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1.
Hybridization and introgression between Quercus alnifolia Poech and Q. coccifera L. is studied by analyzing morphological traits, nuclear and chloroplast DNA markers. The study site is a mixed stand on Troodos Mountains (Cyprus), and the analyzed material includes both adult trees and progenies of specific mother trees. Multivariate analysis of morphological traits shows that the two species can be well distinguished using simple leaf morphometric parameters. A lower genetic diversity in Q. alnifolia than in Q. coccifera and a high interspecific differentiation between the two species are supported by an analysis of nuclear and chloroplast microsatellites. The intermediacy of the four designated hybrids is verified by both leaf morphometric and genetic data. Analysis of progeny arrays provides evidence that interspecific crossings are rare. This finding is further supported by limited introgression of chloroplast genomes. Reproductive barriers (e.g. asynchronous phenology, postzygotic incompatibilities) might account for this result. A directionality of interspecific gene flow is indicated by a genetic assignment analysis of effective pollen clouds with Q. alnifolia acting as pollen donor. Differences in flowering phenology and species distribution in the stand may have influenced the direction of gene flow and the genetic differentiation among effective pollen clouds of different mother trees within species.  相似文献   

2.
Agroforestry is a leading alternative for food security and forest conservation. A full understanding of positive and negative, i.e. allelopathic, interactions between crops and forest trees is necessary for producing crops and conserving forests especially within the threatened Mediterranean forest ecosystems. The present study explored the allelopathic effects of green and senescent leaf and soil extracts of two agroforestry trees—Pinus halepensis and Quercus coccifera—on the germination of wheat, barley, lentil, chickpea, and fababean as the major grain crops of Jordan. Results revealed that allelopathic effects reduced seed germination of these crops. Germination reduction reached a maximum of 75% in fababean treated with green extracts of Q. coccifera and differed among crops and extract sources, but not between tree species. Comparing between green and senescent leaf and soil extract, regarding their effect on germination percentage, it was noticed that these effects were similar in some crops and were different in others. Germination responses were generally different between cereals and legumes where cereals tend to be less affected by allelopathic influences than legumes, especially fababean. We suggest using cereals such as wheat and barley in agroforestry practices in the Mediterranean region of Jordan.  相似文献   

3.
The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase (SPDS) genes derived from an apple by an Agrobacterium-mediated method. Four transgenic clones were confu'med by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.  相似文献   

4.
The Mediterranean evergreen woody plants Quercus coccifera and Pinus halepensis grow in a range of environments where selection by drought, heat and high irradiance can drive genetic and phenotypic differentiation of populations. However, the role of these stresses in filtering out maladaptive genotypes remains unknown. We hypothesize that this filtering is an important process for woody Mediterranean species due to their low phenotypic plasticity reported in previous studies. We have studied the response of saplings of Q. coccifera and P. halepensis, originating from two contrasting populations (a rock outcrop and a garrigue formation), to water stress. Isozyme characterization of genetic diversity was done to determine whether populations were genetically distinct. Water response analysis was based on water relations, gas exchange, chlorophyll a fluorescence, pigment content, antioxidant status and morphological and structural parameters. Ecotypic differentiation was found for both Q. coccifera and P. halepensis populations, with a higher population isozyme similarity and a higher frequency of dominance of a few genotypes at the rock outcrop in both the species. P. halepensis exhibited small but significant differences between populations for plastic responses to water, with lower phenotypic plasticity in saplings from the rock outcrop. Although it was not found in Q. coccifera, this pattern suggests that ecotypic differentiation rendering stress-tolerant ecotypes involves a decreased plasticity. Phenotypic plasticity was not high but it explained over 75% of the total variability among individual plants. Thus, and although evidence for ecotypic divergence was found in both the species, saplings were plastic enough to blur ecotypic differentiation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

5.
Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT50) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT50 values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC50 values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.  相似文献   

