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1.
Claudia Voelckel Tamara Krügel Klaus Gase Nadja Heidrich Nicole M. van Dam Robert Winz Ian T. Baldwin 《Chemoecology》2001,11(3):121-126
2.
Large-scale effects of diffuse heavy metals pollution on terrestrial ecosystems are still underestimated. We studied the relation between the biodiversity of vascular plants and the feeding Lepidoptera, in our case leaf-miners and pollinating adult butterflies, in a Dutch nature reserve over a period of five years. We found that 5% of the 56 plants species which provide food and habitat to Microlepidoptera during their larval stage were affected by heavy metal pollution. Furthermore, the numerical abundance of leaf-mining larvae remained rather constant, despite of significant increases of the concentrations of Cd, Cu, Ni and Zn pollutants in leaves and litter. 相似文献
3.
Letizia Mattiacci Sara Rudelli Bettina Ambühl Rocca Sem Genini Silvia Dorn 《Chemoecology》2001,11(4):167-173
Summary. Plant responses to herbivory might directly affect the herbivore (“direct” defences) or might benefit the plant by promoting
the effectiveness of natural antagonists of the herbivores (“indirect” defences). Brussels sprouts attacked by Pieris brassicae larvae release volatiles that attract a natural antagonist of the herbivores, the parasitoid Cotesia glomerata, to the damaged plant. In a previous study, we observed that feeding by caterpillars on the lower leaves of the plant triggers
the systemic release of volatiles detectable by the parasitoids from upper leaves of the same plant.?The role of these systemically
induced volatiles as indirect defence and the dynamics of their emission were investigated in wind-tunnel dual choice tests
with C. glomerata. The systemically induced emission of volatiles varied depending on leaf age and on plant age. Systemic induction affected
parasitoid effectiveness, as induced plants could be more easily located by parasitoids than non-induced ones.?The role of
the systemic induction as a direct defence was investigated through behavioural and feeding tests with P. brassicae. In dual choice assays, 1st instar larvae preferred to feed and fed more on systemically induced than on non-induced leaves.
In single choice assays, the leaf area consumed by caterpillars was larger on systemically induced leaves than on non-induced
control leaves. However, caterpillars fed on systemically induced leaves attained the same weight as those feeding on non-induced
controls. In addition, P. brassicae pupae whose larvae were fed on systemically induced leaves had longer developmental times than those of larvae fed on non-induced
leaves. Adult oviposition behavior was not influenced by systemic induction.?We conclude that systemically induced responses
in cabbage might reduce P. brassicae fitness both directly, by affecting their development and feeding behavior and indirectly by making caterpillars and pupae
more vulnerable to attack by carnivores. The occurrence of a possible relationship between direct and indirect defence is
discussed.
Received 24 January 2001; accepted 3 May 2001. 相似文献
4.
Cu(铜)和Zn(锌)是环境中最常见的重金属污染元素,为探究其对白星花金龟幼虫的毒性,采用滤纸接触法、人工土壤法和菌渣培养法研究了高Cu、高Zn对白星花金龟幼虫的生长及氧化胁迫效应。结果表明,滤纸接触法和人工土壤法中试验浓度Cu、Zn对白星花金龟幼虫死亡率无明显影响。菌渣培养法中虫体的取食抑制率和体重增长抑制率均与Cu、Zn浓度呈显著性正相关关系;Cu处理诱导了虫体可溶性蛋白含量的增加,抑制了SOD(超氧化物歧化酶)、GST(谷胱甘肽转移酶)的活性和MDA(丙二醛)的产生,对CAT(过氧化物酶)活性没有显著影响;Zn浓度为3 500和5 000 mg·kg-1的处理组可溶性蛋白含量被显著诱导、MDA含量被显著抑制,浓度为2 000和6 500 mg·kg-1处理组的SOD活性被激活(P0.05),Zn胁迫未对CAT、GST活性造成明显影响。表明Cu、Zn污染对白星花金龟幼虫生长具有毒性效应,在评价高浓度的重金属污染对虫体的毒性作用时,不能仅采用SOD、CAT、GST等指标作为标志物,需要综合其他指标进行分析。 相似文献
5.
