不同水分条件下杨树-玉米复合系统凋落物分解特性

为探讨水分变化对农林复合生态系统凋落物分解特性的影响,以河西走廊杨树（Populus）-玉米（Zea mays）凋落物为研究对象,设置正常水分（9200 m³/hm²,对照）,轻度干旱胁迫（减少15%,7800 m³/hm²）,中度干旱胁迫（减少30%,6400 m³/hm²）3种不同水分处理条件,采用分解袋法研究了不同水分条件下杨树叶和玉米秸秆的质量残留率、分解速率和养分含量变化特征。结果表明：（1）随着干旱胁迫的加剧,两种凋落物的质量残留率均增加,而分解速率降低。经过164 d的分解后,杨树叶和玉米秸秆的质量残留率分别为70.43%-77.49%、63.55%-68.29%。分析表明：水分和时间对各类型凋落物的质量残留率均有极显著的影响（P<0.001）,但二者的交互作用不显著（P>0.05）;干旱胁迫显著降低了玉米秸秆的分解速率,但杨树叶的分解速率却只是在中度干旱胁迫下显著降低（P<0.05）。对于不同类型凋落物而言,分解速率表现为玉米秸秆>杨树叶。（2）两种类型凋落物的氮（N）残留率在分解过程中表现为降低的趋势,但随着干旱程度的加大,N的残留率增加,表明水分抑制了N的释放过程。分解164d后,同一类型凋落物不同水分条件下的N残留率均存在显著差异。对于同一水分条件下不同凋落物而言,玉米秸秆的N残留率最低,而杨树叶最高。总的来说,水分降低对干旱区农林复合系统内凋落物的分解和氮元素含量具有显著的抑制作用。     

凋落物多样性及组成对凋落物分解及土壤微生物群落的影响——二氧化碳倍增条件下

受全球变化的影响生物多样性的丧失日益严重,及时了解凋落物物种多样性及其组成如何直接或者通过调节微生物群落来间接影响凋落物分解已经成为生态学领域的热点问题之一。在呼伦贝尔典型草原区,羊草（Leymus chinensis）为原生群落建群种,茵陈蒿（Artemisia capillaris）、麻花头（Serratula centauroides）、二裂委陵菜（Potentilla bifurca）在退化及恢复群落中的多度均较大,本研究以此4种植物的凋落物为研究对象,在两倍于当前大气CO₂浓度（800 μmol/mol）条件下,通过嵌套实验设计来研究凋落物多样性（凋落物组成）对凋落物质量、C、N残余率和残余C/N的影响,并深入分析凋落物初始性质以及土壤革兰氏阳性菌（G⁺）、革兰氏阴性菌（G^-）、细菌（B）、真菌（F）及土壤总微生物磷脂脂肪酸（Phospholipid Fatty Acid,PLFA）含量和F/B对凋落物分解的影响。结果表明：（1）凋落物多样性及组成对凋落物质量、C、N残余率以及残余C/N均具有显著影响;凋落物组成对G⁺ PLFAs含量具有显著影响;（2）冗余分析（Redundancy Analysis,RDA）结果表明凋落物组成对凋落物分解和土壤微生物群落相关指标的影响高于凋落物多样性;（3）结构方程模型（Structural Equation Model,SEM）结果表明凋落物初始木质素含量和初始C/N均对凋落物分解具有显著影响,其中凋落物初始木质素含量起主导作用,其还可通过对土壤真菌PLFAs含量的影响来间接影响凋落物N残余率和残余C/N。所得结果可为大气CO₂浓度升高条件下退化草原生态系统的物质循环特征的预测乃至草原生态系统功能的合理评估提供数据支持。     

