青海东部农区引进燕麦品种各器官C、N、P生态化学计量学特征变化研究

以4个引种燕麦(Avena sativa)为典型代表,对其不同生育时期根、茎、叶中的C、N、P含量及其化学计量学特征进行测定,探讨不同生育时期燕麦C、N、P元素含量及其化学计量比的变化规律,为燕麦饲草的科学收获提供理论依据。结果表明：燕麦全株C、N、P含量分别为322.30～333.97、17.42～75.62、2.74～5.42 mg·g^-1,燕麦根C、N、P含量分别为298.42～317.92、11.47～73.71、2.82～3.42 mg·g^-1,燕麦茎C、N、P含量分别为311.25～338.86、10.15～75.16、2.44～5.06 mg·g^-1,燕麦叶C、N、P含量分别为330.80～372.47、30.64～113.80、2.59～8.65 mg·g^-1;各器官间C、N、P含量表现为叶>茎>根。此外,燕麦各器官C、N、P含量的积累过程具有一定季节特征,C含量积累过程受生育时期影响较小,表现出较强的稳定性;而N和P含量的积累过程受生育时期影响较大,其在拔节期～抽穗期均...     

天山高寒草原植物叶片氮磷化学计量特征对氮沉降的响应

人类活动和气候变化导致的大气氮沉降急剧升高，将会影响高寒草原植物养分循环。为了研究氮沉降对高寒草原植物养分含量及生态化学计量学特征的影响。依托2009年在新疆天山巴音布鲁克高寒草原设置的长期氮沉降研究平台，于2017年7月和10月采集溚草（Koeleria cristata）、二裂委陵菜（Potentilla bifurca）和天山赖草（Leymus tianschanicus）3种植物的成熟叶和老叶，分析3种植物叶片N、P元素生态化学计量对不同施氮水平的响应规律。结果表明：① 3种植物养分浓度及其化学计量比在成熟叶和老叶之间存在较大差异，成熟叶和老叶的N、P含量分别为12.78 mg·g^-1、0.88 mg·g^-1和6.88 mg·g^-1、0.46 mg·g-1mg·g^-1。3种植物成熟叶和老叶的N元素含量均为：二裂委陵菜>天山赖草>溚草,P元素含量同N元素含量趋势一致；② 氮添加增加了成熟叶和老叶N浓度，分别达12%和48%；成熟叶与老叶P浓度对氮添加的响应规律不一致，成熟叶P浓度对氮添加的响应与物种有关，而老叶P浓度呈一致的下降趋势；氮添加对成熟叶和老叶N∶P的比值影响亦不同，其中相对于成熟叶，老叶的N∶P呈显著增加趋势。③ 植物叶片的N元素、P元素和N∶P比三者之间的相关分析表明:N元素和N∶P之间呈显著正相关关系(P<0.05),在生长旺盛期和枯黄期，溚草和天山赖草的N与P元素之间没有发现显著相关性(P>0.05)，而二裂委陵菜呈现一定的差异性，在生长旺盛期二裂委陵菜叶片N与P元素呈显著的正相关、枯黄期呈显著的负相关(P<0.05)。表明长期氮的添加显著影响了3种植物叶片的养分含量和生态化学计量，不同物种间存在一定差异，未来氮沉降升高将会影响天山山地草原的植物养分循环。     

天山中段植物叶片碳氮磷化学计量及其海拔变化特征

海拔影响生态系统的生物地球化学过程和格局等诸多性质。研究干旱区植物叶片碳氮磷化学计量特征及其与海拔的关系,有助于揭示干旱区生态系统化学计量特征的空间格局变化规律,并预测其对全球变化的响应。通过对天山南北植物叶碳(C)氮(N)磷(P)计量特征的比较研究,分析海拔对其的影响。结果表明:天山中段植物叶C、N和P的平均含量分别为(414.3±47.3)、(21.4±8.1)、(1.39±0.64)mg·g-1,叶C∶N、C∶P和N∶P的均值分别为18.7±7.3、288.6±133.9、15.4±5.8。天山以北和天山以南的叶N含量和C∶N差异不显著,天山以北的叶C和P含量显著大于天山以南,而叶C∶P和N∶P显著小于天山以南。相关分析表明天山以北和以南的叶C与N、P、N∶P无显著相关,天山以北的叶C与C∶P无显著相关,其余元素及其比值之间均显著相关。随着海拔升高,天山南北植物的叶化学计量特征表现出相似的变化趋势:叶P含量升高,而叶C含量和C∶P、N∶P降低;但叶N含量与海拔间无显著的线性关系。     

