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1.
Kevin J. Delaney 《Plant Ecology》2008,199(2):187-200
Insect herbivory has variable effects on plant physiology; so greater understanding is needed about how injury alters photosynthesis
on individual injured and uninjured leaves. Gas exchange and light-adapted leaf chlorophyll fluorescence measurements were
collected from uninjured and mechanical partial leaf defoliation in two experiments with Nerium oleander (Apocynaceae) leaves, and one experiment with Danaus plexippus herbivory on Asclepias curassavica (Asclepiadaceae) leaves. Gas exchange impairment (lower photosynthetic rate (P
n
), stomatal conductance (g
s)) indicates water stress in a leaf, suggests stomatal limitations causing injury P
n
impairment. The same pattern of gas exchange impairment also occurred on uninjured leaves opposite from injured leaves in
both N. oleander experiments. This is an interesting result because photosynthetic impairment is rarely reported on injured leaves near injured
leaves. No photosynthetic changes occurred in uninjured A. curassavica leaves opposite from D. plexippus-fed leaves. Partially defoliated leaves that had P
n
and g
s reductions lacked any significant changes in intercellular leaf [CO2], C
i. These results neither support, nor are sufficient to reject, stomatal limitations to photosynthesis. Manually imposed midrib
vein severance in N. oleander experiment #1 significantly increased leaf C
i, indicating mesophyll limitations to photosynthesis. Maximal light-adapted leaf photochemical efficiency () and also non-photochemical quenching (q
N) were reduced by mechanical or insect herbivory to both study species, suggesting leaf trouble handling excess light energy
not used for photochemistry. Midrib injury on N. oleander leaves and D. plexippus herbivory on A. curassavica leaves also reduced effective quantum yield (ΦPSII) and photochemical quenching (q
P); so reduced plastoquinone pools could lead to additional PSII reaction center closure. 相似文献
2.
A procedure for in vitro plant regeneration of Alnus acuminata from epicotyls with cotyledonary buds was developed using different media formulations with different growth regulators and carbon sources. The development of multiple buds on explants at the initiation step was obtained with MS at 1/2 strength with either 1 or 2M of BAP but not without it. Multiplication gave up to 15 elongating shoots by explant, the best medium being MS supplemented with vitamins from B5 medium, 1M of BAP and 87mM sucrose. Rooting of about 88% occurred in the medium MS with 83 mM sucrose and 1M IBA. Alnus acuminata did not developed well on WPM. Roots of in vitro propagated plants were nodulated by Alnus-infective Frankia. The root nodules show a typical alder root nodule anatomy and differentiation pattern and effectively fixed nitrogen. Rhamnaceae-infective Frankia did not nodulate in vitro cultivated Alnus acuminata suggesting that symbiotic recognition was not altered by in vitro regeneration of the plant. 相似文献
3.
Ectomycorrhizal (EM) basidiomycete fungi are obligate mutualists of pines and hardwoods that receive fixed C from the host
tree. Though they often share most recent common ancestors with wood-rotting fungi, it is unclear to what extent EM fungi
retain the ability to express enzymes that break down woody substrates. In this study, we tested the hypothesis that the dominant
EM fungus in a pure pine system retains the ability to produce enzymes that break down woody substrates in a natural setting,
and that this ability is inducible by reduction of host photosynthetic potential via partial defoliation. To achieve this,
pines in replicate blocks were defoliated 50% by needle removal, and enzyme activities were measured in individual EM root
tips that had been treated with antibiotics to prevent possible bacterial activity. Results indicate that the dominant EM
fungal species (Suillus granulatus) expressed all enzymes tested (endocellulase D-glucosidase, laccase, manganese peroxidase, lignin peroxidase, phosphatase and protease), and that activities of these enzymes
increased significantly (P < 0.001) in response to defoliation. Thus, this EM fungus (one of the more specialized mutualists of pine) has the potential
to play a significant role in C, N and P cycling in this forested ecosystem. Therefore, many above-ground factors that reduce
photosynthetic potential or divert fixed C from roots may have wide-reaching ecosystem effects. 相似文献
4.
Akiyoshi Yamada Daisei Kitamura Masanobu Setoguchi Yosuke Matsuda Yasushi Hashimoto Norihisa Matsushita Masaki Fukuda 《Ecological Research》2008,23(6):983-993
Monotropastrum humile is nearly lacking in chlorophyll and obtains its nutrients, including carbon sources, from associated mycorrhizal fungi.
