白花树花粉生活力检测方法与贮藏特性研究

以江西吉水种源的白花树花粉为研究材料,进行了扫描电子显微镜下的花粉形态结构观察以及采用离体培养基法、I2-KI和TTC染色等花粉生活力测定方法的比较研究,探讨了不同贮藏条件对花粉萌发的影响。研究结果表明:白花树花粉粒为长球型,具3孔沟,外壁面具细网状纹饰;花粉平均极轴长52.33±0.577μm,平均赤道轴长26.89±0.502μm;3种花粉生活力测定方法中以离体培养基法最有效,花粉萌发的最佳组合为:10%蔗糖+0.05 g·L-1硼酸+100 mg·L-1GA3+3 h;花粉最佳贮藏条件为-80℃密封保存,贮藏180 d后花粉的萌发率仍可达40.97%。     

黄牡丹花粉生活力测定方法的比较研究

以黄牡丹的新鲜花粉为试材,利用单因子试验比较了液体培养基中蔗糖浓度、硼、钙、镁、钾对黄牡丹花粉萌发的影响,在此基础上进行了正交试验,比较了蔗糖、H₃BO₃及CaCl₂对黄牡丹花粉萌发的影响;通过对醋酸洋红染色法、I-KI染色法和TTC染色法的比较,寻找快速测定黄牡丹花粉生活力的方法。试验结果表明:蔗糖及H₃BO₃对黄牡丹花粉萌发有极显著影响。在pH值为6.0时,蔗糖150 g·L^-1+H₃BO₃30 mg·L^-1+CaCl₂20 mg·L^-1适宜黄牡丹花粉培养,萌发率为68.7%;纯水培养没有造成花粉原生质体破裂,内含物外流,但萌发率极低,仅为3%;200 g·L^-1以上的高浓度蔗糖溶液和300 mg·L^-1以上的高浓度盐溶液会造成原生质体失水萎缩,质壁分离,这两种情况都抑制花粉萌发;TTC染色法测得的花粉活力率为64.9%,是快速测定黄牡丹花粉生活力的最适染色法。     

松褐天牛成虫高毒力绿僵菌菌株筛选及液体振荡培养条件

对3株绿僵菌菌株通过不同温度水浴处理,发现了孢子的萌发条件;并开展了3菌株对松褐天牛成虫的毒力测定,筛选出Ma₇₈₉菌株的致病力较强。通过正交试验对其液体振荡培养条件进行了分析,选出了菌丝体生长最适培养基为蔗糖20 g·L^-1,酵母粉10 g·L^-1,KH₂PO₄ 3.0 g·L^-1,MgSO₄·7H₂O 1.0 g·L^-1,CaCl₂ 0.5 g·L^-1;培养液生孢子最适培养基为蔗糖20 g·L^-1,蛋白胨10 g·L^-1,KH₂PO₄ 1.5 g·L^-1,MgSO₄·7H₂O 2.0 g·L^-1,CaCl₂ 0.5 g·L^-1。     

不同营林措施对马尾松林土壤呼吸影响

以三峡库区马尾松飞播林为研究对象,针对不同营林措施:除灌(清除所有除灌产生的枝叶)、采伐I(采伐强度15%,采伐树干,并未对枝叶进行清除)、采伐II(采伐强度70%,采伐剩余物处理同采伐I)、对照,采用LI-8100土壤CO₂通量测定系统对其土壤呼吸速率进行为期1年的连续观测,分析了不同营林措施对于土壤呼吸的影响以及不同营林措施下土壤呼吸产生差异的原因。结果显示:年土壤呼吸速率均值除灌(1.82±0.07 μmol·m^-2·s^-1)< 对照(2.18±0.05 μmol·m^-2·s^-1)< 采伐I(2.37±0.07 μmol·m^-2·s^-1)< 采伐II(2.86±0.1 μmol·m^-2·s^-1);采伐强度与土壤呼吸速率增值呈正比;不同营林措施与对照土壤呼吸速率均在夏季生长旺盛期7-8月达到最大值;高强度的采伐显著提高了土壤温度与湿度,对照、除灌、采伐I、采伐II土壤呼吸敏感性指数Q₁₀值依次为: 2.18±1.09、1.65±0.07、2.20 ±0.09,2.36±0.09。     