西沙永兴岛抗风桐与海岸桐群落凋落叶分解及中型土壤动物的贡献

我国南海诸岛主要是珊瑚岛。植物凋落物分解是生态系统元素循环的关键环节,但目前关于南海珊瑚岛生态系统凋落物分解的研究还是空白。以我国西沙群岛的优势树种抗风桐（Pisonia grandis）和海岸桐（Guettarda speciosa）为研究对象,采用凋落物袋法,分别于分解期间的第3、6、9、13和15个月取样,探究中型土壤动物对两种植物群落中凋落物分解过程中质量损失和养分释放的影响。结果表明：与没有中型土壤动物存在的情况（0.1 mm凋落物袋）相比,分解开始后的6个月内,中型土壤动物存在（2 mm凋落物袋）使抗风桐和海岸桐凋落叶分解速率分别提高了12.3%和4.8%（P<0.05）;分解6-15个月期间,中型土壤动物存在使抗风桐和海岸桐凋落叶分解速率分别提高了33.0%和12.3%（P<0.05）。中型土壤动物排除显著影响了不同分解阶段凋落叶总碳（Total carbon,TC）、总氮（Total nitrogen,TN）、纤维素、木质素和半纤维素的残留率变化。中型土壤动物群落组成受土壤温度显著影响（P<0.05）,它们对凋落叶分解的贡献可能主要受优势类群如真螨目和寄螨目的影响。相较海岸桐,抗风桐凋落叶的分解周期更短,中型土壤动物对其的贡献更大;选用抗风桐作为南海珊瑚岛退化植被恢复或新建的先锋种对促进生态系统元素循环更有利。     

黄土丘陵区人工林刺槐和油松凋落叶在不同降雨时期的分解特征

凋落物分解是维持生态系统养分循环和能量流动的关键过程,但在雨热同期的黄土丘陵区,不同降雨时期凋落物基质质量动态对该区不同树种凋落物分解速率的影响还不清楚。采用凋落物分解袋法,基于野外原位分解实验分析黄土丘陵区主要人工林刺槐（Robinia pseudoacacia Linn.）和油松（Pinus tabulaeformis Carr.）凋落叶在不同降雨时期的分解特征和分解过程中凋落叶基质质量的变化与分解速率之间的关系。研究结果发现：（1）经过391 d的分解,刺槐凋落叶的平均质量损失速率为（51.0±8.44）mg/d,显著地高于油松凋落叶（36.7±4.83）mg/d;雨季期间两树种凋落叶的质量损失速率均显著地高于旱季,其中夏季多雨期间凋落叶的质量损失速率最高,冬季微量降雨期间质量损失速率最低。（2）在整个分解过程中两树种凋落叶C和N含量都表现为净释放且主要发生在雨季,P含量表现为释放与富集交替进行;刺槐凋落叶C/N比、C/P比和N/P比呈波动的趋势,油松凋落叶C/N比则显著地增加且在夏季多雨期出现峰值,C/P比呈波动的状态,N/P比变化较小。（3）不同降雨时期刺槐凋落叶的质量损失速率与凋落叶P含量动态显著正相关,与C含量、C/P比和N/P比动态显著负相关。油松凋落叶质量损失速率与C/N比动态显著正相关,与C、N含量动态显著负相关,与N/P比动态呈负二次函数的关系。这些结果说明黄土丘陵区刺槐和油松凋落叶在不同降雨时期分解速率之间的差异显著且两树种凋落叶的分解都集中在雨季期间;此外凋落叶分解主要受到凋落叶N含量和N/P比动态变化的制约,与刺槐凋落叶相比,N含量与N/P比对油松凋落叶的限制作用更强。     

