Influence of chemical and biological treatments on volatile oil composition of Artemisia annua Linn.

The relative abundance of isoprenoids and other volatile components in the aerial parts of Artemisia annua Linn. (Asteraceae) after different nutritional treatments was analyzed by GC and GC/MS. Hydro-distillation of untreated (control) plants yielded 0.28 ± 0.04% essential oil on fresh weight basis. Monoterpenes were predominant in the essential oil of which cis-limonene-1,2-epoxide (22.1%), artemisia ketone (11.5%), iso-pinocamphone (11.4%), thujyl alcohol (9.9%) and camphor (8.4%) were the major components. The essential oil distilled from A. annua treated with Azospirillum (2 ml/plant) amounted to 0.30 ± 0.03% of fresh weight and consisted mainly of neral (31.1%), β-caryophyllene (25.1%), artemisia ketone (10.0%), thujyl alcohol (9.4%), trans-bergamotene (8.5%) and spathulenol (4.8%). The essential oil from plants treated with basal N, P, K and S application (in the form of urea P₂O₅, K₂O and gypsum at a rate of 120, 50, 100 and 50 kg/ha, respectively) amounted to 0.32 ± 0.03% of fresh weight and consisted mainly of thujyl alcohol (33.3%), β-caryophyllene (15.5%), cis-undec-5-ene (14.4%), artemisia ketone (6.0%), trans-nerolidol (5.8%) and undec-4-ene (4.6%). The hydrodistillation of A. annua treated with Glomus (Mycorrhizal soil 50 g/plant) yielded 0.50 ± 0.02% essential oil on fresh weight basis. The sesquiterpenes were predominant in this essential oil and consisted of β-caryophyllene (51.2%), trans-bergamotene (15.4%), α-gurjunene (14.3%), germacrene D (5.1%) and ledol (4.5%) as major components. The only monoterpenes in the essential oil were neral, nerol and pulegone (each less than 1%). These findings suggest that A. annua treated with Glomus lacks glandular trichomes—the primary sites of synthesis of monoterpenes.     

Molecular characterization and comparative analysis of four new genes from Sec2 locus encoding 75K γ-secalins of rye species

Using a PCR-based strategy, four new 75K γ-secalin genes were isolated from Secale cereale, Secale vavilovii, Secale sylvestre, and Secale strictum in genus Secale (rye). Based on amino acid sequences, the primary structure of the 75K γ-secalin subunits was demonstrated, which was composed of four main structural regions: (a) a conservative 19 amino acids signal peptide, (b) a steady short N-terminal region of 12 amino acids containing a cysteine residue, (c) a repetitive domain, which began with the conservative tetrapeptides PQ₃ and was rich in glutamine and proline. PFPQ₁₋₂(PQQ)₁₋₂ was the core repeat motif in the repetitive region. Besides amino acid substitutions, this region showed variations in length due to the insertion and deletion events. In the repetitive region of EF432549 (Secale strictum), there were two octapeptides (PFPQQPQQ and PVPQQSQQ) insertions. On the contrary, deletion events of two residues (QT) took place in EF432546 (Secale sylvestre). Accounting for the amino acid replacement, an extra cysteine residue appeared in the repetitive region of EF432546, which did not exist in other genes, and (d) a conserved 143 amino acids C-terminal domain including eight cysteine residues. The implications of the results for quality improvement are discussed.     

Hydrothermal Processing of Barley (cv. Blenheim): Optimisation of Phytate Degradation and Increase of FreeMyo-inositol

Optimal conditions were developed for hydrothermal processing of whole barley kernels (cv. Blenheim) to degrade phytate (myo-inositol hexaphosphate) and to increase the content of freemyo-inositol. The hydrothermal treatment comprised of two wet steeps, where lactic acid solution of different concentrations was used, and two dry steeps followed by successive drying. Experiments were performed as a central composite design and evaluated by multiple linear regression. The variables in the experiments were temperature in the first wet and dry steep (T₁), temperature in the second wet and dry steep (T₂) and lactic acid solution concentration in both wet steeps (C) and mathematical models were developed in these variables. Optimal conditions for maximal phytate degradation and for maximal increase of freemyo-inositol wereT₁=48 °C,T₂=48–50 °C andC=0·8%, at these conditions the amount of phytate was reduced by 95–96% and the freemyo-inositol concentration was increased from 0·56 to 2·45 μmol/g d.m. We conclude that this hydrothermal process can be used to produce a barley product (cv. Blenheim) with a low phytate content and a high level of freemyo-inositol.     

