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1.
Sugi, Cryptomeria japonica D. Don, is one of the most important forestry species in Japan. We here report the development of 217 CAPS markers derived from sugi cDNA libraries. More than half of a set of STS markers produced could be converted into CAPS markers using restriction endonuclease analysis. Of the 217 markers, 71 showed different patterns of polymorphism when they were digested with a range of endonucleases and, in total, 347 polymorphisms were found in the various combinations of STSs and endonucleases. When the polymorphisms gave co-dominant patterns in a screening program, the polymorphic information content (PIC) used to evaluate the value of the polymorphisms was relatively high (0.33, on average) compared to the information yielded by commonly used markers, like isozymes. The results of a segregation analysis suggest that approximately 80% of the CAPS markers developed here will show co-dominant inheritance. From logistic regression analysis, the polymorphisms were found to be associated more strongly with intron than with exon regions. Sixty two markers were subsequently mapped on the previously reported linkage map, 15 of which showed abnormal segregation, presumably caused by linkage with lethal factors. Received: 7 December 2000 / Accepted: 23 January 2001  相似文献   

2.
 Quantitative traits, including juvenile growth, flower bearing and rooting ability, of a woody plant species, Cryptomeria japonica D. Don, were analyzed in a three-generation pedigree with 73 F2 progenies using a linkage map with 85 genetic markers (72 RFLP, 11 RAPD, one isozyme and one morphological loci). A cluster of quantitative trait loci (QTLs) related to juvenile growth and female flower bearing was detected on linkage group 2. Some of the influence of this cluster could be attributed to pleiotropic effects of a dwarf locus located in its vicinity. QTLs related to male and female flower bearing were detected at different locations and showed different effects from each other, suggesting that the genetic systems controlling male and female flowering are different. No large QTL affecting rooting ability was detected in the material analyzed in this study. Received: 15 December 1997 / Accepted: 4 February 1998  相似文献   

3.
A synthetic phenylglycoside (beta-GlcY) that interacts specifically with arabinogalactan-proteins (AGPs), a class of plant cell surface proteoglycans, has been used to study the spatial distribution of AGPs in the xylem tissue of radiata pine. These studies demonstrated that AGPs were located in the compound middle lamella (CML) of the newly developed tracheid. Abundant, low salt extractable AGPs were purified from xylem tissue. Monosaccharide analysis showed that arabinose and galactose were the main sugars present. Linkage analysis showed that most of the arabinose was in the furanose form, at the terminal and 5-linked positions, and the majority of the galactose was in the pyranose form at the terminal 3-, 6- and 3,6-linked positions; a linkage composition typical of AGPs. The AGPs had an abundance of characteristic amino acid residues including alanine, hydroxyproline, proline, and serine. Separation of the AGPs using reversed-phase high performance liquid chromatography showed that one main fraction was eluted, which tested positive for AGPs by dot-blot analysis using anti-AGP monoclonal antibodies. Sedimentation equilibrium analysis showed that this main fraction contained a 226 kDa species. We have examined the function of AGPs in tracheid differentiation using an established radiata pine callus culture system grown on media containing beta-GlcY. The effect of beta-GlcY on the cultures was to reduce the overall tracheid differentiation rate in a concentration dependent manner, ultimately resulting in cell death. These studies provide further evidence that AGPs play an important role in tracheid differentiation, and thus may be an important biological target for improving wood quality.  相似文献   

4.
 Most coniferous species exhibit severe inbreeding depression. Selfed individuals usually have decreased viability, reduced vigour and morphological defects. The number of filled seeds after selfing Pinus radiata plus tree 850.55 was 48% that of the outcrossing, and 26.1% of the selfed seedlings died at an early stage. The segregation of 172 markers (covering 56% of the genome) in selfed progenies of radiata pine plus tree 850.55 was studied. Based on the segregation ratio of the markers, genes associated with inbreeding depression on viability were identified (P<0.05). Using the Expectation/Conditional Maximization (ECM) algorithm, we estimated the location, degree of dominance and selection coefficient of viability genes. Nine viability genes were discovered. Seven of them appeared to be dominant and one partially dominant (degree of dominance=0.4). The other gene was overdominant or pseudo-overdominant, with selection coefficients for the two homozygotes of 0.4 and 0.42, respectively. Of the genes showing dominance or partial dominance, seven were sub-lethal with selection coefficients ranging from 0.55 to 0.79; one gene (SDPr), which was responsible for seedling death within the first month following germination, was lethal. Received: 13 December 1998 / Accepted: 28 December 1998  相似文献   