亚热带不同植被恢复阶段林地凋落物层现存量和养分特征

为揭示亚热带森林植被自然恢复过程中,凋落物层现存量及其养分元素储存能力的演变,采用空间代替时间的方法,在位于亚热带丘陵区的长沙县选取地域相邻、生境条件基本一致的檵木+南烛+杜鹃灌草丛（Loropetalum chinense+Vaccinium bracteatum +Rhododendron simsii scrub-grass-land,LVR）、檵木+杉木+白栎灌木林（L.chinense+Cunninghamia lanceolata+Quercus fabri shrubbery,LCQ）、马尾松+柯+檵木针阔混交林（Pinus massoniana +Lithocarpus glaber +L.chinense coniferous-broad leaved mixed forest,PLL）、柯+红淡比+青冈常绿阔叶林（L.glaber+Cleyera japonica+Cyclobalanopsis glauca evergreen broad-leaved forest,LAG）作为一个恢复序列,设置固定样地,采集未分解层（U层）、半分解层（S层）、已分解层（D层）凋落物样品,测定凋落物层现存量和主要养分元素含量、储量及其释放率,分析植物多样性指数与凋落物层现存量、养分元素含量的相关性。结果表明：1）凋落物层及各分解层凋落物现存量随着植被恢复而增加;同一恢复阶段D层凋落物现存量最高,占凋落物层现存量的41.59%-51.02%,不同分解层凋落物现存量的差异随着植被恢复而增大;各恢复阶段凋落物分解率为0.44-0.61,周转期为1.65-2.28 a。2）凋落物层及各分解层凋落物主要养分元素含量均表现为：N > Ca > Mg > K > P,随着植被恢复呈现出不同的变化特征,其中N、P含量总体上呈增加趋势,K含量LAG（除U层外）最高,PLL最低,Ca含量LCQ最高,PLL最低,Mg含量LAG（除U层外）最高,LVR最低;同一恢复阶段N、P（除PLL、LAG外）、K、Ca、Mg含量随着凋落物的分解而下降。3）不同恢复阶段凋落物层主要养分元素的储量依次为：N > Ca > Mg > K > P;凋落物层及各分解层凋落物主要养分元素总储量及各种养分元素的储量总体上随着植被恢复而增加;同一恢复阶段随着凋落物的分解,N、P储量增加,而K、Ca、Mg储量变化不大;随着植被恢复,凋落物层养分元素储存能力和转化归还能力提高,特别是N,养分元素总释放率下降,有利于养分的固持。4）乔木层、灌木层、草本层的植物多样性指数对凋落物层现存量和主要养分元素含量的影响不同,其中乔木层的影响最明显。     

海拔和郁闭度对祁连山青海云杉林叶凋落物分解的影响

为了探究海拔和郁闭度对青海云杉林叶凋落物分解的影响,本文选择海拔为2850 m,3050 m,3250 m和3450 m四个梯度和高、中、低三个林分郁闭度,采用分解网袋法,研究青海云杉叶凋落物分解速率及分解过程中N、P元素变化。结果表明,质量损失率随时间在波动增大。分解速率先减小后增大,不同海拔下分解速率为K₃₄₅₀ > K₃₀₅₀ > K₃₂₅₀ > K₂₈₅₀,不同郁闭度下分解速率为K_低 > K_中 > K_高,青海云杉叶枯落物分解50%和95%所需时间约为5.3 a和22.7 a。枯落物分解过程中,N、P含量和累积系数在不同海拔和郁闭度下的变化不同,与季节变化有关。研究结果为祁连山森林生态系统地球化学循环奠定基础。     

