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1.
Matings of male-sterileC. japonica and fertile eliteC. japonica, as well as backcross seedlings of male-sterile trees, were carried out to clarify the genetic trait of male sterility of theC. japonica. The seeds from male-sterileC. japonica were germinated in an incubator and grown them in the greenhouse between 1994 and 1997. The seedlings were treated with 100 ppm gibberellin at early July 1994 and early July 1995 to promote the formation of male flowers. In the middle of January 1995, the male flowers of all seedlings were examined under the microscope to confirm the production of pollen. In January 1996, pollen did not developed in to the male flowers from the seedlings between the fertiled elite and backcrossC. japonica. In January 1997, all seedlings of eliteC. japonica produced pollen in their male flowers; however, pollen did not developed in 55 out of 120 backcrossed seedlings. This evidence suggests that the heredity pattern of male sterility inC. japonica is nuclear male sterility controlled by a pair of recessive genes.  相似文献   

2.
The electric conductivity of pollen life-force and male flowers ofLarix olgemis on condition of low temperature adversity has been respectively measured by means of fluorescent dying method and conductivity method in 1992 and 1994. The results indicate that: (1) If the same clonal pollen is treated at equal time at different low temperatures, there are significant differences in pollen life-force, the pollen life-force is the largest between O°C and -3°C, in higher or lower temperature range, the pollen life-force will decrease. The measurement of electric conductivity of male flowers proves that the low temperature of below -3°C is the main reason that the cell membrane is damaged and the pollen life-force decreases. (2) The same clonal pollen life-force at the same low temperature will gradually decrease with the increasing of frozen time. Its main reason is that suffocation and losing body fluid result in the damage of cell membrane, the measurement of electric conductivity of male flowers can prove that. (3) If pollen is treated with the same low temperature, the humidity will be the main factor of affecting pollen life-force. (4) There are significant differences inLarix olgensis’s resistance against low temperature in its different growth stage, the male flower’s resistance of near pollen spreading period is low. (5) The resistance is different within clones. (6) The resistance against low temperature ofLarix can be increased by means of chemical treatment.  相似文献   

3.
Pollen flow from external sources is important for the conservation of tree species in fragmented forests or small populations, because it can be sufficient to prevent differentiation among them, and appears to be able to prevent the loss of their genetic diversity through genetic drift. In this study, we examined the genetic heterogeneity of pollen pools accepted by each Quercus semiserrata seed parent at the Khun Wang Royal Agriculture Research Center, Thailand, both within and among two mast fruiting years (2005 and 2007), using paternity analysis and analysis of molecular variance (AMOVA). The mating systems of the trees were also examined using the multilocus mating system model (MLTR), after determining the genotypes at eight microsatellite loci of 26 seed-trees and 435 seeds from 8 seed-trees in the 2 mast fruiting years. The average distance of effective pollen flow within the plot was estimated to be 52.4 m, and 95% of effective pollen was dispersed within 200 m, indicating that effective pollen flow is highly localized and that most effective pollen is contributed by near-neighbor trees. The proportion of effective pollen that immigrated from external sources was estimated to be 26.2%. The AMOVA analysis based on the pollen haplotypes showed that the pollen pools, both total and for each reproductive year, significantly genetically differed among the seed parents. Using a mixed mating model, the estimate of biparental inbreeding for the total population (tm − ts) was 0.013, indicating that a low proportion of mating occurred among close relatives. The effective number of pollen donors (Nep) was estimated to be 9.987 using the TwoGener model, or 10.989 using the mixed mating model. The effective number of pollen donors of seeds was higher in the mast fruiting year 2005 than in the other examined year, 2007. Consequently the allelic richness and genetic diversity of seeds produced in 2005 were higher than those produced in 2007. Overall, the results show that high outcrossing rates, high levels of gene flow from other populations and heterogeneity in the pollen received by an individual may enhance the ability of populations to maintain effective population sizes. Therefore, these processes may be sufficient to prevent loss of genetic diversity through genetic drift of Q. semiserrata at this study site.  相似文献   

