不同浓度钙营养液对烟草矿质营养吸收与积累的影响

本文采用温室水培的方法,研究了不同的钙素供应水平对烟草各种矿质养分的吸收与积累的影响。结果表明,在其它养分形态与浓度一致条件下,随着钙浓度从75mgL-1提高到900mgL-1,烟草生长量呈抛物线型变化。钙浓度为150mgL-1时烟株干物质量最大。超过150mgL-1,随钙的增加而下降,当钙素达900mgL-1(K/Ca为1/6)时,烟株生长严重受抑。随着供钙水平由低到高,烟株氮、磷、钾、锌、锰含量均呈抛物线型变化,含钙量呈直线上升关系,而镁和铜含量则随钙浓度提高而显著下降。烟株各养分积累量均随营养液钙浓度提高呈抛物线型变化,但不同养分出现最大积累量时的营养液钙浓度却不相同。不同供钙水平上烟叶中各元素含量的变化特征与全株的结果基本一致。在低钙浓度范围(75~300mgL-1),钙对钾有协合关系,增钙促进提钾,大于300mgL-1后有拮抗作用,提钙导致降钾。钙与镁、锌、铜、锰间也存在明显的交互作用。烟叶中各元素含量与积累量的变化趋势与整株基本一致。     

吉县蔡家川流域不同森林植被的林地水源涵养功能

林地（枯落物层和土壤层）是森林植被水源涵养功能的主体,在水土保持中具有举足轻重的作用。根据蔡家川流域林地枯落物和土壤的分析与测定,研究比较了晋西黄土区不同森林植被的林地水源涵养功能。结果表明,不同植被类型枯落物的最大有效拦蓄量的大小为:虎榛子林（2.85 mm）>沙棘林（2.38 mm）>刺槐林（1.88 mm）>油松×刺槐林（1.31 mm）>油松林（0.77 mm）。不同植被类型0~60 cm土层的林地土壤最大拦蓄量为:虎榛子林（248.2 mm）>油松×刺槐林（241.0 mm）>刺槐林（210.2 mm）>草地（209.8 mm）>油松林（198.1 mm）。晋西黄土区不同森林植被的林地水源涵养功能研究,为该区水土保持林的合理经营与利用提供了科学依据。     

Uptake by dietary exposure and elimination of aflatoxins in muscle and liver of rainbow trout (Oncorhynchus mykiss)

Uptake and elimination of aflatoxins (AFs) by rainbow trout ( Oncorhynchus mykiss ) during a long-term (21 days) dietary exposure were studied to assess contamination by AFs in aquaculture fish fed AF-containing feed. The uptake factor (UF) of aflatoxin B(1) (AFB(1)) in muscle ranged from 0.40 × 10(-3) to 1.30 × 10(-3). AFB(1) concentrations in liver were 165-342 times higher than in muscle. AFs from feed were more highly accumulated in liver than in muscle. Aflatoxicol (AFL) and aflatoxin M(1) (AFM(1)) were detected in muscle and liver and also in the rearing water. AFL concentrations were higher than AFM(1) by 2 orders of magnitude in muscle, and AFL was a major metabolite of AFB(1). The elimination rate constants (α) of AFB(1) and AFL in muscle (1.83 and 2.02 day(-1), respectively) and liver (1.38 and 2.41 day(-1), respectively) were very large. The elimination half-life (t(1/2)) of AFB(1) was 0.38 days (9.12 h) in muscle and 0.50 days (12.00 h) in liver. The elimination half-life of AFL in muscle and liver was 0.34 day (8.16 h) and 0.29 day (6.96 h), respectively. These data show that AFs are eliminated rapidly and are not biomagnified in fish. Thus, AFB(1) concentration in muscle of fish fed AFB(1)-containing feed (ca. 500 μg/kg) decreased to below the detection limit (20 ng/kg) of the most sensitive analytical method at 1.54 days (36.96 h) after the change to uncontaminated feed.     

Binding of ferric iron to the cell walls and membranes of Bifidobacterium thermophilum: effect of free radicals.