5.
Using constant heat sap flow sensors, xylem water fluxes in ten tree species and two liana species were monitored for 5–10 days during the beginning of the wet season in May, 1993. For a subset of the trees, a branch was also monitored at the top of the crown for 5 days. Xylem flux (J S) was related diurnally in all plants to vapor pressure deficit (D) measured within the upper-third of the canopy, and to incoming shortwave radiation R S above the canopy. Cross-correlation analysis was used to estimate time lags between diurnal patterns of J S and D or R S, and between J S in stems and branches. The maximum correlation coefficient from cross-correlation of J S with R S (range=0.57–0.92) was often higher than the maximum of J S with D (range=0.43–0.89), indicating that diurnal J S was more dependent on R S than D. Time lags (lag corresponding to maximum correlation) of J S at stem-base with D was shorter (0–45 min) than with radiation (5–115 min), highly variable within a species, and uncorrelated to the height or exposure of tree crowns or liana in the canopy. On a stand level, not accounting for the diel lag between stem sap flux and canopy flux resulted in errors in estimated canopy transpiration of up to 30%. Received: 19 October 1998 / Accepted: 8 June 1999  相似文献   

6.
Gao M  Showalter AM 《Planta》2000,210(6):865-874
 Arabinogalactan-proteins (AGPs) are highly glycosylated cell surface proteins that are thought to function in plant growth and development. The developmentally regulated expression of LeAGP-1, a novel and major AGP in tomato, was examined in different organs and tissues of tomato (Lycopersicon esculentum Mill. cv. UC82B) plants with an anti-peptide antibody (i.e. the PAP antibody) directed specifically against the lysine-rich subdomain of the LeAGP-1 core protein. During cell differentiation in tomato plants, LeAGP-1 was associated with cell wall thickening and lignification of particular cell types. Specifically, LeAGP-1 was detected in secondary wall thickenings of maturing metaxylem and secondary xylem tracheary elements in roots and stems, and in thickened cell walls of phloem sieve elements. However, LeAGP-1 was also present in thin-walled, cortical parenchyma cells of seedling roots as well as thick-walled collenchyma cells in young stems, both of which are not lignified. Based on these observed patterns, possible roles for LeAGP-1 in plant growth and development are discussed. Received: 17 August 1999 / Accepted: 7 October 1999  相似文献   

7.
An investigation was made of the effects of tracheid dimensions on variations in the maximum density of Picea glehnii Mast., which were associated with climatic changes. Radial cell diameter and the thickness of the tangential cell walls of the last-formed cells in 90 annual rings of nine trees with different annual ring widths were analyzed by image analysis. Correlations between maximum density and tracheid dimensions indicated that changes in maximum density were due mainly to changes in cell wall thickness of the last-formed cells in annual rings and were not due to changes in radial cell diameter. The effects of climatic factors on tracheid dimensions were examined by application of dendroclimatological techniques. A chronology of cell wall thickness that represented common signals among trees was established. Simple correlation and response function analyses of the chronology revealed that cell wall thickness was influenced positively by summer temperature and negatively by precipitation in August, and these responses were similar to those of maximum density. The study demonstrated that variations in maximum density were due to variations in the cell wall thickness of the last-formed cells, which varied depending on the weather in summer. Received: 8 February 1999 / Accepted: 7 October 1999  相似文献   