4.
Genus Eurydoxa Filipjev in China is reviewed and noted for the first time. Based on the present study, two species are recognized, including rhodopa Diakonoff and advena Filipjev. All available information for the species is reviewed and provided.  相似文献   

5.
The common ragweed, Ambrosia artemisiifolia is a widespread invasive weed species in Europe. In order to estimate the deteriorative effect of native arthropods on the invasive ragweed the effect of three indigenous aphid species on plant development and pollen production was studied. Common ragweed plants grown in a greenhouse were artificially infested with five apterous individuals of either Aphis fabae, Brachycaudus helichrysi or Myzus persicae at the 4-leaf stage. Feeding by all three aphid species over a 5-week period significantly reduced plant height, the number of male inflorescences, the length of racemes, pollen emission and plant dry mass. Brachycaudus helichrysi produced the largest colonies, followed by A. fabae and M. persicae. In a host plant choice test, B. helichrysi showed significant preference for ragweed over sunflower, whereas A. fabae preferred sunflower and M. persicae did not show any preference. In a field experiment, the growth rate of A. fabae on caged ragweed plants was similar to that in the greenhouse, but the final numbers of B. helichrysi and M. persicae after 30 days was ten and seven times lower than under greenhouse conditions, respectively. On exposed field plants, B. helichrysi was more abundant than other species. However, no aphid species affected the height or dry mass of either caged or exposed plants during a 30-day period. Under controlled conditions aphids effectively hampered development and pollen production of ragweed, however, under Hungarian field conditions the development of ragweed was much more dynamic, therefore no deleterious effect of aphid feeding occurred.  相似文献   

6.
Pollen development and floral morphology of Populus pseudo-simonii were investigated by stain-squashing and anatomical techniques. It took approximately 16 days for the pollen to develop from pollen mother cells to mature pollen in the greenhouse. Meiosis of pollen mother cells was regularly applied and completed by a process of simultaneous cytokinesis. Pollen development was considerably asynchronous. The meiotic division was initiated at the bulgy middle position of the flower bud and proceeded towards the tip and base of the bud. The number and size of the nucleoli varied during pollen development and at most eight nucleoli formed in each daughter nucleus at the meiotic telophase, suggesting a paleopolyploid origin of the genus Populus. An association between floral morphology and pollen development was found and the ratio of width to length of flower buds or catkins presented an S-shaped curve related to pollen development as a function of time. The investigation on the pollen development and floral morphology of P. pseudo-simonii is important for further cross breeding programs of the section Tacamahaca.  相似文献   

7.
An Olethreutine speciesCymolomia hartigiana (Saxesen, 1840), attacking toAbies nephrolepis Max., is reported for the first time from Daxing'anling, Heilongjiang, China. The morphological characteristics are briefly re-described with illustrations. Also its damage and biology are noted. Foundation item: This study was carried out under the financial support by KOSEF (Korea Science & Engineering Foundation) with the program of “Korea and China Young Scientist Exchange Program” (2002–2003). Biography: *BYUN Bong-Kya (1963-), male, Ph.D., Researcher in Korea National Arboretum, Korea. Responsible editor: Chai Ruihai  相似文献   

8.
The transgenic rice lines Kemingdao 1 (KMD1) and Kemingdao 2 (KMD2) contain a synthetic cry1Ab gene derived from Bacillus thuringiensis Berliner and are highly resistant to rice stem borers and foliage-feeding lepidopterans. Propylea japonica (Coleoptera: Coccinellidae) is an important predator of rice insect pests; it also uses rice pollen as a food source under natural conditions. In the present study, the effects of KMD1 and KMD2 pollen expressing Cry1Ab protein on the fitness of P. japonica were assessed in the laboratory. P. japonica larvae and adults were provided with the following four diets: KMD1 pollen with the aphid Myzus persicae, KMD2 pollen with M. persicae, nontransgenic Xiushui 11 (parent variety of KMD1 and KMD2) pollen with M. persicae, and M. persicae only (KMD1–pollen, KMD2–pollen, XS11–pollen, and aphid treatments, respectively). The results showed that the longevity of female adults in the KMD1–pollen treatment was significantly lower than that in the XS11–pollen treatment, but was not significantly different from that in the KMD2–pollen and aphid treatments. Newly emerged males in the KMD2–pollen treatment were evidently less vital than those in the XS11–pollen treatment, but not significantly different from those in the KMD1–pollen and aphid treatments. The development, survival and reproduction indices for the three pollen treatments did not differ significantly from one another. In short, Bt toxin expressed in Bt rice pollen had no evident negative impacts on P. japonica fitness when the pollen was used as a food by this beetle.This revised version was published in March 2005 with corrections to the names of the authors.  相似文献   

