Copper uptake and phytotoxicity as assessed in situ for durum wheat (Triticum turgidum durum L.) cultivated in Cu-contaminated, former vineyard soils

This work assessed in situ, copper (Cu) uptake and phytotoxicity for durum wheat (Triticum turgidum durum L.) cropped in a range of Cu-contaminated, former vineyard soils (pH 4.2–7.8 and total Cu concentration 32–1,030 mg Cu kg⁻¹) and identified the underlying soil chemical properties and related root-induced chemical changes in the rhizosphere. Copper concentrations in plants were significantly and positively correlated to soil Cu concentration (total and EDTA). In addition, Cu concentration in roots which was positively correlated to soil pH tended to be larger in calcareous soils than in non-calcareous soils. Symptoms of Cu phytotoxicity (interveinal chlorosis) were observed in some calcareous soils. Iron (Fe)–Cu antagonism was found in calcareous soils. Rhizosphere alkalisation in the most acidic soils was related to decreased CaCl₂-extractable Cu. Conversely, water-extractable Cu increased in the rhizosphere of both non-calcareous and calcareous soils. This work suggests that plant Cu uptake and risks of Cu phytotoxicity in situ might be greater in calcareous soils due to interaction with Fe nutrition. Larger water extractability of Cu in the rhizosphere might relate to greater Cu uptake in plants exhibiting Cu phytotoxic symptoms.     

Foliar fertilization to control iron chlorosis in pear (Pyrus communis L.) trees

The effectiveness of foliar fertilization to re-green chlorotic leaves in iron-deficient pear trees has been studied. Trials were made to assess the influence of (i) the level of Fe deficiency, (ii) the leaf surface treated (adaxial or abaxial), and (iii) two different surfactants, L-77 and Mistol. Treatments were ferrous sulphate alone, ascorbic, citric and sulphuric acids, applied either alone or in combination with ferrous sulphate, Fe-DTPA and water as a control. Solutions were applied with a brush and leaves were treated twice each year. None of the treatments caused a full recovery from Fe deficiency chlorosis. Treatments containing Fe caused the largest re-greening effects, and FeSO₄ had a similar re-greening effect to Fe(III)-DTPA. Increases in leaf Chl were more pronounced with abaxial leaf surface applications and in severely deficient leaves. Using Fe(III)-DTPA in foliar sprays does not seem to be justified, since their effects are not better than those of FeSO₄. The joint use of Fe(III)-DTPA and L-77 and that of FeSO₄ and citric acid do not seem to be suitable. With a single foliar application, FeSO₄ combined with acids gave slightly better results than FeSO₄ alone. Acidic solution applications without Fe may be effective in alleviating chlorosis in some cases, especially in the case of citric acid. In the current state of knowledge, foliar fertilization cannot offer yet a good alternative for full control of Fe chlorosis, although its low environmental impact and cost make this technique a good complementary measure to soil Fe-chelate applications and other chlorosis alleviation management techniques. Abbreviations: Chl – chlorophyll; EDDCHA – ethylenediamine di(5-carboxy-2-hydroxyphenylacetic) acid; EDDHA – ethylenediamine di(o-hydroxyphenylacetic) acid; EDDHMA – ethylenediamine di(o-hydroxy-p-methylphenylacetic) acid; EDDHSA – ethylenediamine di(2-hydroxy-5-sulfophenylacetic) acid     

The effect of high pH and P on the development of lime-chlorosis in two seedling populations ofEucalyptus obliqua L'Hérit

Summary Glasshouse experiments have shown that the application of an acidulating agent to a calcareous soil can increase growth and alleviate severe chlorosis in an acidic population ofE. obliqua. In contrast, a calcareous population showed only a slight response to this treatment and maintained adequate growth and a low frequency of chlorosis on both control and treated calcareous soils. Foliar analyses of seedlings of the acidic population showed that alleviation of chlorosis was concomitant with a reduction in the levels of P, Ca and K, and an increase in uptake of Fe. However, the total Fe content of foliage was poorly correlated with the occurrence of severe chlorosis. Although this evidence suggested that the differential susceptibility ofE. obliqua to lime-chlorosis can be reduced by increasing the availability of Fe, the greater concentration of Fe in chlorotic seedlings indicated that lime-chlorosis may also be due to an inactivation of Fe within the plant (i.e. by P). This hypothesis was partly confirmed by a water culture experiment which showed that a combination of relatively high pH and high external levels of P could induce severe chlorosis in seedlings of the acidic population. In contrast, it appears that the calcareous population has a more efficient mechanism for absorbing Fe and holding it in an available form, even when external concentrations of P are high. It is suggested that plants which have an efficient mechanism for the uptake of Fe at relatively high pH and are less susceptible to the detrimental effects of P have been selected for on these alkaline calcareous soils.     

