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1.
MoP中。几or“qeeK“e np“enoc叱几eH“,IK几月aREPosaH“幻y3旧epe众双a日Ho一zP”朋eKa刀““nPo只。卫狱a助T nPHa月eKaTb K ee6e BH“MaH“e aHaToM阳·代PH溯oros,Ho,Ke咪a几eHH幻,八0代x flop OH“ocTaIOTc只Bce水cHe双OCTaToqHo”3y叨HH日MH· KaK H3留eTHo,HeRoTop目e eoe江eH。,0 Mop中朗orM“6e几RH”MeloTe只B Tpy仄axC·K .Hoffmann“H.weyoberzh(2572),:M:彻or”,月e丁,r”。neps目e6日几0 onoeaoaF .G,Parsons,(189斗).Qe仄yeTo及HaKoo丁Me丁。T、,qTo onoeaH“e Parson,毗八oe,aTo·qHo…  相似文献   

2.
<正>苹果蠹蛾Cydia pomonella(L.)是世界重要的苹果害虫,原产于欧洲中南部,现在已经入侵世界5大洲71个国家。该入侵昆虫1953年首次报道在中国新疆发现,目前已入侵新疆、甘肃、宁夏、内蒙古、黑龙  相似文献   

3.
Martin  A. J.  Seaby  R. M. H.  Young  J. O. 《Hydrobiologia》1994,273(2):67-75
The effect of predator and prey body size on the feeding success of the British lake-dwelling leeches Glossiphonia complanata and Helobdella stagnalis was examined in the laboratory, and any involvement of size difference between the leeches in allowing coexistence in the field assessed. G. complanata breeds in advance of H. stagnalis and maintains a body size advantage throughout their annual life-cycle. In experiments, conducted at 14 °C and a photoperiod of 16 hrs L: 8 hrs D, three size classes of leeches of each species were each exposed to each of three size classes of each of five prey species, viz. Tubifex sp., Chironomus sp., Asellus aquaticus, Lymnaea peregra and Potamopyrgus jenkinsi. For each prey species, three different types of experiments were performed: one leech exposed to four prey individuals; four leeches of the same species with sixteen prey; and two leeches of each species with sixteen prey. In the first experiment, all sizes of G. complanata were capable of feeding on all sizes of the prey types offered; the same was true for H. stagnalis with exceptions of feeding on large A. aquaticus and large L. peregra. For both species, but especially for G. complanata, there was a trend within each size class of leech for decreasing proportions of fed leeches with increasing prey size, and within each size class of prey for an increasing proportion of fed leeches with increasing leech size; however there were several exceptions to these trends. Both leeches fed extensively on Tubifex sp. but there were significant differences in the proportions feeding on other prey types; G. complanata fed more on A. aquaticus and the two snail species, and less on Chironomus, than H. stagnalis. The effect of increasing the number of leech individuals from one to four individuals, of the same or mixed species, had little effect on the proportion of leeches which had fed. It is concluded that large G. complanata will have access to large individuals of certain prey taxa denied H. stagnalis, which may lessen the intensity of interspecific competition.  相似文献   

4.
The differentiation from early spermatid to spermatozoon is described with special emphasis on the formation of the helix of chromatin and mitochondrial junctions. The role of microtubules in morphogenesis is discussed.

New observations on the role of the recently described spermatheca are presented; phagocytosis and digestion of spermatozoa are proven, and the various origins of the sperm found in the spermatheca are specified.  相似文献   

5.
D. J. Price 《Genetica》1975,45(4):497-508
Chiasma frequency variation has been studied in 12 populations ofCepaea hortensis and the results compared with those previously obtained forC. nemoralis from the same populations. Variation in chiasma frequency is effectively restricted to a single large bivalent. In both species there are significant differences between populations in chiasma frequency. Although mean population mean chiasma frequencies are similar inC. hortensis andC. nemoralis, C. hortensis is less variable thanC. nemoralis. This can be seen, to a greater or lesser extent, at several levels-(i) within cells, (ii) between cells, (iii) between snails, and (iv) between populations-and is most noticeable when interstitial chiasmata are considered separately from terminal chiasmata. Data from 6 populations suggest that chiasma frequency remains stable between successive years. It is suggested that, since sympatric populations were studied, the most likely explanation for differences in chiasma frequency statistics between the two species is thatC. hortensis andC. nemoralis are responding differently to similar selective pressures.  相似文献   