9.
After the treatment of pollen oflarix olgensis at the different low temperature, the pollen vitality was observed by using fluorescent staining method. Several conclusions were obtained: 1) 0°C–3°C is the best temperature range for storing pollen ofLarix olgensis. 2) At the same temperature, humidity is the key factor influencing the pollen vitality. 3) Different clones shows different resistance to low temperature. Among the ten clones 2# clone shows the highest resistance.  相似文献   

10.
In honeybee, Apis mellifera, colonies infested with larval and adult small hive beetles (SHB), hive material, and in particular honey, tends to ferment, probably due to SHB-associated yeasts such as the predominant Kodamaea ohmeri. Here, we test the effects of organic acids on K. ohmeri and on SHB-infested honey/pollen combs. Organic acids were applied at standard concentrations used by beekeepers to control other pests. In laboratory tests, the growth of K. ohmeri was significantly inhibited by lactic, formic and acetic acids. Treatments of SHB-infested honey/pollen combs (N = 18 colonies) with acetic acid significantly increased mortality of adult SHB and treatments with formic acid significantly reduced larval infestation. Our data suggest that treatment of honeybee colonies and storage rooms with organic acids could also help in reducing SHB damage.  相似文献   

11.
Starch-gel electrophoresis was used to resolve nine polymorphic enzyme loci from leaf tissue collected from 20 Korean populations ofEurya japonica in order to determine differences in allele frequencies between male and female trees. In addition, 84 adults were sampled and mapped in a population located on Naenaro Island in Korea to examine spatial genetic structure using spatial autocorrelation analysis. Allele frequencies between males and females gave few contribution to the genetic structuring within populations. Only nine (5%) of 180 cases were significantly different from both sexes in allele frequencies. On the other hand, Moran'sI was significantly different from the expected value in 31 (23.5%) of 132 cases. In the shortest distance (0<5m),I was significantly positive in 10 (22.7%) of 44 cases. The results indicate that a significant small scale genetic structure was detected in the population and patch widths were inferred to be approximately 5–7 m. A nonrandom distribution of genotypes may be indicative of restricted gene flowvia seed and pollen dispersal, and patchy establishments of genetically distinct individuals. These factors are responsible for shaping population genetic structure ofE. japonica.  相似文献   

12.
Fredericksen  T.S.  Justiniano  M.J.  Mostacedo  B.  Kennard  D.  McDonald  L. 《New Forests》2000,20(1):45-64
A comparative study of the regeneration ecology ofthree lesser-known leguminous timber species wasconducted in the seasonally dry forests of SantaCruz, Bolivia to determine species regenerationstrategies and make silvicultural recommendationsfor these species. The study included arepresentative from each subfamily of Leguminosae:Anadenanthera colubrina (Vell. Conc.) Benth.(Mimosaceae), Copaifera chodatiana Kunth.(Caesalpinaceae), and Centrolobium microchaeteC. Martius (Fabaceae). After production in themid-late dry season, seeds of all species sufferedhigh (>30%) rates of predation. For seedssurviving predation, Anadenanthera germinatedwithin three days after the first rains and a highgermination capacity (82%), but most seedlings diedfrom inadequate light or during subsequent periodsof drought. Copaifera germinated more slowlybut had high germination capacity (85%). Centrolobium had very low germination capacity(4%) and germinative energy. Most successfulregeneration of Centrolobium occurred viasprouting from damaged roots on or near loggingroads where it had a density of 261 root sprouts/ha.Anadenanthera regenerated best from seedin areas with soil disturbance or burning. Theregeneration of these species will likely increaseunder more intensive logging and/or post-harvestcompetition control treatments in logging gaps. Themore shade-tolerant Copaifera is most suitedto the current regime of light selective logging,but all three species are likely to be responsive topost-harvest competition control treatments. Impacts of controlled and natural fire were mixed,but generally seedling regeneration and growth wereeither not significantly affected or were increasedby fire.  相似文献   