6.
This study evaluated oxalic acid accumulation and bioremediation of chromated copper arsenate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. palustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2 g/l and 3.2 g/l for these fungi, respectively. Fomitopsis palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85%, respectively; however, C. puteana remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palustris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.An erratum to this article can be found at  相似文献   

7.
Dimorphandra jorgei MF Silva (Caesalpinaceae) and Swartzia macrostachya Benth. var. riedelii Cowan (Fabaceae) are tree species from the southern Bahian Atlantic Forest, identified for the restoration of degraded areas. The objective of this research is to study their seed germination and seedling growth to develop simple methods for seedling production in small scale nurseries. Because the species have distinct dormancy and germination characteristics, the seeds were submitted to different treatments. D. jorgei seeds were immersed in hot water, scarified and stored for 12 weeks in the laboratory environment (25°C). S. macrostachya seeds were submitted to different combinations of drying and storage in the laboratory environment or refrigerator (4°C). Seedlings were submitted to two light treatments for 3 months: partial shade (52% of full sun) and full shade (12% of full sun). In D. jorgei, the highest germination occurred for scarified seeds (87%) and for seeds stored for 12 weeks and then scarified (69%). In S. macrostachya the undried control seeds had the highest germination, followed by that of the refrigeration storage treatment, without predrying (99% and 97%, respectively). The average values for the growth parameters were greater in full shade for D. jorgei, while S. macrostachya seedlings showed greater growth rates in partial shade. Two months growth is recommended before D. jorgei seedlings are of the sufficient size and leaf number for field planting. On the other hand, a period of 4 months is recommended for S. macrostachya, due to its relatively slow growth.  相似文献   

8.
Leaf morphological variation was examined in recruits of two hybridising oaks in a small sympatric area from Central Spain. Nuclear microsatellites were used to identify hybrids and assess the parental lineage. By Bayesian clustering analysis, 5% of hybrids were found. Principal component analysis was used to reduce 15 morphometric variables to four components associated with leaf size, lobation/pubescence and overall shape of the leaf. The percentage of variance due to genetic factors was evaluated through nested analysis of variance. As much as 70% of variance component was due to the factor “species” for lobation/pubescence, suggesting high adaptive value for these traits, possibly related to ecological constraints of the species. The genetic component of variance for leaf size and overall shape of the leaf was below 33%. Age and height of the recruits did not correlate with sun-leaf morphology. Competition indexes and diameter of the recruits showed slight, although significant, correlations with leaf size and lobation/pubescence components, pointing to some trade-offs between competition for light and leaf morphology of Q. petraea and Q. pyrenaica recruits.  相似文献   

9.
Fertility variation and effective number of parents were estimated in the 100 individuals from each of three plantation populations (P1, P2 and P3) of the endangered Pinus nigra. subsp. pallasiana var. pyramidata established in the Isparta–Golcuk district in southern Turkey in 1990. Potential relations between cone yield and growth characters (height, diameter at breast height, diameter at base and crown diameter) were also investigated. Large differences were found among populations and within populations for cone production and growth characters. Mean cone production was eight (ranging from 6.5 in P2 to 9.1 in P1) for the three populations. The 10 most productive individuals for cones produced 32% of the total cones in P1, 39% in P2 and 34% in P3; 21, 16 and 6 individuals, respectively did not produce any cones in the populations. According to the correlation analyses, the relation between cone yield and growth characters changed for the populations, while height, diameter at breast height and crown diameter were positively significantly correlated (r = 0.182, 0.135 and 0.209; p ≤ 0.05) with cone production for the three populations. Fertility variation was 1.81 in total of three populations, ranging from 1.72 in P3 to 3.45 in P1). Effective number of parents was 142 (55.2 of number of parents censused; 29%, P1; 49.8%, P2; 58.3%, P3).  相似文献   

