AM1 Treatment Research Articles

Resilience of oilseed rape plants to drought stress after exogenous application of AM1, an ABA-mimicking ligand

AM1 (ABA-mimicking ligand) is a newly identified signaling molecule for plants during drought tolerance. To investigate the potential role of AM1 in response of rapeseed to drought stress, we conducted experiments by growing rapeseed plants under different levels of drought stress with or without applying AM1 or ABA in a rain shelter. The results indicated that drought significantly inhibited rapeseed growth by damaging the photosynthesis system, increasing active oxygen accumulation, destroying the oxidative system, and worsening membrane lipid peroxidation. Exogenously applied AM1 and ABA both relieved the damage to rapeseed that was induced by drought stress. Compared with the drought-treated rapeseed, the AM1 treatment significantly improved plant height, number of green leaves, root collar thickness, leaf area, dry matter weight, and root cap ratios of rapeseed. In addition, Pn, Gs, Ci, Tr were significantly increased by the AM1 treatment. The AM1 treatment also alleviated the drought-induced reductions in Fv/Fm, ΦPSII, qN and ETR; induced an increase in NPQ; and resulted in decreased active oxygen accumulation and membrane lipid peroxidation. Although the ABA treatment relieved photosynthetic fluorescence and antioxidation system parameters to some extent, the effect was inferior to AM1 treatment. Yield under AM1 treatment was higher than that under ABA treatment but was still far lower than that of normal water supply control. In summary, AM1 is functionally similar to ABA in terms of drought relief and regulation, moreover has a better effect.

AM1 is a potential ABA substitute for drought tolerance as revealed by physiological and ultra-structural responses of oilseed rape

Abscisic acid (ABA) is an important signaling molecule for plants under drought tolerance. However, ABA itself has many limitations to be used in agriculture practically. Recently, AM1 (ABA-mimicking ligand) has been found to replace ABA. In this study, we have investigated AM1’s potential role for drought tolerance by growing two contrasting rapeseed (Brassica napus L.) genotypes: Qinyou 8 (drought sensitive) and Q2 (drought resistant) with exogenous ABA or AM1 application under well-watered and drought-stressed conditions. Results demonstrate that drought stress has hampered plant growth (relative height growth rate, plant biomass, leaf area), plant water status (leaf relative water content, root moisture content, leaf water potential), photosynthetic gas exchange attributes like net photosynthesis rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (E); chlorophyll fluorescence parameters like photosynthetic efficiency (Fv/Fm), effective quantum yield of PSII (Φ PSII ), photochemical quenching coefficient (qL), electron transport rate (ETR) and chlorophyll content, especially for Qinyou 8 significantly compared to well-watered plants. Whereas increased root/shoot ratio (R/S), water use efficiency (WUE) and non-photochemical quenching (NPQ) was recorded in both genotypes under drought stress. On the other hand, exogenous ABA or AM1 treatment has regulated all the above parameters in a rational way to avoid drought stress. Chloroplast transmission electron microscope images, especially for Qinyou8, have revealed that oxidative stress induced by drought has blurred the grana thylakoids, increased the size or number of plastoglobules due to lipid peroxidation, and the presence of starch granules depict weak capacity to convert them into simple sugars for osmotic adjustment. However, intact grana thylakoid, few plastoglobules with no or very few starch granules were observed in the chloroplast from ABA- or AM1-treated plants under drought. More importantly, AM1-treated plants under drought stress have responded in an extremely similar way like ABA-treated ones. Finally, it is suggested that AM1 is a potential ABA substitute for plant drought tolerance.

