6个玉簪品种的抗氧化酶特性及同工酶分析

以6个玉簪品种为试验材料,研究了不同玉簪品种幼苗抗氧化酶活性及其同工酶谱的差异性。结果表明:在非胁迫环境中,品种‘火与冰’和‘梦想’的SOD,POD活性显著高于其他品种;CAT活性品种间差异不显著。同工酶谱分析表明:6个玉簪品种叶片SOD和CAT同工酶谱带相似;不同品种在POD同工酶带型分布及显色强度上存在差异;品种‘火与冰’和‘梦想’均存在其特征谱带。总体认为,品种‘火与冰’和‘梦想’抗逆性较强。     

杜鹃叶片解剖结构与植株耐热性的关系

为研究杜鹃Rhododendron simsii叶片解剖结构与其耐热性的关系,以7个杜鹃品种为试验材料,利用人工气候室进行高温胁迫实验,观察其表型遭受高温胁迫后的变化情况,计算不同品种热害指数;利用电镜扫描观察参试杜鹃品种叶片解剖结构的11项指标,采用隶属函数对各品种的耐热性进行综合评价,与其表型变化对照分析。结果表明:杜鹃不同品种间,11项解剖结构指标差异均达到极显著水平。主成分分析结果表明,11项解剖结构指标在叶片结构差异中所起的作用近似,基于11个指标应用隶属函数法对7个参试杜鹃品种的耐热性进行综合评价,其耐热性排序为:‘宝玉’‘丹顶’‘白香玉’‘霸王红’‘瑞紫’‘红苹果’‘西子妆’,这与高温胁迫后不同品种的表型变化相一致。     

十堰市引种栽培油橄榄品种的叶片与果实表型性状分析

以十堰市引种栽培的6个不同油橄榄品种为研究对象,测定各品种的叶片及果实表型性状，采用方差分析比较不同油橄榄品种间的性状差异，采用Person相关分析研究各表型性状间的相关性，研究结果表明：不同油橄榄品种间的叶片及果实表型性状存在显著差异，‘皮削利’、‘鄂植-8号’和‘云台’果实较大，‘豆果’、‘阿尔波萨纳’与‘奇迹’果实较小；部分表型性状间相关性显著，可根据叶片性状初步筛选果肉率高的优良品种,为油橄榄品种鉴别及良种选育提供依据。     

杂交相思母本苗高对扦插效果的影响

以不同高度等级的杂交相思实生苗作扦插母本,通过对萌条数量、扦插成活率、苗高、地径、根系生长及生物量的影响试验观测,结果表明:不同高度等级实生苗木作母本与萌条数量、扦插成活率、苗高、地径、根系生长及生物量差异显著;定植的母株越高,扦插苗成活率越高,扦插苗质量越好。     

杉木品种‘洋020’无性系生长对比分析

基于福建省邵武故县水北管护站13年生‘洋020’无性系和杉木2代实生苗人工试验林,通过对树高、胸径以及单株材积、红心比率、木材基本密度的调查,对不同杉木良种在试验区内的各坡位上的生长状况进行分析和评价,结果表明：两个品种在中坡位及下坡位的生长量均优于上坡位,但2代实生苗大部分性状在坡间的差异并不显著,而‘洋020’无性系在中坡位生长表现显著优于上坡位。在中坡位,‘洋020’无性系的平均树高可达18.4 m,平均胸径达15.1 cm,单株立木材积为0.2157 m3;2代实生苗平均树高为17.1 m,平均胸径为16.5 cm,单株立木材积为0.2158 m3。总体上‘洋020’无性系平均树高较2代实生苗高,2代实生苗平均胸径高于‘洋020’无性系,两者在单株材积、木材基本密度上并无差异。‘洋020’无性系红心比率分布较为集中,主要在20%～30%之间。2代实生苗红心比率分布较为分散,在15%～45%之间均有分布。除了木材基本密度,‘洋020’无性系各主要生长性状变异系数均大幅度低于2代实生苗,表现出更优的林分齐性。     

