Role of the free amino acid pool of the copepod Acartia tonsa in adjustment to salinity change

The free amino acid pool of the calanoid copepod Acartia tonsa was reduced in proportion to the decrease in external salinity within 24 h, with a corresponding increase in ammonia excretion and a transient rise in oxygen consumption. The free amino acid pool was not increased in response to increased salinity. Catabolism of free amino acids is important in the reduction of cellular osmotic pressure in reduced salinities. Antagonistic demands of osmotic preservation and nutritional metabolism on the free amino acid pool may limit the production of the species in waters of higher salinity.     

Effect of salinity adaptation on nitrogen metabolism in the freshwater fish Tilapia mossambica. I. Tissue protein and amino acid levels

Water, proteins and total free amino acids were estimated in different tissues of the euryhaline fish Tilapia mossambica after adaptation to various strenghts of sea water. The water content did not vary significantly in any tissue on salinity adaptation. The soluble and insoluble proteins displayed a general and considerable decrease in muscle, liver and heart; the decrease in the soluble fraction in the heart and the proteins of the muscle in 75% sea water (100% sea water=32.5 S) were significant. The gill proteins did not alter with salinity; the kidney proteins tended to increase slightly in 100% sea water (SW). The total free amino-acid content decreased insignificantly in all tissues on adaptation to 25% SW; in higher salinities, however, the content increased significantly. This increase was sudden and steep in 50% SW, and gradual and less steep in 75 and 100% SW. It is suggested that constancy in water content may contribute to the great adaptability of T. mossambica to heterosmotic media, and that the total free amino acids may be involved in isosmotic intracellular regulation. The possibility of amino acid increase as a result of protein breakdown is also indicated.     

Amino acid metabolism and protein turnover in larval turbot (Scophthalmus maximus) fed natural zooplankton or Artemia

The present paper studied the influence of different food regimes on the free amino acid (FAA) pool, the rate of protein turnover, the flux of amino acids, and their relation to growth of larval turbot (Scophthalmus maximus L.) from first feeding until metamorphosis. The amino acid profile of protein was stable during the larval period although some small, but significant, differences were found. Turbot larvae had proteins which were rich in leucine and aspartate, and poor in glutamate, suggesting a high leucine requirement. The profile of the FAA pool was highly variable and quite different from the amino acid profile in protein. The proportion of essential FAA decreased with development. High contents of free tyrosine and phenylalanine were found on Day 3, while free taurine was present at high levels throughout the experimental period. Larval growth rates were positively correlated with taurine levels, suggesting a dietary dependency for taurine and/or sulphur amino acids. Reduced growth rates in Artemia-fed larvae were associated with lower levels of free methionine, indicating that this diet is deficient in methionine for turbot larvae. Leucine might also be limiting turbot growth as the different diet organisms had lower levels of this amino acid in the free pool than was found in the larval protein. A previously presented model was used to describe the flux of amino acids in growing turbot larvae. The FAA pool was found to be small and variable. It was estimated that the daily dietary amino acid intake might be up to ten times the larval FAA pool. In addition, protein synthesis and protein degradation might daily remove and return, respectively, the equivalent of up to 20 and 10 times the size of the FAA pool. In an early phase (Day 11) high growth rates were associated with a relatively low protein turnover, while at a later stage (Day 17), a much higher turnover was observed. Received: 19 March 1997 / Accepted: 14 April 1997     

Aspects of nitrogen metabolism of the common mussel Mytilus edulis: Adaptation to abrupt and fluctuating changes in salinity