Insects feeding on aboveground and belowground tissues can influence each other through their shared plant and this is often mediated by changes in plant chemistry. We examined the effects of belowground root fly (Delia radicum) herbivory on the performance of an aboveground herbivore (Plutella xylostella) and its endoparasitoid wasp (Cotesia vestalis). Insects were reared on three populations of wild cabbage (Brassica oleracea) plants, exhibiting qualitative and quantitative differences in root and shoot defense chemistry, that had or had not been exposed to root herbivory. In addition, we measured primary (amino acids and sugars) and secondary [glucosinolate (GS)] chemistry in plants exposed to the various plant population-treatment combinations to determine to what extent plant chemistry could explain variation in insect performance variables using multivariate statistics. In general, insect performance was more strongly affected by plant population than by herbivory in the opposite compartment, suggesting that population-related differences in plant quality are larger than those induced by herbivory. Sugar profiles were similar in the three populations and concentrations only changed in damaged tissues. In addition to population-related differences, amino acid concentrations primarily changed locally in response to herbivory. Whether GS concentrations changed in response to herbivory (indole GS) or whether there were only population-related differences (aliphatic GS) depended on GS class. Poor correlations between performance and chemical attributes made biological interpretation of these results difficult. Moreover, trade-offs between life history traits suggest that factors other than food nutritional quality contribute to the expression of life history traits. 相似文献
6.
Galerucella placida Baly (Coleoptera: Chrysomelidae) is a potential biocontrol agent of the rice-field weed Polygonum orientale L. (Polygonaceae). The volatile organic compound (VOC) profiles from undamaged and mechanically damaged plants, and from plants 12- and 36-h following continuous feeding of female G. placida adults and 2nd instar larvae were identified and quantified by GC–MS and GC-FID analyses. Twenty-four and 21 compounds were identified in volatiles of undamaged and insect feeding plants, respectively; whereas 22 compounds were detected in volatiles of mechanically damaged plants. Decanal and 1-dodecanol were unique to undamaged plants, and linalool was detected in volatiles of undamaged and mechanically damaged plants, but not in volatiles of insect damaged plants. However, the beetles are not attracted by none of these volatile components, when tested individually in Y-shaped glass tube olfactometer bioassays. In all plants, methyl jasmonate was predominant. 1-Undecanol was the least amount in undamaged plants, and plants 12-h after feeding by G. placida adults and larvae; whereas 1-tridecanol was the least abundant in plants 36-h after feeding by G. placida adults and larvae, and mechanically damaged plants. The beetles showed significant preference to the whole volatile blends from plants 12-h after feeding by larvae and plants 36-h after feeding by either larvae or adults compared to those of undamaged plants. Further, G. placida responded to individual synthetic compounds, 3-hexanol, 1-octen-3-ol, nonanal, and geraniol at 7, 1.38, 3.75 and 4.5 µg/25 µL CH2Cl2, respectively, and provide a basis for attraction of the potential biocontrol agent in the field. 相似文献
7.
Laboratory-reared red drum (Sciaenops ocellatus ) larvae were used to evaluate the potential of chymotrypsin as an indicator of nutritional condition in marine fish larvae. The response of chymotrypsin activity to food deprivation and reductions in nutrient intake was determined. Enzyme activity declined rapidly to undetectable levels in food-deprived larvae 6–18 days old. Larvae fed poor-quality live prey (starved rotifers, Brachionus plicatilis ) exhibited reductions in growth (18%) and enzyme activity (84%) relative to larvae fed high-quality prey (enriched rotifers). Potential sources of variation in chymotrypsin activity unrelated to nutritional status, including diel periodicity, and exogenous enzymes sources were examined. A diel pattern in chymotrypsin activity was detected with an 8.7-fold increase in activity occurring from low to high points during a 24-h period. Highest activity levels occurred late in the day (1600 hours) and lowest activity in the morning prior to feeding (0800 hours). The estimated contribution of exogenous enzymes from prey in the digestive tract to measurements of larval enzyme activity was small, reaching a maximum of 4.1% on day 18 in well-fed larvae. Results indicate that exogenous enzymes will not lead to the misclassification of larvae in poor condition. A relationship between chymotrypsin activity and standard length was established for well-fed and food-deprived larvae that could potentially be used to determine the nutritional condition of wild-caught larvae. 相似文献
8.