8.
 Methods to present three-dimensional (3D) and time series of 3D datasets (4D) are demonstrated using the recent advances in confocal microscopy and computer visualization. The process of cell sorting during tip formation in the slime mould Dictyostelium discoideum is examined as an example by in vivo confocal microscopy of spectrally different green fluorescent protein (GFP) variants as reporters of cell-type specific gene expression. Also, cell sorting of the co-aggregating slime mould species D. discoideum and D. mucoroides is observed using a GFP variant and a spectrally distinguishable fluorescent vital stain. The confocal data are handled as 3D and 4D datasets, their processing and the advantages of different methods of visualization are discussed step by step. Selected sequences of the experiments can be viewed on the Internet, giving a much better impression of the complex cellular movements during Dictyostelium morphogenesis than printed photographs. Received: 17 February 1998 / Accepted: 14 June 1998  相似文献   

9.
Soil respiration was measured for 2 years in an artificial gap and in an undisturbed area in a Japanese cedar (Cryptomeria japonica D. Don) forest to estimate the contribution of root respiration to total soil respiration. Measurement plots were set up at the center of the gap, the edge of the gap, the edge of the surrounding stand and within the stand. Using a small gap (2.5 m × 2.5 m) enabled us to maintain the same soil temperature and soil moisture as found in the stand. Seasonal fluctuations in soil respiration, increasing in summer and decreasing in winter, corresponded to changes in the soil surface temperature. Soil respiration in the gap site did not differ significantly from those in the stand in the first year of gap formation. However, in the second year, the minimum CO2 flux was observed at the center of the gap and the maximum at the edge of the surrounding stand. Assuming that the differences between soil respiration in the center of the gap and that in the stand were equal to the root respiration, the root respiration rate was calculated from the relationship between the root respiration rates (Rr) and the soil surface temperature (Ts) by Ln(Rr) = 0.07Ts + 3.48. The average contribution of root respiration to total soil respiration, as estimated from the soil surface temperature in the stand by using the above equation, was 49%. After taking root decomposition into consideration, the contribution of root respiration to soil respiration increased from 49 to 57%.  相似文献   

10.
Abstract Water storage and nocturnal increases in osmotic pressure affect the water relations of the desert succulent Ferocactus acanthodes, which was studied using an electrical circuit analog based on the anatomy and morphology of a representative individual. Transpiration rates and osmotic pressures over a 24-h period were used as input variables. The model predicted water potential, turgor pressure and water flow for various tissues. Plant capacitances, storage resistances and nocturnal increases in osmotic pressure were varied to determine their role in the water relations of this dicotyledonous succulent. Water coming from storage tissues contributed about one-third of the water transpired at night: the majority of this water came from the nonphotosynthetic, water storage parenchyma of the stem. Time lags of 4 h were predicted between maximum transpiration and maximum water uptake from the soil. Varying the capacitance of the plant caused proportional changes in osmotically driven water movement but changes in storage resistance had only minor effects. Turgor pressure in the chlorenchyma depended on osmotic pressure, but was fairly insensitive to doubling or halving of the capacitance or storage resistance of the plant. Water uptake from the soil was only slightly affected by osmotic pressure changes in the chlorenchyma. For this stem succulent, the movement of water from the chlorenchyma to the xylem and the internal redistribution of water among stem tissues were dominated by nocturnal changes in chlorenchyma osmotic pressure, not by transpiration.  相似文献   

11.
 In vitro somatic embryogenesis was achieved from zygotic embryo explants of a woody angiosperm species, the spindle tree, cultivated on various culture media differing in their sugar type and concentration, or in the applied osmotic potential. The highest frequency of somatic embryogenesis was obtained with a 350 mM sucrose, or a 89 mM glucose concentration in the culture medium. Experiments with culture media differing only in osmotic potential indicated that a minimal threshold osmotic potential is required to stimulate the emergence of somatic embryos. Elevated concentrations of glucose have an inhibitory effect, independent of their osmotic effect, while elevated concentrations of sucrose mainly act osmotically, stimulating the emergence of numerous somatic embryos. Received: 15 July 1997 / Revision received: 27 October 1997 / Accepted: 24 March 1998  相似文献   

