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1.
F. Fontaine E. Kiefer C. Clément M. Burrus J. L. Druelle 《Trees - Structure and Function》1999,14(2):83-90
In the present work, we described the fate of proventitious epicormic buds on the trunks of 40-year-old Quercus petraea trees and in parallel the vascular trace they produced in the wood. Our results show that small and large individual epicormic
buds can survive as buds for 40 years and that both are composed of a terminal meristem and scales. Meristematic areas are
detected in the scale axils of small buds; in addition to these meristems the large buds also have secondary bud primordia.
The small buds are connected to the pith of the main stem by a unique trace, whereas the large buds are connected by one or
multiple traces. A single trace might imply that the whole bud is still alive and multiple traces might indicate that the
terminal meristem has died. In the latter case, each trace is connected to a secondary bud of the large bud. The buds found
in a cluster are composed of a terminal meristem and scales with axillary meristems in the scale axils. A cluster is connected
to the pith of a stem either by a unique trace when it seems to be the result of partial abscission of an epicormic shoot
or multiple traces when it might have originated from an epicormic bud in which the terminal meristem has died. Whatever the
type of the bud, the vascular trace in the bark is composed of a cambium, secondary xylem and parenchyma cells and the trace
present in the wood had parenchyma cells with vestiges of secondary xylem. Each year, the vascular trace should be produced
in the bark by the cambium of the tree but not by the bud itself. On 40-year-old Q. petraea, we observed a proliferation of epicormic buds and in parallel a multiplication of the number of vascular traces in the trunk,
but the knots caused by the traces of epicormic buds in the wood, either as individuals or in clusters, are minor since their
colours are only slightly darker than those of woody rays and they are less than 2 mm in diameter. The knots will appear when
epicormic buds develop into shoots.
Received: 30 March 1999 / Accepted: 09 June 1999 相似文献
2.
3.
F. Fontaine Jean-Louis Druelle Christophe Clément Monique Burrus Jean-Claude Audran 《Trees - Structure and Function》1998,13(1):54-62
The persistence of large epicormic shoots is one of the main factors that reduces timber quality and value in Quercus petraea. The early phases of epicormic shoot formation, i.e. the initiation of the epicormic buds, their survival and their proliferation
over the years, are not clearly understood. In the present work, we studied the initiation of the axillary buds giving rise
to epicormic buds and shoots, and followed their behaviour during the first 5 years using both scanning electron microscopy
and light microscopy. Two types of proventitious epicormic buds have been identified. The first type has small axillary buds
associated with the rings of bud-scale scars which are found at the base and tip of each growth unit. These buds are made
of a terminal meristem surrounded only by scales; no leaf primordium is detected. During the second and third years of epicormic
life, meristematic areas appear in the scale axil. Progressively, the meristematic areas organize into secondary bud primordia
composed solely of the terminal meristem surrounded by scales. The second type of epicormic bud has secondary buds produced
by a large axillary bud when this large bud either developed into a shoot or partially abscised. The epicormic potential in
Q. petraea is characterized by a balance between the epicormic buds in apparent rest, enclosing meristematic areas and secondary bud
primordia, and their mortality over the years.
Received: 22 January 1998 / Accepted: 8 May 1998 相似文献
4.
Theoretically, complete rejuvenation of mature trees should occur through somatic embryogenesis, however, this has not been
extensively studied. The main objective of the present study was to increase the efficiency of in vitro clonal propagation
for mature Quercus robur (100–300 years old), by induction of somatic embryogenesis as rejuvenation step prior to establishment of shoot culture through
micropropagation of somatic embryo-derived plantlets. Shoot culture lines of “mature” origin were established from epicormic
shoots of two centenarian oak genotypes (Sainza and CR-0) and maintained by axillary shoot proliferation. Embryogenic lines
were also initiated from epicormic leaf explants of the same genotypes and maintained by secondary somatic embryogenesis.