6.
The chromosome number ofA. thaliana from three localities in Central Bohemia was found to be 2n=10. All the chromosomes (length 1,5–2,6μm) belong to the atelocentric type, four pairs (m) having the centromere in the median and one pair (sm) in the submedian region. In connection with the discussion on the origin ofH. suecica the author presents the following preliminary results: a) the failure to cross the tetraploidCardaminopsis arenosa (L.)Hayek withA. thaliana; b) the successful crossing of the diploidC. petraea (L.)Hiit. withA. thaliana; c) the discovery of a diploid population ofC. arenosa (2n=16) in the Tatra Mts. (Czechoslovakia).  相似文献   

7.
The present study compares fin damages in gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) according to their wild, escaped or farmed origins. In addition, the potential applicability of fin condition indices (Fin Erosion Index ‘FEI’ and Fin Splitting Index ‘FSI’) as identification tools is discussed. Farmed seabream fins evidenced more erosion and splitting (FEI ± SD: 2.1 ± 0.3; FSI ± SD: 1.9 ± 0.6) than wild seabream fins (FEI: 0.8 ± 0.6; FSI: 1.2 ± 0.9), a result of farming conditions in open‐sea cages. Escaped seabream fin erosion was between that of farmed and wild seabream (FEI: 1.6 ± 0.4), which could indicate that fins in farmed fish recover over time from farming abrasions once they are in the wild. However, the fins of escaped seabream seem to be weaker than those of the wild fish, and therefore might be more susceptible to suffer other types of erosion such as splitting or nipping (FSI: 2.3 ± 0.7). No significant differences were found in seabass FEI according to their origins, although wild seabass presented significantly more split caudal fins (FSI: 3.3 ± 2.8) than the farmed seabass (FSI: 1.2 ± 1.1) and escapees (FSI: 2.5 ± 1.6). Therefore, FEI for seabream could be used as tools not only to distinguish between wild and farmed fish, but also to identify recent escapees, improving further assessments on the contribution of seabream escapees in fishery landings. However, the healing potential of damaged fins must be considered for the proper identification of escapees. Use of fin condition indices from both species could be helpful for aquaculture management, to assess fish welfare in fish farms stocks, and improve the knowledge of handling, stock densities and open‐sea cage environment conditions.  相似文献   

8.
以海巴戟(Morinda citrifolia L.)种子为试材,在不剥除种皮的情况下,在MS无激素培养基上播种1年内未见发芽,在剥除种皮的情况下,在MS无激素培养基上发芽率最高,50d内可达75%。海巴戟子叶和下胚轴均能单独由细胞分裂素BA0.7~2.0mg/L诱导不定芽发生,不定芽可直接从外植体发生,也可从愈伤组织发生,添加生长素NAA0.05~0.1mg/L则完全抑制不定芽发生,同时强烈促进愈伤组织生长和不定根发生。带芽茎段在BA1.5mg/L配合低浓度生长素时均能通过腋芽萌发和不定芽发生而增殖。芽梢在NAA0.1mg/L、IBA0.1mg/L或IAA0.1mg/L均有根群发生,但NAA0.1mg/L诱导生根时切口愈伤组织较多,部分不定根由愈伤组织发生。而IAA0.1mg/L诱导生根时根群欠发达,以IBA0.1mg/L最佳。  相似文献   