Mytilus edulis L. were exposed to abrupt (3015 and 1530) and fluctuating (sinusoidal 12 h cycles of 301530) changes in salinity, and the changes in the total osmoconcentration of the haemolymph were recorded. The response of nitrogen metabolism to the altered extracellular osmotic concentrations was investigated in terms of the concentrations of the total NPS (ninhydrin-positive substances) pool and the individual amino acids of the tissues, the concentration of the amino acids of the haemolymph, and the rates of excretion of ammonia and amino acids by whole individuals. The haemolymph became isosmotic with the seawater with abrupt changes in salinity, but with fluctuating salinity was slightly hyperosmotic as the salinity decreased and then slightly hypo-osmotic as the salinity increased. This resulted in a reduction in the extent of the extracellular osmotic change compared to the change in fluctuating salinity to which it was exposed. Total NPS of the tissues decreased with an abrupt decrease in salinity and increased with an abrupt increase in salinity, but a seasonal dependence of the response was indicated. The short-term response of tissue NPS to fluctuating salinity was equivocal, but with long-term exposure the concentration declined. Ammonia and amino acid excretion increased with both an abrupt decrease in salinity and fluctuating salinity and decreased with an abrupt increase in salinity. Haemolymph amino acids increased with an abrupt decrease in salinity. The increased rates of nitrogen excretion accounted for the reductions in the NPS concentrations of the tissues except in the early stages of fluctuating salinity. Taurine, aspartate, threonine, serine, glycine and arginine declined with an abrupt decrease in salinity while alanine and glutamate increased slightly. With an abrupt increase in salinity, alanine and ammonia accumulated in the tissues and then declined while the other amino acids increased slowly over a longer time-course. Similar individual amino acid responses were seen with long-term exposure to fluctuating salinity, except for taurine which did not decrease in concentration. On the basis of the changes in tissue amino acids and ammonia, it is suggested that the alanine dehydrogenase reaction is the primary nitrogen-fixing reaction in marine bivalves such as M. edulis.     

Protein and amino acid composition of the tergal gland secretions ofBlatta orientalis andEurycotis floridana (Dictyoptera: Blattidae)

Summary Nymphs and adult females ofBlatta orientalis and nymphs ofEurycotis floridana produce a proteinaceous sticky secretion which accumulates on the last abdominal tergites. The proteic patterns do not differ between individuals of the same species. HPLC analyses show that all the common amino acids are found in both species, aspartic and glutamic acids representing 24 to 37% of the total amount of amino acids. InB. orientalis, glutamic acid is the more abundant amino acid whereas inE. floridana it is the aspartic acid. The secretion appears and accumulates rapidly on isolated insects. Behavioural assays revealed that these secretions have a defensive role.     

成团泛菌(Pantoea agglomerans)对镉胁迫下蒌蒿耐受性的影响

为探讨功能微生物对镉(Cd)胁迫下蒌蒿耐受性的影响,以成团泛菌(Pantoea agglomerans)J2为对象,通过盆栽试验,研究不同Cd处理水平下J2菌对蒌蒿生长、生理、Cd富集转运与根际微生态的影响。结果表明:J2菌可显著促进蒌蒿株高、地上部干重、地下部干重、总生物量及根冠比的增加。在J2菌的作用下,蒌蒿叶绿素a、叶绿素b和总叶绿素含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均显著增加,丙二醛(MDA)含量明显减少。J2菌可显著促进蒌蒿对Cd的富集转运,蒌蒿地上部、地下部与总Cd含量均显著增加,地上部生物富集系数(BCF)明显大于地下部,转运系数(TF)相比于对照增加了7.5%~37.4%。J2菌可显著增加蒌蒿根际土壤细菌、放线菌数量及微生物总量,明显减少真菌数量。研究表明成团泛菌J2对蒌蒿生长、生理、Cd富集转运与根际微生态可产生积极影响,在一定程度上可提高蒌蒿植株对Cd的耐受性。     

Modulation of the free amino acid pool and protein content in populations of the brine shrimp Artemia spp.