Enhanced transfer of biologically fixed N from faba bean to intercropped wheat through mycorrhizal symbiosis

In Morocco, the use of seed legumes is limited because significant water deficits and the low availability of soil phosphorus (P) limit nitrogen fixation. However, little is known about the ability of faba bean-rhizobium symbiosis to fix nitrogen in P-deficient soils and to transfer fixed nitrogen (N) to intercropped wheat. Arbuscular mycorrhizal fungi (AM) and their extraradical hyphae networks play an important role in the facilitation process by promoting interconnectivity and the transfer of nutrients, such as N and P, between associated plants. The aim of this study was to analyse the impact of AM inoculation on N2 fixation and the transfer of fixed N from faba bean to intercropped wheat. Germinated faba bean and wheat seeds were transferred into 1–l pots filled with a P-deficient soil that was collected from the Haouz valley near Marrakech (Morocco). Plants from the two species were grown in pots in either pure or mixed stands under greenhouse conditions, and each cropping system was subjected to three mycorrhizal inoculation treatments with a non-inoculated (AM0) and two concentrations of Rhizophagus irregularis inoculants containing 1000 (AM1) or 2000 (AM2) spores pot−1. The 15N isotope dilution method was used to determine the amount and proportion of atmospheric N fixed by faba bean (Ndfa%) and the fixed N that was transferred to wheat. Mycorrhizal inoculation had a significantly positive effect on the shoot dry weights and total shoot N in faba bean, but not in wheat. The cropping system had no significant effect on the plant growth and total shoot N in both faba bean and wheat. The Ndfa percentage was very high in all of the treatments, varying from 86 to 91%. The total N fixed by faba bean was 27% significantly higher in the AM2 treatment compared with the AM1 and AM0 treatments for both cropping systems combined. The estimated proportions of fixed N that were transferred from faba bean to wheat were far higher in AM1 (50%) and AM2 (32%) treatments than in AM0 (15%) treatment as well as for the total transferred fixed N. As corroborated by a parallel observation of root mycorrhizal colonization, these results suggest that the development of mycorrhizal networks stimulates the transfer of fixed N from faba bean to wheat, which could significantly contribute to the facilitation process under intercropping conditions.

AM1, MNDO AND MINDO/3 TREATMENTS OF HÜCKEL TYPE CYCLACENES

Hückel type cyclacenes having R = 3–10 have been subjected to quantum chemical analyses at the level of AM1, MNDO and MINDO/3 (UHF and RHF) type semi-empirical treatments. The structures have been found to be stable but endothermic in nature. No cryptoannulenic effect has been observed when AM1 (UHF) and MNDO (UHF) treatments are used. Whereas MINDO/3 (UHF) and all the RHF type calculations indicated certain degree of cryptoannulenic effect R = 4 through 8 for the heat of formation values. Frontier molecular orbital energies of the systems have also been reported.

Combined DFT Theoretical Calculation and Solid-State NMR Studies of Al Substitution and Acid Sites in Zeolite MCM-22

The distributions of Brönsted acidic protons and their acid strengths in zeolite H-MCM-22 have been characterized by density functional theory (DFT) calculations as well as magic angle spinning (MAS) NMR experiments. The embedded scheme (ONIOM) that combines the quantum mechanical (QM) description of active sites and semiempirical AM1 treatment of the neighboring environment was applied to predict the aluminum substitution mechanism and proton affinity (PA), as well as adsorption behaviors of acetone and trimethylphosphine oxide (TMPO) onto the zeolite. Our theoretical results indicate that the Al substitution takes place in the order of Al1-OH-Si2 > Al8-OH-Si8 > Al5-OH-Si7. The DFT theoretical and NMR experimental results suggest that the acid strength of the three Brönsted acid sites in H-MCM-22 zeolite is slightly lower than that of H-ZSM-5 zeolite and the accessible Brönsted acidic protons most likely reside in both the supercages (at the Al8-OH-Si8 and Al1-OH-Si2 sites) and external surface pocket (at the Al8-OH-Si8 site) rather than in the sinusoidal channels (Al5-OH-Si7), with the Al1-OH-Si2 site having the strongest acid strength (as probed by TMPO). This may partially explain the special selectivity of acid-catalyzed reactions occurring inside the channels of H-MCM-22 zeolite.

