金花茶花粉贮藏特性

采用花粉离体培养法,研究不同含水量、贮藏温度对金花茶花粉生活力的影响。结果表明:花粉生活力随贮藏时间的延长而降低,随贮藏温度的降低而延长。在室温条件下,花粉干燥处理萌发率高于非干燥处理,室温非干燥条件下,花粉生活力下降最快,10 d左右基本丧失生活力;在4℃和-20℃低温条件下,贮藏一定时间的花粉活力仍可达50%以上。花粉最佳的贮藏条件为冷冻干燥(-20℃)。     

迎春花粉生活力测定及贮藏方法的研究

利用离体培养法、碘-碘化钾染色法和氯化三苯基四氮唑染色法对花粉生活力进行了测定,并研究了不同贮藏条件对花粉萌发的影响。结果表明:培养基中添加不同浓度的蔗糖和硼酸对花粉的萌发有很大影响,最适培养基为:25%蔗糖+0.005%硼酸,萌发率达92.04%。花粉生活力随贮藏时间的延长而下降,不同的贮藏条件对其有显著的影响,最佳贮藏方法为-80℃干贮,耐贮藏时间超过26 d。     

翠竹花粉的活力及储藏效果研究

[目的]以南京林业大学竹种园内开花的翠竹花粉为试验材料,研究在不同条件下花粉的活力和储藏效果,为翠竹杂交育种的生产实践提供基础理论数据。[方法]利用花粉离体培养法研究花粉在不同培养基组分、不同采样时间、不同温度及储藏条件下的萌发特性。[结果]翠竹花粉在不同浓度配比的培养基中萌发率差异显著,以10%蔗糖+0.01%H3BO3+0.06%CaCl_2·2H_2O培养基上培养2.5 h花粉萌发率最高;一天之中以上午9:00的花粉萌发率最高;翠竹花粉离体萌发适合的温度范围较宽,在26 30℃内花粉都有较高的萌发率。随着储藏时间的延长,翠竹花粉萌发率逐渐下降;不同储藏方式对花粉的萌发率有较大的影响,在储藏过程中未经干燥处理的花药的花粉萌发效果好于干燥后的,4℃低温保存下花粉萌发率相对较好,可延长花粉的储藏寿命,96.0 h后仍保有活力。[结论]翠竹花粉在10%蔗糖、0.01%H3BO3、0.06%CaCl_2·2H_2O的培养基中萌发效果最好,萌发适宜的温度范围是2630℃,在储藏过程中低温不干燥的环境有利于延长花粉寿命。     

不同贮藏条件下锥栗花粉生活力研究

为了解决锥栗杂交育种中的花期不遇问题,以‘华栗4号’花粉为试材,研究了在室温和4、-20、-80℃这4个贮藏温度条件下干燥处理和非干燥处理对锥栗花粉生活力的影响情况。结果表明:在不同贮藏温度条件下‘华栗4号’的花粉生活力和耐贮藏能力不同;花粉适宜的贮藏条件为非干燥、低温环境。花粉生活力随贮藏时间的延长而下降,室温干燥条件下贮藏的花粉其生活力下降最快,贮藏27 d后花粉活力基本丧失;4℃的温度条件较利于花粉的短期贮藏,贮藏30 d后其萌发率仍为32.6%;而-20和-80℃的温度条件均较利于花粉的长期贮藏,且-80℃下贮藏的效果最佳,-80℃下贮藏270 d后花粉仍有一定的生活力,而在-20℃下贮藏210 d后花粉的生活力已基本丧失。     