香樟凋落叶分解过程对两种间作作物生长和光合特性的影响

采用盆栽试验方法,探讨了香樟(Cinnamomum camphora)凋落叶不同土壤添加水平(0 g/盆为CK、25 g/盆、50 g/盆,100 g/盆)对受体作物小白菜(Brassica chinensis)、莴笋(Lactuca sativa)幼苗生长和光合特性的影响。结果显示:(1)香樟凋落叶分解对两种作物的地径、株高、生物量、叶片数和叶面积均有明显的抑制作用,且抑制效应随凋落叶添加量的增加而增强,但随着分解时间的延长其抑制作用逐渐减弱甚至表现为促进作用。(2)香樟凋落叶分解对两种作物的光合色素含量均有明显的抑制效应,并随凋落叶添加量的增加抑制作用增强,且持续时间延长。(3)经凋落叶处理的两种作物叶片净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)、水分利用率(WUE)总体上均低于CK,而胞间CO₂浓度(C_i)在各凋落叶处理下均高于CK。(4)随着土壤中凋落叶量的增加,两种作物在光饱和以及CO₂饱和状态下的最大净光合速率(P_{n max})、表观量子效率(AQY)、羧化速率(CE)、光呼吸速率(R_p)和暗呼吸速率(R_d)均不断下降,而光补偿点(LCP)、光饱和点(LSP)、CO₂饱和点(CSP)、CO₂补偿点(CCP)因受体作物的不同,表现出不同的变化趋势。研究表明,土壤中香樟凋落叶分解释放的化感物质,能通过降低受体作物的光合色素合成和光合能力,限制其营养生长,最终影响生物量积累;相对于莴笋,小白菜对香樟凋落叶分解产生的化感胁迫效应具有更强的耐受性,可能更适宜在香樟林间种植。     

半干旱草地不同植物枯落物分解对放牧和封育的响应

为探究放牧和封育对半干旱草地植物枯落物分解的影响,选取赖草、牛枝子及其混合物为研究对象,调查了不同网孔分解袋中宁夏半干旱草地植物枯落物分解特征及对放牧和封育的响应规律。结果表明：（1）放牧样地250目网孔中,枯落物质量残留率表现为牛枝子显著高于赖草和混合物（P<0.05）,而在放牧样地30目网孔、封育样地2种网孔中,枯落物质量残留率均表现为3种枯落物间无显著差异。（2）250目网孔中,放牧和封育样地枯落物分解衰减常数均表现为混合物显著高于牛枝子,而赖草居中;并且,牛枝子枯落物分解衰减常数表现为封育样地显著高于放牧样地。30目网孔中,放牧和封育样地枯落物分解衰减常数均表现为赖草、混合物显著高于牛枝子（P<0.05）;并且,牛枝子枯落物分解衰减常数表现为封育样地显著高于放牧样地（P<0.05）。（3）在放牧样地,仅牛枝子枯落物R_m表现为30目显著低于250目网孔（P<0.05）,k表现为30目显著高于250目网孔（P<0.05）;土壤动物对枯落物分解的贡献率表现为混合物显著低于牛枝子,赖草居中（P<0.05）。而在封育样地,仅牛枝子枯落物k表现为30目显著高于250目网孔（P<0.05）;土壤动物对枯落物分解的贡献率表现为混合物和牛枝子均显著高于赖草,且混合枯落物的土壤动物贡献率表现为封育样地显著高于放牧样地（P<0.05）。（4）枯落物残留率与其初始N、P、木质素/N、C/P呈显著相关性（P<0.05）;枯落物分解衰减常数与其初始N、P、木质素、N/P、C/P和木质素/P间均呈显著相关性（P<0.05）。研究表明,植物种类组成显著影响枯落物的残留率和分解衰减常数。放牧与封育管理通过影响网孔中土壤动物分布来调控半干旱区草地植物枯落物的分解,而且封育管理更有利于促进土壤动物对低质量枯落物（牛枝子）的分解。     