In vitro rooting of almond (Prunus dulcis Mill.)

Summary Shoot cultures of the paper shell almond (Prunus dulcis Mill.) cultivars ‘Ne Plus Ultra’ and ‘Nonpareil’ were subcultured for 4 wk at 4°C on growth regulator-free basal medium under low light conditions. Elongated shoots were excised and their response to a range of rooting treatments determined. Various concentrations of indole-3-butyric acid (IBA) and α-naphthaleneacetic acid were compared over a range of incubation periods to determine the optimum auxin for root formation. In addition, the effect of shoot base shading, phloroglucinol (PG), and basal salt composition were examined. The treatment resulting in the best rooting of both cultivars was shoot insertion for 12 h into water-agar (0.6% w/v) with 1.0 mM IBA, followed by 2 wk in basal medium without auxin but with 100.0 μM PG. Explants were maintained under dark conditions for 3 d at the start of the treatment period, then exposed to light. Extending the darkening period did not improve rooting ability. Whilst half-strength Murashige and Skoog basal medium was suitable for rooting “Ne Plus Ultra’ shoots, full-strength Almehdi and Parfitt medium resulted in the best rooting of ‘Nonpareil’. Under these conditions, 60.0% of explants developed adventitious roots.     

Plant growth and nutrient uptake characteristics of Fe-deficiency chlorosis susceptible and resistant subclovers

The objective of this study was to evaluate the growth and nutrient-uptake characteristics of Fe-deficiency resistant and susceptible subclover (Trifolium subterraneum L., T. yanninicum Katzn. and Morley, T. brachcalycinum Katzn. and Morley) cultivars on a calcareous soil. Ten subclover cultivars showing varying susceptibilities to Fe-deficiency chlorosis (Karridale, Nangeela, Geraldton, Mt. Barker, Woogenellup, Larisa, Trikkala, Rosedale, Koala and Clare) were grown on a low-Fe, calcareous soil (Petrocalcic Paleustoll) under moist (18% water content, 85% of water holding capacity) and water-saturated conditions using a Cone-tainer^® culture system. Chlorosis and its correlation with growth traits and mineral nutrition of the 10 cultivars were examined. The Fe-deficiency susceptibilities of the 10 cultivars decreased in the above order under the moist condition, but in slightly different order under the saturated condition. Shoot and root dry weights, total dry weight, and root-to-shoot ratio were each negatively correlated with chlorosis under both soil-moisture conditions, as was total shoot content of P, Ca, Fe, Mn and Zn. Shoot P and Fe concentrations were each positively correlated with chlorosis under the moist soil condition. Iron and Cu utilization efficiencies (biomass per unit weight of nutrient) in the shoot were each negatively correlated with chlorosis under the moist soil condition. These results suggest that there may be several characteristics of Fe-deficiency chlorosis resistance in subclovers, such as a more effective soil-Fe mobilizing mechanism(s), more balanced nutrition, lower required Fe concentration in the shoot, higher shoot-Fe utilization efficiency, and higher root/shoot ratio under Fe-deficiency stress conditions.     

Post-emergence treatment of iron-related rice-seedling chlorosis

A number of nutritional problems have been reported for production of rice (Oryza sativa L.) on organic soils (Histosols). One of these, termed rice-seedling chlorosis, occurs when rice is drill-seeded into certain drained Histosols, and results in chlorotic, weakened seedlings that often die before or during imposition of the permanent flood. The condition can be predicted on the basis of soil testing and can be prevented by applying water-soluble Fe with the seed at planting. Greenhouse and field studies were conducted to determine the degree to which this problem can be corrected by the use of post-emergence foliarly applied Fe when the condition is not attended to at planting. It was determined that foliar application of Fe improved seedling growth, reduced seedling mortality, and increased rice grain production relative to no treatment. Nevertheless, prediction by the use of soil testing and prevention by application of Fe at seeding appears to be a more effective method for correcting seedling chlorosis than post-emergence foliar application of Fe.Florida Agricultural Experiment Station, Journal Series No. R-01230.     

