Proteolytic properties of Funastrum clausum latex

As part of a screening of latex endopeptidases from plants growing in Argentina, the presence of proteolytic activity in the latex of Funastrum clausum stems is reported. The proteases present in the crude extract showed the main characteristics of the cysteine proteolytic class, i.e. optimum pH at alkaline range, isoelectric point (pI) higher than 9.0, and inhibition of proteolytic activity by thiol blocking reagents. A remarkable thermal stability was also evident in the crude extract. Endosterolytic preference tried on p-nitrophenyl esters of N-alpha-carbobenzoxy-L-amino acids was higher for the alanine, asparagine and tyrosine derivatives. Preliminary peptidase purification by two-step ionic exchange showed the presence of two proteolytic fractions with molecular masses of approximately 24.0 kDa according to SDS-PAGE.     

Detection and partial characterization of extracellular proteases of the pathogenic fungi Endocronartium pint,Gremmeniella abietina and Heterobasidion annosum

Protease activities from 10 homokaryotic isolates of Heterobasidion annosum., two isolates of Grem-meniella abietina and six isolates of Endocronartium pini were studied. All the fungi showed in vitro protease activity with denatured casein. The greatest caseinolytic activity was at acidic pH, but Heterobasidion annosum and Gremmeniella abietina showed caseinolytic activity at basic pH also. Protease preparations from Heterobasidion annosum were able to degrade proteins from total phloem extracts of Pinus sylvestris, Picea abies, Betula pendula and Juniperus communis. At basic pH the artificial substrates hippuryl arginine (HA) and hippuryl phenylactic acid (HPLA), were hydrolysed most rapidly by Heterobasidion annosum at pH 8.1, indicating high exopeptidase activity at this pH. According to inhibitor studies with EDTA (ethylenediaminetetraacetic acid), E64 (L-trans-epoxy-succinyl-leycylamide-(4-guanidino)-butane-agmatine) and pin2 (potato trypsin/chymotrypsin inhibi-tor) both cysteine and serine proteases were present in proteases secreted by these pathogens, although only very low protease activity at basic pH was detected with Endocronartium pini.     

Antifungal activity of fruit pulp extract from Bromelia pinguin

The methanol extract of the fruit pulp of Bromelia pinguin was evaluated for its antifungal activity. The extract showed a significant activity against some Trichophyton strains, although Candida strains were generally insensitive.     

软枣猕猴桃花青素加工稳定性研究

花青素的稳定性易受加工条件的影响,为提高花青素在果蔬深加工过程中的稳定性,以软枣猕猴桃为试材,对其花青素进行提取,比较光照、pH值、温度及金属离子对花青素保存率的影响。结果表明:避光处理是软枣猕猴桃花青素加工过程保持稳定性的有效方法;pH值3.0、温度25℃时花青素稳定性始终保持在较高水平;K^+、Na^+、Ca^2+对保持花青素的稳定性显著优于Mg^2+、Cu^2+。     

不同地理居群山桐子的果实含油率与脂肪酸含量

随着煤炭、石油等化石能源价格的不断上涨,加快可再生能源,尤其是生物质能源的发展,以推进能源替代,被认为是解决全球能源危机的最理想途径之一(唐红英,2008)。目前,世界各国,尤其是发达国家,都致力于开发高效、无污染的生物质能源利用技术,以保障能源安全,实现CO2减排,促进经济、社会的可持续发展(Holdren,1991)。根据专家预     

The smell and odorous components of dried shiitake mushroom, Lentinula edodes III: substances that increase the odorous compound content

This study formed part of an effort to improve the quality of dried shiitake mushroom [Lentinula edodes (Berk.) Pegler], in accordance with consumer preferences, and deals with the search for substances that increase the odorous component content. From analysis of sulfur and sulfur-containing substances in the culture substrate, rice bran was found to be the main source of sulfur, and 75% of this was present as cysteine and methionine. The sulfur-containing substances were added to a sawdust medium containing only rice bran and sawdust as a substrate; shiitake mushrooms were cultivated in the medium, the fruiting bodies were dried, and the 1,2,4-trithiolane content in the fruiting bodies was measured as an indicator of the odorous compounds. Of the sulfur-containing substances, those that increased odorous compounds the most were cysteine and methionine. The efficiency of cysteine in this regard was higher than that of methionine. It was also noted that the amount of glutamic acid increased the odorous compounds in combination with cysteine and methionine. Furthermore, the addition of both amino acids and glutamic acid had no negative effect on the yield. These results showed that it is possible to produce dried shiitake mushrooms with a smell suitable for particular consumer preferences.     