滇中亚高山地带性植被凋落物分解对模拟氮沉降的响应

模拟氮（N）沉降对凋落物分解特征的影响对研究森林生态系统物质循环响应大气N沉降的内在机理和应对N沉降全球化具有重要意义。从2018年2月至2019年1月，对滇中亚高山常绿阔叶林（Evergreen broad-leaf forest）和高山栎林（Quercus semecarpifolia forest）两种地带性植被进行模拟N沉降试验，利用尼龙网袋法对两种林型凋落叶和凋落枝进行原位分解试验，N沉降处理水平分别为对照CK（Control check，0 g N m^-2 a^-1）、低氮LN（Low nitrogen，5 g N m^-2 a^-1）、中氮MN（Medium nitrogen，15 g N m^-2 a^-1）和高氮HN（High nitrogen，30 g N m^-2 a^-1）。结果表明：常绿阔叶林凋落叶和凋落枝分解率分别为44.84%和21.96%，均高于高山栎林的35.97%（凋落叶）和17.51%（凋落枝）；N沉降处理使得常绿阔叶林和高山栎林的凋落叶和凋落枝质量损失95%的时间在对照（CK）的基础上均有一定程度的增加，其中以HN处理下最为显著；经过1年的分解，两种林型凋落叶、枝纤维素和木质素降解均受到N沉降的抑制作用；两种林型中凋落物质量残留率、纤维素和木质素残留率三者间呈极显著正相关。针对滇中亚高山区域范围内的两种地带性植被，凋落物分解对N沉降的响应方向主要取决于凋落物基质质量，其中尤以纤维素和木质素为重要影响因素。     

杉木人工林凋落物分解对氮沉降的响应

凋落物分解是陆地生态系统养分循环的关键过程,是全球碳（C）收支的一个重要主要组成部分,正受到全球大气氮（N）沉降的深刻影响。探讨大气氮沉降条件下森林凋落物的分解,有利于揭示森林生态系统C平衡和养分循环对全球变化的响应。选择福建沙县官庄林场1992年栽种的杉木（Cunninghamia lanceolata）人工林为研究对象,自2004年开始野外模拟氮沉降试验,至今12年。氮沉降处理分4个水平,N0、N1、N2和N3分别为0、60、120、240 kg N hm^-2 a^-1。2015年12月开展分解袋试验,对经过氮沉降处理12年的凋落物（叶、枝、果）进行模拟原位分解,每3个月收回一次分解袋样品,为期2年,同时测定凋落物干物质残留量及其C、N和磷（P）含量。结果表明,经2年分解后,氮沉降条件下凋落物叶、枝和果的干物质残留率平均值分别为27.68%、47.02%和43.18%,说明分解速率大小依次为叶 > 果 > 枝。凋落物叶、枝和果的分解系数平均为0.588、0.389和0.455,周转期（分解95%年限）分别为4-5年、6-8年和5-7年。低-中氮处理（N1和N2）均促进凋落物叶、枝和果的分解,以N1的效果更明显,而N3起到抑制作用。N1处理的凋落物叶、枝和果的周转期分别为：4.50年、6.09年和5.85年,N2处理的分别为4.95年、8.16年和6.19年。模拟氮沉降在一定程度上增加了凋落物叶、枝和果分解过程中的N和P含量,但降低了C含量。凋落物叶、枝和果分解过程中C元素呈现释放-富集-释放模式,N和P元素呈现释放与富集交替,除枝的N元素外,其他均表现为释放量大于富集量。     

Y-chromosome Data and Tribal Affiliations of Allenopithecus and Miopithecus

The phylogeny of Old World monkeys has remained unresolved in part because of a lack of resolution in the Cercopithecinae. Competing morphological hypotheses have had Allen's swamp monkey (Allenopithecus nigroviridis) and the talapoins (Miopithecus spp.) as basal branches of either the tribe Cercopithecini or the tribe Papionini. Previous molecular analyses have not adequately addressed the issue. To better understand the evolutionary history of these primates, we sequenced and subjected to phylogenetic analysis 3.1 kb of 2 loci (TSPY and SRY) from the non-recombining portion of the Y-chromosome. Individuals from the genera Allenopithecus, Miopithecus, Erythrocebus, Chlorocebus, and Cercopithecus were surveyed and their sequences compared with those previously published for the Papionini and Colobinae. The results suggest Allenopithecus and Miopithecus are more closely related to the Cercopithecini than Papionini. Our data also support the hypothesis that within the Cercopithecini, Erythrocebus and Chlorocebus share a close evolutionary relationship, distinct from the other members of the tribe.     