Bifidobacterium thermophilum (ATCC 25866) was incubated with 100-120 microM (59)FeSO(4) and 300 microM excess of H(2)O(2) for up to 120 min in the presence and absence of glucose. Samples were withdrawn after 5, 30, 60, and 120 min. These were protoplasted and (59)Fe(III) measured in the supernatant fraction (cell walls) and protoplasts (cell membranes). These experiments were also repeated in the presence of 400 microM Al(III), which, in whole cells, caused an increase in Fe(III) binding. The amount of iron in the cell wall fraction was constant regardless of time of incubation, was unaffected by Al(III), and was reduced by approximately 20% by glucose. On the other hand, the amount of iron on the protoplasts increased with time and was affected by both Al(III) (upward) and glucose (downward). Scatchard plots indicated that the number of Fe(III) binding sites on the cell walls was 37.6 nmol/mg of dry cell weight at zero time, whereas that of cell membranes was (1)/(10) of that. It was concluded that Fe(III) binding by bifidobacterial cell walls was instantaneous and marginally dependent on free radical action. That of the cell membranes was time-dependent and was due to lipid peroxidation initiated by free radicals. Bifidobacteria can therefore function in the intestinal tract as probiotics by making Fe(OH)(3) unavailable to pathogens and by moderating free radical activity in the intestinal tract.     

Prediction of the ripening times of ewe's milk cheese by multivariate regression analysis of capillary electrophoresis casein fractions

The effect of the ripening time on the proteolytic process in cheeses made from ewe's milk during a 139-day ripening period was monitored by the use of capillary electrophoresis of pH 4.6 insoluble fraction. Totals of 18 and 21 peaks were recognized and matched in the electropherograms obtained with a fused-silica capillary and a neutral capillary (hydrophilically coated), respectively. These peaks correspond to intact ovine caseins and their hydrolysis products (alpha(s1)-casein I, alpha(s1)-casein II, alpha(s1)-casein III, alpha(s2)-casein, beta(1)-casein, beta(2)-casein, p-kappa-casein, alpha(s1)-I-casein, gamma(1)-casein, gamma(2)-casein, and gamma(3)-casein). The alpha(s)-caseins (alpha(s1)- and alpha(s2)-casein) displayed similar degradation pattern to one another, but different from those of beta-caseins (beta(1)- and beta(2)-casein). beta-Caseins were very much undergoing lesser degradation during the ripening time than alpha(s)-casein. Finally, partial least-squares regression and principal components regression were used to predict the ripening time in cheeses. The models obtained yielded good results since the root-mean-square error in prediction by cross validation was <8.6 days in all cases.     

Effect of arsenic on concentrations and translocations of mineral elements in the xylem of rice

By using Particle-Induced X-ray Emission (PIXE) technique, the effect of arsenic (As) on the mineral contents and translocation in the xylem of rice (Oryza sativa L. cv. ‘Akihikari’) was studied. The results suggest that exogenous As increased the concentrations of phosphorus (P), calcium (Ca) magnesium (Mg), sulfur (S), and manganese (Mn) in xylem, while the concentrations of potassium (K) remained unchanged. The highest concentration of As to the rice roots did not have any clear effect on the translocation of P, Ca, S, and chlorine (Cl) in the xylem, indicating that the increasing concentrations of the minerals may be due to a condensation effect, resulting from the repression of water movement in xylem by As-toxicity. Among the metal micronutrients, As decreased the concentrations and translocations of iron (Fe), zinc (Zn), and copper (Cu).     

Identification of methanol-soluble compounds in sesame and evaluation of antioxidant potential of its lignans

The methanol extract of sesame (Sesamum indicum) seeds was fractionated and purified with the assistance of conventional column chromatography to afford 29 compounds including seven furofuran lignans. Among these isolates, (+)-samin (1) was obtained from the natural source for the first time. In addition, (-)-asarinin (30) and sesamol (31) were generated by oxidative derivation from (+)-sesamolin (2) and (+)-sesamin (3), two abundant lignans found in sesame seeds. To evaluate their in vitro antioxidant potential, the seven isolated lignans (1-7) and the two derivatives (30 and 31) were examined for the scavenging activities on DPPH free radicals and superoxide anions. Moreover, the capability of chelating ferrous ions and reducing power of these sesame lignans were also measured. The results suggest that, besides the well-known sesamolin and sesamin, the minor sesame lignans (+)-(7S,8'R,8R)-acuminatolide (5), (-)-piperitol (6), and (+)-pinoresinol (7) are also adequate active ingredients and may be potential sources for nutritional and pharmacological utilization.     