Effects of GA<Subscript>3</Subscript> and ABA on the respiratory pathways during the secondary bud burst in black currants

The effects of exogenous gibberellic acid (GA₃) and abscisic acid (ABA) on the total respiratory rate, percentages of total respiratory rate contributed by respiratory pathways [Embden-Meyerhof- Parnas Pathway (EMP), Pentose Phosphate Pathway (PPP), and Tricarboxylic Acid Cycle (TCA)], and conversion of starch to soluble sugars in the buds of black currants during secondary bud burst were investigated to determine the relationship between respiratory rates and secondary bud burst. ‘Adelinia’, a black currant cultivar that is prone to secondary bud burst after the first harvest, was used in this study. Mature bushes of Adelinia were sprayed with 30 mg/L GA₃ and 50 mg/L ABA to manipulate bud burst. The results showed that exogenous applications of GA₃ and ABA had opposite effects on bud respiratory rate. Generally, GA₃ treatment increased the total respiratory rate and respiratory rate of the TCA and PPP, and the respiratory rates after GA₃ treatment were higher than those of control. While ABA treatment mostly decreased the total respiratory rate and the respiratory rate of TCA and PPP in buds in comparison to control. In terms of the percentage of the three respiratory rates in comparison to the total respiratory rate, GA₃ treatment significantly increased the percentage of TCA and PPP respiratory rate in comparison to the control (P < 0.01), whereas ABA decreased the rates. GA₃ significantly increased the content of soluble sugars and decreased the starch content, while the starch content in buds after ABA treatment was significantly higher than that of the control. All results showed that PPP is a critical process for the second bud burst in black currants. While the EMP–TCA pathway is still dominant in bud respiration, provides a series of basic materials and energy (ATP). The conversion of starch to soluble sugars is essential for bud burst. Thus, we conclude that an energy shortage is a main contributor in ABA inhibition of the secondary bud burst of black currants.     

不同叶果型栀子植株果内栀子苷和西红花苷含量分析

为给栀子种质资源评价及其活性成分的开发利用提供参考依据,对6种叶果型栀子植株(共60株)的叶片、果实形态参数,果实内部栀子苷、西红花苷含量进行了观测和分析。测定结果表明:同一栽培群体下栀子植株果实中的栀子苷、西红花苷含量间差异显著,其含量范围分别为1.75%~5.60%、0.33%~4.05%,大果型和中、小果型其栀子苷含量间存在显著差异。相关性分析结果表明,栀子苷与果实纵径间具有显著的正相关性(r=0.280),而与西红花苷含量间有极显著的正相关性(r=0.482),其它形态参数与栀子苷、西红花苷含量间均无显著相关性。稳定性试验结果表明:多数植株样本两年内果实中的栀子苷、西红花苷含量均稳定,而少数植株的含量却突增。同一栽培群体中的栀子植株存在着丰富的遗传多样性,果实内部栀子苷、西红花苷含量受遗传分化的影响均较大。     

Phenology and pollination of Manilkara zapota in forest and homegardens

Knowledge on reproductive phenology and pollination biology are basic elements that should be considered in the management and exploitation of plant species that offer non-timber products. The tropical tree Manilkara zapota is a species from which non-timber products have been obtained for centuries by Mayan communities in Mexico. Nevertheless, there are no quantitative reports on its reproductive biology and the factors that limit fruit production. The present study describes the reproductive phenology, breeding system and pollination of this species in two contrasting environments: medium-height, subdeciduous forest, and homegardens (“solares”) in a Mayan community in the state of Yucatan. Significant differences were found between environments both in the temporal distribution of flower and mature fruit production, as well as in the proportion of mature fruits. Homegarden trees showed the greatest fruit production, although flower production did not differ between environments. Mature fruits were of better quality (i.e., greater fresh weight) in homegardens. Hand pollination experiments showed that M. zapota is self-compatible, and that there is pollinator limitation for fruit production in trees that grow in homegardens. We propose that water and soil nutrients are the main factors limiting M. zapota fruit production in forests, while in homegardens the main factor appears to be pollinator availability.     

白花树天然群体表型多样性研究

调查了9个群体的14个表型性状,采用巢式方差分析、变异系数、相关分析和聚类分析等方法,分析了群体间和群体内表型多样性.结果表明:白花树表型性状在群体间和群体内都存在丰富的变异,群体间表型分化系数为59.08％,大于群体内变异;侧枝、叶片、果实和种子4类表型性状的平均变异系数分别为31.02％、16.85％、8.2％和6...     