黑果枸杞茎叶生长及其生态化学计量特征对灌水施肥的响应

在石羊河中游田间条件下,通过灌水和施肥调节黑果枸杞生长。测定不同时期黑果枸杞茎、叶生长量及其化学计量学特征变化,分析器官水平生长速率与化学计量学特征的关系,验证生态化学计量学理论"生长速率假说"。灌水施肥显著促进了茎长、基径和叶片长、宽及叶干重的生长(P<0.05),而茎长、基径、叶面积和叶干重的相对生长速率与对照之间无显著差异。各处理下黑果枸杞新梢C含量及C∶N、C∶P随生育期进程呈增加趋势,而N、P及N∶P呈降低趋势;灌水和施肥处理后茎C含量及C∶N、C∶P、N∶P低于对照,茎N、P含量高于对照。各处理叶片C、N、P含量在生育期内呈降低趋势,而C∶N、C∶P及N∶P呈增加趋势;灌水和施肥后叶片C含量及C∶N、C∶P、N∶P低于对照,叶片N、P含量高于对照。茎C含量及C∶N、C∶P显著高于叶片(P<0.05),而N、P含量及N∶P显著低于叶片(P<0.05)。生长速率假说认为,生物个体的生长速率与体内的N∶P、C∶P具有负相关关系,与N、P含量呈显著的正相关关系。各处理黑果枸杞茎、叶的生长速率与其N、P含量及C∶P、N∶P总体相关性不显著。表明施肥灌水调节下黑果枸杞茎叶生长及化学计量学特征不支持生长速率假说。     

河西走廊藜麦C、N、P生态化学计量学特征对物候期的响应

藜麦（Chenopodium quinoa）是南美洲传统作物,具有极高的营养价值和较强的环境适应能力,但其在我国西北干旱区的适应性还有待深入研究。生态化学计量学是对有机体的元素组成（主要是C、N、P）及其关系进行研究的科学,能一定程度地反映有机体的特征及其与环境的关系。在河西走廊大田栽培条件下,本试验研究了藜麦主要物候期的碳（C）、氮（N）、磷（P）含量及其生态化学计量比的变化。结果表明：随物候期的变化,藜麦的有机碳（organic carbon,OC）含量变化不显著,而全氮（total nitrogen,TN）和全磷（total phosphorus,TP）含量则显著降低;各器官间的OC含量较稳定,而TN和TP含量差异显著且叶和穗较高。藜麦的C∶N、C∶P随物候期的变化呈升高趋势,N∶P则呈先降低后显著升高趋势;根和茎C∶N、C∶P较高而叶N∶P较高。物候期和器官显著影响藜麦的C、N、P含量和计量比,后者与藜麦的生长和物质积累速度显著相关。     

天山北坡4种栽培杨树的功能性状分析

植物功能性状可以用来推断植物生活史策略,反映生态系统功能。为了研究天山北坡4种栽培杨树适应环境的生态策略差异,对其主要功能性状进行比较分析。结果表明,4种杨树的叶片大小、叶片厚度、叶干物质含量、茎皮厚度、木材密度和根、茎、叶全N,P,K含量均差异显著;但4种杨树间比叶面积差异不显著;新疆杨单叶面积和干物质量最大,胡杨叶片厚度和木材密度最大,钻天杨茎皮厚度最大;4种杨树的叶片N含量均显著高于茎和根,茎和根的N和P含量差异均不显著,除胡杨外,其他3种杨树叶片P含量均显著高于茎和根,K含量在4种杨树的根、茎、叶器官中表现不一致;钻天杨根、茎、叶的N,P,K养分含量都相对较高,俄罗斯杨的根、茎、叶的N,P,K养分含量都相对较低。4种杨树功能性状不同反映了植物对环境的适应性差异。     