Although the frequency of somatic embryo conversion into plantlets was low in pedunculate oak, shoot culture lines could be
established and maintained by axillary branching from several germinated somatic embryos. For each genotype and shoot culture
line of the two origins (mature tree and somatic plantlets), shoot multiplication rate and elongation as well as rooting ability
parameters were compared. Compared with “mature-origin” shoot cultures and after more than one year propagation in vitro,
shoot lines established from somatic plantlets produced a significantly higher proportion of elongated, rootable shoots (from
26.0–31.6 to 36.8–40.5%) with increased rooting ability (from 3.3–45.6% to 23.2–89.8%). In the case of 300-year-old Sainza
genotype such a high organogenic capacity was similar to shoot cultures initiated from basal sprouts. Basal sprouts are considered
as “mature” material that retains juvenile characteristics compared with epicormic shoots forced from crown branches. Somatic
embryogenesis only slightly improved plant regeneration of shoot cultures from basal sprouts, thus validating their use as
“juvenile control”. The present results provide evidence that some rejuvenation occurred during the process of somatic embryogenesis
and resulted in improved shoot growth and rooting of somatic embryo-derived culture compared with “mature” shoot culture.
The results reported in this study might be useful in embryogenic systems with low plant conversion rates. The proposed experimental
model might also be useful in finding molecular markers of plant ontogeny. 相似文献
5.
Oregon white oak or Garry oak (Quercus garryana Dougl. ex Hook.) is a shade-intolerant, deciduous species that has been overtopped by conifers during the past century in parts of its range due to an altered disturbance regime. We examined the response of suppressed Oregon white oak trees in western Washington, USA, to three levels of release from overtopping Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco). We treated individual oak trees with either full release from competition, partial (“half”) release from competition, or a stand-level thinning of Douglas-fir not directed toward release (control). Five years after treatment, oak trees had suffered no mortality or windthrow. Stem diameter growth was 194% greater in the full-release treatment relative to the control. Acorn production varied widely by year, but in years of higher production, acorn production was significantly greater in both release treatments than in the control. Frequency of epicormic branch formation was significantly increased for years 1 and 2 by the full release; the greatest response occurred between 2 and 6 m above ground level. The greatest number of epicormic branches formed on trees on which the majority of original limbs had died back prior to treatment. Trees with relatively less crown dieback at the time of treatment generally had greater stem growth and acorn production responses to release treatments. Our findings indicate that these released Oregon white oak trees are beginning to recover after an extended period of suppression. 相似文献
6.
Background and Aims
There is increasing evidence that suppressed bud burst and thus epicormic shoot emergence (sprouting) are controlled by water–carbohydrate supplies to entire trees and buds. This direct evidence is still lacking for oak. In other respects, recent studies focused on sessile oak, Quercus petraea, have confirmed the important constraints of sprouting by epicormic ontogeny. The main objective of this paper was thus to provide provisional confirmation of the water–carbohydrate control and direct evidence of the ontogenic constraints by bringing together results already published in separate studies on water status and distribution of carbohydrates, and on accompanying vegetation and epicormics, which also quantify epicormic ontogeny.Methods
This paper analyses results gained from a sessile oak experiment in which part of the site was free from fairly tall, dense accompanying vegetation. This experiment was initially focused on stand water status and more recently on the carbohydrate distribution of dominant trees. External observations of the epicormic composition and internal observations with X-ray computer tomography were undertaken on 60 and six trees, respectively.Key Results
Sprouting was more intense in the part of the stand free from accompanying vegetation and on upper trunk segments. A clear effect of epicormic ontogeny was demonstrated as well: the more epicormics a trunk segment bears, the more chances it had to bear sprouts.Conclusions
These results indirectly infer water–carbohydrate control and show direct evidence of constraints by epicormic ontogeny. These results have far-reaching consequences related to the quantification of all functions fulfilled by any type of epicormic structure in any part of the tree. 相似文献7.