Nystatin and killer toxin sensitivity of free and immobilizedSaccharomyces cerevisiae

The inhibitory effect of nystatin and killer toxin on the growth of free and covalently-immobilizedSaccharomyces cerevisiae cells was studied. The resistance of immobilized cells to both agents was accompanied by increased amounts of phospholipids and sterols. The possible relationship between these changes in the membrane composition and the transduction of a signal across the cytoplasmic membrane is discussed.     

The hernandez and fernandez genes of Drosophila specify eye and antenna

The formation of different structures in Drosophila depends on the combined activities of selector genes and signaling pathways. For instance, the antenna requires the selector gene homothorax, which distinguishes between the leg and the antenna and can specify distal antenna if expressed ectopically. Similarly, the eye is formed by a group of "eye-specifying" genes, among them eyeless, which can direct eye development ectopically. We report here the characterization of the hernandez and fernandez genes, expressed in the antennal and eye primordia of the eye-antenna imaginal disc. The predicted proteins encoded by these two genes have 27% common amino acids and include a Pipsqueak domain. Reduced expression of either hernandez or fernandez mildly affects antenna and eye development, while the inactivation of both genes partially transforms distal antenna into leg. Ectopic expression of either of the two genes results in two different phenotypes: it can form distal antenna, activating genes like homothorax, spineless, and spalt, and it can promote eye development and activates eyeless. Reciprocally, eyeless can induce hernandez and fernandez expression, and homothorax and spineless can activate both hernandez and fernandez when ectopically expressed. The formation of eye by these genes seems to require Notch signaling, since the induction of ectopic eyes and the activation of eyeless by the hernandez gene are suppressed when the Notch function is compromised. Our results show that the hernandez and fernandez genes are required for antennal and eye development and are also able to specify eye or antenna ectopically.     

Molecular identification and differentiation of Brevibacterium species and strains

Amplified ribosomal DNA restriction enzyme analysis (ARDRA), pulsed field gel electrophoresis (PFGE) and ribotyping were used to differentiate among 24 strains of Brevibacterium linens, Brevibacterium casei and Brevibacterium epidermidis obtained from type culture collections or isolated from various smear ripened cheeses. ARDRA was applied to the 16S rDNA. B. linens was shown to be a quite heterogenic group with 2 to at least 4 copies of rrn operons per strain with aberrant nucleotide sequences. AccI gave genus specific restriction patterns and was used to separate Brevibacterium from Corynebacterium species. The expected species specificity of TaqI applied to B. linens type culture strains, but not to all strains isolated from cheese. By AvaI restriction, B. casei and B. linens were differentiated from B. epidermidis and the orange pigmented Arthrobacter casei, a new species of coryneform bacteria; by XmnI restriction, B. linens and B. epidermidis were differentiated from B. casei. One of 4 B. linens genotypes could not be distinguished from B. casei by this method. Here, the typical orange B. linens pigments were used for classification, which was confirmed by partial sequencing of the 16S rDNA.     

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A–C (1–3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC₅₀'s 4.1 and 9.7 μg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 μg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC₅₀'s 2.0 and 5.8 μg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.2, 16.6 and 22.4 μg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 μg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).     

Theoretical Study of Antagonists and Inhibitors of Mammalian Adenosine Deaminase: I. Adenosine and Its Aza- and Deazaanalogues

Aza- and deazaanalogues of adenosine, including their 1-protonated forms (except for that of 1-deazaadenosine), were studied by computer computation to find a relationship between their molecular structures and substrate properties for the mammalian adenosine deaminase. The atomic charge distribution and maps of the electrostatic potential around their van der Waals molecular surface were calculated for these compounds using the ab initio STO-3G method. The conformational studies are carried out by the MM⁺ method of molecular mechanics. The mechanism that determines the substrate selectivity of mammalian adenosine deaminase is discussed.     

