余甘子果实贮藏保鲜初步研究

对来自福建省生产区惠安县、南安县余甘子果实试样进行贮藏保鲜特性初步研究。结果表明,蒂腐率与采样时间有关,9月底采样蒂腐率高于12月初采样。各品种(类型)或优株之间差别较大。品种(类型)之间失重率比腐烂率差异小。失重率与腐烂率显著相关联且与时间呈显著或极显著典型非线性相关。各处理中常温袋贮腐烂率较低,失重率也较小。果实可溶性固形物与果实单宁含量趋势一致,果实单宁含量与果实腐烂率趋势相反。品种(类型)和优株之间可溶性固形物有一定差异,贮藏过程中同一试样完好果可溶性固形物变化小,相同试样气干状态可溶性固形物比袋贮高。     

余甘子生物学特性及其利用初步研究

本文介绍了余甘子形态特征、物候期、结果特性、生长发育周期、生态习性以及果实贮藏加工利用技术等,指出了当前余甘子研究和开发利用中存在的问题,并提出了相应对策措施。     

宜昌主栽猕猴桃品种耐贮性特征

以‘金桃’‘翠玉’‘金艳’‘黄金果’‘东红’‘徐香’‘红阳’7个宜昌猕猴桃主栽品种为试材，探究在冷藏、冷藏后常温存放5 d两种条件下，果实失重率、硬度、可溶性固形物三个指标随贮藏时间的变化。研究表明，果实失重率均随贮藏时间的延长而上升，冷藏后常温存放5 d的条件下果实失重率高于冷藏条件，两种条件均为‘黄金果’失重率最高，‘徐香’失重率最低。果实硬度随贮藏时间的延长而下降，冷藏条件下，较耐贮的为‘金桃’‘徐香’，其次是‘翠玉’‘黄金果’‘红阳’，贮藏性较差的为‘金艳’‘东红’。冷藏后常温存放5 d的条件下，果实硬度下降较快，‘红阳’最不耐贮。两种条件下均为果实可溶性固形物含量与硬度呈反比，可溶性固形物含量均为‘红阳’>‘金艳’或‘东红’>‘黄金果’>‘翠玉’>‘徐香’>‘金桃’。     

霜冻前后野生余甘子果实功能成分的变化

【目的】探明余甘子果实经过霜冻后风味更佳的原因。【方法】以永仁县野生余甘子林同一居群7株代表性植株为研究对象,在霜冻前后,采用随机抽样的方法,测定余甘子果实形态和功能成分指标,分析各指标的相关性,并比较了霜冻前后各指标的变化。【结果】同一居群不同余甘子样株果实的蛋白质含量、氨基酸含量、总酸含量、总糖含量、SOD活性、维生素C含量、总酚含量、硒含量均有差异,其中霜冻前变异系数最大为硒含量(31.65),其次为氨基酸含量(27.52)。果实蛋白质含量与维生素C含量呈极显著负相关,与总糖含量、总酚含量呈极显著相关;果实维生素C含量与总酚含量呈极显著负相关。霜冻后,余甘子果实形态差异显著,营养物质蛋白质、氨基酸、总糖、总酚含量均增加。其中,氨基酸含量极显著增加,由26.82μmol/g增大到36.97μmol/g,总糖含量显著增加,由47.82 mg/g增加到52.97 mg/g,蛋白质含量增大,总酚含量均值变化最小,但蛋白质含量和总酚含量差异均未达显著水平,果实SOD活性、总酸含量、硒含量极显著降低,维生素C含量显著降低。【结论】霜冻有改变余甘子果实营养物质形成和积累的作用。生产中,霜冻前有利于采集维生素C、硒含量较高的余甘子果实;霜冻后余甘子果实蛋白质、氨基酸、总糖含量较高,有利于采集到的营养价值高且口感较好的果实。     

温度湿度对双孢蘑菇贮存效果的影响

通过对在不同温度、湿度条件下双孢蘑菇失重率、呼吸强度和褐变度的变化情况的考察来研究贮藏条件对双孢蘑菇贮存效果的影响。试验表明:低温对双孢蘑菇的失重率、呼吸强度和褐变度有抑制作用;高湿条件可减少双孢蘑菇采后的失重率,但会增加褐变度。     

