油松无性系雌雄球花量变异和稳定性评价

于１９８５～１９９５年在河南省卢氏县油松种子园连续观测了３１个无性系的雌雄球花产量，结果表明，雌、雄球花量无性系间差异达极显著水平，两者无性系重复力在分析的６ａ中分别高于６５．１２％和８６．４９％。无性系雌、雄球花量与年度的互作效应亦达到极显著水平，其方差分量分别为１２．０３％和３７．９４％。由于雌、雄球花量存在大小年现象，无性系选择尚须在稳定性筛选的基础上进行。不同无性系雌、雄球花量年份稳定性差异大，所分析的３１个无性系中，雌、雄球花量稳定的无性系各有２０和２２个，因此，选择花量大且稳定的无性系建园是可能的。此外，还就雌、雄球花量变异对球果中饱籽和空籽数及种子遗传组成的影响作了讨论     

红松种子园树木开花结实规律

通过对草河口１９７７年营建的红松种子园８年的观察研究发现，各无性系雌球花开花株率呈增加趋势，系间差异显著；雄球花多集中在树冠中、下部，少数无性系花粉在园中起垄断作用；种子园中只开雄球花的树木比例大，占５３．８５％，只开雌球花的树木比例很小，占１．０３％，开两性花的占２７．６９％。系间结实量差异极显著，年度间相关紧密，但与树体生长性状相关不显著。     

红松种子园树木开花结实规律

通过对草河口１９７７年营红松种子园８年的观察研究发现，各无性系雌球花开花株率呈增加趋势，系间差异显著；雄球花多集顺树冠中、下部，少数无性系花粉在园中起垄断作用；种子园中只开雄球的树木比例大，占５３．８５％，只开雌球的树木比例很小，占１．０３％，开两性花的占２７．６９％。系间结实量差异极显著，年度间相关紧密，但与树体生长性状相关不显著。     

思茅松无性系种子园雌雄球花分布特性及人工辅助授粉的研究

在云南省林业科学院普文试验林场思茅松种子园开展了16个无性系的雌雄球花空间分布特性及人工辅助授粉的研究，结果表明：各无性系间雌雄球花数量及雌雄比均差异极显著，存在偏雌偏雄的变异；雌雄球花数量的空间分布存在一定的规律性，在垂直方向上，79％以上的雌球花分布于树冠的中上部，80％的雄花分布在树冠的中下部；在水平方向，东 西、南、北4个方位球花数量的分布基本一致。种子园的落花现象比较严重，且不同无性系的落花率不同；人工辅助授粉有助于雌球花的保存和座果率的提高。     

辽宁兴城油松种子园无性系开花习性的研究

1982－1984年在辽宁兴城种子园，3年的观测表明，49个无性系花期早晚和长短有较大差别，这与无性系本身的特性，花期前的积温，花期内的温度和湿度以及球花着生部位等有关，由于种子园中有部分无性系花期不遇，由此减少的杂交组合至少在1／10以上，嫁接后第九年雌球花产量较上年成倍增加，到第10年总产量仍持续上升，但早期结实量大于平均水平的约30％无性系，雌球花产量已有下降趋势。迄今种子园中开花株数和雄球花产量稳定增长，多数无性系植株平均着花量约在700个上下，但仍有约半数无性系的1／3植株尚未开雄球花，种子园中花粉量不足，每公顷约产花粉2．8－3．7公斤，且种子园各无性系花粉比例极不平衡，5个无性系的雄花量占部量的一半以上。     

矮化马尾松无性系二代种子园开花结实特征分析

对马尾松无性系二代矮化种子园开花结实及生长性状进行研究,以达到科学精细化管理,进一步提高种子产量和品质目的。结果表明,55个无性系中偏雌球花无性系占43.64%,偏中型无性系占30.91%;64%的无性系提供80%以上雌球花、雄球花和球果产量,其中19个无性系贡献率达到50%以上;无性系间的雌球花量、雄球花量、球果产量、侧枝粗、抽梢长等指标均存在显著差异;球果产量与雌球花量和雄球花量存在极显著相关,雌球花量和雄球花量与成花枝条数、胸径、侧枝数、侧枝角度、冠幅大小密切相关,与抽梢长度无关,碗状型树型能够显著提高母株雌球花量、雄球花量和球果产量。     

华山松种子园无性系开花习性研究

云南楚雄华山松种子园的无性系,其雌球花着生在树冠外围枝条,而雄球花主要着生在树冠的内膛枝条。在水平方向上,雌球花多着生在树冠南部,雄球花的分布比较均衡;在垂直方向上,雄球花基本分布在树冠的中下部,雌球花则分布在树冠的中上部。大多数无性系的雄球花散粉期比雌花可授期早2~4 d;不同无性系间的雌雄花期具有一定的同步性。各无性系间雌、雄球花数量存在极显著差异,且有明显的偏雌或偏雄特性。雄球花量与无性系生长性状间存在显著正相关,雌球花量与树体生长相关性不显著。     