 Free amino acid (FAA) and protein content were measured in various developmental stages of Artemia franciscana, from cysts to Instar III metanauplii. In addition, decapsulated cysts of 15 Artemia populations from different localities were compared with respect to their FAA and protein content. Furthermore, the content and composition of the FAA pool were modulated by hatching the cysts at various salinities, and by enriching the nauplii with algae or a lipid-enrichment emulsion. The FAA content increased threefold from cysts to nauplii, and Instar III metanauplii contained nearly 50% taurine of total FAA. Cysts of A. franciscana were found to contain one-third the amount of FAA compared to the other Artemia species investigated. The content and pool composition of FAA was successfully modulated in 11 of 13 populations, where by the content of FAA was significantly increased when hatched at high salinity. Finally, enrichment elevated the content of FAA and changed the pool composition, thereby showing a dietary effect. Algal enrichment also increased the protein content. Received: 27 September 1999 / Accepted: 17 July 2000     

Protein Metabolic Response to Carbon Tetrachloride in A Freshwater Fish,Sarotherodon Mossambicus

Exposure of a freshwater teleost, Sarotherodon mossambicus, to a sublethal concentration (26 ppm) of carbon tetrachloride for periods up to 30 days led to significant changes in the soluble protein fractions (albumin and globulins) and free amino acid content. the decrease in total protein content was greater in liver than in muscle. the protein loss was expected due to the impairement of protein synthetic activity during stress conditions.     

洞庭湖湿地Cd富集植物蒌蒿(Artemisia selengensis)的耐性生理机制研究

采用盆栽植株和外源Cd胁迫的方法,分别对不同生长期蒌蒿植株根、叶组织中的抗氧化酶活性、可溶性蛋白及MDA含量进行测定,以揭示蒌蒿在Cd胁迫下的抗氧化机理和耐受机制。研究结果表明,Cd胁迫对上述生理指标均有显著影响:≤20mg·kg-1的Cd处理可使幼苗期植株器官中的可溶性蛋白含量增加16.5%～19.1%,100mg·kg-1的Cd含量水平则导致其含量减少近30%,可溶性蛋白含量的变化与植株的生物量积累关系密切;3种酶活性在0～10mg·kg-1的Cd处理下未显示出明显变化,幼苗期植株CAT、POD活性在10～80mg·kg-1的Cd胁迫下增加明显,高于此浓度范围则使酶蛋白受到破坏而失活,中等含量水平(≤40mg·kg-1)的Cd处理经过长时间作用可使植株逐渐适应胁迫环境,胁迫强度较大的Cd处理可显著提高SOD酶的活性;Cd胁迫过程中植株MDA积累量不断增加。3种抗氧化酶活性的增强在蒌蒿植株耐受Cd胁迫方面能起到较好的防御作用。     

Implications of salinity fluctuation for growth and nitrogen metabolism of the marine diatom Ditylum brightwellii in comparison with Skeletonema costatum

In 1987 effects of salinity fluctuations on growth of Ditylum brightwellii (West) Grunow, isolated from the Eastern Scheldt estuary (SW Netherlands) in 1981, were studied. D. brightwellii was grown in a 12 h light: dark cycle at constant salinity in brackish media. Ammonium-limited cultures were subjected to a salinity fluctuation. By decreasing the salinity to 4.8 photosynthesis and cell division were inhibited; cells were deformed. Protein and carbohydrate contents increased slightly, dark respiration was stimulated and cellular levels of glucose decreased at low salinity; this indicated a possible role of sugars in osmoregulation. Ammonium was accumulated in cultures, amino acids may have been stored; the role of the vacuole as a storage compartment was discussed. Both the ammonium uptake capacity and the affinity for ammonium decreased. Nitrogen limitation was relieved in the transient state. [With the activity of the nitrogen assimilation enzymes glutamine synthetase (GS) and glutamate synthase (GOGAT) being uninhibited by lower salinity.] Recovery from hypo-osmotic stress during a salinity increase was initiated by stimulated photosynthesis; chlorophyll a increased, but persistant contractions of cytoplasm (with chloroplasts) may have delayed cell growth. The glutamate dehydrogenase (GDH) activity decreased further whereas the cellular level of alanine increased in the presence of large ammonium pools; this may indicate a temporary activity of ADH (alanine dehydrogenase). Skeletonema costatum (Greville) Cleve, recovered faster from hypoosmotic stress than did D. brightwellii. Due to an osmotic shock from 13.6 to 7.1 S both species excreted amino acids and glucose; S. costatum accumulated more glucose, D. brightwellii accumulated more amino acids. S. costatum may with the competition for nitrogen in waters with an unstable salinity; it will replace D. brightwellii.Contribution no. 427 Delta Institute for Hydrobiological Research, Yerseke, The Netherlands     