Molecular Chaperone-Assisted Production of Human α-1,4-<Emphasis Type="Italic">N</Emphasis>-Acetylglucosaminyltransferase in Silkworm Larvae Using Recombinant BmNPV Bacmids

In this study, human α-1,4-N-acetylglucosaminyltransferase (α4GnT) fused with GFP_uv (GFP_uv-α4GnT) was expressed using both a transformed cell system and silkworm larvae. A Tn-pXgp-GFP_uv-α4GnT cell line, isolated after expression vector transfection, produced 106 mU/ml of α4GnT activity in suspension culture. When Bombyx mori nucleopolyhedrovirus containing a GFP_uv-α4GnT fusion gene (BmNPV-CP ⁻/GFP_uv-α4GnT) bacmid was injected into silkworm larvae, α4GnT activity in larval hemolymph was 352 mU/ml, which was 3.3-fold higher than that of the Tn-pXgp-GFP_uv-α4GnT cell line. With human calnexin (CNX) or human immunoglobulin heavy chain-binding protein (BiP, GRP78) coexpressed under the control of the ie-2 promoter, α4GnT activity in larval hemolymph increased by 1.4–2.0-fold. Moreover, when BmNPV-CP ⁻/GFP_uv-α4GnT bacmid injection was delayed for 3 h after BmNPV-CP ⁻/CNX injection, the α4GnT activity increased significantly to 922 mU/ml, which was 8.7-fold higher than that of the Tn-pXgp-GFP_uv-α4GnT cell line. Molecular chaperone assisted-expression in silkworm larvae using the BmNPV bacmid is a promising tool for recombinant protein production. This system could lead to large-scale production of more complex recombinant proteins.     

Characterization of the tolerance to iron chlorosis in different peach rootstocks grown in nutrient solution

Iron chlorosis is an important problem in peach trees, but differences exist between peach rootstocks in their tolerance to Fe chlorosis in calcareous soils. The purpose of this investigation was to characterize the tolerance of different rootstocks to Fe chlorosis induced by bicarbonate in nutrient solution. The rootstocks studied included peach (Nemaguard), plums (Brompton, San Julian A and Puebla de Soto 101) and almond × peach hybrids (Adafuel and GF677). Young plants obtained from rooted cuttings or from in vitro culture techniques were grown individually, under controlled conditions, in flasks with 700 mL of aerated nutrient solution low in iron and with or without 10 mM bicarbonate or 10 mM phosphate. Susceptiblity to bicarbonate-induced chlorosis was inversely correlated with both the Fe content in young leaves and the reducing capacity of roots, but not with the phosphorus content in young leaves. The plum Puebla de Soto 101 and the hybrid GF677 showed the lowest degree of chlorosis and the highest reducing capacity. Phosphate did not induce chlorosis.     

Differences in responses to iron deficiency among various cultivars of mungbean (Vigna radiata (L.) Wilczek)

Ten mungbean cultivars were evaluated for their resistance to iron deficiency in view of chlorosis symptoms, plant growth and seed yield under field conditions on a calcareous soil in Thailand. The KPS2 cultivar was highly susceptible; the KPS1, PSU1 and Pag-asa 1 cultivars were somewhat susceptible; the VC1163B cultivar was moderately tolerant; the CN36, CN60, UT1 and CNM-I cultivars were tolerant; and the CNM8509B cultivar was very tolerant to iron deficiency. Foliar application of a solution of 5 g L^-1 ferrous sulphate was effective in correcting chlorosis that was induced by iron deficiency, and it enhanced both the growth and the yield of susceptible cultivars. Compared with the susceptible cultivar KPS2, the tolerant cultivar UT1 had a greater ability to lower the pH of the nutrient solution in response to iron deficiency. The root-associated Fe³⁺-reduction activity of UT1 that had been grown in -Fe medium was similar to that of the plants grown in +Fe medium when the acidification of the medium occurred. Acidification of the medium in response to iron deficiency might contribute to the efficient solubilization of iron from calcareous soils, and it related more closely to the resistance to iron deficiency than Fe³⁺ reduction by roots in mungbean cultivars.     