不同林龄胡杨林叶片与土壤的化学计量特征

为了解天然胡杨林生态系统的C、N、P、K含量及化学计量特征,在新疆轮台县轮南镇选取5种不同林龄胡杨林(幼龄林、中龄林、近熟林、成熟林和过熟林),研究不同林龄胡杨叶和林下土壤C、N、P、K含量及化学计量特征。结果表明:(1)不同林龄胡杨叶的C、N、P、K含量分别为437.77、13.67、1.87、5.26 g·kg-1,林龄对叶片C、N、P、K含量影响不显著。不同林龄胡杨叶片C∶N、C∶P、C∶K、N∶P、N∶K、P∶K为35.46、187.04、87.86、8.40、2.66、0.57,林龄对叶片的C∶P、C∶K影响显著,对C∶N、N∶P、N∶K、P∶K影响不显著。(2)土壤的C、N、P、K含量分别为6.89、0.62、0.57、18.69 g·kg~(-1),林龄对土壤C、N、P、K含量影响显著。不同林龄土壤C∶N、C∶P、C∶K、N∶P、N∶K、P∶K为11.48、12.34、0.36、1.12、0.032、0.032,林龄对土壤化学计量影响差异显著。(3)胡杨叶片N∶P比为8.40,远远小于阀值14,表明胡杨生长发育过程中严重受土壤氮素含量限制。     

氮添加对天山高寒草原土壤酶活性和酶化学计量特征的影响

为探究氮添加对高寒草原生态系统土壤酶活性的影响,于2018年在中国科学院巴音布鲁克草原生态系统研究站,选择4个氮添加水平（对照,N0,0 kg·hm^-2·a^-1;低氮,N1,10 kg·hm-2·a^-1;中氮,N3,30 kg·hm^-2·a^-1;高氮,N9,90 kg·hm^-2·a^-1）,开展土壤酶活性对氮添加响应的研究,分析土壤酶活性对氮添加的响应特点,土壤酶化学计量比以及土壤酶活性与土壤环境因子的关系。结果表明：与对照相比,氮添加在N3水平显著增加β-1,4葡萄糖苷酶（βG）、β-D-纤维二糖水解酶（CBH）和β-1,4木糖苷酶（βX）酶活性（P < 0.05）,N1和N3水平显著增加碱性磷酸酶（AKP）活性（P < 0.05）,N3水平显著降低多酚氧化酶（PPO）活性（P < 0.05）,氮添加对亮氨酸氨基肽酶（LAP）活性影响不显著,N3水平下显著增加N-乙酰-β-D氨基葡萄糖苷酶（NAG）活性（P < 0.05）。相关分析表明,8种土壤酶活性均与土壤有机碳（SOC、NAG除外）和总磷（TP）显著相关,与土壤总氮（TN）不相关。研究区土壤酶活性C∶N∶P化学计量比为1∶1∶1.2,与全球生态系统的土壤酶活性C∶N∶P的比值1∶1∶1相偏离,表明该研究区土壤微生物生长受磷素限制。冗余分析（RDA）进一步揭示出土壤有机碳和土壤全磷含量是影响土壤酶活性的主要因子。     

阴坡-阳坡梯度上的植物叶片N:P化学计量学特征研究

通过对甘南亚高山草甸不同生境的18个植物样地的调查,研究了物种叶片N、P含量及其化学计量学特征,并结合分析土壤养分,探讨了它们与土壤N、P含量、有机质、水分及N∶P比值之间的关系。研究结果显示:甘南亚高山草甸植物叶片N含量在不同坡向之间的变化范围为4.46 ～ 26.59 mg· g^-1,平均为16.24 mg·g^-1;P含量变化范围为0.71 ～ 1.98 mg·g^-1,平均为1.37 mg·g^-1;N∶P比值变化范围为6.43～ 17.75,平均为11.60。叶片N含量及N∶P在不同坡向梯度上没有显著差异(P＞0.05)；叶片P含量在不同生境下差异显著。物种之间叶片N、P含量及N∶P均有显著差异(P＜0.05),而物种与生境的交互作用对叶片N、P含量及N∶P之间差异不显著。根据限制性因子的N∶P阈值判断,该地区植物生长受N限制,这也体现了该地区植物对其生境的一种适应。     