Does defoliation induce chemical and morphological defenses in the leaves of silver birch seedlings under changing climate?

Summary.  We examined the effects of defoliation con-currently with elevated temperature and CO₂ on some chemical and morphological characteristics in the leaves of silver birch seedlings (Betula pendula). We also analyzed the consequent changes in the palatability of leaves for adult blue alder leaf beetles (Agelastica alni). Under the different climatic treatments, the seedlings were subjected to three fertilizer treatments (0 kg, 130 kg and 270 kg N ha⁻¹) and defoliation treatments (0%, 25% and 50% of the total leaf area). In each climatic treatment, fertilization increased the nitrogen content in the leaves, but decreased total concentrations of soluble phenolics, detected by high-performance liquid chromatography (HPLC), and insoluble condensed tannins. Defoliation, both independently and in combination with elevated temperature and CO₂, decreased the concentrations of the phenolics. Compared to the intact controls, the leaves of the defoliated seedlings were smaller and tougher. Under elevated temperature, the beetles consumed a smaller amount of the leaves of plants subjected to the high fertilization, while under ambient climatic conditions, fertilization increased the feeding. The total leaf consumption was higher under the ambient climatic conditions than under elevated temperature, elevated CO₂ or the combination of elevated temperature and CO₂.     

Seasonal changes in nucleic acids,amino acids and protein content in juvenile Norway lobster (<Emphasis Type="Italic">Nephrops norvegicus</Emphasis>)

The objective of this study was to describe the seasonal variations in nucleic acid contents and amino acid profiles in the muscle of juvenile Nephrops norvegicus. RNA and protein contents, and RNA:protein and RNA:DNA ratios varied significantly between seasons, being highest in spring and lowest in autumn/winter ( P<0.05). Though DNA content increased significantly from autumn to summer ( P<0.05), protein:DNA ratio did not show significant seasonal variations ( P=0.05). In respect to protein-bound amino acid content (BAA), a significant increase was observed from winter to summer ( P<0.05). Both essential (EAA) and non-essential amino acids (NEAA) increased significantly (27.6% and 27.8%, respectively; P<0.05), mainly due to the considerable increase in arginine and proline (59.1% and 225.2%, respectively; P<0.05). A significant decrease was observed in the free amino acid content (FAA) from winter to summer ( P<0.05); and a higher percentage decrease occurred in free non-essential (FNEAA; 27.9%) in comparison to free essential amino acids (FEAA; 21.8%). The significant increase in RNA and BAA contents from winter to spring may be related to protein synthesis. On the other hand, the lowest values obtained in winter may be due to a reduction in feeding activity; in this period the muscle protein must be progressively hydrolysed, which is evident with the higher FAA content. The liberated amino acids enter the FAA pool and become available for energy production.     

Constitutive or induced defences - how does <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> defend itself from larval feeding?

Summary. Following herbivory, induced responses involving plant secondary metabolites have been reported in a number of tree species. Although a wide range of plant secondary metabolites appear to operate as constitutive plant defences in trees belonging to the Eucalyptus genus, no induced responses have as yet been reported following foliar-chewing insect damage. We empirically tested whether branch defoliation (artificial and larval) of 2-year-old Eucalyptus globulus Labill. trees altered the abundance of specific plant secondary metabolites immediately (3 months after initial larval feeding) and 8 months after the cessation of larval feeding. Metabolites assayed, included essential oils, polyphenolic groups and foliar wax compounds and in all cases their abundance was not significantly altered by defoliation. However, the level of foliar tannins after 3 months of larval feeding did display a trend that suggested elevated levels as the result of defoliation, though this trend was not evident 8 months later, indicating that, if real, the response was a rapid and not a delayed induced response. The level of foliar tannins was also negatively correlated to both average larval survival and average percentage branch defoliation, suggesting that foliar tannins may operate as toxins and/or anti-feedants to M. privata larval feeding.     

