Phenylalanine ammonia lyase as a precursory enzyme of legume stem lignification

1995 ◽  
Vol 75 (1) ◽  
pp. 135-140 ◽  
Author(s):  
J. E. Bidlack ◽  
D. R. Buxton ◽  
R. M. Shibles ◽  
I. C. Anderson

In some instances, lignin content may not be significantly correlated with phenylalanine ammonia lyase (PAL) activity because: (1) PAL is not committed exclusively to lignin, and (2) the time of maximum PAL activity may not coincide with maximum lignin deposition. This study evaluates correlations and timing of PAL activity and lignin deposition during legume stem maturation. Three forage legumes, alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), and red clover (Trifolium pratense L.), were established, and basal stem regrowth was sampled, biweekly, for 10 wk, for dry weight (DW), cell wall (CW), lignin, and PAL analyses. Nonlinear regression of lignin content by the Gompertz function indicated that lignin increased sigmoidally, and PAL activity by the third-order quadratic demonstrated rapid initial increases in activity, followed by decreases, as a function of regrowth days. First derivative of the Gompertz function demonstrated that changes in lignin deposition closely resembled changes in PAL activity. Among species, peak deposition of DW and CW content occurred 3–11 d prior to maximum lignin deposition. Time of maximum PAL activity occurred 8 d prior to maximum lignin deposition in birdsfoot trefoil and red clover and 3 days after maximum lignin deposition in alfalfa. Across species, lignin content was not positively correlated with PAL activity on a protein basis. However, lignin deposition was positively correlated with PAL per unit protein (r = 0.76, P < 0.05) and lignin content was positively correlated with PAL on a per plant basis (r = 0.60, P < 0.05). These results indicate that the activity of PAL is related to lignin deposition in a cause-and-effect relationship. Key words: Alfalfa, birdsfoot trefoil, cell wall, lignin, phenylalanine, ammonia lyase, red clover

1992 ◽  
Vol 72 (3) ◽  
pp. 809-818 ◽  
Author(s):  
J. E. Bidlack ◽  
D. R. Buxton

Cell-wall (CW) components greatly influence digestibility of forages as they mature. There is only limited information on the timing of rates of deposition of CW components. This investigation examined differences in CW and CW component deposition in greenhouse-grown alfalfa (Medicago sativa L.), birds-foot trefoil (Lotus corniculatus L.), red clover (Trifolium pratense L.), orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), and switchgrass (Panicum virgatum L.). Plant material was sampled from the basal 10 cm of forage after harvesting at 3–5 cm above the soil level. Samples analyzed included sheaths from orchardgrass, sheaths and stems from bromegrass and switch-grass, and stems from all legumes. After establishment and herbage removal, samples were collected biweekly between 2 and 10 wk of regrowth. Results indicated that, except for orchardgrass, maximum rates of CW and CW component deposition usually occurred earlier in legumes compared with those of grasses. Maximum CW deposition for all species occurred within 1–3 d of maximum dry weight deposition. Among CW components in grasses and legumes, maximum deposition of hemicellulose occurred first, followed by that of cellulose (1–6 d later), and then lignin (up to 14 d after maximum hemicellulose deposition). Maximum cellulose deposition in all species occurred at the same time as maximum CW deposition.Key words: Cell wall, deposition, cellulose, hemicellulose, lignin, forage


2015 ◽  
Vol 43 (2) ◽  
pp. 554-560 ◽  
Author(s):  
Olivera STAJKOVIC-SRBINOVIC ◽  
Dušica DELIC ◽  
Nataša RASULIC ◽  
Dragan CAKMAK ◽  
Djordje KUZMANOVIC ◽  
...  

In the present study the effects of Rhizobium inoculation and lime application on the mineral composition (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, B) of red clover (Trifolium pratense L.), in very acid soil were evaluated. Inoculation with Rhizobium leguminosarum bv. trifolii significantly increased shoot dry weight (SDW) of red clover plants (three times greater), as well as N, Mg, Fe, Mn and Cu contents in plants compared to the control. Application of lime and Rhizobium together, depending on the lime rate (3, 6 or 9 t ha-1 of lime) and the cut, increased SDW significantly, but decreased the contents of N, P, K, Mg, Mn, Zn and B in plants. Regardless of the changes, in all treatments in both cuts, contents of N, K, Ca, Mg, Mn and Zn in plants were among sufficiency levels (Mg content was elevated in the second cut), while Fe content was mainly high, as well as Cu (in the second cut). Contents of P and B in plants were somewhat lower than sufficiency levels, but above critical level. Therefore, red clover can be grown with satisfactory yield and mineral composition in acid soil with Rhizobium inoculation only, but the application of P and B fertilization is desirable.