Interactions Between High pH and Iron Supply on Nodulation and Iron Nutrition of Lupinus albus L. Genotypes Differing in Sensitivity to Iron Deficiency

Poor growth of white lupin (Lupinus albus L.) on alkaline soils may result from its sensitivity to iron deficiency and poor nodulation. This study examined interactive effects of iron supply and high pH on the growth and nodulation of three genotypes differing in their sensitivity to iron deficiency. Three genotypes (P27486, Ultra and WTD180) were grown for 17 days in buffered solutions with Fe supply of 0.2, 2 and 20 μM. Solution pH was adjusted to 5.2, 6.5 or 7.5. Plant growth, nodulation and nutrient concentrations in plants were measured. Decreasing Fe supply decreased chlorophyll concentration in young leaves by up to 92%. Increasing pH decreased chlorophyll concentration by an average of 40% at pH 6.5 and by 47% at pH 7.5. The decrease of chlorophyll was less obvious in P27485 than in Ultra or WTD180. Shoot biomass was reduced by up to 18% by Fe deficiency, with such decrease being less for P27486. Increasing pH exacerbated the effect of Fe deficiency on shoot biomass only of Ultra. Decreasing Fe supply decreased nodule number by an average of 54%, and increasing pH decreased nodule number by 80%. P27486 formed the greatest number of nodules while WTD180 the least. P27486 had high Fe uptake and low internal requirement. Irrespective of genotype, leaf chlorosis positively correlated with cluster root formation. The results suggest that a combination of Fe deficiency and high pH impaired nodulation in L. albus, and that selection of genotypes for both tolerance of iron deficiency and good nodulation at high pH is important for a successful lupin crop on alkaline soils.     

Intraspecific variability of cadmium tolerance in hydroponically grown Indian mustard (<Emphasis Type="Italic">Brassica juncea</Emphasis> (L.) Czern.) seedlings

Indian mustard (Brassica juncea (L.) Czern.) is a promising plant species for phytoremediation of heavy metal polluted soils. However, genetic variability of metal tolerance in Indian mustard has not been studied. We evaluated intraspecific variation of Cd tolerance of this species by screening 64 varieties in hydroponics. The tolerance index (TI), calculated as percentage of root length of Cd-treated (7 μM CdCl₂) over untreated control seedlings, significantly varied from 34 to 79%, depending on the variety. Information about phenotypic and economic traits of the studied varieties was taken from the literature and subjected to a cluster analysis. The varieties were distributed into three clusters and most of the varieties characterized by the highest TI values (TI > 65%) were grouped together in one cluster. Moreover, TI negatively correlated with the following characteristics: yellow seed colour (R = −0.35, P = 0.005), total oil content (R = −0.33, P = 0.008), oleic acid (R = −0.25, P = 0.047) and linoleic acid (R = −0.36, P = 0.004) contents in seeds. The results showed the presence of significant variability for Cd tolerance in Indian mustard. The knowledge about correlations between Cd tolerance and phenotypic characteristics of plants might be utilized for rapid selection of cultivars to be used for phytoremediation of polluted soils.     

Differences between Bradyrhizobium strains NC92 and TAL1000 in their nodulation and nitrogen fixation with peanut in iron deficient soil

The effects of Bradyrhizobium (strains NC92 and TAL1000) and Fe supply on nodulation and nitrogen fixation of two peanut (Arachis hypogaea L.) cultivars (cv. Tainan 9 (Fe inefficient) and cv. 71-234 (Fe efficient)) grown under Fe deficient conditions (imposed by adding 40% CaCO₃ to a ferruginous soil) were examined in a glasshouse experiment. When inoculated with TAL1000 without Fe, both cultivars had low shoot N concentration, very low nodule numbers and weight and no measurable acetylene reduction activity per plant. Inoculation with NC92 without Fe increased all these parameters substantially; addition of Fe with NC92 had no further effect on N concentration but doubled nodule number, weight and acetylene reduction activity per plant. Addition of Fe with TAL1000 increased all parameters to the same level as Fe+NC92, indicating that the poorer nodulation and N₂ fixation of TAL1000 in the absence of Fe, resulted from a poorer ability in getting its Fe supply from the alkaline soil. The nodules from all treatments with measurable activity had the same specific acetylene reduction activity suggesting that Fe deficiency limited nodule development.The results support previous suggestions that Bradyrhizobium strains differ greatly in their ability to obtain Fe from soils and that selection of Fe efficient strains could complement plant breeding in the selection of legume crops for Fe deficient soils.     