马尾松种子园的花量分析

对福建省五一林场的马尾松种子园开花习性进行了观测和分析。结果表明无性系间和年度间的雌雄球花量差异达极显著水平,且雌雄球花量在年度间亦达显著相关,另外还分析了各无性系的雄球花贡献率及对子代贡献率较大的无性系。     

马尾松无性系种子园球花量变化研究

对福建漳平五一国有林场马尾松种子园雌、雄球花量观察和分析。结果表明 ,种子园雌、雄球花产量变异主要来源于年份、无性系、无性系与年份互作等效应。它们二者在无性系间、无性系与年份互作间遗传相关关系不显著 ,而在无性系内分株间、年份间相关达到极显著和显著水平。并结合实践 ,提出建园材料再选择 ,以及对现有种子园采用选择性疏伐等提高种子园球花产量 ,克服雄球花显少有效技术措施     

杉木无性系间球花产量变异的分析

摘要 1989年春在黎平县东风林场对杉木优树收集区中45个无性系和种子园六大区第五小区16个无性系(共计183株母树)的雌、雄球花产量进行了调查。统计分析结果表明:不同于性系间在雌、雄球花产量上存在着极显著的差异,种子园中少量无性系雌、雄球花产量占垄断地位的现象明显;群体间与个体间在雌、雄球花产量上的差异大小顺序为:无性系内分株间>种源内无性系间>种源区内种源间>种源区间。     

Vertebrate and insect pests and hemi-parasitic plants of Parkia biglobosa and Vitellaria paradoxa in Nigeria

This study investigated the occurrence and diversity of hemi-parasitic plants, vertebrate and insect pest species of Parkia biglobosa (Keay), and Vitellaria paradoxa (Gaertn.) as well as the strategies for their control in the parklands of the Nigerian humid savanna. Results indicated that of the two major hemi-parasitic plants encountered, Tapinanthus globiferus was the more widespread with wider host range than T. dodonifolius. Mechanical control by cutback of infested branches was ineffective for both species. The major vertebrate pests consist of 6 avian species from 3 families: Nectaridae, Plocidae and Cuculidae; a fruit bat, Epomops frangueti and an unidentified squirrel. The species fed on both the fruits of the trees and the seeds of the hemi-parasitic plants. Twenty insect species from 14 families were encountered on P. biglobosa compared to 33 species from 17 families on V. paradoxa in all the ecological zones covered in the study. Species diversity was comparatively higher in the fallow than in the cultivated land. The majority of the insects encountered was of little significance and may not warrant application of control. Cirina forda (Saturnidae:lepidoptera) was a major pest causing 60%–90% defoliation of mature trees of V. paradoxa. All larval stages were destructive but control at this stage is not advised because it provides incidental source of food to locals. Control after pupation using a slow-release insecticide with a soil penetration depth of 15–20 cm is suggested.This revised version was published online in November 2005 with corrections to the Cover Date.     

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.     

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.     

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.     

Growth, nitrogen fixation and mineral acquisition of Alnus sieboldiana after inoculation of Frankia together with Gigaspora margarita and Pseudomonas putida

The role of tetrapartite associations among Frankia, Gigaspora margarita (an arbuscular mycorrhizal fungus), Pseudomonas putida (rhizobacterium), and Alnus sieboldiana in growth, nitrogen fixation, and mineral acquisition of A. sieboldiana was investigated. Seedlings of A. sieboldiana were inoculated with Frankia isolated from root nodules of alder, followed by inoculation of G. margarita and P. putida, and were grown for 5 months in a greenhouse. The seedlings inoculated with Frankia and G. margarita together produced the highest biomass of shoots and root nodules. Nitrogen-fixation activity, measured by acetylene reduction assay, was observed when Frankia was inoculated. The activity, on a per-nodule gram basis, decreased after G. margarita inoculation, but on a per-plant basis there was no significant difference in the activity among inoculation treatments. The mineral content in the seedlings changed after inoculation with Frankia, but not after inoculation with P. putida and/or G. margarita. The results showed a synergistic interaction among Frankia, the mycorrhizal fungus, and the rhizobacterium on the growth of A. sieboldiana.     