杂种落叶松嫩枝离体培养与芽增殖研究

以生长和生根兼优的杂种落叶松无性系日永8×长混18-10的嫩枝和休眠芽为试验材料,开展了嫩枝生长和芽增殖的离体组织培养技术研究,确定了两种试验材料的最佳灭菌条件及最适培养基。结果表明:15%的次氯酸钠溶液处理10 min,材料无菌存活率达到91.7%,灭菌效果最好;最适嫩枝生长培养基为B培养基;芽增殖过程中,最适腋芽萌发诱导培养基为BEMB培养基,单个嫩枝平均诱导萌发2个腋芽;无外源激素的改良BEMB培养基(硝态氮与铵态氮含量比为6:1),最适于腋芽成枝诱导,成枝率为36.5%;培养基MCM+1.5 mg·L^-1 ZT +0.15 mg·L^-1 KT,最适用于休眠芽不定芽诱导,不定芽诱导率为39.1%,增殖倍数为2.6。     

苦楝SSR-PCR反应体系优化及引物筛选

[目的]借鉴以往楝属文献报道的SSR引物,筛选高度多态性、稳定性高、重复性好的苦楝SSR引物,为苦楝遗传图谱构建、QTL定位和分子标记辅助选择育种等研究领域应用奠定基础.[方法]本研究采用单因素法和正交试验设计进行SSR-PCR反应体系优化,并利用该体系以8个不同种源的苦楝基因组DNA为模板,从135对候选SSR引物中进行引物筛选.[结果]苦楝SSR-PCR最优反应体系为:1.0 μL 50 ng·μL^-1模板DNA,1.2 μL 100 μmol·L^-1引物,1.0 μL 10 mmol·L^-1 dNTPs,0.8 μL 25 mmol·L^-1 Mg²⁺,0.15 μL 5 U·μL^-1 Taq酶,1.5 μL 10×Buffer,补ddH₂O至15 μL;最终筛选出15对具有高度多态性、稳定性高、重复性好的SSR引物.[结论]本研究成功优化了苦楝SSR-PCR反应体系,并成功筛选出15对适用于苦楝的SSR引物.     

鹅掌楸Genomic-SSR反应体系优化

The optimization of the Genomic-SSR reaction system is a basic protocol when the Genomic-SSR is used for genetic analysis in Liriodendron. The concentrations of Mg²⁺, dNTP, Primer and rTaq were tested by L₉(3⁴) orthogonal experiment and single factor gradient experiment to gain the optimal reaction system. The results indicated that the optimal reaction system should contain 75 ng of genomic DNA, 1 μL of 10×buffer, 0.4 μL of 10 mmol·L^-1 dNTP, 0.75 μL of 2.5 mmol·L^-1 MgCl₂, 0.25μL of 10 μmol·L^-1 Primer, 0.05 μL of 5 U rTaq and final volume of 10μL. Repeated trials and two verification tests showed that this optimal reaction system was stable, reliable, efficient and suitable for the applications of Genomic-SSR in Liriodendron population genetics and quantitative genetics research.     

Characterization and role of glucose-6-phosphate dehydrogenase of Populus suaveolens in induction of freezing resistance

Glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) was purified from the leaves of 8-week-old Populus suaveolens cuttings. The enzyme activity in the absence and presence of reduced dithiothreitol (DTT_red) was determined. The results show that the G6PDH activity is not inactivated by pre-incubation with DTT_red, indicating that the purified enzyme probably presented in cytosol of P. suaveolens. The catalytic characteristics and kinetic parameters of cytosolic G6PDH purified from P. suaveolens cuttings were also studied. The results show that G6PDH is characterized by K _m value of 360 μmol·L⁻¹ for G6P and 16 μmol·L⁻¹ for NADP, a pH range of 7.3-8.9, and the maximum activity around pH 8.2. The enzyme activity is inhibited by various metabolites such as NADPH, NADH, GTP, UTP, ATP, AMP, ADP, CoA, acetyl CoA, fructose-6-phosphate (F6P), erythrose-4-phosphate (E4P), ribose-5-phosphate (R5P) and 3-phosphoglycerate (3-PG) (all at 1 mmol·L⁻¹ except for NADPH and NADH) to different extents. NADPH is the most effective inhibitor of enzyme activity, with an inhibition of 72.0%. The addition of metal ions such as MgCl₂, CaCl₂ and KCl (all 1.0 mmol·L⁻¹) to the standard reaction mixture has no remarkable influence on the cytosolic G6PDH activity. However, CdCl₂ (1.0 mmol·L⁻¹) causes high inhibitory effect on the enzyme activity. To explore the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation, the changes in the cytosolic G6PDH activity and freezing resistance (expressed as LT₅₀) of P. suaveolens cuttings during freezing acclimation at −20 °C were investigated. The results reveal that freezing acclimation decreases LT₅₀ of cuttings, and increases the activity of cytosolic G6PDH compared with control ones, while 2 d of de-acclimation at 25 °C result in a decrease in cytosolic G6PDH activity, and caused an increase in LT₅₀. Furthermore, the change in cytosolic G6PDH activity is found to be closely correlated to the degree of freezing resistance of cuttings during freezing acclimation. It is suggested that cytosolic G6PDH may be involved in the induction of freezing resistance of cuttings. [Supported by the Foundation of State-designated Base for Biology Researching and Teaching in Beijing Forestry University]     

红楠ISSR-PCR反应体系的建立和优化

为建立稳定的红楠ISSR-PCR最佳反应体系,在探索红楠基因组DNA提取的基础上,利用单因子试验和正交试验设计对反应体系进行优化。首先采用单因子试验对Mg²⁺、引物、模板DNA、dNTPs的不同浓度水平进行优化,找出ISSR-PCR反应各因素的最佳浓度;同时为进一步增加结果的可靠性,采用正交试验设计方法 对Mg²⁺、引物、模板DNA、dNTPs 4个因素3个浓度水平进行优化和筛选。综合两种试验方法结果,最终获得了红楠ISSR-PCR最佳反应体系:反应体系为20 μL,Taq酶0.05 U·μL^-1,Mg²⁺ 2.0 mmol·L^-1,模板DNA 1 ng·L^-1,dNTPs 0.3 mmol·L^-1,引物(835) 0.5 μmol·L^-1,1×PCR缓冲液。建立重复性好、稳定性优良的ISSR-PCR反应体系,为下一步红楠群体遗传结构和遗传变异研究提供了技术支持。     

非生长季刺槐林土壤CH4通量的变化特征及其影响因子

[目的]探讨在非生长季不同天气条件下45年生刺槐林土壤CH₄通量的日变化和季节变化特征,并确定其主要影响因子.[方法]2014年10月-2015年4月(非生长季),在华北低山丘陵区黄河小浪底森林生态系统定位研究站,利用基于离轴积分腔输出光谱技术的土壤CH₄通量自动观测系统,对土壤CH₄通量进行连续观测,同步观测林内大气温度和相对湿度、5 cm深处土壤温度和土壤湿度、林内总辐射以及降雨量,分析各因子间的相互关系并确定影响土壤CH₄通量的主要因子.[结果]表明:(1)在非生长季,刺槐人工林土壤为大气CH₄重要的汇,变化范围为-0.15~-2.34 nmol·m^-2·s^-1 .晴天的林地土壤吸收CH₄能力 (-0.78 nmol·m^-2·s^-1) 明显高于阴天(-0.61 nmol·m^-2·s^-1)、降雨或降雪天气 (-0.58 nmol·m^-2·s^-1),而且呈"V"型日际变化特征;在2014年11月-2015年1月,土壤吸收CH₄能力逐渐下降,并维持相对较低的水平,直至2015年3月达到最大值 (-2.34 nmol·m^-2·s^-1);(2)土壤CH₄通量与大气温度、5 cm深处土壤温度呈显著负相关,与相对湿度呈正相关;在2015年1月,土壤CH₄通量与总辐射呈正相关;(3)在生长末期土壤上冻阶段和冬季土壤冻结阶段,大气温度和相对湿度为影响土壤CH₄通量的主要因子;而在生长季初期,主要的影响因子为大气温度和5 cm深处土壤温度.[结论]非生长季刺槐林土壤表现为大气CH₄的汇,在非生长季初期土壤吸收CH₄的能力最弱,主要受大气温度和相对湿度的影响,而在非生长季末期土壤吸收CH₄的能力逐渐增加,主要受大气温度和土壤温度的影响.     