10.
In order to investigate the functions of the gene PsG6PDH and the mechanisms underlying freezing tolerance of Populus suaveolens, the recombinant expression vector pET-G (pET30a-G6PDH), which contained full encoding region of PsG6PDH gene, was established. The recombinant was identified by lawn-PCR and double enzyme digestion and then transformed into expression host XA90 and induced by isopropyl-â-D-thiogalactoside (IPTG) to express 100 kD polypeptide of G6PDH fusion protein. The results showed that the expressed amount of the fusion protein culminated after 1 mmol•L–1 IPTG treatment for 4 h and that pET-G product was predominately soluble and not extra-cellular secreting.  相似文献   

11.
Trees of the family Dipterocarpaceae are the dominant trees in Southeast Asian tropical forests where they play an important ecological role and are also important commercially. An experiment was conducted to determine the effect of ectomycorrhizal fungi on the growth of dipterocarp species in peat soils. Seedlings of Shorea pinanga were inoculated with spores of two ectomycorrhizal fungi, Pisolithus arhizus and Scleroderma sp. were grown in pots containing sterilized peat soil for 7 months. The percentage of ectomycorrhizal colonization on S. pinanga exceeded 86%. Colonization of S. pinanga roots by ectomycorrhizal fungi resulted in increased shoot height, stem diameter, number of leaves, and shoot fresh and dry weight. Survival rates of S. pinanga were greater for inoculated seedlings than control seedlings. These results suggest that inoculation of ectomycorrhizal fungi can improve the early growth of S. pinanga grown in tropical forests and that this technique will accelerate the rehabilitation of degraded dipterocarp forests.  相似文献   

12.
We examined the saccharification and fermentation of meals from Acacia mangium wood, Paraserianthes falcataria wood, and Elaeis guineensis trunk. The levels of enzymatic hydrolysis of cellulose and ethanol production were highest for P. falcataria wood and lowest for A. mangium wood. Ultrasonication pretreatment of meal further increased the rates of hydrolysis and ethanol production in meal from P. falcataria wood. Through this pretreatment, hemicelluloses (xylan and xyloglucan) and cellulose were released in the meal from P. falcataria wood. Loosening of hemicellulose associations can be expected to make P. falcataria wood more useful for bioethanol production.  相似文献   

13.
Cercidiphyllum japonicum and C. magnificum are deciduous tree species that produce large numbers of sprouts. They are found mainly in riparian and/or disturbed areas. C. japonicum is distributed in the montane zone in Japan, whereas C. magnificum is distributed mostly in the subalpine zone of central Japan. However, the two species sometimes coexist, e.g., on the talus slope at the valley head of the Chichibu Mountains. We investigated differences in sprouting traits in these two species by comparing class distributions of sprout diameter at breast height (DBH) and heights of individuals on the talus slope. Sprout DBH and individual height were smaller in C. magnificum as compared to C. japonicum. Moreover, the analysis of the DBH-class distribution of each species indicated that C. magnificum had numerous small sprouts and experienced high mortality, whereas C. japonicum had fewer small sprouts and low mortality. It is likely that the sprouting traits of C. magnificum make it more adapted to severe conditions in the subalpine zone than those of C. japonicum.  相似文献   

14.
Generic equations are proposed for stem, branch and foliage biomass of individual trees in even-aged pure stands of Cryptomeria japonica, Chamaecyparis obtusa and Larix kaempferi. Biomass data was collected from a total of 1,016 individual trees from 247 stands throughout Japan, and five regression models were assessed by root mean square error, mean bias, fit index (FI), and AIC. The results show that a power equation using diameter at breast height (dbh) and height is the most suitable for all species and components. This equation is more accurate than the familiar power equation that uses ‘dbh2 height’, and it expresses the greater volume of branch and foliage mass of trees with a lower height/diameter ratio. A power equation using dbh is more reasonable for models with dbh as the only independent variable and more accurate than a power equation using ‘dbh2 height’ for estimating branch and foliage mass. Estimating error for branch and foliage mass is larger than that for stem mass, but the entire aboveground biomass can be estimated with an error of less than 19%, except in the case of small trees with dbh less than 10 cm.  相似文献   