12.
 We produced a monoclonal antibody, AE03, which recognized mucous granules in the basal disk gland cells in Hydra and the secreted mucus with which they stick onto substrate. AE03 also recognized atrichous isorhizas, one of the four types of nematocyst present in tentacles, and their nematoblasts present in the body column. With this monoclonal antibody, we could observe the detailed morphogenesis of the atrichous isorhiza from the beginning of its formation. The elongation and invagination processes of external tubes and correspondence between the external tubes and the thread of discharged nematocysts were confirmed. Received: 20 May 1997 / Accepted: 21 September 1997  相似文献   

13.
 The spatio-temporal variation of water potential and the corresponding changes in diameter in a woody axis cross-section have been modelled. The two-dimensional space model is based on the assumption that the water flux is regulated by Darcy’s law which leads to a diffusion type equation. This equation takes into account the water movements to and from the xylem vessels in space and time. The water potential of the vessels being given, a numerical solution provided the values of the water potential variations of the wood and peripheral elastic tissues in the woody axis cross-section throughout the day. By specifying that the predawn water potential equilibrates throughout the whole section, this study enabled us to determine a range of satisfactory values of parameters. A first validation was given by an application of the model to a peach-tree. It was performed by comparing the calculated variations in diameter of a trunk to those which were measured. In conclusion we discuss some physiological consequences of the model. Received: 25 January 1997 / Accepted: 13 October 1997  相似文献   

14.
 During the normal development of echinoids, an animal cap consisting of 8 mesomeres in a 16-cell stage embryo differentiates exclusively into ectoderm. Micromeres in an embryo at the same stage differentiate into primary mesenchyme cells (PMC) and coelomic pouch constituents. An animal cap and a quartet of micromeres were isolated from a 16-cell stage embryo and recombined to make a chimeric embryo devoid of presumptive endoderm and secondary mesenchyme cells (SMC). The PMC in the chimeric embryo were completely removed at the mesenchyme blastula stage. The PMC-depleted chimeric embryos formed an archenteron derived from the mesomeres. Some secondary mesenchyme-like cells (induced SMC) were released from the archenteron tip. A considerable fraction of the induced SMC formed the typical mesenchyme pattern after migrating into the vegetal region, synthesized skeletogenic mesenchyme cell-surface protein (msp130) and produced the larval skeleton. These findings indicate that induced SMC derived from the presumptive ectoderm have the same nature as natural SMC in both the timing of their release and their skeletogenic potential expressed in the absence of PMC. Received: 14 November 1996 / Accepted: 30 December 1996  相似文献   

15.
 The Ph1 (pairing homoeologous) gene is the major factor that determines the diploid-like chromosome behavior of polyploid wheat. This gene, which is located on the long arm of chromosome 5B (5BL), suppresses homoeologous pairing at meiosis while allowing exclusive homologous pairing. In an effort to tag the specific chromosomal region where this gene is located, we have previously microdissected chromosome arm 5BL from bread wheat and produced a plasmid library by random PCR amplification and cloning. In this work we isolated from this library a 5BL-specific probe, WPG90, and mapped it within the interstitial deleted chromosome fragments carrying Ph1 in common and durum wheat. A PCR assay of Ph1 based on WPG90 was developed that allows an easy identification of homozygous genotypes deficient for this gene. Received: 19 June 1996 / Accepted: 18 October 1996  相似文献   

16.
In the embryonic ventral neuroectoderm of Drosophila melanogaster the proneural genes achaete, scute, and lethal of scute are expressed in clusters of cells from which the neuroblasts delaminate in a stereotyped orthogonal array. Analyses of the ventral neuroectoderm before and during delamination of the first two populations of neuroblasts show that cells in all regions of proneural gene activity change their form prior to delamination. Furthermore, the form changes in the neuroectodermal cells of embryos lacking the achaete-scute complex, of embryos mutant for the neurogenic gene Delta, and of embryos overexpressing l’sc suggest that these genes are responsible for most of the morphological alterations observed. Received: 20 August 1999 / Accepted: 3 November 1999  相似文献   