The dikaryon #5026 (A2B2)+#5132 (A7B7) of the basidiomyceteCoprinus macrorhizus was treated with ultraviolet light (UV),N-methyl-N′-nitro-N-nitrosoguanidine (NG), and 5-bromouracil (BU) in order to induced developmental variations in fruiting. Among a total of
11,383 isolates, 742 were homokaryons. Fruiting test was made with the remaining 10,641 dikaryotic isolates, of which 1,594
showed abnormality in basidiocarp development. Both UV and NG were very efficient in inducing such variations, but BU was
not. The induced variations were classified into seven basic types as follows: 1) “knotless”, in which hyphal knots, the first
sign of fruiting, do not differentiate; 2) “primordiumless,” in which hyphal knots are formed, but no further development
occurs; 3) “maturationles”, in which primordia are formed, but the maturation of primordia into adult fruit bodies does not
occur; 4) “elongationless”, in which the elongation of stipe is blocked, and a basidiocarp with a very short stipe is produced;
5) “expansionless,” in which pilei do not expand normally; 6) “sporeless,” in which the formation of basidiospores is blocked
and albinic pilei bearing none or only a small amount of spores are produced; and 7) “autolysisless,” in which the autolysis
of pilei does not appear to occur. It has been noticed that the four steps of maturation, i.e. stipe elongation, pileus expansion,
spore formation, and perhaps pileus autolysis, can proceed independently. Compound types of variations such as “elongation-expansionless,”
“elongation-sporeless,” “expansion-sporeless,” and “elongation-expansion-sporeless” were also induced. UV treatment induced
maturationless at the highest rate, while NG treatment sporeless.
Contributions from the Division of Plant Morphology, Department of Biology, Faculty of Science, Okayama University. No. 117. 相似文献
8.
The credo of every scientist working in the field of applied science is to transfer knowledge “from science to market,” a
process that combines (1) science (fundamental discoveries and basic research) with (2) technology development (performance
assessment and optimization) and (3) technology transfer (industrial application). Over the past 7 years, we have intensively
investigated the potential of the white rot fungus, Physisporinus vitreus, for engineering value-added wood products. Because of its exceptional wood degradation pattern, i.e., selective lignification
without significant wood strength losses and a preferential degradation of bordered pit membranes, it is possible to use this
fungus under controlled conditions to improve the acoustic properties of tonewood (i.e., “mycowood”) as well as to enhance
the uptake of preservatives and wood modification substances in refractory wood species (e.g., Norway spruce), a process known
as “bioincising.” This minireview summarizes the research that we have performed with P. vitreus and critically discusses the challenges encountered during the development of two distinct processes for engineering value-added
wood products. Finally, we peep into the future potential of the bioincising and mycowood processes for additional applications
in the forest and wood industry. 相似文献
9.
Sylvie Pažoutová Petr Šrůtka Jaroslav Holuša Milada Chudíčková Miroslav Kolařík 《Mycological Progress》2010,9(4):501-507
The inconspicuous inner-bark parasite Obolarina dryophila is reported from wood of Quercus petraea and as an endophyte of Salix alba. In addition, viable ascospores of O. dryophila have been found in the gut of the oak bark weevil Gasterocercus depressirostris, suggesting a possible dissemination mechanism for the fungus. A phylogenetic analysis based on three genes (nrDNA, actin,
β-tubulin) placed Obolarina inside the genus Biscogniauxia as a close relative of the oak pathogens B. atropunctata and B. mediterranea. 相似文献
10.
In this study, we present the detailed molecular investigation of the ectomycorrhizal (ECM) community of Quercus petraea and Quercus robur seedlings grown in bare-root forest nurseries. In all tested oak samples, mycorrhizal colonization was nearly 100%. Morphological
observation and molecular investigations (sequencing of fungal ITS rDNA) revealed a total of 23 mycorrhizal taxa. The most
frequent and abundant fungal taxa were Hebeloma sacchariolens, Tuber sp., and Peziza sp.; from the detected fungal taxa, 20 were noted for Q. petraea and 23 for Q. robur. Depending on the nursery, the species richness of identified ECM fungal taxa for both oak species ranged from six to 11
taxa. The mean species richness for all nurseries was 5.36 and 5.82 taxa per Q. petraea and Q. robur sample, respectively. According to the analysis of similarity, ECM fungal communities were similar for Q. petraea and Q. robur (R = 0.019; p = 0.151). On the other hand, detected fungal communities were significantly different between nurseries (R = 0.927; p < 0.0001). Using the Spearman rank correlation, it was determined that the ectomycorrhizal diversity (in terms of richness,
the Shannon diversity, evenness, and Simpson dominance indices) is significantly related to the soil parameters of each nursery.