Weed Science ◽  
1981 ◽  
Vol 29 (4) ◽  
pp. 433-439 ◽  
Author(s):  
Robert E. Hoagland ◽  
Stephen O. Duke

Effects of 16 herbicides representing 14 herbicide classes on growth and extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) were examined in light- and dark-grown soybean [Glycine max(L.) Merr. ‘Hill’] seedlings. High purity (96 to 100%) herbicides were supplied via aqueous culture at various concentrations: 0.5 mM amitrole (3-amino-s-triazole), 0.1 mM atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], 0.07 mM diclofop-methyl {methyl ester of 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoicacid}, 0.5 mM DSMA (disodium methanearsonate), 0.2 mM fenuron (1,1-dimethyl-3-phenylurea), 0.05 mM fluridone {1-methyl-3-phenyl-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone}, 0.5 mM MH (1,2-dihydro-3,6-pyridazinedione), 0.5 mM metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one], 1.8 μM nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], 0.5 mM norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], 0.05 mM paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), 0.15 mM perfluidone {1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl] methanesulfonamide}, 0.2 mM propanil (3′,4′-dichloropropionanilide), 0.1 mM propham (isopropyl carbanilate), 0.5 mM TCA (trichloroacetic acid), and 0.05 mM 2,4-D [(2,4-dichlorophenoxy)acetic acid]. Dark-grown soybean seedlings (3-day-old) were transferred to control solutions (2 mM CaSO4) or to herbicide solutions (in 2 mM CaSO4) and grown at 25 C in continuous white light (200 μE•m-2•s-1) or continuous darkness until harvested 24 or 48 h after transfer. After 48 h, growth (fresh weight, dry weight, elongation) was inhibited by most of the chemicals. Other signs of toxicity (necrosis, secondary root stunting, and root tip swelling) were noted for some treatments. Roots were most affected, although hypocotyls were generally not changed. Hypocotyl elongation was stimulated by atrazine, fluridone, and norflurazon after 48 h light. Extractable PAL activity from soybean axes was decreased by atrazine, fenuron, metribuzin, norflurazon, propanil, propham, and 2,4-D. Amitrole and paraquat were the only herbicides that increased extractable PAL activity. Other compounds tested had no effect on the enzyme. None of the herbicides significantly affected in vitro PAL activity.


Weed Science ◽  
1978 ◽  
Vol 26 (1) ◽  
pp. 32-36 ◽  
Author(s):  
J. Segura ◽  
S. W. Bingham ◽  
C. L. Foy

The phytotoxicity of glyphosate [N-(phosphonomethyl) glycine] on seeds (protected or non-protected with soil) and seedlings of Italian ryegrass(Lolium multiflorumLam.) and red clover(Trifolium pratenseL.) was studied in the greenhouse. Percent germination of Italian ryegrass seeds covered with soil was significantly reduced with glyphosate applied at 4 kg/ha. The direct treatment over the seeds on the soil surface was more toxic, reducing the number of established seedlings at dosages of 3 and 4 kg/ha. In the two red clover seed treatments, germination was significantly reduced with 2 kg/ha of herbicide. Even though germination was reduced at intermediate rates of glyphosate, shoot growth and tillering were improved and yields of dry weight were equivalent to that of untreated plants. Postemergence applications of glyphosate were phytotoxic to both species with the effects becoming more pronounced at increasing dosages. However, at equal dosage, red clover was less susceptible than Italian ryegrass. The patterns of foliar absorption and translocation of14C from14C-glyphosate was similar in Italian ryegrass and red clover.14C was translocated throughout the plants and exhibited apoplastic and symplastic movement.


2008 ◽  
Vol 54 (No. 7) ◽  
pp. 294-300 ◽  
Author(s):  
R. Yan ◽  
S. Gao ◽  
W. Yang ◽  
M. Cao ◽  
S. Wang ◽  
...  

<I>Jatropha curcas</I> L. embryos were germinated and grown in vitro under nickel concentrations of 100, 200, 400 and 800 &mu;mol to observe the effects of high nickel concentrations on seedling growth. Observed biological makers included biomass, and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and phenylalanine ammonia-lyase (PAL) in the cotyledons. The fresh weight of cotyledons in all the tested nickel concentrations was lower than that of the control, but dry weight of cotyledons increased with increasing nickel concentrations up to 200 &mu;mol. SOD activity increased significantly up to 400 &mu;mol and then decreased at 800 &mu;mol nickel. POD activities were induced remarkably at 100 and 200 &mu;mol, but the activity decreased with increasing nickel concentrations. Similarly, a negative link between CAT activity and nickel concentrations was observed in this experiment. PAL activity had a positive correlation to nickel concentrations, and the highest activity was found at 400 &mu;mol nickel. Electrophoresis analysis suggested that a significant correlation between nickel concentrations and isoenzyme patterns of SOD and POD was observed, and these results were consistent with the changes of the activity assayed in solutions.