Role of the solvent glycerol in the Maillard reaction of d-fructose and l-alanine

The volatiles in the headspace above a solution of [(13)C(6)]fructose and alanine in glycerol/water, heated in a closed vial at 130 degrees C for 2 h, were analyzed by solid-phase microextraction in tandem with GC-MS. Carbonyl compounds and pyrazines were among the detected components. The examination of their mass spectra showed that most of the 1-hydroxy-2-propanone and 2,3-pentanedione were (13)C(3)-labeled, the majority of the 2-methylpyrazine and 2-ethyl-3-methylpyrazine were (13)C(5)-labeled, and 2,5-dimethylpyrazine and 3-ethyl-2,5-dimethylpyrazine were mainly (13)C(6)-labeled. This is in agreement with the literature, and corresponds to the incorporation of fructose carbons, and in the case of 2,3-pentanedione, 2-ethyl-3-methylpyrazine, and 3-ethyl-2,5-dimethylpyrazine alanine carbons, into the molecules. However, minority fractions of 1-hydroxy-2-propanone (10%) and 2,3-pentanedione (14%) were found unlabeled, 2-methylpyrazine (10%) and 2-ethyl-3-methylpyrazine (11%) only doubly labeled, and 2,5-dimethylpyrazine (20%) and 3-ethyl-2,5-dimethylpyrazine (27%) only triply labeled, suggesting they contain carbons originating from the solvent glycerol. This could be confirmed by reaction of fructose and alanine in [(13)C(3)]glycerol/water, which produced the same volatiles, with 11-27% existent in their (13)C(3)-labeled form. Hence, glycerol participated not only as a solvent but also as a precursor in the reaction.     

Photodegradation of hexythiazox in different solvent systems under the influence of ultraviolet light and sunlight in the presence of TiO2, H2O2, and KNO3 and identification of the photometabolites

The photodegradation of the carboxamide acaricide hexythiazox in three different solvent systems (aqueous methanolic, aqueous isopropanolic, and aqueous acetonitrilic solutions) in the presence of H(2)O(2), KNO(3), and TiO(2) under ultraviolet (UV) light (λ(max) ≥ 250 nm) and sunlight (λ(max) ≥290 nm) has been assessed in this work. The kinetics of photodecomposition of hexythiazox and the identification of photoproducts were carried out using liquid chromatography-mass spectrometry. The rate of photodecomposition of hexythiazox in different solvents followed first-order kinetics in both UV radiation and natural sunlight, and the degradation rates were faster under UV light than under sunlight. Hexythiazox was found to be more efficiently photodegraded in the presence of TiO(2) than in the presence of H(2)O(2) and KNO(3). Two major photoproducts were separated in pure form using column chromatography and identified according to IR, (1)H NMR, and mass spectral information as cyclohexylamine and 5-(4-chlorophenyl)-4-methylthiazolidin-2-one. Another nine photoproducts were identified according to LC-MS/MS spectral information. The plausible photodegradation pathways of hexythiazox were proposed according to the structures of the photoproducts.     

Effects of growth regulators on mineral nutrition of tomato

This research deals with the effects of exogenous growth regulators on mineral nutrition of the tomato plant (Lyeopersieon esaulentum Mill. cv. Miguel Pereira). To study the influence on mineral nutrition, (2‐chloroethyl) trimethylammonium chloride (CCC) , at concentration of 2,000 ppm, succinic acid‐2, 2‐dimethylhydrazide (SADH) (4,000 ppm), gibberellic acid (GA) (100 ppm), (2‐chloroethyl) phosphonic acid (CEPA) (200 ppm), indole‐3‐acetic acid (IAA) (100 ppm) and 6‐furfurylamino purine (FAP) (500 ppm) were applied. Higher levels of nitrogen, calcium and magnesium occurred in the stem of plants sprayed with CCC. Treatments with FAP, SADH and CEPA caused an increase in nitrogen level in the stem. CEPA also increased calcium content in stems. These growth regulators did not alter the levels of macronutrients in the leaves in relation to control.     