13.
The fresh pollen vitality,the effect of different storage conditions on the pollen vitality,and the difference of vitality among the species of seven species of Syringa were determined in Shenyang,China.The results indicated that the pollen vitality (81.5%) of Syringa villosa was the highest among the seven tested species,followed by S.microphylla and S.meyeri,and that of S.oblata var.affinis was the lowest.The low temperature was the best condition for storage of pollen of Syringa,and the most proper temperature for the storage was 0-2℃.The storability of S.microphylla was the best of all,and it could be stored over 60 days at the temperature of 0-2℃,next was S.villosa and S.meyeri.  相似文献   

14.
The results of the monitoring of Thysanoptera species on cultivated plants in Slovenia (2000–2001), Croatia (1994–1996), and Serbia and Montenegro (1988–2003) are presented in this study. The aim of the investigation was to study the host plant distribution of the predator Aeolothrips intermedius Bagnall and its potential prey. Banded thrips were found on 30 different host plant species belonging to 16 botanical families, always in mixed populations with phytophagous or facultative phytophagous insects (including 18 Thysanoptera species). On the vegetative parts of the cultivated plants, banded thrips were found less numerous in spite of the massive population of some harmful thrips species. This indicates highly important role of pollen as alternative food for Aeolothrips intermedius.  相似文献   

15.
Horizontal starch-gel electrophoresis was used to study crude enzyme extraction from young leaves of 234 clones of Populus tomentosa Carr. selected from nine provenances in North China. Ten enzyme systems were resolved. One hundred and fifty-six clones showing unusual allozyme band patterns at locus Mdh-1 were found. Three allozyme bands at locus Mdh-1 were 9:6:1 in concentration. Further studies on the electrophoretic patterns of ground mixed pollen extraction of 30 male clones selected at random from the 156 clones were conducted and it was found that allozyme bands at locus Mdh-1 were composed of two dark-stained bands and a weak band. Only one group of the malate dehydrogenase (MDH) zymogram composed of two bands was obtained from the electrophoretic segregation of pollen leachate of the same clones. A comparison of the electrophoretic patterns one another suggested that the locus Mdh-1 coding malate dehydrogenase in diploid species of P. tomentosa was duplicated. The duplicate gene locus possessed three same alleles and was located in mitochondria. The locus duplication of alleles coding malate dehydrogenase in P. tomentosa was discovered and reported for the first time. [Supported by the “Tenth Five-year Plan” National Key Project in Science and Technology (Grant No. 2002BA515B0303) and the National “863” Project (Grant No. 2002AA241071)]  相似文献   

16.
When pine trees are invaded by pine wilt diseases, the severely infected pine trees will die and fall down, or they will be removed when found to be damaged by the disease. It gives rise to the invasion of other species in these empty niches originally occupied by pine trees, i.e., competing surrounding trees or understory shrubs will invade the empty niches during the following years. As a result, the spatial distribution and pattern of the main tree species in a pine forest will change, and a niche variety in the main population will occur. In the end, the direction of the succession and restoration of the pine forest ecosystem will be affected. In our study, a Pinus massoniana forest with the dominant shrub, Pleioblastus amarus, was invaded by pine wood nematode and was clear cut. Selecting this community as our research object, we studied the effect of the invasion of the pine wood nematode on the growth of the dominant shrub, P. amarus, in this Pinus massoniana forest. Our results show that, after the attacked pine trees were removed, the niche was occupied by Pleioblastus amarus and other shrubs, which benefited the growth of P. amarus to its climax. Growth of P. amarus at the climax stage was greater compared with the unhealthy pine forest and the control group.  相似文献   