Antibacterial activity of plant extracts from Brazilian southeast region

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.     

利用三种梢栖真菌生物防治落叶松枯梢病的研究

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。     

Antimicrobial activity of some endemic plants growing in the Eastern Black Sea Region, Turkey

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.     

Anti-HBV activities of Streblus asper and constituents of its roots

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.     

Screening of antioxidant activity of three Euphorbia species from Turkey

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.     

Growth and physiological response of six Australian rainforest tree species to a light gradient

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 A_max 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 A_max 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.     

Photosynthetic characteristics of Fagus sylvatica and Quercus robur established for stand conversion from Picea abies

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.     

Effects of prescribed fire and season of burn on direct and indirect levels of tree mortality in Ponderosa and Jeffrey Pine Forests in California,USA

Many forests that historically experienced frequent low-intensity wildfires have undergone extensive alterations during the past century. Prescribed fire is now commonly used to restore these fire-adapted forest ecosystems. In this study, we examined the influence of prescribed burn season on levels of tree mortality attributed to prescribed fire effects (direct mortality) and bark beetles (Coleoptera: Curculionidae, Scolytinae) (indirect mortality) in ponderosa pine, Pinusponderosa Dougl. ex Laws., and Jeffrey pine, Pinusjeffreyi Grev. and Balf., forests in California, USA. A total of 816 trees (9.9% of all trees) died during this 3-yr study. Significantly higher levels of tree mortality (all sources) occurred following early and late season burns compared to the untreated control, but no significant difference was observed between burn treatments. The majority (461 trees) of tree deaths were attributed to direct mortality from prescribed burns and was strongly concentrated (391 trees) in the smallest diameter class (<20.2 cm diameter at breast height, dbh). For the largest trees (>50.7 cm dbh), significantly higher levels of tree mortality occurred on early season burns than the untreated control, most of which resulted from indirect mortality attributed to bark beetle attacks, specifically western pine beetle, Dendroctonus brevicomis LeConte, and mountain pine beetle, D. ponderosae Hopkins. Red turpentine beetle, D. valens LeConte, was the most common bark beetle species found colonizing trees, but tree mortality was not attributed to this species. A total of 355 trees (4.3% of all trees) were killed by bark beetles. Dendroctonus brevicomis (67 trees, 18.9%) and D. ponderosae (56 trees, 15.8%), were found colonizing P. ponderosa; and Jeffrey pine beetle, D. jeffreyi Hopkins, was found colonizing P. jeffreyi (seven trees, 2.0%). We also found pine engraver, Ips pini (Say) (137 trees, 38.6%), and, to a much lesser extent, Orthotomicus (=Ips) latidens (LeConte) (85 trees, 23.9%) and emarginate ips, I. emarginatus (LeConte) (3 trees, 0.8%) colonizing P. ponderosa and P. jeffreyi. Few meaningful differences in levels of indirect tree mortality attributed to bark beetle attack were observed between early and late season burns. The incidence of root and root collar pathogens (Leptographium and Sporothrix spp.), including species known to be vectored by bark beetles, was low (18% of trees sampled). The implications of these and other results to management of P. ponderosa and P. jeffreyi forests are discussed in detail.     

Insecticidal activity of Vitex mollis

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.