15.
Genetic divergence was studied in selected 36 genotypes of Dalbergia sissoo Roxb. on the basis of seven morphological parameters. The divergence among genotypes was estimated by Mahalanobis method and genotypes were grouped into clusters by Tocher’s method. All the genotypes were classified into seven distinct clusters on the basis of seven morphological traits. Cluster 1 was the largest with 25 genotypes followed by Cluster 2 (four genotypes). Cluster 3, 5, 6 and 7 were the divergent clusters. The D 2 analysis revealed that D 2 value (39.42) between clone 5040 and clone 201 was recorded maximum. The intra-cluster distance ranged from 0.00 (Cluster 3, 5, 6 and 7) to 3.89 (Cluster 1), the Cluster 3 (clone 33) was the most divergent cluster with maximum inter cluster distance (13.97) with the Cluster 7. By the divergence analysis, the parents for hybridization from diverse clusters could be selected for heterotic hybrids.  相似文献   

16.
The efficiency of the botanical insecticide (BI) NeemAzal T/S (containing 1% Azadirachtin A), on the basis of azadirachtin applied in a dose of 20 g a.i. ha−1 against Brassica pod midge (Dasineura brassicae), has been monitored for 4 years. The biological efficiency of BI was compared with the efficiency of some synthetic insecticides. It was ascertained that BI was very efficient in decreasing the number of damaged oilseed rape pods (ranging from 56.5 to 85.9% compared to untreated plants) and its efficiency was comparable with synthetic insecticides based on Chloronicotinyl (Thiacloprid) and Neonicotinoid (Acetamiprid). BI’s efficiency was, in some years, even significantly higher compared to pyrethroid (λ-cyhalothrin). The high biological efficiency of azadirachtin that we ascertained was significantly reflected in increasing potential crop yields. The yield increase of azadirachtin ranged between 9.3 and 19.4% compared to the control sample. Azadirachtin showed the highest yield for the whole time of experimentation, and in some years the yield increase was significantly higher compared to some synthetic agents.  相似文献   

17.
The morphology of charcoals was investigated by scanning electron microscopy. Charcoal of Quercus variabilis was prepared in an electric furnace under nitrogen gas atmosphere at 400, 600, 800 and 1,000°C. Charring temperature greatly affects the structure of charcoal. In charcoal prepared at 400°C, most of the morphological characteristics remained relatively unchanged with the exception of the cell-wall layering. The cell walls appeared homogenous and glass-like. Above 400°C, there was an increase in cell-wall thinning and volumetric shrinkage with an increase in the charring temperature. These two factors were responsible for most of the observed changes in structure. Fracture surfaces became increasingly rough and disrupted. Vessel elements were increasingly distorted and tyloses disintegrated with increases in temperature. Parenchyma cells exhibited greater shrinkage except at the pits. This resulted in the appearance of distinctive small protuberances over the surface of the parenchyma cells. Rhomboidal calcium crystals were found to be abundant at all the temperatures studied, but at 800 and 1,000°C the crystals had a sponge-like appearance.  相似文献   

18.
Nodal segments from secondary branches of saplings of Phyllostachys bambusoides were inoculated in MS medium to assess the in vitro morphogenic response of leaf sheath through the induction to callogenesis by Picloram(4-amino-3,5,6-trichloropicolinic acid) at different concentrations of carbohydrate under the same conditions with presence or absence of luminosity.In our experiment,secondary explants were kept in MS medium containing 8.0 mg·L-1 of Picloram for the callus formation.Calluses were transferred in MS medium supplemented with sucrose,fructose and glucose(control,2%,4% and 6%).Results show that Picloram induced the callogenesis in leaf sheath.The secondary embryogenesis was formed in yellow-globular callus.The sucrose as carbohydrate source in the absence of light was more efficient to induce rhizogenesis.Glucose was more efficiency in the presence of light.Callogenic induction and further embryogenesis evidenced the competence and determination of leaf sheath cells.  相似文献   