2006 ◽  
Vol 144 (2) ◽  
pp. 173-181 ◽  
Author(s):  
C. H. E. C. POLI ◽  
J. HODGSON ◽  
G. P. COSGROVE ◽  
G. C. ARNOLD

The effects of manipulation of sward maturity on ingestive behaviour and diet selection of grazing cattle were tested in two experiments using legumes which are equally preferred by cattle. Yearling heifers, in groups of three, grazed plots formed by alternate 2·4 m wide strips of a mixture of birdsfoot trefoil (Lotus corniculatus L.) and white clover (Trifolium repens L.) (BW) and strips of red clover (Trifolium pratense L.) (RC). The treatments comprised four combinations of each of the two swards at two contrasting levels of maturity/height replicated over four successive 3-day periods, in an order which balanced the effect of previous treatments. Observations of the distribution of grazing activity and biting rate were made over 3-hour periods each evening and in the morning of Day 2.Rate of biting was generally greater on immature than mature swards, and on BW than on RC, with little evidence of interactions between these effects. The animals demonstrated partial preference throughout the two studies, the proportion of grazing time devoted to BW being 0·40±0·010 in Expt 1 and 0·47±0·017 in Expt 2. The distribution of grazing time between sward type and maturity combinations was influenced progressively by herbage mass and height contrasts as strips were grazed down. An overall analysis using the results from these studies and a companion experiment indicated differences between studies in partial preference for BW and RC which appeared to be related to variations in sward morphology.


Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 719
Author(s):  
Tiantian Yang ◽  
Emil Engelund Thybring ◽  
Maria Fredriksson ◽  
Erni Ma ◽  
Jinzhen Cao ◽  
...  

To investigate the effects of changes in biopolymer composition on moisture in acetylated poplar wood (Populus euramericana Cv.), the acetylation of control wood was compared to the acetylation of wood with reduced hemicellulose or lignin content (about 9% reduction of total specimen dry weight in both cases). Time-domain nuclear magnetic resonance relaxometry of water-saturated wood gave spin–spin relaxation times (T2) of water populations, while deuteration in a sorption balance was used to characterize the hydroxyl accessibility of the wood cell walls. As expected, the acetylation of pyridine-swelled wood reduced hydroxyl accessibility and made the cell wall less accessible to water, resulting in a reduction of cell wall moisture content by about 24% compared with control wood. Hemicellulose loss per se increased the spin–spin relaxation time of cell wall water, while delignification had the opposite effect. The combined effect of hemicellulose removal and acetylation caused more than a 30% decrease of cell wall moisture content when compared with control wood. The acetylated and partially delignified wood cell walls contained higher cell wall moisture content than acetylated wood. An approximate theoretical calculation of hydroxyl accessibility for acetylated wood was in the low range, but it agreed rather well with the measured accessibility, while acetylated and partially hemicellulose-depleted and partially delignified wood for unknown reasons resulted in substantially lower hydroxyl accessibilities than the theoretical estimate.


Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 825-829 ◽  
Author(s):  
S. G. Taylor ◽  
D. G. Shilling ◽  
K. H. Quesenberry ◽  
G. R. Chaudhry

Whole plant and tissue culture experiments were conducted to determine the difference in phytotoxicity of 2,4-D and its metabolite, 2,4-DCP, to red clover. At the whole plant level, the mean concentration of 2,4-DCP (10 mM) required to cause 50% growth inhibition (I50) of shoot dry weight was 24 times greater than for 2,4-D (0.42 mM). Using callus tissue, the I50value for 2,4-DCP (0.28 mM) was 22 times greater than for 2,4-D (0.013 mM) based on dry weights. The callus tissue was 36 and 32 times more sensitive to 2,4-DCP and 2,4-D than shoot tissue based on dry weights, respectively. These data indicate that 2,4-DCP was less phytotoxic than 2,4-D to red clover both in vitro and in vivo.


2005 ◽  
Vol 73 (1) ◽  
pp. 3-11 ◽  
Author(s):  
J. Kimpinski ◽  
L.M. Edwards ◽  
C.E. Gallant ◽  
H.W. Johnson ◽  
J.A. MacLeod ◽  
...  

A field study assessing the influence of the previous crop, the crop sequence, and aldicarb treatments on root lesion nematode populations and crop yields was carried out in Prince-Edward-Island, Canada. The most recent crop had the greatest impact on nematode numbers. The crop sequences had an influence in some cases on root lesion nematode populations (primarily Pratylenchus penetrans) and on crop yields. In commercial barley (Hordeum vulgare) fields, root lesion nematodes in roots were greatest when barley followed a red clover (Trifolium pratense) timothy (Phleum pratense) ley, and stunt nematodes (Tylenchorhynchus spp., primarily T. dubius, and Merlinius spp.) were more common when barley followed barley. The combined dry weight of foliage and grain was larger when barley was planted after potato (Solanumtuberosum) and smaller when barley followed barley or a red clover-timothy mixture. Under experimental field conditions, root lesion nematode populations were largest in barley roots when barley followed potato and grain yields were smallest when barley followed barley. Changes in nematode populations in potato were not associated with crop sequences. Potato tuber yields were higher in the sequences that began with wheat (Triticum aestivum) or barley than in the sequences that began with potato or soybean (Glycine max). Aldicarb reduced the numbers of root lesion nematodes in roots with concomitant yield increases in potato and soybean.


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