小麦与花生间作改善花生铁营养的效应研究

采用砂-土联合培养根箱试验装置,模拟田间试验研究石灰性土壤小麦与花生间作改善花生Fe营养的效应结果表明,石灰性土壤高pH和高CaCO3是导致花生缺Fe黄化的主要原因。叶片已发生黄化的花生与小麦间作可明显改善花生缺Fe症状,间作16d后花生根际土壤有效铁含量、花生新叶叶绿素和活性Fe含量均显著提高。小麦与花生间作对改善花生Fe营养的效应可能与缺Fe小麦根分泌的Fe载体对土壤中Fe活化有关。     

pH对砖红壤和黄棕壤Cu~(2+)吸附与解吸的影响

对砖红壤和黄棕壤在不同浓度、不同pH下吸附和解吸Cu2+进行了测定。结果表明, 2种土壤Cu2+吸附量均随平衡液中Cu2+浓度增加而增大,两者关系较好地符合Langmuir吸附方程。Cu2+吸附量随pH升高而增加,Cu2+分配系数的对数与pH呈极显著的线性正相关,吸附一个Cu2+所释放H+的平均数砖红壤(1. 19)大于黄棕壤(1. 01)。可解吸Cu2+的数量随pH升高和吸附Cu2+的数量增加而增加,在pH4~6下,黄棕壤吸附Cu2+及可解吸Cu2+的比例(平均为10. 5% )大于砖红壤(平均为3. 1% )。由此认为, 2种土壤吸附Cu2+虽以专性吸附为主,但砖红壤的表面吸附点位较少,专性吸附点位的比例较高,对Cu2+的亲和性或专性吸附性大于黄棕壤。     

Pathway of dephosphorylation of myo-inositol hexakisphosphate by phytases of legume seeds

Using a combination of high-performance ion chromatography analysis and kinetic studies, the pathway of dephosphorylation of myo-inositol hexakisphosphate by the phytases purified from faba bean and lupine seeds, respectively, was established. The data demonstrate that the legume seed phytases under investigation dephosphorylate myo-inositol hexakisphosphate in a stereospecific way. The phytase from faba bean seeds and the phytase LP2 from lupine seeds degrade phytate by sequential removal of phosphate groups via D-Ins(1,2,3,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), and D-Ins(1,2)P(2) to finally Ins(2)P, whereas the phytases LP11 and LP12 from lupine seeds generate the final degradation product Ins(2)P via D-Ins(1,2,4,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), and D-Ins(1,2)P(2).     

Sorption of carbofuran and diuron pesticides in 43 tropical soils of Sri Lanka

To better understand the environmental fate of pesticides in Sri Lankan soils, we studied the sorption behavior of two commonly used pesticides (carbofuran and diuron) in 43 surface soils representing a range of soil physicochemical properties from dry and wet zones of Sri Lanka. For carbofuran, the K(d) (L/kg) values varied from 0.11 to 4.1 (mean, 0.83; median, 0.62) and K(oc) ranged from 7.3 to 120.6 (mean, 41.65; median, 36.1), whereas for diuron K(d) values varied from 0.5 to 75 (mean, 9.6; median, 5.15) and K(oc) ranged from 55.3 to 962 (mean, 407; median, 328). A comparison of sorption data on these tropical soils with published studies (mostly European and north American soils) showed that the ranges of sorption coefficients from Sri Lankan soils were within the wide range of K(oc) values reported in the literature. However, these values for both pesticides in soils from dry zones of Sri Lanka were consistently higher (up to two times) than those from the wet zone. The wide range of K(oc) values in Sri Lankan soils may be due to the possible difference in the nature of soil organic carbon, which needs to be further investigated.     

农业旅游开发对内蒙呼伦贝尔草原生态环境的影响

研究了农业旅游开发对呼伦贝尔沙质土壤草甸草原植被—土壤等生态环境的影响。结果显示:1）农业旅游开发显著降低了植被覆盖度、丰富度指数、均匀度指数和多样性指数（p < 0.05）,对植被优势度指数没有显著影响（p > 0.05）;2）农业旅游开发增加了土壤容重和pH,降低了土壤含水量和电导率;3）农业旅游开发显著增加了土壤粗沙（p < 0.05）,显著降低了土壤粘粉粒（p < 0.05）,对细沙和极细沙没有显著影响（p > 0.05）;4）农业旅游开发显著降低了土壤氮素（全氮和碱解氮）和钾素（全钾和有效钾）（p < 0.05）,而土壤磷素（全磷和有效磷）则不受农业旅游开发的影响（p > 0.05）,其中土壤钾素（全钾和有效钾）变化幅度较大,对农业旅游开发表现较为敏感;5）相关性分析表明:农业旅游开发下植被属性主要取决于土壤有效养分。     

Deactivation of triplet-excited riboflavin by purine derivatives: important role of uric acid in light-induced oxidation of milk sensitized by riboflavin