Direct lipase-catalyzed lipophilization of chlorogenic acid from coffee pulp in supercritical carbon dioxide

The direct esterification of chlorogenic acid (5-CGA) by immobilized Candida antarctica lipase B (Novozym 435) in supercritical CO₂/t-butanol has been studied. The Taguchi approach was applied to evaluate the effects of temperature (35–55 °C), pressure (150–250 bar), t-butanol (2–10%, v/v), and the enzyme amount (10–30 mg/ml), on the ester concentration and overall conversion. Optimum reaction conditions were established at: 150 bar, 55 °C, 10% t-butanol (v/v), 20 mg/ml of lipase. Addition of 20 mg/ml of molecular sieves (3 Å) was also necessary to minimize the inhibiting effect of the increasing water concentration. Maximum conversions reached 77, 82 and 85% in 25 h using geraniol, pentanol and heptanol as aliphatic chain donors, respectively. HPLC analysis demonstrated the selective esterification of 5-CGA from a coffee pulp aqueous-methanolic extract, which reached a conversion to heptyl ester of 65% at the optimal condition. The supercritical CO₂ selectivity towards the esterified product was the working principle of this study, by which minimized interphase transport limitations and enhanced mass-transfer phenomena substantially improved the reaction kinetics.     

Interspecific and Intraspecific Variation in Grain and Groat Characteristics of Wild Oat (Avena) Species: Very High Groat (1→3),(1→4)-β- -glucan in an Avena atlantica Genotype

Grain characteristics and groat composition have been evaluated in 35 genotypes from nine taxonomic species of Avena, including three species (A. agadiriana, A. atlantica, A. damascena) for which no previous data are available. There was substantial interspecific and intraspecific variation for all characteristics measured. The proportion of groat in the grain ranged from 32·7–62·1%, and mean groat weight from 2·4–37·4 mg. Groat protein concentrations ranged from 13·9–41·3%, and exceeded 32% in one A. atlantica, two A. damascena and one A. murphyi genotype. Groat β-glucan concentration showed very wide variation (2·2–11·3%) are there were substantial interspecific and intraspecific differences. The highest β-glucan concentrations were found in genotypes of A. atlantica. Although there were interspecific and intraspecific variations in groat oil concentration (4·2–10·6%), and in fatty acid composition, data were within previously reported ranges for A. sativa. Overall these data indicate that some of the genotypes of the wild species studied may be of value for breeding oats with improved levels of β-glucan and protein, and that further studies are warranted into both interspecific and intraspecific variations in grain quality factors in wild oat species.     

The Role of Dextrins in the Stickiness of Bread Crumb made from Pre-Harvest Sprouted Wheat or Flour Containing ExogenousAlpha-Amylase

Dextrins were extracted in water from bread made from pre-harvest sprouted wheat or standard flour supplemented with exogenousalpha-amylases. The dextrins were separated by gel permeation chromatography and the dextrin content (% of crumb weight) determined for different degree of polymerisation (DP) size classes; DP 1–2, DP 3–10, DP 11–50, DP 51–200 and DP >200. There were significant correlations between the dextrin content in each size class and crumb stickiness (r=0·84–0·91, 22 df ). The most significant correlation (r=0·96) was between total dextrin content and crumb stickiness. Addition of dextrins of various DP ranges from various sources to standard flour produced bread with sticky crumb. Again, the degree of stickiness was generally related to the amount of total dextrin in the crumb and not to size distribution of dextrins. In this instance, extensive enzymic hydrolysis of starch was not necessary to produce sticky crumb; the dextrins caused crumb stickiness directly. Addition of dextrins to reconstituted gluten–starch flour produced bread with unexpectedly low dextrin levels and correspondingly low stickiness scores. It is concluded that, to produce sticky crumb, high levels of dextrin of any size are necessary in the crumb; a sticky mass is produced when dextrins dissolve in the excess «free» water that is normally «bound» to starch, gluten and other insoluble components of bread crumb.     

