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[目的]确定白皮松种子萌发的适宜条件,揭示不同温度下种子萌发过程中的呼吸途径和激素变化规律.[方法]将种子置于不同温度下进行萌发试验,测定发芽率、发芽速率(SG)和平均发芽时间(MGT),并探索温度对磷酸己糖异构酶(PGI)、苹果酸脱氢酶(MDH)、葡萄糖-6-磷酸脱氢酶(G-6-PDH)和6-磷酸葡萄糖脱氢酶(6-P... 相似文献
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将河沙、泥炭土、黄心土按照不同比例配成基质,研究不同基质对降香黄檀(Dalbergia odorifera T.Chen)种子发芽率、发芽势、发芽时间和成苗率的影响,筛选出适宜其萌发的基质配比。结果表明:不同基质对降香黄檀种子的萌发影响显著,黄心土(发芽率72.7%、发芽势49.3%、发芽时间12.7d、成苗率69.71%)和泥炭土(发芽率68.0%、发芽势53.3%、发芽时间13d、成苗率74.15%)适宜降香黄檀种子的萌发,而河沙中的种子所需萌发时间长(17.7d)、成苗率低(27.90%)。结合成本考虑,黄心土是降香黄檀播种较理想的基质。 相似文献
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虎皮楠等珍稀树种种子萌发温度研究 总被引：1，自引：0，他引：1
研究了虎皮楠等10个珍稀树种种子的萌发适宜温度.结果发现,10个树种种子的萌发温度差异较大.其中适于在较低温度(15-20℃)下萌发的种子有尖萼厚皮香、香港四照花、金叶含笑和八月桂;适于在较高温度(25-30℃)下萌发的种子有香花崖豆藤、虎皮楠和东京白克木;对发芽温度要求较宽的树种有伯乐树、椤木石楠和蓝果树. 相似文献
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奥氏黄檀属红木类珍贵用材树种,在常规条件下,奥氏黄檀种子发芽率相对较低,通过研究不同贮藏方式、不同种子处理及不同播种基质对奥氏黄檀种子萌发的影响,提高奥氏黄檀种子发芽率,结果表明,播种前,采用40℃温水浸泡自然冷却,再用冷水浸泡24h,种子发芽率为70.3%,高于其它处理;为保持种子有较高的活性,应将种子贮藏在低温(4-5℃)的环境中,发芽率较高,为69.3%;奥氏黄檀种子萌发适宜的基质为江沙+林地表土(体积比1︰1),种子在18d便开始出苗,完成出苗需33d,发芽率为72.7%,均高于其它4种基质。 相似文献
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为了研究黄檀种子超干贮藏的适宜含水量,采用人工老化法研究超干贮藏对黄檀种子发芽率及生活力的影响。通过对含水量为2.4%~12.1%老化黄檀种子的发芽率、发芽势、发芽指数、活力指数以及电导率等指标的检测,结果表明黄檀种子含水量(MC)降至4.5%,能显著提高抗老化劣变的能力。在同等老化处理(50℃,15 d)后,未超干种子(MC=12.1%)完全失去了发芽能力,而超干种子(MC=2.4%~4.5%)的发芽率仍保持在64%以上。电导率测定结果表明,超干种子经回水处理后细胞膜系统的完整性良好。 相似文献
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试验在保持温度、光照、基质等适宜的条件下,主要研究了土壤湿度分别为5%、10%、15%、20%的不同处理对沙棘种子萌发的影响,并采用发芽指数和活力指数对沙棘种子发芽效果进行了评价。试验结果表明,在不同的土壤湿度条件下,沙棘种子的萌发指标明显不同,其发芽率、发芽势、发芽指数和活力指数在土壤湿度为5%~20%范围内随土壤湿度的增加呈现出先增加后减小的趋势,10%~15%的处理其值较大。平均发芽时间也表现出明显的差异,在土壤湿度为5%~20%的范围内,随土壤湿度的升高呈现出先减小后增加的趋势,沙棘种子的活力指数先减小后增加,10%~15%的处理其值较小。从而得出,沙棘种子发芽的适宜湿度范围10%~15%。 相似文献
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测定了去除内果皮的山杏种子不同温度浸水处理的吸水性、温度对去除胚尖处种皮和不去种皮种子萌发的影响；萌发过程中种子内可溶性糖含量的动态变化；激素对种子萌发的影响及萌发期间种子内ａ-淀粉酶活性和过氧化氢酶活性的变化。结果表明，５０℃低温浸种２４ｈ可达山杏萌发所需水分条件及活力指数；层积处理以２～５℃效果最好；ＧＡ３在适宜浓度下能打破休眠，促进种子发芽、茎根伸长和幼苗生长；种子萌发期间可溶性糖含量呈不断增加趋势，ａ-淀粉酶活性不断增强；层积后种子内ａ-淀粉酶活性显著增强。 相似文献
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Oliveira DF Pereira AC Figueiredo HC Carvalho DA Silva G Nunes AS Alves DS Carvalho HW 《Fitoterapia》2007,78(2):142-145
A screening was conducted with 26 plants collected in the Brazilian southeast region, to identify plant extracts with antibacterial properties against Aeromonas hydrophila, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Initially, the agar diffusion method was employed. Then, those extracts presenting activity were submitted to a broth microdilution assay to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). It was observed that 13 of the tested extracts showed antibacterial activity. The best results were obtained with those from Lantana lilacina and Phyllanthus tenellus. 相似文献
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从落叶松梢栖真菌筛选出对落叶松枯梢病病原菌有抑制作用的菌株,对落叶松枯梢病进行生物防治。将自落叶松梢部分离到的11种梢栖真菌与落叶松枯梢病病原菌进行对峙培养,根据被覆盖程度、抑菌率、拮抗系数和防治预试验的结果,综合评价后发现:粪生粪壳、深绿木霉和球毛壳3种梢栖真菌对落叶松枯梢病有良好的拮抗作用。利用这3个菌株在黑龙江省勃利县通天一林场国富沟进行林间防治试验,结果表明:防治效果为粪生粪壳>代森锰锌400倍液>深绿木霉>球毛壳;深绿木霉和粪生粪壳喷洒浓度50%和球毛壳喷洒浓度75%时,真菌多样性最多,梢栖真菌系统较其他浓度更为稳定,与化学防治相比,既达到了防治目的又具有不污染环境的优势。 相似文献
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Growth and physiological response of six Australian rainforest tree species to a light gradient 总被引：1，自引：0，他引：1
An understanding of growth and photosynthetic potential of subtropical rainforest species to variations in light environment can be useful for determining the sequence of species introductions in rainforest restoration projects and mixed species plantations. We examined the growth and physiology of six Australian subtropical rainforest tree species in a greenhouse consisting of three artificial light environments (10%, 30%, and 60% full sunlight). Morphological responses followed the typical sun-shade dichotomy, with early and late secondary species (Elaeocarpus grandis, Flindersia brayleyana, Flindersia schottiana, and Gmelina leichhardtii) displaying higher relative growth rate (RGR) compared