Osmoregulation of the grass shrimp Palaemonetes pugio Exposed to polychlorinated biphenyls (PCBs).

Glycine was the most abundant free amino acid (FAA) in abdominal muscle of grass shrimp Palaemonetes pugio, accounting for over 50% of the total pool. Arginine, alanine, proline, taurine and serine were also present at relatively high concentrations. Following transfer from 17%. to 2 and 32%. S, new steady-state levels of total FAA were observed at 72 h. Total FAA and the sum of glycine, alanine and proline exhibited a positive correlation with salinity. Exposure to Aroclor 1254 did not have appreciable effects on total FAA levels, indicating that disruption of intracellular osmoregulation was not a major consequence of PCB toxicity. However, changes in individual amino acid concentrations in exposed shrimp were reflective of an altered metabolic state. Glycine, which did not show changes immediately following exposure, underwent large decreases after transfer to PCB-free water and indicated a delayed effect of PCB exposure. A correlation between salinity and the sum of glycine, alanine and proline did not exist in exposed shrimp.     

镉胁迫对拟南芥中氨基酸及其衍生物的影响

研究拟南芥对镉胁迫的氨基酸及其衍生物响应.结果表明,镉胁迫使大部分检测到的化合物发生变化,并且在不同镉浓度情况下(Cd5和Cd50)显示了共同的响应,只是响应幅度不同.同一代谢途径中的化合物含量变化具有相关性:α-酮戊二酸衍生类型(谷氨酸和谷氨酰胺)和草酰乙酸衍生类型(天冬氨酸和天冬酰胺)氨基酸含量都降低,除脯氨酸外;3-磷酸甘油酸衍生类型(丝氨酸和甘氨酸)氨基酸含量都增加;丙酮酸衍生类型的氨基酸(缬氨酸、亮氨酸和异亮氨酸)含量几乎没有变化;由莽草酸转化而来的酪氨酸含量降低,另外,镉胁迫诱导胺类(β-丙氨酸、4-氨基丁酸、腐胺和酪胺)化合物含量显著增加.     

Energy substrates for eggs and prefeeding larvae of the dolphinCoryphaena hippurus

Changes in the chemical composition of developing dolphin (Coryphaena hippurus) eggs and prefeeding yolksac larvae were determined in order to estimate probable dietary requirements of first-feeding larvae. Daily dry matter, protein nitrogen (PN), non-protein nitrogen (NPN), lipid, gross energy content, fatty acid and amino acid profiles from Day 1 to Day 2 eggs and Day 1 to Day 3 larvae were compared. Lipid was the primary endogenous energy source accounting for the daily caloric deficit through both the egg and larval stages, except over the day of hatching. The catabolism of lipid by embryos (0.078 cal d^–1) was greater than that by yolksac larvae (0.036 cal d^–1). The higher demand for energy by embryos was related to a greater rate of protein synthesis during the egg stage. The ratio of PN:NPN increased during egg development without change in total nitrogen content, but was constant throughout the yolksac larvae period. The lipid content per embryo did not decrease over the hatching period (Day 2 to 3, postspawning). However, there was a loss in amino acid content not totally accounted for by sloughing of the chorion at hatching. This loss, as protein, accounted for 0.053 cal of gross energy, which represented 70% of the total estimated energy needs of the fish over this period. Loss of non-essential amino acids (25%) was higher than that of essential amino acids (13%). Proline and tyrosine accounted for 32% of the total loss of amino acids at this time. The only preferential use of fatty acids over any period was a small but significant drop in the content of C22:6n-3 prior to the onset of feeding (Day 5, postspawning). It is speculated that the pattern of energy-substrate use of first-feeding dolphin larvae will reflect the pattern of endogenous energy use during the egg and prefeeding yolksac larval stages. Diets or feeding regimens with lipid as the primary energy source, and containing a fatty acid profile similar to that of eggs or yolksac larvae, should be useful in culturing this species, at least during the early feeding stages.     