We conclude that individual nursery may be considered as separate ecological niches that strongly discriminate diversity of
ECM fungi. 相似文献
11.
Concurrent measurements of heat pulse velocity and ultrasound acoustic emission were performed on the trunks of adult Quercus petraea plants under different water stress conditions. On the trunk section of the plants the wood density was measured non-destructively using a mobile computer tomograph which measures the attenuation of a collimated beam of radiation which traverses the trunk. By scanning the trunk in different directions, it is possible to map wood density in the section. As wood density is strictly correlated with water content, this method allows evaluation of the water content in the trunk section and the water conditions in the different parts of the section. The computer-tomograph technique is non-invasive and is not influenced by climatic fluctuations. A close agreement was found between wood density and heat pulse velocity; the relationship between these two parameters and ultrasound acoustic emission is discussed. Trunks of sessile oak appear well suited as water storage reservoirs playing an important role in tree survival during extended periods of low soil water availability, especially in the context of global climatic change. Here the computer-tomograph methodology is described and suggestions arc made for further research development. 相似文献
12.
The functional xylem anatomy and the hydraulic conductivity of intact and treated branch junctions of the diffuse-porous
sugar maple (Acer saccharum Marsh.) were compared to those of the ring-porous black oak (Quercus velutina Lam.). Maple shoots possessed greater growth intensity than those of oak. The extensive growth of the maple trees resulted
in about a two-fold increase in xylem production in the maple branches. Branches were altered by removing a patch of bark
from the base of a branch (near a junction) leaving a bridge of bark on the upper or lower side of the branch. The experimentally
treated branch junctions revealed that, in oak, most (up to 92%) of the water flows in the lower side of a branch, where most
of the large vessels occurred. In maple, most of the conductive tissue was observed to form in the upper side of the branches,
which was equally or more conductive than the lower side. A treatment of longitudinal, parallel scratches in the bark-bridge,
which reduced earlywood vessel width, substantially decreased conductivity (to only 15%) in oak, but had no effect on conductivity
in maple. In maple, such wounding stimulated more wood formation and increased conductivity. In both trees, a narrow bridge
at the junction induced more wood formation and higher conductivity in the branch. The mechanisms controlling wood formation
and water flow in branch junctions of ring- and diffuse-porous trees are discussed.
Received: 14 February 1996 / Accepted: 27 May 1996 相似文献
13.
Conservation of 16 nuclear microsatellite loci, originally developed for Quercus macrocarpa (section Albae), Q. petraea, Q. robur (section Robur), and Q. myrsinifolia, (subgenus Cyclobalanopsis) was tested in a Q. infectoria ssp. veneris population from Cyprus. All loci could be amplified successfully and displayed allele size and diversity patterns that match
those of oak species belonging to the section Robur. At least in one case, limited amplification and high levels of homozygosity support the occurrence of “null alleles” caused
by a possible mutation in the highly conserved primer areas, thus hindering PCR. The sampled population exhibited high levels
of diversity despite the very limited distribution of this species in Cyprus and extended population fragmentation. Allele
sizes of Q. infectoria at locus QpZAG9 partially match those of Q. alnifolia and Q. coccifera from neighboring populations. However, sequencing showed homoplasy, excluding a case of interspecific introgression with
the latter, phylogenetically remote species. Q. infectoria ssp. veneris sequences at this locus were concordant to those of other species of section Robur, while sequences of Quercus alnifolia and Quercus coccifera were almost identical to Q. cerris. 相似文献
14.