The reactivity of purine derivatives (uric acid, xanthine, hypoxanthine, and purine) toward triplet-excited riboflavin in aqueous solution at pH 6.4 is described on the basis of kinetic (laser flash photolysis), electrochemical (square-wave voltammetry), and theoretical data (density functional theory, DFT). Direct deactivation of triplet-excited riboflavin in aqueous solution, pH 6.4 at 24 degrees C, in the presence of uric acid, xanthine, and hypoxanthine strongly suggests a direct electron transfer from the purine to the triplet-excited riboflavin with k = 2.9 x 10(9) M(-1) s(-1) (DeltaH(++) = 14.7 kJ mol(-1), DeltaS(++) = -15.6 J mol(-1) K(-1)), 1.2 x 10(9) M(-1) s(-1) (DeltaH(++) = 34.3 kJ mol(-1), DeltaS(++) = +45.3 J mol(-1) K(-1)), and 1.7 x10(8) M(-1) s(-1) (DeltaH(++) = 122 kJ mol(-1), DeltaS(++) = +319 J mol(-1) K(-1)), respectively. From the respective one-electron oxidation potentials collected in aqueous solution at pH 6.4 for uric acid (E = +0.686 vs normal hydrogen electrode, NHE), xanthine (E = +1.106 vs NHE), and hypoxanthine (E = +1.654 vs NHE), the overall free energy changes for electron transfer from the quencher to the triplet-excited riboflavin are as follows: uric acid (DeltaG(o) = -114 kJ mol(-1)), xanthine (DeltaG(o) = -73.5 kJ mol(-1)), hypoxanthine (DeltaG(o) = -20.6 kJ mol(-1)), and purine (DeltaG(o) > 0). The inertness observed for purine toward triplet-excited riboflavin corroborates with its electrochemical inactivity in the potential range from 0 up to 2 V vs NHE. These data are in agreement with the DFT results, which show that the energy of the purine highest occupied molecular orbital (HOMO) (-0.2685 arbitrary unit) is lower than the energy of the semioccupied molecular orbital (SOMO) (-0.2557 a.u.) of triplet-excited riboflavin, indicating an endergonic process for the electron-transfer process. The rate-determining step for deactivation by purine derivatives can be assigned to an electron transfer from the purine derivative to the SOMO orbital of the triplet-excited riboflavin. The results show that uric acid may compete with oxygen and other antioxidants to deactivate triplet-excited riboflavin in milk serum and other biological fluids leading to a free radical process.     

Fate of fumonisins during the production of fried tortilla chips.

The fate of fumonisin B(1) (FB(1)), a mycotoxin found in corn, during the commercial manufacture of fried tortilla chips was studied. FB(1) and hydrolyzed FB(1) (HFB(1)) concentrations in four lots of corn and in the masa, other intermediates, liquid and waste byproducts, and fried chips were determined by HPLC. FB(1) concentrations in the masa and chips were reduced significantly, up to 80% in the fried chips, compared to that in the raw corn. HFB(1) was also found in the masa and chips, but at low concentrations compared to FB(1). LC-MS analyses corroborated HPLC findings and further showed the presence of partially hydrolyzed FB(1) (PHFB(1)), which, like HFB(1), was formed during the nixtamalization (cooking/steeping the corn in alkaline water to make masa) step and found predominantly in the cooking/steeping liquid and solid waste. No significant amounts of N-(carboxymethyl)-FB(1) or N-(1-deoxy-D-fructos-1-yl)-FB(1), indicative of fumonisin-sugar adduct formation, were found. Thus, FB(1) is removed from corn and diverted into liquid and waste byproducts during the commercial production of fried tortilla chips. Nixtamalization and rinsing are the critical steps, whereas grinding, sheeting, baking, and frying the masa had little effect.     