9.
Interspecific gene flow can lead to the formation of hybrid populations that have a competitive advantage over the parental populations, even for hybrids from a cross between crops and wild relatives. Wild prickly lettuce (Lactuca serriola) has recently expanded in Europe and hybridization with the related crop species (cultivated lettuce, L. sativa) has been hypothesized as one of the mechanisms behind this expansion. In a basically selfing species, such as lettuce, assessing hybridization in natural populations may not be straightforward. Therefore, we analysed a uniquely large data set of plants genotyped with SSR (simple sequence repeat) markers with two programs for Bayesian population genetic analysis, STRUCTURE and NewHybrids. The data set comprised 7738 plants, including a complete genebank collection, which provided a wide coverage of cultivated germplasm and a fair coverage of wild accessions, and a set of wild populations recently sampled across Europe. STRUCTURE analysis inferred the occurrence of hybrids at a level of 7% across Europe. NewHybrids indicated these hybrids to be advanced selfed generations of a hybridization event or of one backcross after such an event, which is according to expectations for a basically selfing species. These advanced selfed generations could not be detected effectively with crop‐specific alleles. In the northern part of Europe, where the expansion of L. serriola took place, the fewest putative hybrids were found. Therefore, we conclude that other mechanisms than crop/wild gene flow, such as an increase in disturbed habitats and/or climate warming, are more likely explanations for this expansion.  相似文献   

10.
The emission of reduced volatile sulfur compounds from twigs of Norway spruce (Picea abies (L.) Karst.) was measured in the field by cryosampling and gaschromatographic analysis. Trees were growing in the Erzgebirge (E-Germany) at Oberbärenburg and at the Kahleberg and at a third stand in NW-Bavaria (S-Germany). Emission rates were also measured for Scotch pine (Pinus sylvestris L.) and Blue spruce (Picea pungens Engelm.) at the Kahleberg. Twigs still attached to the trees were enclosed in a flow-through gas exchange cuvette. H2S was detected as the predominant reduced sulfur compound emitted from the twigs. The mean H2S emission rate from twigs of Norway spruce varied between 0.04 pmol kg-1 dw s-1 at Würzburg and 6.21 pmol kg-1 dw s-1 at the Kahleberg. Comparing different species at the Kahleberg, the mean H2S emission rate was almost the same from twigs of Norway spruce (6.2 pmol kg-1 dw s-1) and Blue Spruce trees (5.9 pmol kg-1 dw s-1) but it was approximately 18 times higher for Scotch pine (110 pmol kg-1 dw s-1). The percentage of SO2-exclusion via H2S-emission of the tree species investigated at the Kahleberg is calculated on the basis of data on SO2 fluxes. It is very small for Norway spruce and Blue spruce. However, for Scotch pine, H2S emission contributes about 10% to the detoxification of SO2.  相似文献   

11.
用试管受精方法来克服远缘杂交不亲和性,以获得用常规杂交技术所不能得到的远缘杂种,仅有石竹科和茄科的例子,而且其中也尚缺乏细胞学和生化方面的资料。在栽培红花烟草×栽培黄花烟草中的种间试管受精工作迄今尚未见报道。我们用试管受精方法在上述种间杂交组合中克服了烟草远缘杂交不亲和性并获得了种间杂种,同时对其进行了形态学和细胞学观察以及过氧化物酶同功酶分析。供试材料为栽培红花烟草(Nicotianatabacum L.cv.千斤黄,2n=48)和栽培黄花烟草(M.rustica L.cv.蛤蟆烟、羊耳烟,2n=48)。其杂交组合为:千斤黄×蛤蟆烟和千斤黄×羊耳烟。  相似文献   

12.
Summary Amylase from chicken pancreas was purified by an affinity method involving filtering a crude extract from pancreas through a Sepharose-wheat albumin column and eluting the retained enzyme with maltose. The purified amylase showed two active bands upon polyacrylamide electrophoresis in an alkaline buffer system and only one band in an acidic buffer system. The enzyme is a Ca2+—glycoprotein which behaves as a typical-amylase. It consists of a single polypeptide chain with molecular weight 53,000 and contains 5.3 moles of reducing sugars per mole of protein. Optimal conditions of pH and temperature for the enzymic activity are 7.5 and 37°C. The enzyme is irreversibly inactivated by removal of Ca2+ by exhaustive dialysis and is activated by the presence in the assay mixture of Cl; other halides are less effective than Cl in activating the enzyme.  相似文献   