双酚A对紫背浮萍生长和光合色素及抗氧化系统影响

以紫背浮萍为实验对象,探究双酚A(bsiphenol A, BPA)对其生长、光合色素含量、抗氧化系统和渗透压调节物质的影响。结果表明,不同浓度(0、1、5、20和50 mg·L~(-1))BPA连续暴露7 d后,与对照组相比,随暴露浓度升高,紫背浮萍湿重和叶绿素含量呈现先显著增加后降低的趋势;暴露组过氧化氢(H_2O_2)含量和抗超氧阴离子自由基活性显著降低;丙二醛(MDA)含量在20和50 mg·L~(-1)组显著升高;暴露组抗氧化酶活性包括超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)和总抗氧化能力(T-AOC)均低于对照组;谷胱甘肽(GSH)含量在高浓度组显著升高,20 mg·L~(-1)组可溶性糖含量显著升高,可溶性蛋白含量在中高浓度组显著增加。研究表明,中低浓度BPA会提高紫背浮萍光合色素含量,有机物积累增多,促进其生长;但随BPA浓度不断升高,紫背浮萍体内产生氧化损伤,抗氧化酶活性及叶绿素含量降低,生长受到抑制。本研究结果将为BPA污染控制及对水生植物生态毒性效应评价提供理论基础。     

Effects of glucosinolate and myrosinase levels in Brassica juncea on a glucosinolate-sequestering herbivore – and vice versa

Summary. Larvae of the turnip sawfly, Athalia rosae L. (Hymenoptera: Tenthredinidae), sequester glucosinolates of their host plants, namely members of the Brassicaceae family, in their haemolymph. Therefore, they need to circumvent myrosinase activities of the plant tissue which normally hydrolyse the glucosinolates after plant damage. Effects of varying levels of glucosinolates and myrosinases on the performance of A. rosae were investigated using homozygous lines of Brassica juncea (L.) with either (1) low glucosinolate (lowGS) and low myrosinase (lowMR), (2) high glucosinolate (highGS) and high myrosinase (highMR), or (3) high glucosinolate (highGS) and low myrosinase (lowMR) levels. To insure that the given quantities remained as constant as possible, newly hatched larvae were enclosed on the second-youngest leaf of a plant, and were offered a new plant of comparable physiological age (6-leaf-stage) every day. The performance of A. rosae was little affected by leaf quality. Body masses of eonymphs and adults were on average lowest on the highGS/highMR-line, but these differences were rarely significant. The pupal developmental times of females and males were longest on the highGS/lowMR-line in only one of two replicate experiments. All other performance traits (developmental times of larvae, egg numbers, adult longevity) were not significantly different. Glucosinolates, sequestered by the larvae, are carried through the pupal stage. The glucosinolate concentration measured in adult insects reflected the level of the host plant line, without showing any obvious costs for sequestration. Obviously, A. rosae is highly tolerant to variation in the glucosinolate-myrosinase system of its host. In addition, induced changes of glucosinolate concentrations and myrosinase activities caused by 24 h-feeding of groups of three small larvae were analysed in the second-youngest leaves. In contrast to the patterns most herbivores evoke on Brassicaceae, namely an increase of both glucosinolate concentration and myrosinase activity, we detected a significant decrease of both traits in all three lines where the respective trait was originally high in the plants. Although glucosinolate levels dropped in the highGS lines about 50%, these still contained higher concentrations than the lowGS line. Whereas the activity of soluble myrosinases remained highest in the highMR line, even after a decrease to almost 30% due to feeding, the levels of insoluble myrosinases converged after feeding in lowMR and highMR lines. Levels of the signalling molecule salicylic acid slightly decreased on average after feeding, whereas jasmonic acid was below the detection threshold in almost all samples. The concentration of several molecules varies strongly in plant tissue with age and can change due to induction by herbivore feeding. Therefore, if performance of an insect species is measured on plants with specific traits, the variability in these traits needs to be carefully controlled in experiments.     