to mature stage species (Cryptocarya erythroxylon and Heritiera trifoliolatum). Growth and photosynthetic performance of most species reached a maximum in 30–60% full sunlight. Physiological responses provided limited evidence of a distinct dichotomy between early and late successional species. E. grandis and F. brayleyana, provided a clear representation of early successional species, with marked increase in Amax in high light and an ability to down regulate photosynthetic machinery in low light conditions. The remaining species (F. schottiana, G. leichhardtii, and H. trifoliolatum) were better represented as falling along a shade-tolerant continuum, with limited ability to adjust physiologically to an increase or decrease in light, maintaining similar Amax across all light environments. Results show that most species belong to a shade-tolerant constituency, with an ability to grow and persist across a wide range of light environments. The species offer a wide range of potential planting scenarios and silvicultural options, with ample potential to achieve rapid canopy closure and rainforest restoration goals. 相似文献
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The Eastern Black Sea Region has an extensive flora because of ample rainfall lasting all year. In this study, antimicrobial effects of 74 crude extracts of 22 endemic plants were investigated. Among the 30 active crude extracts, water-insoluble crude extracts from Betula medwediewii, Heracleum platytaenium, Primula longipes, Anthemis cretica ssp. argaea and Centaurea helenioides were the prominent ones with their MIC values. 相似文献
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Euphorbia acanthothamnos, E. macroclada and E. rigida were investigated for their antioxidant activity. The antioxidant potential of extracts of E. acanthothamnos, E. macroclada and E. rigida was evaluated using different complementary antioxidant tests. 相似文献
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The extracts from leaves, heartwood, barks and roots of the Streblus asper were investigated for anti-HBV activities, separately. The results suggested that the MeOH extracts of the heartwood, barks, and roots exhibited good anti-HBV activities. Further investigations displayed that ethyl acetate and n-butanol soluble parts of their MeOH extracts showed more significant anti-HBV activities. Moreover, a new lignan, together with 11 known compounds, was isolated from n-butanol-soluble part of MeOH extract of the roots of S. asper. The structures were elucidated by spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC) and HR-EI-MS experiments. Compounds 1-3 were evaluated for their anti-HBV activities. Honokiol showed significant anti-HBV activity with IC(50) values of 3.14μM and 4.74μM for HBsAg and HBeAg with no cytotoxicity respectively, while lamivudine (3TC, positive control) exhibited weak anti-HBV activity with IC(50) values of 11.81μM and 25.80μM for HBsAg and HBeAg respectively. 相似文献
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Ungulate herbivory of regenerating conifers in relation to foliar nutrition and terpenoid production 总被引：1，自引：0，他引：1
Owen T. BurneyDouglass F. Jacobs 《Forest Ecology and Management》2011,262(9):1834-1845
Ungulate browsing greatly influences regeneration dynamics of some forest ecosystems, yet the relationship between browse susceptibility and foliar chemistry of forest tree seedlings is not well understood. We applied field fertilization (15N-9P-10K controlled-release fertilizer at 0, 20, 40, and 60 g per seedling) and investigated how subsequent changes in terpenoid production and foliar nutrition influence ungulate browse preference for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla Raf. Sarg.), and western redcedar (Thujaplicata Donn ex D. Don) seedlings across four sites in northwestern Oregon, USA. Fertilization increased foliar N concentration of all three species, but above-ground growth of only Douglas-fir and western hemlock. Foliar monoterpene concentrations for western