美洲黑杨2025及其2个芽变品种苗对持续干旱的生理响应及抗旱性评价

【目的】对美洲黑杨2025及其2个芽变红叶品种‘中红杨’和‘全红杨’干旱胁迫的生理响应进行研究,比较3个品种的抗旱能力,为杨树彩叶新品种的适应性推广提供理论依据。【方法】以美洲黑杨2025及其2个芽变红叶品种‘全红杨’、‘中红杨’嫁接苗为试验材料,采用随机区组设计,盆栽模拟干旱环境,以正常浇水条件为对照,研究不同干旱胁迫处理时间(7、14、21、28天和复水处理7天)下3个杨树品种植株表型、光合特性的响应以及对叶片叶绿素、花色素苷等色素含量的影响。【结果】随干旱胁迫的加重,3个杨树品种叶片色素含量和光合生理指标均极显著下降(P0.01);胁迫后期,净光合速率和水分利用效率相继出现负值;叶片净光合速率、蒸腾速率均与土壤体积含水量呈显著正相关,Pn-Tr模拟方程判定系数R2均大于0.8;同时‘全红杨’叶片各色素含量均与土壤体积含水量呈显著正相关,叶色主要影响因子花色素苷含量亦极显著下降(P0.01),对Pn变化存在一定的解释关系;隶属函数分析得出抗旱能力由强到弱依次为美洲黑杨2025、‘中红杨’和‘全红杨’(P0.05);灰色关联分析发现叶绿素a、b及类胡萝卜素是评价品种抗旱性的首要指标。【结论】干旱胁迫下3个杨树品种各生理指标的变化有显著差异,3个杨树品种叶片Pn、Tr均与土壤体积含水量呈显著正相关,Pn-Tr模拟方程的判定系数R2均大于0.8;基于外部形态及光合生理等各项指标的分析,3个杨树品种的抗旱性差异明显,依次为美洲黑杨2025﹥‘中红杨’﹥‘全红杨’。     

湖南引种蓝莓叶片结构特征的比较及其耐旱性研究

为给湖南省的蓝莓引种栽培提供参考依据,以湖南省蓝莓研究发展中心引种的蓝莓为试验材料,采用常规石蜡制片技术和叶表皮离析法,对26个蓝莓品种叶片的解剖结构和气孔特征进行了观察,对其叶片、上下表皮、角质层和主脉的厚度和气孔的长度与密度等13个与其抗旱性相关的参数进行了观测,并对不同品种的耐旱能力进行了比较分析。结果表明:26个蓝莓品种其叶片的各个结构参数间均存在极显著差异(P0.01),其中,气孔密度的变异系数最大,下表皮厚度的变异系数最小。应用聚类分析方法筛选出的角质层厚度、下表皮厚度、栅栏/海绵比值、气孔长度和气孔密度等5个参数均可作为评判叶片耐旱性的主要因子,采用隶属函数法综合评判得出,耐旱能力较强的蓝莓品种有‘蓝源’‘瑞卡’‘灿烂’‘爱国者’‘美登’和‘伯克利’。     

