) was unacceptably phytotoxic (38%) in 1994, but only slightly phytotoxic (7%) in 1995, reduced clipping yields (>24%), and increased quality of mowed carpetgrass both years. Fluazasulfuron (0.027 and 0.054 kg·ha-1) phytotoxicity ratings were unacceptable at 2 WAT in 1994, but not in 1995. Fluazasulfuron (0.054 kg·ha-1) reduced seedhead height by 23% to 26% in both years. Early seedhead formation was suppressed >70% when applied 2 WAT in 1994, and 43% when applied 6 WAT in 1995. The effects of the chemicals varied with mowing treatment and evaluation year. Chemical names used: 4-(cyclopropyl-x-hydroxy-methylene)-3,5 dioxo-cyclohexane-carboxylic acid ethyl ester (trinexapac-ethyl); N-2,4-dimethyl-5-[[(trifluoro-methyl)sulfonyl]amino]phenyl]acetamide] (mefluidide); [methyl 2-[[[[(4,6-dimethyl-2-pyrimidinyl) amino]carbonyl] amino] sulfonyl]benzoate)] (sulfometuron); (2-[1-(ethoxyimino)butyl-5-[(2-ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one) (sethoxydim); 1-(4,6-dimethoxypyrimidin-2yl)-3-[(3-trifluoromethyl-pyridin 2-yl) sulphonyl] urea (fluazasulfuron).


1999 ◽  
Vol 26 (2) ◽  
pp. 179 ◽  
Author(s):  
Maria X. Henzi ◽  
David L. McNeil ◽  
Mary C. Christey ◽  
Ross E. Lill

In this paper 11 transgenic broccoli (Brassica oleracea L. var. italica) lines containing a tomato antisense 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene from pTOM13 were evaluated. Changes in respiration, ethylene production and ACC oxidase activity were studied in mature flowers. Averaged across all ACC oxidase transgenic lines, there was an initial increase followed by a substantial decrease in ethylene production compared with the controls. Of the 11 transgenic lines, 10 lines showed a significant reduction in fethylene production relative to the controls from 50 h after harvest. Green Beauty flowers showed a significant reduction in respiration between the transgenics and control and demonstrated how ethylene levels could control the stable, or climacteric-like increase in respiration. ACC oxidase activity was higher in transgenic plants, consistent with the initially higher ethylene production. ACC oxidase activity did not, however, reflect the increase in ethylene production found after 50 h for the controls. These results suggest that two ethylene production systems may operate with only the second being inhibited by the antisense ACC oxidase used and that the later system was not detected by the ACC oxidase assay used. The results do show that post-harvest ethylene synthesis and therefore possibly broccoli senescence can be regulated by using an antisense ACC oxidase gene.


1980 ◽  
Vol 33 (9) ◽  
pp. 2061 ◽  
Author(s):  
AL Cossey ◽  
LN Mander ◽  
JV Turner

(4β)-18-Norkaur-16-en-3-one (4a) was alternatively acetalized (ethanediol/Dowex resin) or deoxygenated (tosylhydrazine/sodium borohydride); allylic bromination (N-bromosuccinimide) of the products, followed by alkylation of pyrrolidine gave primary allylic amines which were quaternized with chloroacetonitrile. Potassium t-butoxide-induced [2,3]-sigmatropic rearrangement, followed by acidic hydrolysis and Jones oxidation, gave respectively (4β,15α)-3-oxo-18-norkaur-16-ene-15- carboxylic acid (10a) and (4β,15α)-18-norkaur-16-ene-15-carboxylic acid. Reductions of (4a) and (10a) gave, with K-Selectride, axial (3β)- alcohols and, with sodium borohydride, mainly equatorial (3α)-alcohols. Details of a related conversion of (+)-phyllocladene into (15α)- phyllocladene-15-carboxylic acid are also recorded.


2020 ◽  
Vol 58 (2) ◽  
pp. 223-229
Author(s):  
Arturo Alberto Velázquez-López ◽  
Javier De La Cruz-Medina ◽  
Elizabeth León-García ◽  
Cristóbal Torres-Palacios ◽  
Gilber Vela-Gutiérrez ◽  
...  

Research background. TomloxB is the main isoform of lipoxygenase associated with ripening and senescence of fruits. On the other hand, ethylene, a gaseous hormone, is essential for the regulation of ripening in climacteric fruits like tomatoes. However, the relationship between TomloxB and ethylene production has not been thoroughly studied. Therefore, we aim to assess the effect of exogenous ethylene in transgenic tomatoes that contain a silenced TomloxB gene, and subsequently evaluate lipoxygenase activity, 1-aminocyclopropane-1-carboxylic acid oxidase and ethylene production; as well as to quantify the expression of the genes encoding 1-aminocyclopropane-1-carboxylic acid oxidase and TomloxB.Experimental approach. To investigate the effect of lipoxygenase and 1-aminocyclopropane-1-carboxylic acid oxidase activity, fruits harvested at the stages of break, turning and pink were used. Tomatoes at break stage collected from transgenic and wild type plants were used to determine ethylene production and gene expression. Genetically modified and wild type tomato fruits were exposed to 100 μL/L exogenous ethylene. Lipoxygenase activity was measured spectrophotometrically. Activity of 1-aminocyclopropane-1-carboxylic acid oxidase and ethylene production were determined by gas chromatography. Oligonucleotides for differentially expressed genes: 1-aminocyclopropane-1-carboxylic acid oxidase and TomloxB were used to determine gene expression by real-time PCR.Results and conclusions. The data showed that silencing of TomloxB caused a reduction in lipoxygenase activity and ethylene production in tomato fruits, and also reduced 1-aminocyclopropane-1-carboxylic acid oxidase activity. Hence, the addition of exogenous ethylene increased lipoxygenase activity in all treatments and 1-aminocyclopropane-1-carboxylic acid oxidase activity only in transgenic lines at break stage, consequently there was a positive regulation between TomloxB and ethylene, as increasing the amount of ethylene increased the activity of lipoxygenase. The results suggest that lipoxygenase may be a regulator of 1-aminocyclopropane-1-carboxylic acid oxidase and production of ethylene at break stage.Novelty and scientific contribution. These results lead to a better understanding of the metabolic contribution of TomloxB in fruit ripening and how it is linked to the senescence-related process, which can lead to a longer shelf life of fruits. Understanding this relationship between lipoxygenase and ethylene can be useful for better post-harvest handling of tomatoes.


Sign in / Sign up

Export Citation Format

Share Document