Introducing a new metal accumulator plant and the evaluation of its ability in removing heavy metals
A field study was conducted in a dried waste pool of a lead (Pb) mine in Arak (Iran) to find the accumulator plant(s) and to evaluate the amount of metal bioaccumulation in the root and shoot portion of the naturally growing vegetation. Concentrations of heavy metals were determined both in the soil and the plants that were grown in the dried waste pool. The concentrations of total Cu, Zn, Pb, and Ni in the waste pool were found to be higher than the natural soil and the toxic levels. The results showed that six dominant vegetations, namely, Centaurea virgata, Eleagnum angustifolia, Euphorbia macroclada, Gundelia tournefortii, Reseda lutea, and Scariola orientalis accumulated heavy metals. Based on the results, it was concluded that E. macroclada belonging to Euphorbiaceae is the best Pb accumulator and also a good accumulator for Zn, Cu, and Ni. The bioaccumulation ability of E. macroclada was evaluated in experimental pots. The study showed that the amount of heavy metals in polluted soils decreased several times during two years of phytoremediation. The accumulation of metal in the root, leaves, and shoot portions of E. macroclada varied significantly, but all the concentrations were within the toxic limits. Based on the obtained data, E. macroclada is an effective accumulator plant for soil detoxification and phytoremediation in critical conditions. 相似文献
9.
Ken Keefover-Ring 《Chemoecology》2013,23(1):1-11
Many plant families have aromatic species that produce volatile compounds which they release when damaged, particularly after suffering herbivory. Monarda fistulosa (Lamiaceae) makes and stores volatile essential oils in peltate glandular trichomes on leaf and floral surfaces. This study examined the larvae of a specialist tortoise beetle, Physonota unipunctata, which feed on two M. fistulosa chemotypes and incorporate host compounds into fecal shields, structures related to defense. Comparisons of shield and host leaf chemistry showed differences between chemotypes and structures (leaves vs. shields). Thymol chemotype leaves and shields contained more of all compounds that differed than did carvacrol chemotypes, except for carvacrol. Shields had lower levels of most of the more volatile chemicals than leaves, but more than twice the amounts of the phenolic monoterpenes thymol and carvacrol and greater totals. Additional experiments measured the volatiles emitted from M. fistulosa in the absence and presence of P. unipunctata larvae and compared the flower and foliage chemistry of plants from these experiments. Flowers contained lower or equal amounts of most compounds and half the total amount, compared to leaves. Plants subjected to herbivory emitted higher levels of most volatiles and 12 times the total amount, versus controls with no larvae, including proportionally more of the low boiling point chemicals. Thus, chemical profiles of shields and volatile emissions are influenced by the amounts and volatilities of compounds present in the host plant. The implications of these results are explored for the chemical ecology of both the plant and the insect. 相似文献
10.
Karen M. Kester Steven C. Peterson Frank Hanson D. Michael Jackson R. F. Severson 《Chemoecology》2002,12(1):1-10
Summary. Field observations indicated that hornworms select feeding sites non-randomly on tobacco. We tested the hypotheses that differences
in feeding site locations of larvae of Manduca
sexta L. and Manduca
quinquemaculata (Haworth) (Lepidoptera: Sphingidae) on tobacco could be explained by differential nicotine concentrations within plants and
leaves, species-specific responses to nicotine, or pressure exerted by natural enemies. Results showed that third-instar larvae
of M. sexta fed more proximally and centrally on the leaf, whereas M. quinquemaculata fed more distally. Within-plant selection of leaves did not differ; both species selected leaves in the middle region of
the plant. Nicotine concentrations in a high nicotine genotype, NC95, varied within each leaf, increasing 2—3 fold from the
basal to apical portion of the leaf, and within each plant, increasing 7—10 fold from the first fully expanded leaf to the
twelfth (lowest) leaf. In laboratory bioassays, both Manduca species responded to nicotine as a feeding deterrent. Electrophysiological studies demonstrated that gustatory organs of
both species responded to nicotine at concentrations found in tobacco leaves and that M. quinquemaculata generally showed a less vigorous response to nicotine than M. sexta. Field mortality of M. sexta due to parasitism by Cotesia
congregata (Say) and to parasitism and predation combined differed among feeding sites; predation alone did not. Results suggest that
although nicotine concentration and species specific responses to nicotine play a role in determining feeding site locations,
pressure exerted by natural enemies, especially parasitism by C. congregata, is more important.