油松花粉离体萌发培养基及花粉贮藏条件研究

花粉生活力对油松杂交育种至关重要。为筛选油松花粉离体萌发培养基,探讨不同温度贮藏下花粉的生活力,采用正交试验设计,研究不同水平蔗糖、硼酸和pH值对油松花粉离体萌发的影响;测定不同温度贮藏下油松花粉萌发率随时间的动态变化。结果表明:油松新鲜花粉在蔗糖100 g·L~(-1)、硼酸0.10 g·L~(-1)、琼脂8 g·L~(-1)、pH值6.5的培养基上萌发效果最好,萌发率高达93.12%。不同贮藏温度下油松花粉生活力存在明显差异,-80℃贮藏15 d和30 d的花粉萌发率分别为92.93%和91.27%,萌发率下降不显著;-20℃和4℃贮藏15 d,花粉萌发率下降不显著,但贮藏30 d的花粉萌发率与初始萌发率相比均极显著下降,萌发率分别为88.65%和86.84%;常温25℃贮藏15 d、30 d的花粉萌发率分别为90.27%、82.66%,与初始萌发率均达到极显著差异;由此可见,贮藏温度越低,越有利于花粉生活力的保持。此研究可为油松花粉生活力检测提供一种可靠方法,并为花粉贮藏提供参考依据。     

金花茶花粉离体萌发及低温处理探究

研究了硼酸及蔗糖浓度、培养时间、含水率、低温对金花茶花粉离体萌发的影响。结果表明,硼酸及蔗糖浓度对花粉萌发均有显著影响,当硼酸浓度0.1g/L和蔗糖浓度100g/L时,花粉萌发率最高;25℃培养24h后花粉充分萌发;花粉含水率为70.39%和52.67%时,低温处理导致花粉活力降低,甚至丧失,不利于花粉低温保存。含水率为39.89%和30.90%时,花粉低温处理后的萌发相对保持率均维持在86%以上;含水率39.89%的花粉出现"冷刺激"现象,低温处理后萌发率回升,新鲜花粉低温保存前进行适当干燥处理有利于萌发。研究结果将为金花茶种苗繁育提供参考。     

油茶花粉特性及其不同贮藏条件下生活力的研究

以攸县油茶和黄蛋红花茶的花粉为试验材料,研究了其花药内花粉数量、花粉离体培养萌发率及不同贮藏条件下的花粉活力.结果表明:攸县油茶和黄蛋红花茶的单花药花粉平均数量分别约为5400粒与6700粒;二者花粉均在5%蔗糖 0.01%硼酸 1%琼脂的培养基上萌发率最高,萌发率分别为70.9%与73.1%;在4℃冰箱、-20℃冰冻、室温和25℃干燥状态下贮藏1周,攸县油茶和黄蛋红花茶的萌发率分别为35%、2.1%、21.0%、27.5%和36.7%、13.3%、26.7%、21.5%.     

崇左金花茶花粉萌发及在不同贮藏条件下活力变化的研究

2015年7月,采集崇左金花茶Camellia chuangtsoensis S.Y.Liang et L.D.Huang花粉,分别置于室温25℃,4℃,-20℃和-80℃保存。采用离体液体培养基法筛选出最佳崇左金花茶花粉的萌发条件,在此基础上试验不同贮藏温度和不同贮藏时间对花粉萌发率的影响。结果表明,崇左金花茶花粉萌发的最适培养基为12%蔗糖+0.12%H3BO3。花粉-20℃条件下贮藏5个月时,花粉萌发率仍可达原来的(68.93%)25%;在-80℃条件下贮藏5个月时,花粉萌发率可达原来的32%,-80℃条件下保存的花粉其萌发率略高于-20℃。     

‘高原红’海棠花粉特性与生活力测定研究

以5年生观赏海棠‘高原红’嫁接苗为试验材料,采用扫描电镜、花粉离体培养、荧光显微技术等研究了‘高原红’花粉的形态、生活力及贮藏特性,分析了花粉离体培养基成分、离体与活体萌发的区别及花粉贮藏过程中活力的变化。探讨了花粉萌发及贮藏特性,旨在为揭示花粉萌发特性、建立花粉贮藏体系提供理论依据。结果表明:硼酸与蔗糖溶液均对‘高原红’花粉萌发有显著的影响,单因素最佳培养基为10%蔗糖溶液;离体与活体花粉在萌发时间上有一定程度的差异,离体萌发较快于活体萌发,且活体萌发中花粉管在授粉后第8—12 h为快速伸长期;花粉贮藏过程中,室温(17—20℃)下贮藏的花粉活力急速下降,花粉管长度与4,-20℃及-70℃时差异显著,4℃下贮藏的花粉离体萌发率同样呈急速下降的趋势,与-20,-70℃时差异显著,而-20℃与-70℃下贮藏的花粉其离体萌发率之间与花粉管长度之间差异均不显著。     