Infestation by a Nalepella species induces emissions of α- and β-farnesenes, (−)-linalool and aromatic compounds in Norway spruce clones of different susceptibility to the large pine weevil

The emissions of spruce grafts (Picea abies), caused by infestation of an acarid species of the genus Nalepella were investigated. Volatiles of three clones, both healthy and infested, with different susceptibility to the large pine weevil Hylobius abietis were collected by solid phase micro extraction (SPME) and analyzed by gas chromatograph coupled to mass-spectrometry (GC-MS). In addition, enantiomers of the main chiral compounds were separated by a two dimensional-gas chromatograph (2D-GC). In the characteristic flower-like fragrances emitted by the infested grafts large amounts of E-β-farnesene, E,E-α-farnesene, (−)-linalool, methyl salicylate and minute amounts of benzyl alcohol, E-anethole, methyl benzoate, neral and geranial were found. All together, these compounds could explain the characteristic scent emitted by the infested seedlings. Large differences in the emissions of E-β-farnesene, E,E-α-farnesene and methyl salicylate were found between but not within the clones. Handling editor: Heikki Hokkanen.     

Relationship between soluble carbohydrate level and tolerance of meadow fescue callus to Bipolaris sorokiniana (Sacc.) Shoem. and Drechslera dictyoides (Drechsl.) Shoem. metabolites

The aim of the presented work was the search for the relationship between the level of soluble carbohydrates in callus tissues of eight meadow fescue (Festuca pratensis Huds.) cultivars and their growth ability on media containing Bipolaris sorokiniana and Drechslera dictyoides metabolites. Calli were induced from mature grains using the method previously described (Płażek 1994). Callus obtained from single caryopsis was cut into three pieces which were weighted and put on the media with or without pathogen metabolites. Tissue selection was performed by means of “double-layer culture” technique (Lepoivre et al. 1986). After two-week culture in the darkness at temp. of 25°C the calli were weighted again. The sugar level in tissue was measured by means of colorimetric method of Klein & Weissman according to Snell (1961). Fresh mass decrease of calli developing on the media with fungus metabolites was observed by all studied object. The tolerance of calli of the tested cultivars to metabolites of both pathogens was significantly different. However, significant similarity between the tolerance of calli of particular varietes to both fungi was noted. The soluble carbohydrate contents in control tissue of all studied cultivars were similar and their values ranged between 2.4 and 3 % of fresh mass. B. sorokiniana metabolites caused a significant decrease of the sugar content in calli, while D. dictyoides metabolites did not decrease the sugar level.     

Differences in calcium efficiency between cowpea (Vigna unguiculata (L.) Walp.) cultivars

The cowpea (Vigna unguiculata (L.) Walp.) cultivars TVu 354 and Solojo were grown in solution culture at 10 to 1000 M Ca supply. The Ca supply did not vary by more than 10% during the experiment. The pH value was kept constant within 0.1 units at 4.0 by automatic titration. The cultivar TVu 354 proved to be much more Ca-efficient than Solojo. At 10 M Ca supply Solojo died, whereas TVu 354 was hardly affected in dry matter production. The differences in Ca efficiency were independent of the P supply. They could not be explained by differences in Ca uptake or Ca concentrations in the plant tissue. Short-term studies using ⁴⁵Ca, both in the dark and in the light, indicated better transport of Ca from the roots to the shoots and within the shoots to the younger leaves in the Ca-efficient cultivar TVu 354. However, the main reason for the differences between the cultivars in sensitivity to low Ca supply were differences in the Ca requirement of the plant tissue to maintain tissue organization and function. Sequential fractionation of the freeze-dried leaf tissue with hot water, 0.5 M NaCl, 1 M CH₃COOH, and 2 M HCl did not reveal cultivar differences in Ca binding state. The results clearly show that considerable genetic potential in tolerance to low Ca supply exists in cowpea. However, a better understanding of the physiological/biochemical reasons for low internal Ca requirement is needed.     

Screening of wild accessions resistant to gray mold (Botrytis cinerea Pers.) in Lycopersicon

Tomato gray mold (Botrytis cinerea Pers.) is a common disease worldwide, and often causes serious production loss by infecting leaves, stems, flowers and fruits. Presently, no resistant cultivars are available. To find new breeding materials for gray mold resistance, assessment for resistance of the leaflet and stem in six tomato cultivars, 44 wild tomato accessions and a Solanum lycopersicoides accession was performed. Although no correlation was observed (r=−0.127^ns) between resistance of the leaflet and the stem, L. peruvianum LA2745, L. hirsutum LA2314 and L. pimpinellifolium LA1246 showed high resistance both in the leaflet and in the stem. Particularly, in the leaves of LA2745, no lesions were observed even more than two weeks after the inoculation with conidia, and F1s between a cultivated tomato and LA2745 also showed high resistance as observed in LA2745. From these results, LA2745 is thought to be a promising material for breeding gray-mold resistant cultivars.     