Comparative Studies of HighMrSubunits of Rye and Wheat. I. Isolation and Biochemical Characterisation and Effects on Gluten Extensibility

The structural features of highM_rglutenin subunits of wheat were compared with those of analogous proteins from rye. Subunits of two rye cultivars (Danko and Halo) and of the wheat cultivar Rektor were isolated from defatted flours by extraction with 50% (v/v) aqueous propan-1-ol under reducing conditions at 60°C followed by precipitation using a 60% concentration of propan-1-ol. The yields of dialysed and freeze-dried subunits were 0·33% and 0·32% (w/w of flour), respectively (rye cultivars), and 0·91% (Rektor). SDS–PAGE revealed that the rye cultivars contained at least five subunits with mobilities corresponding to the x-type subunits of wheat. Separation by RP–HPLC indicated that the rye cultivars did not differ in the qualitative composition of subunits, but in their quantitative proportions. The surface hydrophobicities of the rye subunits were significantly lower than those of wheat subunits. The amino acid compositions of single rye subunits were characterised by high contents of Glx, Gly and Pro, and they were closely related to those of wheat subunits, except that the Glx content was generally lower and the Cys content higher. Notable differences between rye and wheat subunits were found in their contributions to gluten strength. Whereas wheat subunits, reoxidised with potassium bromate and mixed with a standard wheat flour, caused a significant increase in gluten strength, reoxidised rye subunits had the opposite effect.     

Effects of Cultivar and Environment on β-(1,3)-(1,4)- -glucan Content and Acid Extract Viscosity of Spanish Barleys

The acid extract viscosities and β-glucan contents of ten two- and six-rowed barley cultivars grown at seven locations in three consecutive years in Spain were studied in the present work. The viscosities varied from 2·4 to 24·8 centistokes (cSt) and the mean value was 6·4 cSt. The average β-glucan content of barleys determined by HPLC was 3·5% with a range of 1·9–5·5%. Significant differences were found in both β-glucan content and acid extract viscosity between different cultivars, locations and years. The β-glucan contents and viscosities of winter cultivars were higher than those of spring. Cvs. Barbarrosa and Hatif de Grignon were the genotypes with the highest values for both parameters, while cv. Beka had the lowest viscosity and β-glucan content. Environmental factors influenced both parameters. The acid extract viscosities of barleys were correlated negatively with the amount of precipitation (r=−0·754;P<0·05). Barleys grown in wet and rainy areas (Girona and La Coruña) had lower viscosity values.     

Essential oil composition of Hypericum perfoliatum L. and Hypericum tomentosum L. growing wild in Tunisia

The essential oils obtained by hydrodistillation from the aerial parts of Tunisian native Hypericum perfoliatum L. (sect. Drosocarpium Spach.) and Hypericum tomentosum (sect. Adenosepalum Spach.) were analyzed by GC and GC–MS. Thirty-two compounds were identified in the essential oils of H. perfoliatum with α-pinene (13.1%), allo-aromadendrene (11.4%), germacrene-D (10.6%), n-octane (7.3%), α-selinene (6.5%) and β-selinene (5.5%) as main constituents. Sixty-seven components were identified in the oil of H. tomentosum with menthone (17.0%), n-octane (9.9%), β-caryophyllene (5.3%), α-pinene (5.2%), lauric acid (4.1%) and β-pinene (3.7%) as the most abundant components. Both oils were characterized by the presence of many components which could have numerous applications in food, pharmaceutical and perfume industries.     

Analysis of Aroma and Phenolic Components of Selected Achillea Species

Dried flowers and leaves of four different Achillea species grown wild in several provinces of Iran, including one species collected from three different locations of Isfahan province were analyzed for the headspace volatile components, total phenolics (TP) and tartaric esters (TE). Capillary gas chromatography/mass spectrometry (GC/MS) combined with a purge and trap method was used for quantification of aroma components. Over 70 compounds were determined in the samples. Flower samples from all species contained 2-methyl butanal, α-pinene, α-thujene, camphene, hexanal, β-pinene and 1,8-cineole; however, the major constituents of the aerial parts were determined as α-pinene, camphene, DL-limonene and 1,8-cineole. The largest number of aroma components were found in Achillea tenuifolia Lam. and Achillea millefolium L. In all species, except A. millefolium, the leaves contained more TP and TE than flowers. However, A. wilhelmsii from Semirom in Isfahan province showed the highest values for TP and TE.     

Affinity Chromatography with Immobilised Endoxylanases Separates TAXI- and XIP-type Endoxylanase Inhibitors from Wheat (Triticum aestivum L.)