Fabian Daniel Meyer Jens Paulsen Christian Körner 《Trees - Structure and Function》2008,22(4):463-473
On 26 December 1999, the windstorm “Lothar” hit large parts of western and central Europe. In Switzerland, windthrow losses
reached 12.7 Mio m3 of timber, corresponding to 2.8 times the annual national timber harvest. Although these exceptional losses were due to extreme
peak velocities, recent changes in tree nutrition may have increased forest susceptibility. Previous controlled environment
experiments revealed that wood density (associated with wood stiffness) tends to increase in elevated CO2, and to decrease when N-availability is enhanced (e.g., by soluble N-deposition). Such changes in wood quality could theoretically
influence the risk of wind damage. We used the “Lothar” windstorm as a “natural experiment” to explore links between damage
and wood properties. In 104 windthrow sites across the Swiss Plateau, more than 1,600 wood cores from (1) broken, (2) uprooted
and (3) still standing (not damaged) spruce trees (Picea abies) were collected in February and March 2000. Wood properties, treering width and chemistry of the wood samples were analysed.
Broken trees showed wider treerings in the decade 1990–99 compared to non-broken trees (either uprooted or undamaged trees).
Broken trees also showed lower non-structural carbohydrate (NSC) concentration in sapwood, reflecting active structural carbohydrate
sinks associated with fast growth. There was also a trend for higher tissue N-concentrations in broken trees. No significant
differences between damage types were found in wood density and wood shrinkage during desiccation. We conclude that stem breakage
risk of P. abies is associated with a stimulation of growth in the past decade and with changes in tree nutritional status. However, the risk
for windthrow of whole spruce trees (uprooted but not broken) was not related to the studied wood parameters. 相似文献
15.
In Mediterranean-type ecosystems, seasonal dimorphism is an adaptive strategy aimed to save water by developing brachyblasts
with xeromorphic summer leaves as opposed to dolichoblasts with more mesomorphic winter leaves. The aim of this study was
to analyse the anatomical properties of 1-year-old twigs of Cistus incanus subsp. incanus, a seasonally dimorphic shrub, to highlight properties allowing its adaptation to the Mediterranean environment. A more specific
purpose was to verify the occurrence of seasonal dimorphism in wood anatomy in order to understand: (a) whether and to what
extent the traits of efficiency/safety of water transport are expressed in brachyblasts and dolichoblasts, and (b) the effects
on the formation of growth ring boundaries in wood. Our overall analysis showed that anatomical features of branches in C. incanus are designed to: (a) protect from desiccation by developing thick cuticle and suberized epidermal and sub-epidermal layers;
(b) defend the plant from predators by accumulating phenolics; and (c) regulate water transport through the development of
specific wood anatomy, according to the season, thus optimising properties of efficiency/safety. Regarding the latter point,
our results indicated that brachyblast wood is safer than dolichoblast wood insofar as it has narrower and more frequent vessels;
measurement of other specific anatomical traits, such as vessel wall thickness, suggested that brachyblast wood has a higher
resistance to implosion due to drought-induced embolism. Finally, peculiar anatomy of brachyblast and dolichoblast wood results
in the formation of so-called false rings. Hence, wood rings in C. incanus should be considered to be “seasonal” rather than “annual”. 相似文献
16.
The loculoascomycete Moristroma quercinum sp. nov. and Moristroma japonicum sp. nov. are described from Northern Europe (Denmark, Lithuania, Sweden) and Japan, respectively. M. quercinum is reported from wood of Quercus robur and Q. petraea, and M. japonicum is reported from wood of Quercus mongolica var. grossoserrata. Ascostromata of both species were found on hard heartwood of attached or shed branches. The two new species differ from
the type species of the genus, M. polysporum, by the presence of pycnidia, and by the size of ascostromata, asci and ascospores. Drawings illustrate ascostromata, pycnidia,
asci, hamathecium and ascospores of the two new species. A phylogenetic analysis suggests that Moristroma belongs to the Chaetothyriomycetes, rather than to the Dothideomycetes as previously suggested. 相似文献
17.