Productivity and carbon storage in silvopastoral systems with Pinus ponderosa and Trifolium spp., plantations and pasture on an Andisol in Patagonia, Chile

No information is available about carbon (C) sequestration potentials in ecosystems on Andisols of the Chilean Patagonia. This study was undertaken to measure the size of C stocks in three predominant ecosystems: Pinus ponderosa-based silvopastoral systems (SPS), pine plantations (PPP) and natural pasture (PST), and examine how clover affect tree growth and stocks of soil C. The C contents of trees and pasture were determined by destructive sampling and dry combustion. Soil samples were taken at 0?C5, 5?C20, 20?C40?cm depths in order to determine soil C and N. For PPP and SPS total aboveground tree C was 38.4 and 53.1?kg tree^?1 and belowground was 21.3 and 23.4?kg tree^?1, respectively. Annual diameter increment at breast height was 1 and 2?cm in PPP and SPS, respectively, and was significantly higher in SPS. Trees in SPS, due to lower density and the presence of leguminous pasture, demonstrated enhanced growth and C sequestration. Soil organic C (SOC) stocks at 0?C40?cm depth were 193.76, 177.10 and 149.25?Mg?ha^?1 in SPS, PST and PPP, respectively. The conversion of PPP to SPS and PST to PPP resulted in an increase of 44.51?Mg?ha^?1 and a decrease of 27.85?Mg?ha^?1 in SOC, respectively. Favorable microclimatic conditions in relation to air temperature and soil moisture were observed in SPS as well as a synergy between trees and pasture.     

Veneer strand flanged I-beam with MDF or particleboard as web material III: effect of strand density and preparation method on the basic properties

Optimizing the manufacturing conditions of veneer strand-flanged I-beams was continued in this study and focused on the strand density and preparation method. Three levels of strand density were used, while the strands were prepared by either saw or roll-press splitter. The main results indicated that: within the compaction ratios (1.4–2.3) investigated in this study, the strand with lower density showed slight improvement in the dimensional stability and the bond strength between web and flange, but not in bending properties of the I-beams. The strand preparation method was concluded to be dependent on species for akamatsu, sugi, and bamboo strands; roll-press splitter-prepared strands tended to negatively affect dimensional stability and mechanical properties of the I-beams. When using akamatsu or sugi strands, low density allowed the possibility of using lower resin application rates between strands. Part of this paper was presented at the 54th Annual Meeting of the Japan Wood Research Society in Sapporo, August 2004     

沙棘原汁及饮料中维生素C含量在不同贮存条件下变化规律的研究

沙棘果作为食用的价值之一在于它含有丰富的维生素C。在沙棘饮料生产中,一般多采用鲜果立即榨汁,然后以贮存原汁的方法来保存原料。本试验表明,沙棘原汁及饮料在贮存期间维生素C的含量是较为稳定的,而稳定的差异又与光、温度等有关,并取决于同空气接触的程度。     

（强）热带风暴下海岸带梨园林网防护效益的研究

根据海岸带梨园林网遭受11号强热带风侵害后果园内落果情况的调查资料，研究了梨园林网的防护效益。结果表明：（1主林带背风面不同距离处梨的落果、减产指标随着距离的增加呈低－高－较低的曲线, 梨的保护量和保护率则呈相反的变化规律。（2）梨园林网的有效防护范围为0.5H-16H和24H-28H(H为主林带平均树高);与无林网梨园相比,梨园林网内梨的产量增加了2194.42kg/hm^2,增产率为23.93%,经济损失量减轻1450元/hm^2。     

我国中部地区小杂果的栽培和发展前景

通过对小杂果的生产现状和市场营销状况进行分析，表明小杂果在中部地区具有广阔的发展前景，文中对主要品种的丰产栽培措施进行了总结。     

枣树果实水分含量变化的研究

以5年生～6年生梨枣、金丝小枣和陕抗2号为试材,研究了枣树果实含水量的变化规律和差异。结果表明：枣树果实总含水量从幼果期到白熟期基本稳定,全红期后迅速下降。自由水含量变化近似于＂M＂形,束缚水含量变化近似于＂W＂形,此变化符合枣果实双＂S＂形曲线生长发育过程。枣树果实总含水量与自由水含量呈极显著正相关,与束缚水含量相关性不显著;自由水含量与束缚水含量呈极显著负相关。     

果园微气候及土壤养分对灰枣果实矿物元素含量的影响

为了遴选出影响灰枣果实矿物元素形成的关键因子,分别设计了树体阴阳面、遮阳、喷水及地表覆盖物等果园微气候处理方式,就不同处理下的气象因子及土壤碱解氮(N)、速效磷(P)、速效钾(K)、有机质(OM)及酸碱度(p H)对灰枣果实中的钙(Ca)、镁(Mg)、铁(Fe)、锌(Zn)、锰(Mn)和铜(Cu)等矿物元素的影响情况进行了试验,并采用显著性、通径系数及线性回归等分析方法,探究了枣果中矿物元素含量与气象因子及土壤养分因子之间的关系。结果表明:在一定范围内,p H值的升高,有利于枣果中Mg和Mn含量的增加;平均湿度相对较高,对枣果中Fe的含量有促进作用。土壤N含量能有效增加枣果中Cu的含量;枣果Ca含量的影响因素依次为平均湿度差、OM、N、平均最低温度及平均最小湿度,Ca含量与OM和平均最低温度间均有负相关,而与其他指标间均呈正相关;影响枣果Zn含量的因素依次为N、平均最低温度、平均湿度差、平均温度差和OM,其中Zn含量与N和OM间均存在负相关,而与上述其余各指标间均呈正相关。     