不同降雨频次对粗枝猪毛菜生育期化学计量特征的影响

降水格局变化下,研究植物各器官碳(C)、氮(N)、磷(P)化学计量特征和养分传输通路的构建,有助于理解C、N、P元素分配规律,对本土植物的生存和延续具重要意义。本研究设置4个降水处理:每月增水1次20 mm(W1)、每月增水2次,每次10 mm(W2)、每月增水4次,每次5 mm(W4)和自然降水作为对照(CK)。探讨荒漠植物粗枝猪毛菜(Salsola subcrassa M. Pop.)不同器官(叶、茎、果)C、N、P化学计量特征及其中性洗涤纤维(Neutral Detergent Fiber,NDF)、酸性洗涤纤维(Acid Detergent Fiber,ADF)、酸性洗涤木质素(Acid Detergent Lignin,ADL)含量的差异,以期揭示降水模式变化对典型荒漠植物养分获取的影响。结果表明:(1)各降水频次下,随植株生长,粗枝猪毛菜叶片和果中N含量均逐渐减少,但茎中逐渐增多。与CK相比,W4处理提高了叶片、茎及果在整个生育期内的N含量;叶片和茎中P含量随植物生长均逐渐减少,但果中逐渐增多,与其他处理相比,W4处理提高了茎和果在整个生长时期内P含量。(2)各降水处理下,叶片和茎中C:N值随时间的推移均呈先增后减趋势,其C:P和N:P值逐渐增大,果中C:N与C:P值较稳定,而果中N:P值逐渐减小。与其他处理比,W4处理显著增大了叶片和果在果实成长期内的N:P值(P0.05)。整体上,与CK相比,其余各频次降水均优化了粗枝猪毛菜的养分分配策略。(3)随植株生长,其叶片和茎的NDF、ADF及ADL含量均显著增加(P0.05)且叶片在不同时期同一处理下均达到差异显著(P0.05),与其他处理比,仅W4处理增加了茎和果在果实成长期的ADF含量。综上,W4处理下粗枝猪毛菜的养分分配更利于促进植株生长,表明该植物在高频次、小量级降雨下更利于优化养分分配、完成生活史。     

粉棒束孢谷胱甘肽过氧化物酶对氧化胁迫的响应

谷胱甘肽过氧化物酶（GPX）是生物机体内重要的抗氧化酶之一,在生物细胞抵御外界环境条件的刺激和胁迫时起到非常重要的作用。本文以粉棒束孢Pf340菌株为试验材料,研究不同条件的氧化胁迫对粉棒束孢谷胱甘肽过氧化物酶酶活性的影响,结果表明：三种不同条件下的氧化胁迫处理初期,均可造成菌株细胞GPX酶活性的降低,在胁迫处理的后期,过氧化氢胁迫下GPX酶活性与对照差异较小,而亚甲基蓝和亚硝基二磺酸钾处理下,GPX酶活性比对照有较大的提高,不同类型的氧化胁迫下菌株细胞GPX的生物学效应表现出不同的差异。     

噻菌茂的高效液相色谱分析

本文采用高效液相色谱法,以甲醇＋水（1‰磷酸）为流动相,使用以SHIMADZUVP-ODS、5um为填料的不锈钢柱和二极管阵列检测器,在280nm波长下对试样进行分离和定量分析。结果表明噻菌茂的线性相关系数为1.000 0;标准偏差为0.27;变异系数为0.29%;平均回收率为100.0%。     

Dermestid beetles in ‘evolution Canyon’, lower Nahal Oren, Mt. Carmel, including new records for Israel

Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr _s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr _s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Epidemiology of Toxigenic Fungi and their Associated Mycotoxins for Some Mediterranean Crops

Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Broad bean mottle virus in Morocco; curculionid vectors,and natural occurrence in food legumes other than faba bean (Vicia faba)

Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.