Two lignicolous species ofMycena (Agaricales, Basidiomycetes) are described and illustrated from eastern, Japan:Mycena auricoma sp. nov., forming ephemeral coprinoid basidiomata and belonging to sectionRadiatae, was found on a dead fallen twig ofQuercus serrata. It appears to close to a Malaysian species,“Trogia” crinipelliformis. Mycena spinosissima in sectionSacchariferae, new to Japan, was collected from dead bark ofAphananthe aspera, a dead fallen inflorescence ofCryptomeria japonica, and a dead fallen twig ofQuercus serrata. 相似文献
18.
Somatic embryogenesis was induced in expanding leaf explants excised from epicormic shoots forced from branch segments taken at four different times of year from a mature oak (Quercus robur L.). Branch segments 2–4 cm in diameter produced most shoots when collected in March. Somatic embryos were induced on explants derived from branches of all collection dates, although collection in November seemed to afford the best results. Germination and conversion ability of embryos of embryogenic lines derived from six oak trees depended heavily on genotype, conversion rates ranging from 0 to 70%. RAPD analyses found no evidence of genetic variation either within or between the embryogenic lines established from three of these trees, or between these lines and the trees of origin, or between somatic embryo derived plantlets and the trees of origin. The embryogenic system used in this study appears to be suitable for true-to-type clonal propagation of mature oak genotypes. 相似文献
19.
Jesús Rodríguez-Calcerrada Jose Alberto Pardos Luis Gil Peter B. Reich Ismael Aranda 《Plant Ecology》2008,195(2):273-285
In order to understand better the ecology of the temperate species Quercus petraea and the sub-Mediterranean species Quercus pyrenaica, two deciduous oaks, seedlings were raised in two contrasting light environments (SH, 5.3% full sunlight vs. HL, 70% full
sunlight) for 2 years, and a subset of the SH seedlings were transferred to HL (SH–HL) in the summer of the second year. We
predicted that Q. pyrenaica would behave more as a stress-tolerant species, with lower specific leaf area (SLA), allocation to leaf mass, and growth
rate and less responsiveness to light in these metrics, than Q. petraea, presumed to be more competitive when resources, especially light and water, are abundant. Seedlings of Q. petraea had larger leaves with higher SLA, and exhibited a greater relative growth rate (RGR) in both SH and HL. They also displayed
a higher proportion of biomass in stems (SMF), and a lower root to shoot ratio (R/S) in HL than those of Q. pyrenaica, which sprouted profusely, and had higher rates of photosynthesis (An) and stomatal conductance (gwv), but lower whole-plant net assimilation rate (NAR). On exposure to a sudden increase in light, SH–HL seedlings of both species
showed a short period of photoinhibition, but fully acclimated photosynthetic features within 46 days after transference;
height, main stem diameter, RGR and NAR all increased at the end of the experiment compared to SH seedlings, with these increases
more pronounced in Q. petraea. Observed differences in traits and responses to light confirmed a contrasting ecology at the seedling stage in Q. petraea and Q. pyrenaica in consonance with differences in their overall distribution. We discuss how the characteristics of Q. petraea may limit the availability of suitable regeneration niches to microsites of high-resource availability in marginal populations
of Mediterranean climate, with potential negative consequences for its recruitment under predicted climatic changes. 相似文献
20.
The developmental morphology of Terniopsis malayana, an unusual aquatic angiosperm from Thailand, was examined. A unique vegetative structure called the “ramulus” arises endogenously
in the root tissue. The ramulus has an actively growing apical meristem. The ramulus branches several times to form a “ramulus
complex” consisting of up to six ramuli, which are distichously arranged in almost a single plane. In a ramulus complex, the
new ramulus (ramulus branch) is initiated on the adaxial side of the first (the basalmost) scale in the first ramulus, but
at a site lateral to the first scale in later ramuli, suggesting that the new ramulus arises from axillary or extra-axillary
buds of the immediately older ramulus. Ramulus growth is terminated in association with the loss of the apical meristem, and
its axillary or extra-axillary buds begin to grow to form the next new ramulus instead. The flower occurs in place of the
youngest ramulus, when reproductive. It seems likely that the Terniopsis ramulus and its scale are comparable to the shoot and leaf, and thus a ramulus complex is interpreted as a sympodially branched
shoot. 相似文献