桉叶月见草素B的单体制备及其体内外稳定性研究

采用乙醇提取、大孔树脂吸附、中压柱层析和制备液相等方法从桉叶中分离得到月见草素B(OEB)单体,并对其结构进行了鉴定,分析了OEB在不同极性溶剂中的溶解度,同时考察了热处理条件、p H值及酶的作用对OEB损失率的影响,然后追踪了其在小鼠体内代谢过程,以综合评价OEB的体内外稳定性。结果表明:桉叶醇提所得粗提物经大孔树脂吸附、柱层析及制备液相纯化后可获得OEB单体化合物,纯度94.85%,得率(以桉叶干质量计)2.50%;OEB在水中的溶解度大于其他有机溶剂,热处理温度、p H值、酶的种类及浓度均对OEB的稳定性有影响,高温(80℃)、碱性条件(p H值7)和胰蛋白酶、脂肪酶对OEB的损失率影响更大,损失率最大可达98.85%;OEB在离体血浆作用后出现新组分且损失明显;OEB在小鼠体内的代谢过程表明其在体内胃肠道中均不稳定、易分解,不能直接进入血液,也不能以原型化合物的形式抵达粪便及尿液中。由此可见,OEB在体内外均不稳定,这将为阐明OEB的体内代谢途径及进一步提高其稳定性提供理论依据。     

Midgut cysteine-proteinase activity in the velvetbean caterpillar (<Emphasis Type="Italic">Anticarsia gemmatalis</Emphasis> (Hübner))

Proteinase inhibitors are currently targeted as potential insect control agents, but adaptation to proteinase inhibitors is a recognized limitation to such approach requiring the understanding of how phytophagous species can cope with such compounds. The velvetbean caterpillar (Anticarsia gemmatalis) is a key pest of soybean and well-adapted to its host proteinase inhibitors, which is rich in serine-proteinase inhibitors, particularly trypsin-like proteinase inhibitors. As the expression of cysteine proteinases in the midgut of the velvetbean caterpillar is a potential adaptation to circumvent its host defense, we assessed and characterized the digestive cysteine-proteinase activity from velvetbean caterpillars. Significant soluble and membrane-bound proteolytic activity was obtained and was consistent with those of cysteine proteinases based on the substrate and inhibitors used for their characterization. The K _m and V _max values obtained were 2.35 ± 0.50 mM and 40.89 ± 6.68 nmol min⁻¹ mg⁻¹ for the soluble proteinases and 0.33 ± 0.03 mM and 24.54 ± 0.67 nmol min⁻¹ mg⁻¹ for the membrane-bound proteinases, range of values also consistent with cysteine proteinases. Therefore, the proteolytic activity observed in the velvetbean caterpillar midgut is consistent with that of cysteine proteinases providing preliminary support for the contention of their potential involvement mitigating the negative effects of serine-protease inhibitors in this species.     

纪家林场桉树LH1无性系人工林土壤养分研究

为掌握雷州半岛桉树 LH1 无性系林的土壤养分概况，探索不同整地方式对土壤养分的影响， 研究以全垦、开沟、挖穴 3 种整地方式造林，采用“5 穴综合法”进行土壤取样，分析评价了 LH1 无性 系林的土壤 pH 值、有机质、碱解 N、速效 P、有效 K 等 11 个养分指标，以及各指标与不同整地方式之 间的关系。结果表明，LH1 无性系碱解 N 较缺乏，土壤有机质，速效 P、有效 K 处于中等水平，交换性 Ca、Mg 含量皆低于临界值，微量元素 Zn 丰富，Cu、Mn 适中，B 较缺乏；不同整地方式对除土壤 pH 值 外的其它 10 种养分指标的影响显著（P<0.05），开沟方式土壤中有机质、主要营养元素 N、P、K，以及 中量元素 Ca、Mg 的含量，都要高于挖穴和全垦的整地方式，桉树经营上可以利用开沟的方式营林，以 增加土壤养分；整地方式对土壤中不同微量元素影响作用也很显著，并且在不同土层上表现不同。土壤 养分指标之间既有促进作用，也有拮抗作用，与整地方式紧密相关；生产上可以针对微量元素 B 缺乏的 现状，适量增加微量元素 Mn 或降低 Mg 来加以改善。