楸树、灰楸花粉离体萌发特性及其保存方法

以灰楸、楸树花粉为试材,在固体培养基上离体培养,研究花粉萌发的最适温度、适温下的最佳培养时间及外源钙离子浓度对花粉萌发的影响。结果表明,30～35℃是灰楸花粉发芽的最适温度,25～35℃是楸树花粉发芽的最适温度;2种楸树花粉的最佳培养时间均为3h。外源钙离子能促进楸树、灰楸花粉的萌发,灰楸花粉以1.36～2.04 mmol／L CaCl2·2H2 O作用最为显著,楸树花粉以3.4 mmol／L CaCl2·2H2 O作用最为显著。贮藏条件对花粉的贮藏时间起决定作用。其中在常温常湿条件下,灰楸、楸树的花粉贮藏10天时完全失活;在－20℃、－80℃冷冻条件下灰楸、楸树花粉的活力分别可保持120天、90天以上。表明灰楸、楸树花粉适宜的贮藏条件依次为－20℃、－80℃冷冻。此研究可为楸树、灰楸生产上的花粉贮藏和人工授粉提供参考依据。     

Improving the evaluation of multiple-dowel-type connection strength

Our study focuses on predicting the ultimate short-term load carrying capacity of timber-to-timber connections with dowel-type fasteners. The wide range of possible configurations in practice makes the resolution of these values by tests unrealistic. Moreover, different current regulations do not consider some specific failure mechanisms. In many countries, the reduction of resistance involved by this phenomenon is taken into account by considering an effective number of dowels (n_ef) smaller than the actual number of dowels (n) in the connection. However, these different regulations disagree on the values of n_ef and on other points (spacing, partial coefficient of security, formulas). These discrepancies in design rules invite the fundamental research on this topic and, therefore, new methods are sought in order to estimate the load carrying capacities of the connections. In the light of these, our approach consists of predicting the load carrying capacity with the neural network numerical tool. The results obtained by this analysis tool are satisfactory, although the model remains complex. Subsequently, we focus on the simplification of this numerical model with classical regression techniques in order to implement it in a design code.     

<Emphasis Type="Italic">Ophiostoma</Emphasis> species associated with bark beetles infesting three <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Parasitic Ichneumonoidea on the horse chestnut leaf miner, Cameraria ohridella (Lepidoptera: Gracillariidae) in Slovakia

Parasitic Hymenoptera from the suprafamily Ichneumonoidea attacking the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) were studied in southwest Slovakia during 2000 and 2001. The search for such species resulted in the determination of eight ichneumonid species, Gelis agilis (Fabricius), Itoplectis alternans (Gravenhorst), I. clavicornis (Thompson), I. maculator (Fabricius), Scambus annulatus (Kiss), S. brevicornis (Gravenhorst), Zatypota percontatoria (Müller), Adelognathus sp. and a braconid Colastes braconius Haliday. The most abundant species was S. annulatus. All these species recorded are polyphagous and often facultative hyperparasitoids, except C. braconius, which departs from this norm in not being hyperparasitic. The presence of more diversified native parasitoids and hyperparasitoids from the Ichneumonoidea predicate a slow successive adaptation of the parasitoid fauna to the invasive host, Cameraria ohridella.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