hemlock and western redcedar also increased at higher fertilization rates, while Douglas-fir monoterpene production was not affected by fertilization. Regardless of monoterpene levels, ungulate browse preference was greater for fertilized western hemlock seedlings. The opposite response, however, was observed for western redcedar at two of the four study sites where the likelihood of browse was greater for non-fertilized than fertilized seedlings. Differences in browse preference among species may depend on the type and amount of individual monoterpenes manufactured in response to fertilization. Western redcedar produce α- and β-thujone, oxygenated monoterpenes known to promote gastroenteritis and possibly inhibit microbial rumen activity, which were absent from Douglas-fir or western hemlock. Higher concentrations of α- and β-thujone associated with increasing fertilizer rate provide a plausible explanation as to why ungulates preferred non-fertilized western redcedar. Our results illustrate species-specific adaptation in browse avoidance and selective ungulate browsing behavior of individual trees as linked to foliar chemistry. 相似文献
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Emile S. Gardiner Magnus Löf Joseph J. O’Brien John A. Stanturf Palle Madsen 《Forest Ecology and Management》2009
Efforts in Europe to convert Norway spruce (Picea abies) plantations to broadleaf or mixed broadleaf-conifer forests could be bolstered by an increased understanding of how artificial regeneration acclimates and functions under a range of Norway spruce stand conditions. We studied foliage characteristics and leaf-level photosynthesis on 7-year-old European beech (Fagus sylvatica) and pedunculate oak (Quercus robur) regeneration established in open patches and shelterwoods of a partially harvested Norway spruce plantation in southwestern Sweden. Both species exhibited morphological plasticity at the leaf level by developing leaf blades in patches with an average mass per unit area (LMA) 54% greater than of those in shelterwoods, and at the plant level by maintaining a leaf area ratio (LAR) in shelterwoods that was 78% greater than in patches. However, we observed interspecific differences in photosynthetic capacity relative to spruce canopy openness. Photosynthetic capacity (A1600, net photosynthesis at a photosynthetic photon flux density of 1600 μmol photons m−2 s−1) of beech in respect to the canopy gradient was best related to leaf mass, and declined substantially with increasing canopy openness primarily because leaf nitrogen (N) in this species decreased about 0.9 mg g−1 with each 10% rise in canopy openness. In contrast, A1600 of oak showed a weak response to mass-based N, and furthermore the percentage of N remained constant in oak leaf tissues across the canopy gradient. Therefore, oak photosynthetic capacity along the canopy gradient was best related to leaf area, and increased as the spruce canopy thinned primarily because LMA rose 8.6 g m−2 for each 10% increase in canopy openness. These findings support the premise that spruce stand structure regulates photosynthetic capacity of beech through processes that determine N status of this species; leaf N (mass basis) was greatest under relatively closed spruce canopies where leaves apparently acclimate by enhancing light harvesting mechanisms. Spruce stand structure regulates photosynthetic capacity of oak through processes that control LMA; LMA was greatest under open spruce canopies of high light availability where leaves apparently acclimate by enhancing CO2 fixation mechanisms. 相似文献
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Insecticidal activity of Vitex mollis 总被引：3，自引：0，他引：3
Organic extracts from the leaves of Vitex mollis were assessed for their toxic effect on fall armyworm neonate larvae (Spodoptera frugiperda), an important insect pest of corn. The extracts showed insecticidal and insect growth regulatory activity, being CHCl(3)-MeOH (1:1) extract the most active, also found to be toxic in the Artemia salina test. 相似文献