An affinity-based purification procedure allowed the resolution of two distinct groups of endoxylanase inhibitors with different molecular structures and endoxylanase specificities from wheat wholemeal. The first group comprises the so-called Triticum aestivum L. Endoxylanase inhibitor (TAXI)-type proteins which are of approx. M_r 40 000 and occur in two different molecular forms. These inhibitors were removed from a concentrated cation exchange chromatography fraction from wheat wholemeal on a Bacillus subtilis endoxylanase affinity column. The second group of structurally different endoxylanase inhibitors, the so-called xylanase inhibiting protein (XIP)-type, of approx.M_r 29 000–32 000, with pI values varying between 8·8 and 9·2, was purified from the unbound fraction from the B. subtilis endoxylanase affinity column by chromatography on an Aspergillus niger endoxylanase affinity column followed by gel permeation chromatography. The XIP-type inhibitors are not active against the B. subtilis endoxylanase and were consequently not retained on the B. subtilis endoxylanase column. Further analysis of the XIP-type proteins by high-resolution cation exchange chromatography, SDS-PAGE and iso-electrofocusing, revealed several forms. They had similar endoxylanase specificities and N-terminal amino acid sequences.     

Cereal β-glucans in diet and health

The native mixed linkage β-glucan of cereals is classified as a soluble dietary fibre, with rheological properties generally similar to guar gum and other random coil polysaccharides. The ability of oat and barley products to attenuate postprandial glycemic and insulinemic response is related to content of (1→3)(1→4)-β-d-glucan (β-glucan) and viscosity. A role of viscosity of β-glucan has not been directly demonstrated for lowering of serum cholesterol levels, and not all studies report a statistically significant lowering. The wide range of effectiveness reported may partially be explained by the properties of the β-glucan in the diets used, as well as the dose.     

Effect of growth stage on the content and composition of the essential oil and phenolic fraction of sweet marjoram (Origanum majorana L.)

The variation in the content and composition of Origanum majorana L. essential oil has been studied. Plant material has been harvested at four phenological stages (early vegetative, late vegetative, budding and full-flowering). Essential oil yield varied from 0.04 to 0.09% reached during the full-flowering stage. Analysis of the essential oils by GC and GC/MS revealed the presence of 38 components represented mainly by oxygenated monoterpenes (64.01–71.4%), monoterpene hydrocarbons (21.73–29.92%) and sesquiterpene hydrocarbons (1.47–4.05%). The main components were terpinen-4-ol (29.13–32.57%), cis-sabinene hydrate (19.9–29.27%), trans-sabinene hydrate (3.5–11.61%), γ-terpinene (2.11–8.20%), bornyl acetate (1.52–2.94%) and linalool (1.05–1.39%). On the other hand, phenolic contents varied from 2.706 to 6.834 mg/g of dry weight obtained during the later vegetative stage. RP-HPLC analysis of the methanolic extract of O. majorana L. dried aerial parts showed the predominance of phenolic acids during the early vegetative stage whereas flavonoids predominate during the other stages of growth. The main phenolic acids identified were trans-2-hydroxycinnamic, rosmarinic, vanillic, chlorogenic, gallic and cinnamic whereas the main flavonoids were amentoflavone, apigenin, quercetin, luteolin, coumarin and rutin. Results obtained showed that later vegetative stage is characterized by the highest contents of bioactive compounds and therefore it could be considered as the best stage for harvesting marjoram plants.     

Influence of Temperature on Growth and Production of Pectenotoxin-2 by a Monoclonal Culture of Dinophysis caudata

The effects of temperature on growth and production of Lipophilic Toxins (LT) by a monoclonal culture of Dinophysis caudata was studied. The cell density of D. caudata increased significantly with increasing temperature, and was the highest under 27, 30, and 32.5 °C. Temperature affected the average specific growth rate (µ) during the exponential growth phase (EG), which increased from 15 °C to 30 °C, and then decreased at 32.5 °C. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that this strain of D. caudata produced only pectenotoxin-2 (PTX-2) whose concentration increased significantly with incubation period, except at 32.5 °C. It was significantly different between temperatures ≤18 °C, ≥21 °C, and 32.5 °C. The cellular toxin production (CTP, pg·cell⁻¹·day⁻¹) showed variation with growth phase and temperature, except at 32.5 °C. The average net toxin production (R_tox) was not affected by temperature. During EG, the average specific toxin production rate (µ_tox) increased significantly with increase in temperature, reaching a peak of 0.66 ± 0.01 day⁻¹ at 30 °C, and then decreased. Over the entire growth span, µ_tox was significantly correlated to µ, and this correlation was most significant at 27 and 30 °C. During EG, µ_tox was affected by both temperature and growth. This study shows that temperature affects growth and toxin production of this strain of D. caudata during EG. In addition, a positive correlation was found between toxin production and growth.     