13.
Troyanos  Y.E.  Hipps  N.A.  Moorby  J.  Kingswell  G. 《Plant and Soil》2000,225(1-2):73-82
The effects (and interaction) of two solution concentrations of Mg (50, 500, μM) and two of K (250, 4250 μM) on the growth of micropropagated plants of “F. 12/1” and “Colt” were investigated using a flowing solution culture system. Magnesium inflow and growth of “Colt” and “F. 12/1” were inhibited to a similar extent by an increased concentration of K in the nutrient solution. However, the consequences of this inhibition were different. Reduced inflow of Mg in “F. 12/1” caused Mg deficiency symptoms at high and low concentrations of K, whereas this only occurred with a combination of high K concentration and low Mg concentration in “Colt”. The distribution of dry matter within the plant was significant in determining susceptibility to Mg deficiency. Since “F. 12/1” has a smaller root:shoot ratio than Colt it is unable to sustain the same concentration of Mg in leaves as “Colt” irrespective of external K concentration. The molar ratio of K:Mg in soil solutions should remain <8.5:1 in order to ensure maximum growth of “F. 12/1” and “Colt”. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

14.
Accurate identification of parental plants and their hybrids is essential for an effective breeding programme. Traditional classification of cocoa varieties relies on the characterisation of agricultural traits at plant maturity. A rapid and reliable method is described, based on genotypic analysis. An efficient DNA isolation procedure was developed, yielding unsheared DNA of high purity. Two genetic fingerprinting techniques, RAPD and AFLP, were evaluated for their suitability in distinguishing cocoa varieties. RAPD analysis was unsatisfactory due to the low frequency of polymorphisms and poor reproducibility. AFLP was reliable in distinguishing phenotypically identical, known varieties of cocoa. Importantly, AFLP also revealed intra- and inter-varietal variation.Abbreviations: AFLP, amplified fragment length polymorphism; APS, ammonium persulphate; CTAB, hexadecyltrimethylammonium bromide; DEB, DNA extraction buffer; f.wt., fresh weight; NEB, nuclei extraction buffer; PMSF, phenylmethanesulphonyl fluoride; RAPD, random amplified polymorphic DNA; T4 PNK, Bacteriophage T4 polynucleotide kinase; Taq, Thermus aquaticus; TBE, tris-borate-EDTA; TEMED, NNNN tetramethylethylenediamine.  相似文献   

15.
Nataša Siard 《Anthrozo?s》2013,26(6):741-760
ABSTRACT

Wild boar are present almost throughout Slovenia, causing similar problems as in many other countries, mainly damage to agriculture. Dealing with these problems also involves children. The aim of this study was to assess the effects of age, gender, and farm residence on knowledge, attitudes, and opinions about wild boar management in 11- and 15-year-olds (n = 478) attending schools in/near areas of high wild boar densities, via an anonymous closed-ended questionnaire. Only 52.4% of the questions on factual knowledge were answered correctly, although a relatively high proportion of students (38.3%) reported having seen wild boar in their natural environment. The majority of students (81.4%) expressed affection toward animals in general, while only 11.3% stated that they liked wild boar. The main source of information about these animals was home (40.0%), followed by school (26.1%). Logistic regression analysis revealed that students’ age and gender usually predicted their response (p < 0.05), while living on a farm influenced only the source of information and one attitude question: farm residents were more likely to express affection toward wild boar. The older students were more likely to know more about wild boar, but they also were more likely to be indifferent toward the species. Boys and girls did not differ in their knowledge, but girls were more likely to express fear/dislike of wild boar. In general, older students and girls were more likely to be undecided in their responses. Since we found almost no effect of farm residence on students’ knowledge and opinions, it can be concluded that wild boar problems are recognized generally, not only in agriculture. Because information from home can be biased, we propose that teachers be encouraged to include wild boar topics in their teaching, educating young people properly about wild boar problems and consequently influencing their adult behavior concerning management issues.  相似文献   