Received 22 February 2000; accepted 20 July 2001. 相似文献
11.
The effects of larval diet on the nutritional preferences of butterflies has rarely been examined. This study investigates whether alterations in the larval diet result in changes in adult preferences for nectar amino acids. Larvae of Coenonympha pamphilus were raised on fertilized or unfertilized Festuca rubra, grown under ambient (350 ppm) or elevated (750 ppm) atmospheric CO 2environments. Fertilization led to marked increases in leaf nitrogen concentration. In plants grown under elevated CO 2conditions, leaf water and nitrogen concentrations were significantly lower, and the C/N-ratio increased significantly. Fertilization of the host plant shortened the development time of C. pamphilus larvae, and pupal weight increased. In contrast, larvae of C. pamphilus developed significantly slower on F. rubra grown under elevated CO 2, but adult emergence weight was not affected by CO 2treatment of the plant. C. pamphilus females showed a clear preference for nectar mimics containing amino acids, whereas males, regardless of treatment, either preferred the nectar mimic void of amino acids or showed no preference for the different solutions. Female butterflies raised on fertilized plants showed a significant decline in their preference for nectar mimics containing amino acids. A slight, but not significant, trend towards increased nectar amino acid preference was found in females raised on plants grown under elevated CO 2. We clearly demonstrate that alterations in larval host quality led to changes in butterfly nectar preferences. The ability of the butterfly to either rely less on nectar uptake or compensate for poor larval conditions represents a trade-off between larval and adult butterfly feeding. 相似文献
12.
Piper regnellii (Piperaceae) contains high levels neolignans with diverse biological activities, including insecticidal. Despite the insecticidal activity of these neolignans, Naupactus bipes (Coleoptera: Curculionidae) larvae and adults were found feeding on the leaves (adults) and roots (larvae) of P. regnellii. The present study investigated the metabolic pathway of neolignans from P. regnellii leaves in the beetle N. bipes, focusing on possible biotransformation or sequestration of these compounds by the beetle. Two of the four plant neolignans could be recovered in the feces of adults feeding on P. regnellii leaves. In addition, four degradation products were detected, including the neolignan 3-[(2R,3R)-2,3-dihydro-3-(methyl)-2-(4-hydroxyphenyl)-5-benzofuranyl]-(2E)-propenal (7), an oxidation product of conocarpan, the major plant neolignan. The adult beetle sequesters the neolignan conocarpan selectively from leaves as well as accumulates neolignan 7. Neolignan 7 was also detected in the larvae of lab-reared beetles. 相似文献
13.
Some vascular plants are known to concentrate trace metals and are regarded to be suitable indicators of atmospheric metal deposition. Among plant species used for biogeochemical studies dandelion (Taraxacum officinale.) is convenient for monitoring air/soil pollution. The plant commonly occurs in different ecosystems with relatively parallel stages of ontogenesis over a broad area of geographical regions. Its leaves and roots are easily accessible for sampling. Leaf to root ratios of metal concentrations in dandelion may indicate the source of metals during the growing season. Trace metals in leaves and roots of dandelion from 132 sites in Poland showed higher concentrations in the plants from the SW region compared to those from the NE region of the country. However, the differences were only statistically significant ( = 0.05) for Cd, Ni, and Pb. Geometric means of metal concentrations (mg kg–1, air dried weight) in dandelion leaves of the SW and NE regions were: Cd 0.85, 0.52; Cr 0.99, 0.81; Cu 11.2, 11.1; Fe 184.4, 100.0; Mn 59.7, 51.4; Ni 2.1, 1.5; Pb 4.4, 3.0; and Zn 49.6, 41.3, respectively. Markedly higher concentrations of Cd, Pb, and Zn were found in the leaves of the dandelion over roots in the SW region. These metals are the most serious aerial pollutants in that part of the country. 相似文献
14.