氟虫双酰胺对蚯蚓的生化毒性与细胞毒性研究

双酰胺类杀虫剂已成为全世界第4大类最常用的杀虫剂,具有非常广阔的应用前景。然而,目前关于双酰胺类杀虫剂生态毒性评估方面的研究还比较少。为探究双酰胺类杀虫剂对非靶标生物的毒性作用,选取赤子爱胜蚓(Eisenia fetida)为受试生物,研究了典型双酰胺类杀虫剂氟虫双酰胺对非靶标动物蚯蚓的生化毒性和细胞毒性以及其在人工土和蚯蚓体内的浓度变化情况。结果表明,氟虫双酰胺在人工土壤中十分稳定,在整个暴露期间氟虫双酰胺的浓度变化不超过20%。氟虫双酰胺在蚯蚓体内的含量随染毒浓度的升高和暴露时间的推移而增加,呈明显的时间和剂量-效应关系;在染毒浓度为0.1和1.0 mg·kg-1的处理组中,氟虫双酰胺未对蚯蚓产生明显的氧化胁迫效应。在染毒浓度为5.0和10.0 mg·kg-1的处理组中,蚯蚓体内活性氧(ROS)含量显著高于其他处理组,过量的ROS诱导蚯蚓体内各种抗氧化酶活性发生异常变化,并在蚯蚓体内造成了脂质过氧化、蛋白质羰基化和DNA损伤。研究表明,当土壤中氟虫双酰胺的浓度为5.0和10.0 mg·kg-1时可能会对蚯蚓产生很高的风险。此外,彗星实验对氟虫双酰胺诱导的氧化胁迫较为敏感,可以作为敏感生物标志物对氟虫双酰胺造成的土壤污染进行预警。     

Local and systemic induced responses to cabbage root fly larvae (Delia radicum) in Brassica nigra and B. oleracea

Summary. Feeding by belowground herbivores may induce systemic changes in shoot defence levels that affect the performance of above ground herbivores and higher trophic levels. In this paper two wild Brassica species, B. nigra and B. oleracea were experimentally infested with 10 larvae of the cabbage root fly, Delia radicum. Plant dry masses and glucosinolate levels in shoots, main roots, and fine roots were determined at 3, 7, 12 and 14 days after infestation and compared to those of control plants. The systemic response in the leaves differed between plant species. In B. nigra shoot glucosinolate levels in D. radicum infested plants steadily increased with time until they were almost twice those of controls 14 days after infestation. B. oleracea plants infested with D. radicum did not show significant changes in shoot glucosinolate levels within 14 days, which may be due to the unexpected poorer performance of D. radicum on this species. Both plant species showed a local increase in indole glucosinolates in the main roots, which are the preferred feeding site of D. radicum larvae. B. oleracea plants however showed a stronger (1.9 – 4.7 times) increase in indole glucosinolate levels than B. nigra (1.5 – 2.6 times). The increase in indole glucosinolates in B. nigra main roots, was counterbalanced by a significant decrease in aromatic glucosinolate levels. These differences in local responses to D. radicum feeding between the two species may have contributed to the slower growth rates of the larvae on B. oleracea. D. radicum feeding did not result in altered glucosinolate levels in the fine roots in either plant species. The differences in glucosinolate induction patterns between the summer annual B. nigra and the perennial B. oleracea are discussed in the light of their different life histories.