Phytosiderophore release from nodal,primary, and complete root systems in maize

Some maize (Zea mays L.) hybrids grown in high pH soil in Nebraska suffer from severely reduced yields caused by iron (Fe) deficiency chlorosis. Hybrids which recover from early season Fe-deficiency chlorosis and yield well are termed Fe-efficient or tolerant. Most Fe-efficient gramineous species respond to Fe-deficiency stress by releasing phytosiderophores (mugineic acid and its derivatives) into the rhizosphere, thereby increasing Fe availability and uptake of the Fe³⁺-phytosiderophore complex via a high affinity uptake system. Field-grown Fe-efficient maize recovers from Fe-deficiency chlorosis at a stage when nodal roots have become the dominant root system. Quantifying phytosiderophore release from hydroponically grown plants has been proposed as a viable alternative to time-consuming and variable field trials and has been used successfully to delineate among Fe-efficient and Fe-inefficient lines of oat (Avena sativa L.) and wheat (Triticum aestivum L.). Our objectives were (1) to determine if phytosiderophore release differed between nodal- and primary-root systems of maize, and (2) to compare phytosiderophore release from 12 hybrids. Root exudates secreted during daily 4-h collections were analyzed for their Fe-solubilizing ability, which was equated to phytosiderophore release. Nodal root systems released significantly more phytosiderophore than primary- or complete-root systems. In early experiments, an Fe-efficient hybrid (P3279) released more phytosiderophore from nodal roots than an Fe-inefficient hybrid (P3489). Tests of an additional 10 hybrids showed that phytosiderophore release varied significantly among the cultivars but did not clearly distinguish between hybrids classified as Fe-efficient or Fe-inefficient in individual company trials. We recommend using nodal roots when studying Fe-stress response mechanisms in maize.     

Flavonol glycosides in the leaves ofTrillium apetalon Makino andT. kamtschaticum pallas

Seven flavonol glycosides were isolated from the leaves ofT. apetalon. They were identified chromatographically and spectrally to be: quercetin/kaempferol 3-O-α-arabinopyranosyl-(1→6)-β-galactopyranoside (TQ and TK), quercetin/kaempferol 3-O-[2‴-O-acetyl-α-arabinopyranosyl]-(1→6)-β-galactopyranoside (TAQ and TAK), quercetin 3-O-β-glucoside (ISQ), isorhamnetin 3-O-α-arabinopyranosyl-(1→6)-β-galactopyranoside (TI) and isorhamnetin 3-O-[2‴-O-acetyl-α-arabinopyranosyl]-(1→6)-β-galactopyranoside (TAI). TQ, TAQ, TI and TAI were major constituents. This is the first report on two new isorhamnetin-type glycosides, TI and TAI. The seven flavonol glycosides identical to those ofT. apetalon were isolated and identified in the leaves ofT. kamtschaticum; TQ and TAQ were also major components, but TI and TAI were only minor components. TI and TAI were not detected in the leaves ofT. tschonoskii. These leaf-flavonoid patterns were discussed from a chemosystematic point of view. Part 3 in the series “Studies of the flavonoids of the genusTrillium”. For Part 2 see Yoshitamaet al., (1997) J. Plant Res.110: 379–381.     

β-Amino acid residues: Conformational characterization of an N- and C-protected homo-β-(S)-leucine

Summary An N- and C-protected derivative ofhomo-β-leucine, Fmoc-homo-β-(S)-leucine methyl ester, synthesized from the corresponding proteinogenic parent α-amino acid in enantiopure form has been fully characterized in the solid state by X-ray diffraction analysis. The crystal conformation of this new residue indicates and extended conformation for thishomo-β-residue, with the ϕ torsion angle being more constrained than the μ and ψ angles.     

Identification of three Wx proteins in wheat (Triticum aestivum L.)

Nullisomic analysis of waxy (Wx) protein of hexaploid wheat (Triticum aestivum L.) cv. “Chinese Spring” using two-dimensional polyacrylamide gel electrophoresis revealed that threeWx loci,Wx-A1, Wx-B1, andWx-D1, located on chromosome arms 7AS, 4AL, and 7DS, produce three distinct Wx subunit groups, subunit group-A (SGA), SGB, and SGD, respectively. SGA has a higher molecular weight and a more basic isoelectric point (pI) than the other two. SGB and SGD have the same molecular weight but a slightly different pI range. Owing to the detection of these three subunit groups, we were able to identify the expression of three waxy genes in wheat endosperm and to find two types of mutants among Japanese wheat cultivars, one lacking SGA and the others SGB. These results suggest the possibility of breeding a waxy wheat.