基于cpDNA rps16序列分析兰考泡桐与白花泡桐和毛泡桐的遗传关系

【目的】通过测序法分析兰考泡桐与白花泡桐和毛泡桐在叶绿体rps16序列上的遗传差异,旨在分析三者之间在叶绿体基因上的变化特点和规律,探讨其种间的遗传关系。【方法】选取兰考泡桐、白花泡桐和毛泡桐各15个样本,对其提取的DNA用PCR扩增获得特异片段,并将其纯化与测序。利用软件Clustal X 2.0对所得序列进行排序;运行MEGA 4软件,进行多序列比对,分析其序列特征,并计算出K2P遗传距离。【结果】(1)对获得的rps16序列进行测定分析,得兰考泡桐序列长度分别为932 933 bp;白花泡桐序列长度为932 bp;毛泡桐序列长度分别为916918 bp。对所得rps16序列进行排序后的长度为938 bp,平均GC含量为34.31%。3个种所代表的个体之间共有10个变异位点,占整个序列长度的1.07%。其中有9个变异位点属于碱基插入或缺失类型,占变异位点总数的90%,占整个序列长度的0.96%。有1个变异位点属于碱基替换类型,占整个变异位点总数的10%,占整个序列长度的0.11%。(2)整个rps16片段的序列共有10个变异位点,其中兰考泡桐与白花泡桐在总的变异位点上,具有一致的碱基位点9个,占总变异的90%。而兰考泡桐与毛泡桐相比,没有相同的碱基。【结论】根据三种泡桐的rps16序列的序列特征和变异位点的分析,表明在叶绿体遗传方面,兰考泡桐具有与白花泡桐更多相似的遗传物质,其亲缘关系较近。综上所述,推测兰考泡桐与白花泡桐可能来自同一母系遗传。     

<Emphasis Type="Italic">Bursaphelenchus mucronatus</Emphasis> (Nematoda: Aphelenchoididae) vectored by <Emphasis Type="Italic">Monochamus </Emphasis><Emphasis Type="Italic">urussovi</Emphasis> (Coleoptera: Cerambycidae) in Hokkaido,Japan

Bursaphelenchus mucronatus Mamiya et Enda has been recovered for the first time from adults of the cerambycid beetle, Monochamus urussovi (Fischer), in Hokkaido, Japan. The nematode was also recovered from the inner bark of Picea jezoensis (Siebold et Zuccarini) Carrière and Abies sachalinensis (Fr Schmidt) Masters infested with M. urussovi larvae. PCR–RFLP analysis indicated that B. mucronatus in Hokkaido is the European type.     

Rehabilitation of diseased cacao fields in Peru through shade regulation and timing of biocontrol measures

The objective of this case study was to test the effectiveness of biocontrol for the rehabilitation of abandoned, diseased (moniliasis, witches' broom and black pod) cocoa and to develop testable hypotheses regarding the effect of shade and biocontrol timing. Three trial fields differed in their shade regimes. Biocontrol was administered starting either at flowering or pod filling. Disease incidence and yield were compared with cultural control alone. Biocontrol reduced moniliasis from 49% to 25%, independent of the shading regime and application time. Witches' broom was most severe without shade and unaffected by biocontrol. No significant effects on black pod were observed. Although biocontrol increased percentage healthy fruit independent of shading and timing, only the shaded plot with biocontrol from flowering onwards responded with increased yield. Our hypothesis is: 'In the rehabilitation of abandoned cacao, only fields under sustainable shade management and early onset of biocontrol can realise their production potential.' This revised version was published online in June 2006 with corrections to the Cover Date.     

Populations of adult fungus gnats and shore flies in British Columbia container nurseries as related to nursery environment,and incidence of fungi on the insects

Adult fungus gnat and shore fly populations were monitored in four container nurseries near Victoria, British Columbia. In general, populations of both insects were larger in summer than in winter. Also, both insects were more abundant in the nursery with a plastic-covered, soil floor, which favored moisture accumulation and build up of algae, liverworts and mosses, than in nurseries with other types of floors such as cement. Results of fungus isolations revealed that gnats and flies both harbor the seedling pathogens Botrytis cinerea and species of Fusarium and Phoma, plus several non-pathogenic fungi. The results are discussed in relation to nursery sanitation practices, their effects on gnat and fly populations, and some possible roles of these insects in seedling disease epidemiology.     

Insecticidal activity of certain medicinal plants

The methanol extracts of eight species of medicinal plants were tested for insecticidal activity in third instar larvae of Egyptian cottonworm (Spodoptera littoralis). All extracts showed a certain degree of larval toxicity. The extracts of Ocimum basilicum, Origanum majorana and Salvia officinalis appeared to be highly toxic. The extracts significantly affected the growth indexes [relative growth rate (RGR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD)].