We analyzed the mycorrhizal fungal affinity and species diversity of M. humile var. humile mycorrhizae to clarify how the plant population survives in Japanese forest ecosystems. We classified 78 samples of adult
M. humile var. humile individuals from Hokkaido, Honshu, and Kyusyu Islands into 37 root mycorrhizal morphotypes. Of these, we identified 24 types
as Russula or Lactarius fungal taxa in the Russulaceae, Basidiomycetes, but we could not identify the remaining 13 types as to their genus in the
Basidiomycetes. The number of fungal species on M. humile var. humile was the highest in the plant subfamily. The diversity of fungal species revealed its increased trends in natural forests
at the stand level, fagaceous vegetation, and cool-temperate climate. The most frequently observed fungus colonized mainly
samples collected from sub-alpine forests; the second most frequently observed fungus colonized samples collected from sub-alpine
to warm-temperate forests. These results suggest that Japanese M. humile populations are associated with specific but diverse fungi that are common ectomycorrhizal symbionts of various forest canopy
trees, indicating a tripartite mycorrhizal relationship in the forest ecosystem. 相似文献
5.
Studies of induction in trees have examined rapid induced resistance (RIR) or delayed induced resistance (DIR), but have not
examined induction that occurs in leaves produced by indeterminately growing trees subsequent to, but in the same season as,
damage. We refer to induction that occurs during this time period as intermediate-delayed induced resistance (IDIR). We assessed
the influences of genetic and environmental factors, and their interactions, on temporal and spatial variation in induction
and on tradeoffs between induced and constitutive levels of resistance in indeterminately growing saplings of aspen (Populus tremuloides). We utilized a common garden of 12 aspen genotypes experiencing two levels of defoliation and two levels of soil nutrients.
We assessed concentrations of phenolic glycosides and condensed tannins in damaged leaf remnants collected 1 week after defoliation
to examine rapid and local induction, and in undamaged leaves produced 8 weeks after defoliation to assess intermediate-delayed
and systemic induction. In general, tannins showed RIR, while phenolic glycosides expressed IDIR. For both classes of allelochemicals,
we found high estimates of broad-sense heritability and genetic variation in both induced and constitutive levels. Genetic
variation may be maintained by both direct costs of allelochemicals and by costs of inducibility (phenotypic plasticity).
Such costs may drive the tradeoff exhibited between induced and constitutive levels of phenolic glycosides. IDIR may be important
in reducing total-season tissue loss by providing augmented resistance against late summer herbivores in trees that have experienced
damage earlier in the season. Herbivore-resistant compensatory growth is especially beneficial to young trees growing in competitive
environments. 相似文献
6.
Ectomycorrhizal (ECM) syntheses between four ECM fungi, Laccaria amethystina, Hebeloma mesophaeum, Thelephora terrestris, and Tomentella sp., and Populus maximowiczii seedlings that are known to form ECM at a denuded area of Mt. Usu were performed in volcanic debris in a controlled growth
chamber. The percentage of ECM colonization and seedling growth were determined 3 months after inoculation. Seedlings were
successfully colonized by the inoculated ECM fungi with low contamination ratios. Seedling height and biomass were larger
in the inoculated seedlings than in the control, although the effects of inoculation on seedling growth varied with the ECM
fungus. 相似文献
7.
Mycorrhizal fungi were isolated from the nonphotosynthetic orchid Chamaegastrodia sikokiana and identified as members of Ceratobasidiaceae by phylogenetic analysis of the internal transcribed spacer (ITS) region of
ribosomal deoxyribonucleic acid. The ITS sequences were similar among geographically separated samples obtained from Mt. Kiyosumi
in Chiba Prefecture and Mt. Yokokura in Kochi Prefecture. One of the isolated fungi, KI1-2, formed ectomycorrhiza on seedlings
of Abies firma in pot culture, suggesting that tripartite symbiosis exists among C. sikokiana, mycorrhizal fungi, and A. firma in nature, and carbon compounds are supplied from A. firma to C. sikokiana through the hyphae of the mycorrhizal fungi. To our knowledge, this is the second study to suggest the involvement of Ceratobasidiaceae
fungi in tripartite symbiosis with achlorophyllous orchids and photosynthetic host plants. 相似文献
8.
Tricholoma fulvocastaneum is recorded from Thailand for the first time. This edible ectomycorrhizal fungus is associated with Castanopsis tribuloides (Fagaceae) in mixed evergreen forest in northern Thailand. Conventional and molecular methods were carried out to confirm
its identity. 相似文献
9.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes. 相似文献
10.
In a series of field experiments Diabrotica beetle herbivory was found to influence the magnitude of inbreeding depression in Cucurbita pepo ssp. texana, an annual monoecious vine. Beetles damage flowers and fruits and chew dime-sized holes in leaf tissue between major veins. Inbred plants were found to be more likely to be damaged by beetles and to have more leaves damaged per plant than outcrossed plants. A positive linear association was found between the coefficient of inbreeding and the magnitude of leaf damage, whereas a negative association was found between coefficient of inbreeding and several male and female fitness traits. When pesticides were used to control beetle herbivory, the interaction between coefficient of inbreeding and pesticide treatment was significant for fruit production and marginally significant for pollen quantity per anther. Therefore, the magnitude of inbreeding depression in C. pepo ssp . texana varies depending on the severity of beetle herbivory. 相似文献
11.