Degradation of primisulfuron by a combination of chemical and microbiological processes

Microbial degradation of the herbicide primisulfuron was investigated using enrichment cultures from contaminated soils and 20 axenic cultures. At neutral pH, no disappearance of the herbicide was detected either in the enrichment cultures or in the growth media of the axenic microbial cultures. During the growth of some of the microbial strains, however, the pH of the medium dropped below 6, resulting in the hydrolysis of primisulfuron. The rate of primisulfuron hydrolysis was clearly pH dependent; primisulfuron was more persistent in neutral or weakly basic solutions than in acidic solutions. After hydrolysis of the herbicide, four products were observed. These were identified as methyl 2-(aminosulfonyl)benzoate, 2-amino-4,6-(difluoromethoxy)pyrimidine, 2-N-[[[[[4, 6-bis(difluoromethoxy)-2-pyrimidinyl]amino]carbonyl]amino]sulfonyl ]be nzoic acid, and 2-(aminosulfonyl)benzoic acid. After hydrolysis, it was found that the fungus Phanerochaete chrysosporium mineralized 27 and 24% of (14)C-phenyl- and (14)C-pyrimidine-labeled products, respectively, after 24 days of incubation. Similarly, Trametes versicolor mineralized 13 and 11% of (14)C-phenyl- and (14)C-pyrimidine-labeled hydrolysis products, respectively. In addition, primisulfuron in a hydrolytically stable solution, at pH 7. 0, was rapidly decomposed after ultraviolet irradiation, and two photolysis products were isolated [methylbenzoate and 4, 6-(difluoromethoxy)pyrimidin-2-ylurea]. When (14)C-phenyl-labeled primisulfuron was exposed to photolysis for 24 h, 32% of the initial radioactivity was recovered as (14)CO(2), whereas no (14)CO(2) was detected if the herbicide was labeled at the (14)C-pyrimidine position. Mineralization of (14)C-pyrimidine-labeled products of photolyzed primisulfuron by P. chrysosporium was approximately 25% after 24 days. These results clearly indicate that hydrolysis and photolysis of primisulfuron facilitated microbial degradation.     

Vitamin D and sterol composition of 10 types of mushrooms from retail suppliers in the United States

Vitamin D(2) (ergocalciferol) and sterols were analyzed in mushrooms sampled nationwide in the United States to update the USDA Nutrient Database for Standard Reference. Vitamin D(2) was assayed using HPLC with [(3)H]-vitamin D(3) internal standard and sterols by GC-FID mass spectrometric (MS) confirmation. Vitamin D(2) was low (0.1-0.3 μg/100 g) in Agaricus bisporus (white button, crimini, portabella) and enoki, moderate in shiitake and oyster (0.4-0.7 μg/100 g), and high in morel, chanterelle, maitake (5.2-28.1 μg/100 g) and UV-treated portabella (3.4-20.9 μg/100 g), with significant variability among composites for some types. Ergosterol (mg/100 g) was highest in maitake and shiitake (79.2, 84.9) and lowest in morel and enoki (26.3, 35.5); the range was <10 mg/100 g among white button composites but 12-50 mg/100 g among samples of other types. All mushrooms contained ergosta-5,7-dienol (22,23-dihydroergosterol) (3.53-18.0 mg/100 g) and (except morel) ergosta-7-enol. Only morel contained brassicasterol (28.6 mg/100 g) and campesterol (1.23-4.54 mg/100 g) and no ergosta-7,22-dienol. MS was critical in distinguishing campesterol from ergosta-7,22-dienol.     

Adulticidal activity of phthalides identified in Cnidium officinale rhizome to B- and Q-biotypes of Bemisia tabaci

The residual contact toxicity of three benzofuranoids (Z)-butylidenephthalide (1), (3S)-butylphthalide (2), and (Z)-ligustilide (3) identified in the rhizome of Cnidium officinale (Apiaceae) to B- and Q-biotype females of Bemisia tabaci was evaluated using a leaf-dip bioassay. Results were compared with those of eight conventional insecticides. Based on 24 h LC(50) values, (Z)-butylidenephthalide (254 ppm) and (Z)-ligustilide (268 ppm) were more toxic than (3S)-butylphthalide (339 ppm) against B-biotype females, whereas (Z)-ligustilide (254 ppm) and (3S)-butylphthalide (338 ppm) were more toxic than (Z)-butylidenephthalide (586 ppm) against Q-biotype females. Thiamethoxam, imidacloprid, and acetamiprid differ significantly in toxicity between the B- and Q-biotype females (LC(50), 1.7 to 11.6 vs 364.5 to >3000 ppm). This original finding indicates that the phthalides and the neonicotinoids do not share a common mode of action or elicit cross-resistance. Structure-activity relationship indicates that the presence of conjugation rather than aromaticity appeared to play an important role for phthalide toxicities to the B-biotype females. Global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment justify further studies on C. officinale rhizome-derived materials as potential insecticides for the control of B. tabaci populations.