17.
In light of a recent increase in the aphid populations on young canola (Brassica napus) in autumn in Northwestern Europe, we carried out a survey of their parasitoid species during this season. The study was done in France from 1998 to 2001 using different sampling methods. Results highlighted the presence of two main species of Aphidiinae, Aphidius matricariae and Diaeretiella rapae (and to a lesser extent Aphidius ervi) on Myzus persicae, and of D. rapae on Brevicoryne brassicae. Nine other Aphidiinae species were found occasionally as well as some Aphelinidae parasitoids and hyperparasitoids. There was no difference in parasitoid species pattern between fields in Northern and Southern France. The principal parasitoid species found in the fields were reared in the laboratory to confirm their ability to develop on the canola aphids. Aphidius matricariae and D. rapae were reared successfully on M. persicae, but a low parasitism rate was obtained for A. ervi on this aphid. This study showed that A. matricariae and D. rapae could develop on aphids on canola and that they are present naturally in canola in autumn. However, the parasitism rate is low in autumn, so the options could be the use of these parasitoids in augmentative release biological control programs or in an IPM project on canola fields during this time of the year.  相似文献   

18.
At age 5–6 years, rooted cuttings in a western hemlock (Tsuga heterophylla) clonal seed orchard received either a severe (ST) or moderate (MT) top pruning (upper 50 and 25% of live crown removed, respectively), or were left untopped (UT). Over the following 6 years, UT trees increased in height from 1.5 to 3.9 m, whereas through annual and biennial top and side pruning, MT trees grew to 2.2 m and ST trees were maintained at 2.0 m. Crown pruning had no effect on the subsequent annual production of seed or pollen cones. Spray applications of gibberellin A4/7 in years 2 and 4 of the study increased 5-fold and 2-fold the percentage of trees producing a medium and greater crop, respectively, of seed and pollen cones in each year 3 and 5.  相似文献   

19.
The aim of the study was to investigate dynamics and pattern of natural regeneration and the influence of seedbed and light on germination and initial seedling survival of Scots pine (Pinus sylvestris L.) during three growing seasons. Four 5-m2 plots in a natural Scots pine forest in central Spain were randomly established at the beginning of the regeneration process. Germination and seedling survival were recorded in 100 regeneration sampling subplots (0.25 m2) per plot, while seedbed type and the relative light intensity reaching the forest floor was characterised in 1-m2 subplots. The spatial correlations between survival, light conditions and organic matter depth were analysed through cross-variograms. Germination and survival were highly variable both within and between plots (ranging from 0 to 89%) and affected by high summer temperatures (33–35°C) in 2003. The spatial pattern characterisation of survival by Ripley’s K function showed a dominant cluster distribution. Occurrence tended to be clumped when abundance was greater than 15 seedlings, whereas for lower densities, seedlings were randomly distributed. Seedlings and herbs occupied the same sites where environmental conditions were appropriate for them to live. Spatial association occurred frequently for light and organic matter depth. Results suggested that the Scots pine seedlings in our study in central Spain preferred moderate light conditions (Global Site Factor <0.40). Thus, if this forest is to be naturally regenerated with Scots pine, the shelterwood system (whereby some mother trees are left to provide shelter for at least 5 years), along with mechanical disturbance of the seedbeds, would promote seed germination, as long as a seed source is present. However, regeneration success is affected by year-to-year conditions.  相似文献   

20.
Liu Yuxi 《林业研究》1993,4(1):11-17
After 14 year’s growth observation on the plant growth, it was found that obvious segregation appeared among the haploid pollen plants obtained from anther culture ofPopulus Xiaohei T.S. Hwany ex C. Wang et Tung in vitro. By vegetative propagation, 19 clones were selected and field contrast test was carried out. Statistical analysis result showed a significant difference in volume production. They are superior clones which could be selected from among the pollen plants for utilization. A haploid breeding procedure is suggested in the paper. This study was supported by the National Natural Science Foundation of China  相似文献   

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