Fluctuating asymmetry (FA) has been suggested as a useful indicator of elevation stress and, hence, distribution limits in
plants. However, no plant studies have been carried out to test (i) whether FA shows a gradual increase towards the alpine
distribution limit and (ii) whether FA responds to elevation stress independent of other stressors which is necessary for
FA to be a useful indicator in this context. To test these two hypotheses, this 2-year field study investigated the dose–response
relationship between elevation stress and FA in mountain birch (Betula pubescens) under contrasting levels of insect attack in northern Norway. The results showed that FA increased linearly from sea level
towards the tree line in both years independent of insect attack, which had no observable effect on FA, i.e. insect attack
did not appear to disturb the FA-elevation relation. Thus, in mountain birch, FA appeared to be a reliable indicator of elevation
stress. Further investigation is now needed in order to develop this hypothesis. 相似文献
12.
Plants defend themselves against herbivores via resistance, which reduces damage, and tolerance, which minimizes the negative
effects of damage. Theory predicts the existence of tradeoffs between defense and growth, as well as between resistance and
tolerance, that could maintain the genetic variation for resistance and tolerance often observed in plant populations. We
examined resistance and tolerance among aspen (Populus tremuloides) trees grown under divergent soil nutrient regimes. This common garden experiment revealed substantial genetic variation
for resistance and tolerance under both low- and high-nutrient conditions. Costs of resistance exist, particularly under high-nutrient
conditions where allocation to resistance chemicals competes directly with growth for limited carbon resources. We found no
significant costs of tolerance, however, under either nutrient condition. Despite genetic variation for both resistance and
tolerance, we found no evidence for a tradeoff between these two defense traits suggesting that resistance and tolerance are
complementary, rather than mutually exclusive, defenses in aspen. 相似文献
13.
Noel H. Holmgren 《Brittonia》2018,70(1):115-139
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations. 相似文献
14.
Pudas E Leppälä M Tolvanen A Poikolainen J Venäläinen A Kubin E 《International journal of biometeorology》2008,52(4):251-259
Timing of plant phenophases is a useful biological indicator which shows how nature responds to the variation in climate.
Thus, long phenological observation series help to estimate the impact of changing climate on forest plants. We investigated
whether phenological patterns of downy birch Betula pubescens respond to warming climate and whether the intensity of the responses varies among phytogeographical zones. We studied data
collected by the Finnish National Phenological Network from 30 observation sites across Finland during 1997–2006. The advancement
in the timing of the earliest phenophase, bud burst, ranged from 0.7 days/year in southern boreal zone to 1.4 days/year in
middle and northern boreal zones. Timing of bud burst was most clearly dependent on mean May temperatures. The intensity of
the response to temperature increased from south to north. The advancement of bud burst resulted into a significant lengthening
of the growth period by 1.2–1.6 days per year in northern and middle boreal zones, respectively, whereas the lengthening was
not significant in the southern boreal zone. No trend was observed in the timing of autumn phenophases. 相似文献
15.
Christian Abel Maria Clauss Andrea Schaub Jonathan Gershenzon Dorothea Tholl 《Planta》2009,230(1):1-11
Volatile organic compounds have been reported to serve some important roles in plant communication with other organisms, but
little is known about the biological functions of most of these substances. To gain insight into this problem, we have compared
differences in floral and vegetative volatiles between two closely related plant species with different life histories. The
self-pollinating annual, Arabidopsis thaliana, and its relative, the outcrossing perennial, Arabidopsis lyrata, have markedly divergent life cycles and breeding systems. We show that these differences are in part reflected in the formation
of distinct volatile mixtures in flowers and foliage. Volatiles emitted from flowers of a German A. lyrata ssp. petraea population are dominated by benzenoid compounds in contrast to the previously described sesquiterpene-dominated emissions
of A. thaliana flowers. Flowers of A. lyrata ssp. petraea release benzenoid volatiles in a diurnal rhythm with highest emission rates at midday coinciding with observed visitations
of pollinating insects. Insect feeding on leaves of A. lyrata ssp. petraea causes a variable release of the volatiles methyl salicylate, C11- and C16-homoterpenes, nerolidol, plus the sesquiterpene (E)-β-caryophyllene, which in A. thaliana is emitted exclusively from flowers. An insect-induced gene (AlCarS) with high sequence similarity to the florally expressed (E)-β-caryophyllene synthase (AtTPS21) from A. thaliana was identified from individuals of a German A. lyrata ssp. petraea population. Recombinant AlCarS converts the sesquiterpene precursor, farnesyl diphosphate, into (E)-β-caryophyllene with α-humulene and α-copaene as minor products indicating its close functional relationship to the A. thaliana AtTPS21. Differential regulation of these genes in flowers and foliage is consistent with the different functions of volatiles
in the two Arabidopsis species. 相似文献
16.