Piotr Goliński Zuzanna Magdziak Monika Gąsecka Klaudia Borowiak Jędrzej Dąbrowski 《Chemistry and Ecology》2013,29(4):345-364
The aim of the study was to estimate Zn phytoextraction and changes in biomass of S?×?rubens growing in modified Knop's solution with different levels of Zn addition (0.5, 1.0, 2.5 and 5.0?mM). Obtained results were correlated with secretion of selected low-molecular-weight organic acids (LMWOAs) in the rhizosphere, roots and leaves. An increase in Zn concentration in Knop's solution resulted in Zn accumulation in roots, shoots and leaves. The highest accumulation was observed for plants growing in 5?mM Zn, at concentration levels 4741.36?±?98.66, 1227.31?±?16.57 and 2241.65?±?34.90?mg?kg?1 DW in roots, shoots and leaves, respectively. The bioaccumulation factor and the translocation factor for plants growing in 0.5, 1.0 and 2.5?mM Zn clearly indicate that this Salix taxon is an effective Zn accumulator. The general reduction of Salix biomass with an increase in Zn concentration in the solution was observed. In the rhizosphere, the total LMWOA concentration was almost 0.93?µmol?kg?1 DM for control (Zn free) plants, while for 5.0?mM of Zn it was 4.9?µmol?kg?1 DM. Increasing concentrations of acids were observed in roots (1.34 for the control and 5.57?µmol?kg?1 DM for plants treated with 2.5?mM of Zn). 相似文献
15.
Summary. The effect of rearing larvae of Trichoplusia ni on
individual feeding deterrents or on binary mixtures of deterrents
on their subsequent gustatory sensitivity was measured
in paired choice leaf disc bioassays. Our working hypothesis
was that mixtures of antifeedants (pure allelochemicals)
would mitigate decreased feeding deterrent response following
prolonged exposure in this generalist herbivore. Neonate
larvae were reared on cabbage leaves treated with individual
feeding deterrents (digitoxin, thymol, toosendanin or xanthotoxin),
or with binary mixtures of these until the third instar.
Feeding deterrent responses to each antifeedant or mixture
was then determined in a leaf disc choice bioassay. All of the
mixtures produced additive deterrence when presented to
naïve larvae. Larvae reared on individual antifeedants
showed a significantly decreased feeding deterrent response
(except to digitoxin), whereas larvae reared on binary mixtures
of antifeedants did not show a decreased feeding deterrent
response to any of them. Such mixtures were synergistic
in terms of their feeding deterrence to experienced larvae.
Our experiment supports the hypothesis (Jermy 1986) that
mixtures of deterrents can prevent decreased feeding deterrent
response following prolonged exposure, and provides one
explanation for the multiplicity of chemical defenses found
in many plants. 相似文献
16.
The temporal and multiple-scale spatial variation in the density of mobile epifauna and grazing damage was investigated in populations of the brown seaweed Ascophyllum nodosum (Fucales: Phaeophyta). The relationship between density of grazers and grazing marks was also analyzed. The study was carried out in two locations of the northeastern Atlantic: one at the Isle of Man, in the Irish Sea, and the other at Tjärnö, on the Swedish west coast. Furthermore, the effect of grazing marks on the probability of frond breakage was evaluated in a 1-year experiment carried out on the Isle of Man. High temporal and small-scale spatial variability was recorded in the density of mobile epifauna. A high percentage of species were herbivores, i.e. mesograzers. Adult plants of A . nodosum have several primary vegetative fronds with apical growth. Grazing marks were commonly found along the fronds. Similar levels of grazing damage were detected at the two locations, despite the observed qualitative differences in the grazing assemblages. Small-scale spatial variability in grazing marks was important, with differences in the density of grazing wounds among plants, fronds, and even within fronds. A significant correlation between the proportion of grazed apices and the density of the isopod Idotea spp. and grazing amphipods considered together was detected. This probably reflects the simultaneous feeding activity of these two groups of grazers and suggests the presence of feeding facilitation mechanisms between them. Grazing marks were concentrated in the apical part of the shoots. The results of this study also showed that grazing damage increased the probability of breakage, especially of shorter fronds. This suggests that grazing damage affects the demography of shoots and plants, increasing the transition probabilities to smaller sizes. The presence of interactive effects between grazing and plant density in these A . nodosum populations of northeastern Atlantic shores was also discussed on the basis of the results of this and a previous study. 相似文献
17.
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. 相似文献
18.
V. Plasman M. Plehiers J. C. Braekman D. Daloze J. C. de Biseau J. M. Pasteels 《Chemoecology》2001,11(3):107-112
19.