17.
Summary. Taurine and glutamate were monitored by microdialysis technique during various cerebral insults: a. Application of K+ triggered a cortical spreading depression (CSD). Taurine and glutamate increased concomitantly but recovery of glutamate was faster than that of taurine. b. Application of NMDA induced also CSD but only taurine increased. c. Induction of an infarct triggered repetitive CSDs. Taurine increased rapidly whereas glutamate rose slowly starting with some delay. d. After induction of ischemia, taurine and glutamate increased after onset of depolarisation. The increase of glutamate occurred late after a small, transient increase in parallel with the depolarisation. These data suggest a close functional relationship between the changes of both amino acids. Therefore, they should be monitored together especially in clinical settings: during excitation, only taurine will increase; during overexcitation, taurine will also increase but to a higher maximum followed by a moderate rise of glutamate; after energy failure, taurine will accumulate to its highest level followed by a continuous rise of glutamate. Received January 25, 2000/Accepted January 31, 2000  相似文献   

18.
 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   

19.
 Root samples of 37 species distributed on the beach and along a successional gradient (from mobile to stabilized areas) in a tropical sand dune system on the Gulf of Mexico showed that 97% of the species were mycorrhizal. The mycorrhizal inoculum potential of the sand from several dune areas was compared using two different bioassays. Firstly, the field rate of colonization by arbuscular mycorrhizal fungi of Chamaecrista chamaecristoides seedlings transplanted to random plots in the foredunes and in the mobile area was measured. The seedlings were harvested at intervals during 3 weeks to record mycorrhizal structures. In the mobile area, no mycorrhizal colonization was observed during the experiment. In the foredunes, hyphae and external mycelium were present in 40% of the seedlings as early as 8 days after transplanting. After 15 days, arbuscules and vesicles were observed in 60 and 20% of the seedlings, respectively, and after 21 days, 100, 46 and 20% of the seedlings showed hyphae, arbuscules and vesicles, respectively. Secondly, maize seedlings were transplanted to pots previously filled with sand from the foredunes, mobile dunes, grassland and a Dyphisa robinoides shrub area. After 1 month, the lowest mycorrhizal inoculum potential was recorded for the mobile dunes and the highest for the shrub area. As expected, mycorrhizal inoculum potential increased with dune stabilization. Accepted: 17 July 1996  相似文献   

20.
 Thickets of Rhododendron maximum (Ericaceae) (Rm) in the southern Appalachians severely limit regeneration of hardwood and coniferous seedlings. Experimental blocks were established in and out of Rm thickets in a mature, mixed hardwood/conifer forest in Macon County, N.C. Litter and organic layer substrates were removed, composited and redistributed among plots within the blocks (except for control plots). Seedlings of northern red oak (Quercus rubra) and eastern hemlock (Tsuga canadensis) were planted in the plots and harvested at the end of the first and second growing seasons. Litter manipulation had no effect on total mycorrhizal colonization, but the distribution of Cenococcum geophilum mycorrhizae was altered. After the first year, percent mycorrhizal colonization of hemlocks not in Rm thickets (62%) was at least three times higher than in Rm thickets (19%), and the ramification index (no. of mycorrhizae cm–1) had increased by more than a factor of four (2.83 versus 0.61). In addition, colonization of 1-year-old hemlocks by C. geophilum was significantly higher within blocks with (10.4%) than without (4.6%) Rm. Differences in mycorrhizal colonization, ramification indices and colonization by C. geophilum were absent or less pronounced on 2-year-old hemlocks and 1- and 2-year-old oak seedlings. The biomasses of first year oak roots and shoots and second year shoots were 50% less in Rm thickets. Biomasses of first year hemlock roots and second year shoots were also reduced. Mycorrhizal parameters were correlated with some growth parameters only for hemlock seedlings, but did not explain most of the variation observed. Accepted: 12 February 1999  相似文献   

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