A genetic transformation system has been developed for callus cells of Crataegus
aronia using Agrobacterium
tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with
5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different
types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red
colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli
were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this
is the first time to report an Agrobacterium-mediated transformation system in Crataegus
aronia. 相似文献
17.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner.
The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate
larvae Galleria
mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host. 相似文献
18.
A Sebacinales species was recovered from a clone library made from a pooled rhizosphere sample of Nicotiana attenuata plants from 14 native populations. Axenic cultures of the related species, Piriformospora indica and Sebacina vermifera, were used to examine their effects on plant performance. Inoculation of N. attenuata seeds with either fungus species stimulated seed germination and increased growth and stalk elongation. S. vermifera inoculated plants flowered earlier, produced more flowers and matured more seed capsules than did non-inoculated plants. Jasmonate treatment during rosette-stage growth, which slows growth and elicits herbivore resistance traits, erased differences in vegetative, but not reproductive performance resulting from S. vermifera inoculation. Total nitrogen and phosphorous contents did not differ between inoculated and control plants, suggesting that the performance benefits of fungal inoculation did not result from improvements in nutritional status. Since the expression of trypsin proteinase inhibitors (TPI), defensive proteins which confer resistance to attack from Manduca sexta larvae, incur significant growth and fitness costs for the plant, we examined the effect of S. vermifera inoculation on herbivore resistance and TPI activity. After 10 days of feeding on S. vermifera-inoculated plants, larval mass was 46% higher and TPI activity was 48% lower than that on non-inoculated plants. These results suggest that Sebacina spp. may interfere with defense signaling and allow plants to increase growth rates at the expense of herbivore resistance mediated by TPIs. 相似文献
19.
Mayuko Suzuki Yuhdai Kaya Takahide A. Ishida Kouhei Hattori Kaori Miki Takashi Nakamura Masahito T. Kimura 《Ecological Research》2007,22(3):496-501
Flowering phenology of cleistogamous annual plants Impatiens noli-tangere and Persicaria thunbergii was studied with reference to their mortality in streamside environments in northern Japan. I. noli-tangere produced flower-buds and flowers from late June to October, whereas P. thunbergii did so from mid-August to October. Both species were often killed by rapid current and submergence after heavy rainfall,
which was unpredictable in the timing and intensity. P. thunbergii was more tolerant to rapid current and submergence than I. noli-tangere. Some individuals of I. noli-tangere were killed by herbivory from sawfly larvae in summer, but P. thunbergii individuals were seldom killed by herbivory. In consequence, the percentage of individuals that survived until the end of
September was higher in P. thunbergii than in I. noli-tangere. These situations are assumed to select a long reproductive life in I. noli-tangere and autumn flowering in P. thunbergii. 相似文献
20.
Browsing by ungulates has become a hotly debated issue in many European mountain forests in the past century. Acer pseudoplatanus L. and Fraxinus excelsior L. are broadleaved tree species that are preferentially browsed by roe deer (Capreolus capreolus) in central Europe. We analyzed growth data from shaded saplings of both tree species to quantify the extent to which height
growth after game browsing is reduced in subsequent, unbrowsed years in forest stands.
Sixty saplings of F. excelsior and A. pseudoplatanus from forest stands at Albisriederberg (Switzerland) were available to us that had been dissected into pieces that then were
split in the middle for counting tree rings and assessing ungulate damage. We fitted the von Bertalanffy growth equation to
these height growth data and included a reduction factor for winter browsing.
Both tree species showed significantly reduced height growth in unbrowsed years after one to several browsing events in winter,
and this effect increased with the number of browsing events. Saplings with a high growth rate showed a higher growth reduction.
After winter browsing, height growth of A. pseudoplatanus saplings was less affected in unbrowsed years than that of F. excelsior saplings.
We conclude that browsed saplings of these species in forest stands are not able to compensate browsing-induced height loss,
but that height differences between browsed and unbrowsed saplings probably increase over time. A comparison between our analysis
and the parameters estimated using equations published by Eiberle for predicting age at 130 cm height suggests that our parameter
values are rather conservative estimates of the growth reduction effect after winter browsing. Neither F. excelsior nor A. pseudoplatanus show a distinct pattern in browsing-induced growth reduction with respect to soil moisture, nutrient level, and altitude.
We thus conclude that our results are likely to be valid for a wide range of forested sites. 相似文献