Kevin B. Cordes Aradhana Mehra Margaret E. Farago Dipak K. Banerjee 《Environmental geochemistry and health》2000,22(4):297-316
The main solid waste product from coal-fired power stations is pulverised fuel ash (PFA), which can be enriched in toxic elements. Disposal of PFA by dry (in landfills) or wet (by slurrying) disposal methods can release these elements into the environment. Thereafter, the contaminants can be taken up by biota such as Eichhornia crassipes, a common aquatic plant, which has the ability to accumulate elements from water. This study investigates the uptake of Cd, Cu, Ni and Zn by E. crassipes grown in leachates and slurries prepared from two different PFA samples. PFA samples were obtained from Indraprastha Power Station (IPP Stn.) in New Delhi, India and the Ratcliffe-on-Soar Power Station in the UK. E. crassipes grown in PFA leachates and slurries at 1:5 and 1:50 solid:liquid (PFA:deionised water) ratios show that the plant has a very high accumulation capacity for Cd, Cu, Ni and Zn from both leachates and slurries and the uptake of these metals is stronger in the roots than in the tops of the plant. Metal accumulation, as shown by the accumulation factor (AF) values, is higher from both leachates and slurries for plants grown in the 1:50 (PFA:DIW) ratios than in the 1:5 ratios, initial metal concentrations being higher in the 1:5 ratios than in the 1:50 ratios. Lower metal accumulation in the plants grown in slurries than in leachates is related to the high turbidity of growth medium in slurries resulting in ash particles adhering to the root surfaces thus reducing the surface area of metal absorption. Eichhornia plants are able to reduce the pH of all leachates, especially the highly alkaline Ratcliffe leachates to near neutral conditions. Accumulation of Cd and Zn by the plant is higher from the lower pH IPP leachates than the Ratcliffe leachates, indicating that these metals are more soluble and bioavailable in the acidic medium. However, accumulation of Cu and Ni is independent of the pH of the leachates, indicating that other factors, such as metal species, presence of complexing agents in the growth solutions, and effects of competing metal ions may be contributory factors towards the metal uptake and accumulation by the plant. 相似文献
20.
Jasmonic acid treatment and mammalian herbivory differentially affect chemical defenses and growth of wild mustard (Brassica kaber) 总被引:2,自引:0,他引:2
Summary. Jasmonic acid (JA) is a wound-related hormone found in most plants that, when applied exogenously, can induce increases in
levels of chemical defenses in patterns similar to those induced by mechanical damage or insect feeding. Relative to responses
to insect and pathogen attack, chemical responses of herbaceous plants to mammalian herbivore attack have been little studied.
In a field experiment, we compared the effects of JA treatment and naturally occurring mammalian herbivory on the expression
of trypsin inhibitors, glucosinolates, peroxidase activity and growth of wild mustard (Brassica kaber). Exogenous JA significantly increased trypsin inhibitor activity and glucosinolate concentration, and moderately increased
peroxidase activity in the eighth true leaves of five-week-old plants, relative to untreated controls. In contrast, levels
of these chemical defenses in the eighth true leaves or in regrowth foliage of plants that had ∼80% of their leaf area removed
by groundhogs (Marmota monax) did not differ from that in undamaged and untreated controls. Although exogenous JA significantly elevated levels of chemical
defenses, it did not affect height of plants through the season and only slightly reduced time to first flower. Groundhog
herbivory significantly reduced height and delayed or abolished flowering, but these effects were not substantial unless coupled
with apical meristem removal. We hypothesize that the lack of effect of groundhog herbivory on chemical defenses may be due
in part to the speed and pattern of leaf area removal by groundhogs, or physiological constraints caused by leaf area loss.
Despite having no effect on chemical defense production, leaf area loss by groundhogs was more costly to growth and fitness
than the effects of JA application in this study, but only substantially so if coupled with apical meristem removal. We suggest
that in general, costs of defense production in plants are likely to be minimal when compared to the risk of losing large
amounts of leaf area or primary meristematic tissue. Thus, if they are effective at deterring herbivory, the benefits of inducible
defense production likely outweigh the costs in most cases.
Received 20 December 2000; accepted 3 May 2001 相似文献