余甘子离体快速繁殖技术的初步研究

余甘子 (ＰｈｙｌｌａｎｔｈｕｓｅｍｂｌｉｃａＬ .)为大戟科 (Ｅｕｐｈｏｒｂｉａｃｅａｅ) ,叶下珠属 (Ｐｈｙｌｌａｎｔｈｕｓ) ,落叶小乔木或灌木。在我国主要分布于南亚热带地区[1] 。余甘子果可生食、渍制或榨取果汁 ,果具清热解毒、降血压、防治肝胆病、收敛止泻作用 ,是重要的中药材和制药原料[2 ] ,同时树皮为重要的栲胶原料。余甘子在干热河谷、石质山地等生态脆弱区已作为优良的生态经济兼用造林树种。我国余甘子良种化起步晚 ,虽然只有少数地区开始采用良种 ,但发展势头很快。近几年引进的国外品种已表现出较好的适应性和生长…     

余甘子繁殖试验初报

余甘子(Phyllanthus emblica L.)又名滇橄榄,为大戟科(EuPhorbiaceae)叶下珠属(Phyl-lanthus)落叶小乔木或灌木。在我国主要分布于南亚热带地区。余甘子果可生食、渍制或榨取果汁,果具清热解毒、降血压、防治肝胆病、收敛止泻作用。果汁及其所配制的饮料对强致癌物N-亚硝基化合物在动物和人体内的合成阻断率达90％以上,在防癌方面显示了特殊的功效。云南省余甘子居全国之首,据初步调查产量可达3000万kg,各地、州均有分布,主要分布于海拔800～1300m范围内。虽然具有丰富的资源,但长期以来未引起人们的重视,对它的     

竹醋液壳聚糖复合涂膜对椪柑保鲜效果的研究

为了开发天然柑橘类果实保鲜剂,研究了竹醋液和壳聚糖对采后椪柑的主要致病菌-指状青霉菌的抑制作用,以及对贮藏期椪柑采后生理的影响。结果显示:竹醋液和壳聚糖对指状青霉菌均有抑制作用,最小抑菌浓度为竹醋液1.5%、壳聚糖0.8%。在椪柑采后贮藏中,用竹醋液、壳聚糖以及二者复合物分别处理果实,以清水处理为对照,通过测定椪柑采后生理生化指标来考察竹醋液壳聚糖复合涂膜对椪柑的保鲜效果。结果表明:与对照相比,各个处理都能够降低采后椪柑的病果率、失重率和丙二醛含量,延缓可溶性固形物、可滴定酸以及Vc含量的下降,以及诱导过氧化物酶活性上升。其中竹醋液壳聚糖复合涂膜效果优于二者单独使用。     

柔性气调库中CO2浓度对沾化冬枣果实品质和耐藏性的影响

以沾化冬枣为试材,研究了不同浓度CO2对冬枣果实品质及贮藏效果的影响。结果表明,在温度-1℃~-2℃,氧气3%~5%条件下,1.0%~1.5%的CO2浓度能有效抑制冬枣呼吸作用,减缓可溶性固形物的增加,减少维生素的损失,保持果实硬度,降低冬枣的失重率和腐烂率,保持贮藏品质,延长贮藏期。     

甜樱桃果实采后贮藏保鲜技术研究综述

近年来,甜樱桃面积和产量不断扩大,但是其果实不耐贮藏,研究其果实的贮藏保鲜技术对甜樱桃产业发展具有重要意义。本文从甜樱桃果实采后生理、病害、成熟度对贮藏的影响及贮藏保鲜技术方面综述了近些年国内外对甜樱桃果实采后生理及贮藏保鲜技术的研究。不同的保鲜措施均能在一定程度上减缓果实营养物质含量的下降,降低果实腐烂率,提高贮藏品质。但是目前甜樱桃果实贮藏保鲜措施仍以低温冷藏为主,保鲜效果较差。针对不同地区、不同品种甜樱桃果实寻找无毒、经济、高效的贮藏方式仍是亟需解决的技术问题。另外,需要加强贮藏保鲜技术的推广、果实运输保鲜措施及贮藏配套设施的建设和完善。     

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。     

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.     