How many hydrogen molecules can be inserted into C? Comments on the paper “AM1 treatment of endohedrally hydrogen doped fullerene, nH@C” by L. Türker and Ş. Erkoç [J. Mol. Struct. (Theochem) 638 (2003) 37–40

How many hydrogen molecules can be inserted into C? Comments on the paper “AM1 treatment of endohedrally hydrogen doped fullerene, nH@C” by L. Türker and Ş. Erkoç [J. Mol. Struct. (Theochem) 638 (2003) 37–40

How many hydrogen molecules can be inserted into C 60? Comments on the paper ‘AM1 treatment of endohedrally hydrogen doped fullerene, nH 2@C 60’ by L. Türker and Ş. Erkoç [J. Mol. Struct. (Theochem) 638 (2003) 37–40

The possibility of the formation of endohedral complexes between H 2 molecules and C 60 fullerene is discussed on the basis of general geometric considerations as well as the results of molecular mechanics calculations. The obtained results revealed that only one hydrogen molecule being incorporated inside the C 60 cage can form the stable complex in agreement with geometric considerations and recent experimental data. The reliability of semiempirical methods to study the problem of H 2 insertion into C 60 is also discussed.

Quantum chemical studies on EGDN and its monovalent ions

An explosive material, ethylene glycol dinitrate (EGDN) and its mono ionic forms have been subjected to semiempirical AM1 (UHF) and ab initio 6-31G (UHF) type quantum chemical analyses. The AM1 treatment reveals that the neutral and anionic forms are exothermic whereas the cation is endothermic. All of the systems are found to be stable (by AM1 and 6-31G methods) but the calculations indicate that plus and minus charge developments in AM1 treatment and minus charge development in 6-31G treatment cause drastic geometrical changes in the molecular structures resulting in bond elongation, possibly bond cleavage in esteric N–O bond.

Animunin Powder®의 첨가가 자돈 및 육성돈의 성장과 혈액성상에 미치는 영향

Two experiments were conducted to investigate the effects of Animunin Powder supplementation on the growth performance and blood components in nursery and growing pigs. In Exp. 1, ninety six pigs(initial mean live weights 27.6 ± 2.63kg) were randomly allocated into four treatments with six replications per each treatment. Four treatments were control(CON), control 0.1% Antibiotics(AB), control 0.1% Animunin Powder (AM), and control 0.1% Antibiotics 0.1% Animunin Powder (ABM). During 4 weeks experiment, ADG of pigs was significantly(P 0.05) were found in total protein content of serum and crude protein digestibility of diets. In Exp. 2, seventy five pigs(initial mean live weights 40.22 ± 2.82kg) were randomly allocated into three treatments with 5 replicates per each treatment for 29 days. Three treatments were control(CON), control 0.1% Animunin Powder (AM1) and control 0.2% Animunin Powder (AM2). During the whole experiment, pigs fed AM1 and AM2 diets were shown higher ADG than pigs fed CON diet. The ADFI of AM1 diet is higher(P < 0.05) compared to that of CON diet. Serum IgG and albumin concentration of AM1 and AM2 treatments were greater than those of CON treatment(P < 0.05). Lymphocyte was highest for AM1 and lowest for CON, with intermediate for AM2(P < 0.05). In conclusion, Animunin Powder was effective for improving growth performance and to increase the concentrations of blood IgG, albumin, total protein and lymphocyte in nursery and growing pigs.

AM1 treatment of some ( nH 2+ mC)@C 60 systems

Some ( nH 2+ mC)@C 60 systems (2H 2+4C)@C 60, (3H 2+4C)@C 60 and (H 2+5C)@C 60, are considered for AM1 (RHF) type semiempirical quantum chemical treatment. They were found to be stable and endothermic. In the case of (2H 2+4C)@C 60 and (H 2+5C)@C 60 systems, one of the hydrogen molecules possess elongated σ-bonding indicative of some sort of homolytic dissociation.

AM1 treatment of some dinitro derivatives of [2 2](1,4)-cyclophane

Semiempirical molecular orbital treatment at the level of AM1(RHF) approach has been performed on [2 2](1,4)-cyclophanes ( para-cyclophane derivatives) having two nitro substituents at different positions (the bridge positions and phane-deck(s)). All the isomeric structures presently studied are found to be stable but endothermic.

Certain cyclophane-fused-azaindoline kind spirooxazines and their some isomers: an AM1 treatment

A certain set of spirooxazine structures possessing an azaindoline moiety as well as a cyclophane system have been considered such that the position of aza-nitrogen varied in each structure. Also their isomeric acyclic forms are considered. The AM1 (RHF) type semiempirical quantum chemical treatment on these species has been performed.