Pericarp structure and phylogeny of theLamiaceae-Verbenaceae-complex

Pericarp structure was investigated in 158 species of the familiesLamiaceae andVerbenaceae. Data from 221 out of 262 genera ofLamiaceae s.l. and a few ofVerbenaceae s.str. were collected in a table. A cladistic analysis was performed on the basis of pericarp characters only. The abandonment of subfam.Pogostemonoideae as a taxonomic unit is considered. Examples of groups given additional support by similarities in pericarp characters are: (1) the gynobasic-styled labiates (subfamiliesPogostemonoideae, Lamioideae, Nepetoideae); (2) aLamioideae-Pogostemonoideae-group; (3)Nepetoideae; (4) aWestringia-Hemigenia-Hemiandra-Microcorys group (in subfam.Chloranthoideae); (5) aLepechinia-Chaunostoma-group (inNepetoideae); (6) aPrunella-Cleonia-group (inNepetoideae).     

Effects of carbon concentration and carbon to nitrogen ratio on the growth and sporulation of several biocontrol fungi

Effects of carbon concentration and carbon to nitrogen (C:N) ratio on six biocontrol fungal strains are reported in this paper. All fungal strains had extensive growth on the media supplemented with 6–12 g l⁻¹ carbon and C:N ratios from 10:1 to 80:1, and differed in nutrient requirements for sporulation. Except for the two strains of Paecilomyces lilacinus, all selected fungi attained the highest spore yields at a C:N ratio of 160:1 when the carbon concentration was 12 g l⁻¹ for Metarhizium anisopliae SQZ-1-21, 6 g l⁻¹ for M. anisopliae RS-4-1 and Trichoderma viride TV-1, and 8 g l⁻¹ for Lecanicillium lecanii CA-1-G. The optimal conditions for P. lilacinus sporulation were 8 g l⁻¹ carbon with a C:N ratio of 10:1 for M-14 and 12 g l⁻¹ carbon with a C:N ratio of 20:1 for IPC-P, respectively. The results indicated that the influence of carbon concentration and C:N ratio on fungal growth and sporulation is strain dependent; therefore, consideration for the complexity of nutrient requirements is essential for improving yields of fungal biocontrol agents.     

Origin and development of Tool-making behavior in Africa and Asia

Around two-and-a-half million years ago, some hominid populations in Africa began to modify stones and bones in a manner that can be recognized by prehistorians as artifacts, and, by definition, produced the earliest identifiable archaeological record. It is likely that earlier hominid groups also may have had relatively rich tool-using behavioral repertoires similar to that seen in modern chimpanzees (McGrew, 1992), such tools may have been made of perishable materials or minimally modified and thus difficult to identify. This review will focus on the earliest archaeological traces and the spread of hominids out of Africa and into Eurasia.     

Spatial and temporal patterns of morel fruiting

The biotic and abiotic factors conditioning morel fruit body production are incompletely known. We examined spatial and temporal patterns of Morchella esculenta fruiting over five years in a wooded site in Missouri, USA. Fruiting onset was inversely correlated with spring air and soil temperatures, whereas abundance was positively correlated with rain events (>10 mm) during the 30 d preceding fruiting. The two years with the greatest fruiting had the shortest fruiting seasons (6–7 d). Fruiting season length was positively correlated with soil warming, suggesting that a narrow range of optimum soil temperatures favour the explosive production of fruit bodies. All woody stems of at least 1 cm diam were mapped and stem diameter and crown condition were noted. Morel fruit bodies were significantly closer to stems of Carya spp., Tilia americana and Ulmus americana than predicted by the frequencies of these woody species or their contribution to the total basal area on the site. Although intra-annual clustering of fruit bodies was often observed, inter-annual clustering was not. The spatial pattern of M. esculenta fruiting appears to be associated with vegetation pattern, whereas the onset and abundance of fruiting are determined by the interaction of spring temperatures with availability of supporting precipitation.