Molecular Basis of the Gelatinisation and Swelling Characteristics of Waxy Rice Starches Grown in the Same Location During the Same Season

Six waxy rice samples (grown at the same site during the same season) were investigated to identify those aspects of amylopectin structure and granule composition which differentiate the starches into high (T_p 77·8 °C on average) or low (T_p 66·2 °C on average) gelatinisation temperature. All starches contained less than 2·5% amylose with negligible lipid. Granule dimensions were similar (mean diameter 4·9–5·7 μm) as was the β-amylolysis limit (59·9–63·0%). However, the structural elements of amylopectins within the two groups varied. The low gelatinisation temperature starches contained two major chain fractions upon debranching with iso-amylase, F3 (DP 16) and F1 (DP 51) on average while the high gelatinisation temperature starches contained three fractions, F3 (DP 16), F2 (DP 19) and F1 (DP 40). The proportion of F1/(F2+F3) for the low and high gelatinisation starches representing on average 20·2 and 10·5% respectively. Hence, the higher proportion of exterior chains and especially those with DP 19 appear to confer the higher gelatinisation temperature characteristic of these starches. Debranched β-limit dextrins were prepared from these starches. Regardless of their origin, (high or low gelatinisation temperature), they contained three fractions: F_3β (DP 5), F_2β (DP 13) and F_1β (DP 19). Hence, the high versus low gelatinisation characteristic was imparted by the exterior chains. Using 13-C CP-MAS/NMR it was confirmed that the number of double helices within the starches were approximately constant although small differences in crystallinity were identified by X-ray diffraction. Retrogradation of the solubilised native high and low gelatinisation temperature amylopectin molecules confirmed that the ‘high temperature gelatinisation amylopectin’ molecules form higher dissociation temperature and enthalpy crystalline domains. This confirms that the higher proportion of short and especially relatively longer short chains promotes crystallite formation.     

Nutrient composition of the leaves and flowers ofColocasia esculenta and the fruits ofSolanum melongena

The nutrient composition, ofColocasia esculenta flowers (CF) and leaves (CL), and the green fruits ofSolanum melongena (SM) were carried out as a means to determine their nutritional potential. Results showed that these food materials had high moisture and fiber levels which ranged between 888 and 906 g·kg^–1; and 204 and 303 g·kg^–1 dry weight (dw) for moisture and fiber respectively. The calorific values were between 3889 and 4001 kcals·kg^–1 dw, while the total lipids ranged from 53 in CF to 71 g·kg^–1 dw in SM. The leaves ofColocasia esculenta had the highest crude protein value of 307 g·kg^–1 dw. The flowers had 149 g·kg^–1 dw while SM had 138 g·kg^–1 dw. The amino acid profile in the flowers and leaves ofColocasia esculenta in contrast to SM were balanced comparable to the reference FAO pattern. Ash values were high (ranging from 76 in SM to 98 g·kg^–1 in CL) with potassium being the principal element. Iron and Zinc levels were also high especially in CF (with 303 and 82 mg·kg^–1 dw respectively). These foods also contained moderate quantities of calcium, phosphorus and magnesium but were poor in manganese and copper.     

Endo-β-1,4-xylanase inhibitors in leaves and roots of germinated maize

Extracts of both leaves and roots of germinated maize were found to contain endo–β–1,4–xylanase inhibitors, previously reported only from whole maize meal. The inhibitors seem to be of the xylanase inhibitor protein (XIP) type, since they inhibit endoxylanases of families 10 and 11 and also show some other characteristics similar to XIP inhibitors described in other cereals. Inhibitors from leaves and roots appeared to be similar. A novel property of the inhibitors described in this work is their unusual thermostability. The half-life of inhibitors at pH 4.5 and 100 °C is greater than 10 h. However, the inhibitors are less thermostable at higher pH levels. Because they did not inhibit a plant endoxylanase, the inhibitors may play a role in maize defense against phytopathogens.     