葡萄叶片SPAD值与测定位置及光合色素含量的关系

为了实时、准确、无损地检测葡萄叶片中叶绿素的含量水平,以评价葡萄生长发育与营养状况,确保栽培的科学和施肥的合理,以‘夏黑’‘巨玫瑰’‘户太8号’‘阳光玫瑰’‘金手指’‘摩尔多瓦’这6个品种葡萄叶片为试验材料,采用叶绿素测定仪测定了6个葡萄品种叶片不同位置的SPAD值,使用分光光度计测定了葡萄叶片光合色素含量,探寻了葡萄叶片SPAD值的最适测量位点,分析了SPAD值与光合色素含量的关系,并建立了SPAD值与光合色素含量的线性函数拟合方程。结果表明:6个品种葡萄叶片的SPAD值,叶片顶部的均最高,中部的均次之,基部的均最小;其中,葡萄叶片中部的SPAD值最具有代表性。6个品种葡萄叶片的SPAD值与叶绿素a、叶绿素b、总叶绿素和类胡萝卜素含量均显著相关,其与叶绿素a含量的相关性最高;在不同品种葡萄叶片的SPAD值与叶绿素a、叶绿素总含量、类胡萝卜素含量的线性函数拟合方程中,‘户太8号’的拟合方程决定系数值最高,其叶绿素a、叶绿素总含量、类胡萝卜素含量的决定系数值分别为0.903 5、0.867 2、0.749 9;在叶绿素b与葡萄叶片SPAD值的拟合方程中,‘金手指’的拟合方程为y=0.034 7x-0.084 0,其决定系数R2值(0.773 4)最高。单一品种葡萄叶片的SPAD值与光合色素含量的回归模型的拟合准确率比6个葡萄品种汇总拟合回归模型的要高。     

不同类型黑莓品种的生理生化特性分析与评价

【目的】对引种栽培于南京的不同类型的9个黑莓品种的生理生化特性进行观察测定和综合分析评价,旨在为其生产实践提供理论指导。【方法】以直立类型品种‘纳瓦荷’‘乔克多’‘萨尼’和半直立类型品种‘赫尔’‘三冠王’‘卡伊娃’‘宁植4号’及蔓生类型品种‘黑布特’‘宝森’为研究对象,测定其叶片叶绿素含量、果实品质、相关抗氧化酶活性以及抗氧化物质含量等生理生化指标,并进行综合分析与评价。【结果】直立类型品种叶片叶绿素含量尤其是叶绿素b含量显著高于半直立类型和蔓生类型;直立类型品种叶片总蛋白含量高于其他2个类型;各品种超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性的差异均不显著;直立和半直立类型品种的抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量均较高,均显著高于蔓生品种,与自由基变化一致;直立类型品种果实的总糖含量最高,其中葡萄糖、果糖含量均较高,半直立类型中的‘宁植4号’‘三冠王’和蔓生类型品种中的‘黑布特’排在其次,与可溶性固形物含量情况基本一致;相比于蔓生品种,直立和半直立类型品种果实中花色苷和多酚的含量更高。【结论】黑莓直立和半直立类型栽培品种在南京地区生长表现良好,其叶片光合能力、果实抗氧化能力强,其中‘纳瓦荷’‘乔克多’‘宁植4号’品种的综合表现最佳。     

美国山核桃叶片性状及其与苗木生长量的关系

以湖南省永州市冷水滩采穗圃中的美国山核桃为试材,系统测定了8个品种美国山核桃的叶片基本性状及生长量。结果表明,不同品种叶片特征值及叶面积、比叶重和叶绿素含量及各组分均存在显著差异;不同品种实生苗苗高与地径均存在极显著差异。相关分析表明,品种间叶绿素含量及各组分与叶形指数星显著或极显著正相关;苗高、地径均与叶片几个基本性状呈正相关,且与叶绿素(a／b)值达显著水平;     

<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.     

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.     

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.     

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)].     

A new norlignan from Taxodium ascendens

A new norlignan, (2R,3R,4S,5S)-2,4-bis(4-hydroxyphenyl)-3,5-dihydroxy-tetrahydropyran (1), together with 9 known compounds were isolated from the branches and leaves of Taxodium ascendens. Their structures were mainly determined on the basis of MS, IR, 1D and 2D NMR spectral evidences. Methanol extract showed inhibitory activity on carbonic anhydrase II with an IC₅₀ value of 4.27 µg/ml, acetone extract and methanol extract inhibited activity of cathepsin B with IC₅₀ values of 2.12 and 3.71 µg/ml, respectively.     

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.     

<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.     

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.     

Trees and shrubs as sources of fodder in Australia

Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline.     

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.