16.
水稻(Oryza sativa L.)的受精作用   总被引:1,自引:0,他引:1  
本文对四个水稻品种的双受精过程作了细胞形态学的观察。作者看到,水稻在受精过程中常常有多条花粉管相继伸向珠孔,并把花粉管内含物注入胚囊。注入胚囊的内含物进入两助细胞之一,在卵细胞的一侧形成钩状构造。当合子发育成原胚时,钩状构造就逐渐消失。卵细胞与极核,除了通常的单精受精以外,有少数可能是属于多精受精的现象。卵细胞多精受精时,超数精子不但进入细胞质,而且进入细胞核。精子还可能进入原胚的胚胎细胞。  相似文献   

17.
伊宁苹果蠹蛾(Carpocapsa pomonella L.)之研究   总被引:2,自引:0,他引:2  
  相似文献   

18.
红毛丹(Nephelium lappaceum L.)生态适应性研究   总被引:3,自引:0,他引:3  
采用欧氏距离统计方法,对海南18县市与泰国、马来西亚红毛丹主产区的7个主要气候因子间的距离相似程度进行了分析,发现海南岛保亭县是红毛丹最佳气候宜植区。这与海南试种结果完全吻合,通过实地调查、土样采集分析,结合多年观察以及同泰国、马来西亚产区对比分析,初步明确了引种红毛丹的生态环境条件要求。  相似文献   

19.
岩高兰(Empetrum nigrum L.)新变种   总被引:1,自引:0,他引:1  
马俊莹  张悦 《植物研究》2002,22(4):389-389
发表了采自大兴安岭的岩高兰,与原种的主要区别为果白色(非黑色)。命名为Empetrum nigrum L. var. albium J. Y. Ma et Y. Zhang。  相似文献   

20.
To increase the use efficiency of potassium (K) fertilizer, special attention was paid to the dynamics of soil K in the root zone and non-root zone. Difference in K dynamics between yellowish red soil and yellow cinnamon soil under rapeseed (Brassica napus L.)rice (Oryza sativa L.) rotation was studied using a rhizobox system. Results showed that soil water soluble K (Sol-K) and exchangeable K (Ex-K) in the root zone of both soils were reduced in the early stage of rapeseed growth. Along with plant growth and K uptake, soil Sol-K in the inner (0–20 mm to root zone), middle (20–40 mm) and outer (40–60 mm) compartments of the non-root zone of yellowish red soil migrated towards the root zone. As a result, soil Ex-K was transformed into Sol-K. The changes in soil Sol-K and Ex-K in the non-root zone of yellow cinnamon soil were similar to yellowish red soil, and soil non-exchangeable K (Nonex-K) in the root zone also decreased significantly. In the early stage of rice growth, waterlogging promoted diffusion of soil Sol-K from non-root zone to root zone and transformation of Ex-K into Sol-K. Along with the growth of rice and K uptake, soil Ex-K in each compartment of yellowish red soil decreased significantly. Soil Sol-K and Ex-K in the yellow cinnamon soil declined to a certain extent, and then remained unchanged, while soil Nonex-K kept on decreasing. It revealed that the plants first absorbed K in the root zone, of which K reserve was replenished by a gradual diffusion of K from the non-root zone. The closer to the root zone, the greater the contribution to K uptake by plants. Within one rotation cycle, Ex-K and Sol-K in yellowish red soil were the main forms of K available to the plants, and little Nonex-K could be absorbed. However, in the yellow cinnamon soil, Nonex-K was the main form of K available to the plants, followed by Ex-K and Sol-K.  相似文献   

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