Some endohedrally carbon doped C 60 systems: AM1 treatment

Endohedrally carbon doped C 60 systems, nC@C 60, with n=1, 5, 10, 15 as well as [C@C 60] +2 and [5C@C 60] +2 forms have been subjected to AM1 (RHF) type semiempirical quantum chemical analysis. The results indicate that they are stable but endothermic structures. The endohedral dopants have some influence on the molecular orbital properties of the cage and this effect gets more pronounced as the number of dopants increases. Calculated vibrational spectra are presented.

AM1 treatment of some C 56H 8 type structures obtained from C 60

Certain C 56H 8 type isomeric structures, theoretically obtained from C 60 molecule initially, by deleting two C–C bonds (existing between two adjacent hexagonal units so that two apertures at different sites of C 60 structure arise) and then adding hydrogens to satisfy valencies of the carbons are considered for AM1 (RHF) type semiempirical calculations. The calculations reveal that the considered structures are stable but endothermic. The locations of the apertures highly affect the molecular properties of these systems.

AM1 treatment of phenylboronic acid esters of glycerol

Phenylboronic acid esters of glycerol, which involve 1,2- and 1,3-sites of glycerol for esterification followed by complex formation with the remaining –OH group of glycerol have been considered for AM1(RHF) type semiempirical quantum chemical calculations, in vacuum as well as in aqueous medium. All the species were found to be stable and exothermic. The stability order among the various species considered was established. 1,2-type ester in vacuum or aqueous medium was found to be more stable than the respective types of 1,3-ester.

AM1 Treatment of (Be+ nH 2)@C 70 systems

AM1 type semiempirical quantum chemical calculations at the level of restricted Hartree–Fock approach have been performed on endohedrally Be and various numbers of hydrogen doped C 70 system. The results indicate that (Be+ nH 2)@C 70 (0≤ n≤10) structures are stable and highly endothermic in nature. Moreover, interactions between the endohedral substituents and the cage are weak.

Cycled-fused-borazines—MNDO and AM1 treatments

The Hückel type cycled-fused-borazines which are analogous to cyclacenes are considered for the semiempirical molecular orbital treatment at the level of MNDO and AM1 type calculations. The structures having 3–10 arenoid rings ( R) are considered. It has been found that they should be thermally stable and exogenic. Moreover, these properties get more and more as R increases. The systems exhibit no cryptoannulenic effect on any of the properties presently studied, showing that the peripheral circuits, unlike the ones in cyclacenes, are not influential.

AM1 treatment of endohedrally hydrogen doped fullerene, nH 2@C 60

Endohedrally hydrogen doped C 60 systems, nH 2@C 60 ( n: 9,12,15,19,21,24) have been theoretically investigated at the level of AM1 (RHF) type quantum chemical treatment. It has been found that n:24 is the maximum number of hydrogen molecules which should result a stable composite system. The calculations indicate that all these structures are stable but highly endothermic. Also some geometrical and physicochemical properties of these structures are reported.

AM1 treatment of substitutionally Al and P doped cyclacenes

Cyclacenes of the Hückel type having 3–8 benzenoid rings have been subjected to centric perturbations along one of the peripheral circuits such that Al and P atoms are alternatingly located. The present structure of perturbed cyclacenes let two types of isomeric compounds to arise such that in one case the peri-positions and fusion points occupied by Al and P atoms, respectively, and in the other case reversal of occupation of locations occur. For these structures, Austin model 1 (restricted Hartree-Fock) type semiempirical calculations have been carried out and the systems are analysed from various energetic points of view.

AM1 treatment of substitutionally Al and P doped cyclacenes

Cyclacenes of the Hückel type having 3–8 benzenoid rings have been subjected to centric perturbations along one of the peripheral circuits such that Al and P atoms are alternatingly located. The present structure of perturbed cyclacenes let two types of isomeric compounds to arise such that in one case the peri-positions and fusion points occupied by Al and P atoms, respectively, and in the other case reversal of occupation of locations occur. For these structures, AM1 (RHF) type semiempirical calculations have been carried out and the systems are analyzed from various energetic points of view.