Root diseases in bareroot and container nurseries of the Pacific Northwest: epidemiology, management, and effects on outplanting performance

In forest and conservation nurseries in the Pacific Northwest USA, seedling production can be limited by root diseases caused by fungi in the genera Fusarium Link:Fr., Cylindrocarpon Wollenw., Phytophthora de Barry, and Pythium Pringsh. Fusarium, Cylindrocarpon, and Pythium are the most ubiquitous, whereas incidence of Phytophthora is mostly associated with coastal bareroot nurseries. All of these root pathogens are encouraged by water saturated soils or media. Seedlings infected with Fusarium, Phytophthora, or Pythium often appear chlorotic or necrotic with extensive root decay. Cylindrocarpon often causes serious root decay without shoot symptoms. The best approach to mitigate losses from these diseases is to use a holistic integrated pest management program. This program should combine chemical controls with cultural practices, particularly those that increase soil permeability and drainage and reduce potential sources of inoculum, especially by disinfesting seeds and containers reused for crops. In general, we found that seedlings meeting nursery specifications for outplanting on forest soil (proper height, root collar diameter, healthy shoot color, lack of disease symptoms) but having these disease organisms on their root systems perform as well as non-infected seedlings.     

Biomass and production of fine and coarse roots of trees under agrisilvicultural practices in north-east India

An understanding of the rooting pattern of tree species used in agroforestry systems is essential for the development and management of systems involving them. Seasonal variation, depth wise and lateral distribution of biomass in roots of different diameter classes and their annual production were studied using sequential core sampling. The investigations were carried out in four tree species under tree only and tree+crop situations at ICAR Research Farm, Barapani (Meghalya), India. The tree species were mandarin (Citrus reticulata), alder (Alnus nepalensis), cherry (Prunus cerasoides) and albizia (Paraserianthes falcataria). The contribution of fine roots to the total root biomass ranged from 87% in albizia to 77% in mandarin. The bulk of the fine roots (38% to 47%) in the four tree species was concentrated in the upper 10 cm soil layer, but the coarse roots were concentrated in 10–20 cm soil depth in alder (46%) and albizia (51%) and at 0–10 cm in cherry (41%) and mandarin (48%). In all the four tree species, biomass of both fine- and coarse-roots followed a unimodal growth curve by showing a gradual increase from spring (pre-rainy) season to autumn (post rainy) season. Biomass to necromass ratio varied between 2 to 3 in the four tree species. The maximum (3.2) ratio was observed during spring and the minimum (2) in the rainy season. In alder and albizia, the fine roots were distributed only up to 1 m distance from the tree trunk but in the other two species they were found at a distance up to 1.5 m from the tree trunk. The annual fine root production varied from 3.6 Mg ha^–1 to 6.2 Mg ha^–1 and total production from 4.2 to 8.4 Mg ha^–1 in albizia to mandarin, respectively. Cherry and mandarin had a large number of woody roots in the surface layers which pose physical hindrance during soil working and intercultural operations under agroforestry. But the high biomass of roots of these two species may be advantageous for sequential or spatially separated agroforestry systems. However, alder and albizia have the most desirable rooting characteristics for agroforestry systems.This revised version was published online in November 2005 with corrections to the Cover Date.     

Antinephritis and radical scavenging activity of prenylflavonoids

Antinephritis activity of 5 prenylflavonoids similar to glabridin (1-5), isolated from Morus alba, Artocarpus communis, Glycyrrhiza uralensis and G. inflata, was evaluated in mice with glomerular disease (Masugi-nephritis). Oral administrations of artonin E (2) or licochalcone A (4) for 10 days (30 mg kg(-1) day(-1)) reduced the amount of urinary protein excretion compared to nephritic mice. ESR spectroscopy demonstrated that morusin (1) and licorisoflavan A (5) increased the radical intensity of sodium ascorbate by about two times. Morusin, licoricidin (3), licochalcone A and licorisoflavan A showed weak scavenging activity against superoxide anion radical.     

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.     

Antioxidant and antimicrobial activities of Onosma argentatum and Rubia peregrina

The n-hexane-dichloromethane (1:1) extract of the roots of Onosma argentatum and the methanol extract (partitioned between water and chloroform, ethyl acetate and n-butanol, respectively), of the underground parts (roots and rhizomes) of Rubia peregrina were tested in vitro for their antioxidant and antimicrobial activities. The highest antioxidant activity (98%) was observed at 0.1% concentration for the roots of O. argentatum. It was 96% at 0.25% concentration on the ethyl acetate fraction of R. peregrina. O. argentatum extract was effective on Staphylococcus aureus, Bacillus subtilis and Escherichia coli. The ethyl acetate and chloroform fractions of R. peregrina were effective on S. aureus and E. coli, respectively. These two species did not have any antifungal activity.