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.     

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.     

Ungulate herbivory of regenerating conifers in relation to foliar nutrition and terpenoid production

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.     

Long-term effects of single prescribed fires on hardwood regeneration in oak shelterwood stands

One of the arguments against using prescribed fire to regenerate oak (Quercus spp.) forests is that the improvement in species composition of the hardwood regeneration pool is temporary and multiple burns are necessary to achieve and maintain oak dominance. To explore this concern, I re-inventoried a prescribed fire study conducted in the mid-1990s to determine the longevity of the effects of a single prescribed fire on hardwood regeneration. The initial study was conducted in three oak shelterwood stands in central Virginia, USA. In 1994, each stand was divided into four treatments (spring, summer, and winter burns and a control) and the hardwood regeneration was inventoried before the fires. During the burns, fire intensity was measured and categorized in each regeneration sampling plot. Second-year postfire data showed marked differences in species mortality rates, depending on season-of-burn and fire intensity: oak and hickory (Carya spp.) regeneration dominated areas burned by medium- to high-intensity fire during the spring and summer while yellow-poplar (Liriodendron tulipifera) and red maple (Acer rubrum) seedlings dominated unburned areas and all areas treated with low-intensity fire regardless of season-of-burn. The treatments were re-inventoried in 2006 and 2007 to determine whether these fire effects were still present. The new data show that the species distributions by season-of-burn and fire intensity found in 1996 still existed 11 years after the treatments. The fact that fire effects in oak shelterwood stands can last at least a decade has important management implications for resource professionals interested in sustaining oak forests in the eastern United States.     

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.     

Predisposition to bark beetle attack by root herbivores and associated pathogens: Roles in forest decline,gap formation,and persistence of endemic bark beetle populations

Bark beetles are largely known for their ability to undergo intermittent population eruptions that transform entire landscapes and pose significant economic hardships. However, most species do not undergo outbreaks, and eruptive species usually exert only minor disturbances. Understanding the dynamics of tree-killing noneruptive species can provide insights into how beetles persist at low densities, and how some spatiotemporal patterns of host predisposition may more likely favor breaching eruptive thresholds than others. Elucidating mechanisms behind low-density populations is challenging, however, due to the requirement of long-term monitoring and high degrees of spatial and temporal covariance. We censused more than 2700 trees annually over 7 years, and at the end of 17 years, in a mature red pine plantation. Trees were measured for the presence of bark beetles and wood borers that breed within the primary stem, root weevils that breed in root collars, and bark beetles that breed in basal stems. We quantify the sequence of events that drive this decline syndrome, with the primary emergent pattern being an interaction between below- and above-ground herbivores and their fungal symbionts. This interaction results in an expanding forest gap, with subsequent colonization by early-successional vegetation. Spatial position strongly affects the likelihood of tree mortality. A red pine is initially very likely to avoid attack by tree-killing Ips beetles, but attack becomes increasingly likely as the belowground complex spreads to neighboring trees and eventually make trees susceptible. This system is largely internally driven, as there are strong gap edge, but not stand-edge, effects. Additional stressors, such as drought, can provide an intermittent source of susceptible trees to Ips beetles, and elevated temperature slightly accentuates this effect. New gaps can arise from such trees as they subsequently become epicenters for the full complex of organisms associated with this decline, but this is not common. As Ips populations rise, there is some element of positive feedback, in that the proportion of killed trees that were not first colonized by root organisms increases. This positive feedback is very weak, however, and we propose the slope between beetle population density and reliance on host stress as a quantitative distinction along a gradient from noneruptive through eruptive species. Almost all trees colonized by Ips were subsequently colonized by wood borers, likely a source of negative feedback. We discuss implications to our overall understanding of cross-scale interactions, between-guild interactions, forest declines, and eruptive thresholds.