Variability in essential oil and bioactive chiral monoterpenoid compositions of Indian oregano (Origanum vulgare L.) populations from northwestern Himalaya and their chemotaxonomy

The chemical composition of essential oils isolated from aerial parts of native populations of Origanum vulgare L. from northwestern Himalaya was investigated by enantioselective gas chromatography (enantio-GC), capillary-gas chromatography (capillary-GC) and GC–MS. Seventy compounds, which accounted for 84.9–97% of the oil composition, have been identified. The oils were allotted to two main groups; the first group had a high percentage of components belonging to the thymol/carvacrol biosynthetic pathway and the second was characterized by a different sesquiterpene composition and a high linalool and bornyl acetate percentage. Essential oils of O. vulgare populations from Rilkot and Dhanachuli areas in northwestern Himalaya were characterized by high monoterpenoids proportions as compared to Nainital and Bhowali populations, which were dominated by sesquiterpenoids. High proportions of thymol (29.2–82%) were found only in two populations. Composition of the samples collected from Dhanachuli area differed from Nainital and Bhowali collections by a unique presence of carvacrol. Notably, there were significant differences in the concentration of rest of the terpenes in all the collections. On enantio-GC, enantiomeric excess for (3R) (−)- and (3S) (+)-linalool, (S) (+)- and (R) (−)-terpinen-4-ol, (S) (−)- and (R) (+)-α-terpineol, (1S) (−)-bornyl acetate and (1S) (−)-borneol were established in populations from Bhowali and Dhanachuli area. Moreover, linalool type oregano may be useful in promoting wider commercial utilization of the biodiversity of this species.     

Asperlones A and B,Dinaphthalenone Derivatives from a Mangrove Endophytic Fungus Aspergillus sp. 16-5C

Racemic dinaphthalenone derivatives, (±)-asperlone A (1) and (±)-asperlone B (2), and two new azaphilones, 6″-hydroxy-(R)-mitorubrinic acid (3) and purpurquinone D (4), along with four known compounds, (−)-mitorubrinic acid (5), (−)-mitorubrin (6), purpurquinone A (7) and orsellinic acid (8), were isolated from the cultures of Aspergillus sp. 16-5C. The structures were elucidated using comprehensive spectroscopic methods, including 1D and 2D NMR spectra and the structures of 1 further confirmed by single-crystal X-ray diffraction analysis, while the absolute configuration of 3 and 4 were determined by comparing their optical rotation and CD with those of the literature, respectively. Compounds 1, 2 and 6 exhibited potent inhibitory effects against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with IC₅₀ values of 4.24 ± 0.41, 4.32 ± 0.60 and 3.99 ± 0.34 μM, respectively.     

Yield formation of CO2-enriched hybrid rice cultivar Shanyou 63 under fully open-air field conditions

Hybrid indica rice (Oryza sativa L.) cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle and high yield potential. However, no attention has been given to its yield responses to rising atmospheric [CO₂] in conjunction with nitrogen (N) availability. Therefore we conducted a free air CO₂ enrichment (FACE) experiment at Yangzhou, Jiangsu, China (119°42′0′′E, 32°35′5′′N), in 2004–2006. A three-line hybrid indica rice cv. Shanyou 63 was grown at ambient and elevated (ca. 570 μmol mol⁻¹) [CO₂] under two levels of supplemental N (12.5 g Nm⁻² and 25 g Nm⁻²). Elevated [CO₂] had no effect on phenology, but substantially enhanced grain yield (+34%). The magnitude of yield response to [CO₂] was independent of N fertilization, but varied among different years. On average, elevated [CO₂] increased the panicle number per square meter by 10%, due to an increase in maximum tiller number under enrich [CO₂], while productive tiller ratio remained unaffected. Spikelet number per panicle also showed an average increase of 10% due to elevated [CO₂], which was supported by increased plant height and stem dry weight per tiller. Meanwhile, elevated [CO₂] caused a significant enhancement in both filled spikelet percentage (+5%) and individual grain weight (+4%). Compared with the two prior FACE studies on rice, hybrid indica rice cultivar appears to profit much more from elevated [CO₂] than japonica rice cultivar (ca. +13%), not only due to its stronger sink generation, but also enhanced capacity to utilize the carbon sources in a high [CO₂] environment. The above data has significant implication with respect to N strategies and cultivar selection under projected future [CO₂] levels.