19.
A dramatic decline in forest cover in eastern Africa along with a growing population means that timber and poles for building and fuelwood are in short supply. To overcome this shortage, the region is increasingly turning to eucalyptus. But eucalyptus raises environmental concerns of its own. Fears that it will deplete water supply, affect wildlife and reduce associated crop yields have caused many countries in the region to discourage farmers from planting this exotic. This paper is part of a series of investigations on the growth and water use efficiency of faster growing eucalyptus hybrids, which was introduced from South Africa to Kenya. The hypothesis is that the new hybrids are more efficient in using water and more suitable for the semi-arid tropics than existing eucalyptus and two popular agroforestry species. Gas exchange characteristics of juvenile Eucalyptus grandis (W. Hill ex Maiden), two eucalyptus hybrids (E. grandis × Eucalyptus camaldulensis Dehnh.), Grevillea robusta (A. Cunn) and Cordia africana (Lam) was studied under field and pot conditions using an infrared gas analyzer was used to measure photosynthetic active radiation (PAR), net photosynthetic rate (A), stomatal conductance (g s) and transpiration rate (E) at CO2 concentrations of 360 μmol mol−1 and ambient humidity and temperature. A, E and g s varied between species, being highest in eucalyptus hybrid GC 15 (24.6 μmol m−2 s−1) compared to eucalyptus hybrid GC 584 (21.0 μmol m−2 s−1), E. grandis (19.2 μmol m−2 s−1), C. africana (17.7 μmol m−2 s−1) and G. robusta (11.1 μmol m−2 s−1). C. africana exhibited high E values (7.0 mmol m−2 s−1) at optimal soil moisture contents than G. robusta (3.9 mmol m−2 s−1) and eucalyptus (5.3 mmol m−2 s−1) in field experiment and G. robusta (3.2 mmol m−2 s−1) and eucalyptus (4.2 mmol m−2 s−1) in pot-grown trees. At very low soil moisture content, extremely small g s values were recorded in GC 15 and E. grandis (8 mmol m−2 s−1) and G. robusta (14 mmol m−2 s−1) compared to GC 584 (46.9 mmol m−2 s−1) and C. africana (90.0 mmol m−2 s−1) indicating strong stomatal control by the species. Instantaneous water use efficiency ranged between 3 and 5 μmol mmol−1 and generally decreased with decline in soil moisture in pot-grown trees but increased with declining soil moisture in field-grown trees.  相似文献   

20.
The underlying principles and traditional knowledge concerning indigenous agroforestry systems (AFS) around the world have been used successfully in the design of improved systems; but lately there has been a slow-down in that effort. Recognizing that Cinderella, by analogy, refers to an individual whose attributes were unrecognized or one who unexpectedly achieved success after a period of obscurity and neglect, we propose Cinderella agroforestry systems for such underexploited and “forgotten” AFS. In order to highlight their unrecognized potentials, a few such systems that are location-specific and little-known outside their areas of existence were selected from around the world. Each selected system is unique in terms of its production, environmental, and sociocultural attributes; but none had been described in quantitative terms of ecology and production. A qualitative SWOT (strengths–weaknesses–opportunities–threats) analysis of the systems showed several commonalities among them. While sustainability, multi-functionality, and high sociocultural values are common strengths, low levels of production and lack of research- and technology inputs to improve the system are the major weaknesses. The opportunities emanating from strengths and weaknesses are also common to all the systems; and “threats” to these systems arise mostly from ramifications of government policies. Given the acknowledged role of AFS in climate-smart agriculture and the current global momentum for working with communities to better manage landscapes, learning from success stories of the Cinderella AFS could suggest models for sustainable development, and efforts in that direction should also be incorporated into global agroforestry research agendas.  相似文献   

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