大气CO2浓度升高对谷子生长发育及玉米螟发生的影响

人类活动导致全球大气CO_2浓度持续升高,研究大气CO_2浓度升高对C4作物谷子(Setaria italica)生长发育及虫害发生的影响,可以为谷子等C4作物制订应对气候变化栽培措施提供理论依据。本研究利用OTC(Open Top Chamber)系统,设两个CO_2浓度梯度(正常大气CO_2浓度、正常CO_2浓度+200μmol·mol-1)模拟CO_2浓度升高对谷子生长发育的影响。结果表明:大气CO_2浓度升高后,谷子净光合速率(Pn)、气孔导度(gs)、叶片蒸腾速率(Tr)和水分利用率(WUE)分别增加38.73%、27.53%、6.93%和40.56%;谷子叶片光系统Ⅱ最大光化学量子产量(Fv/Fm)和非光化学淬灭系数(NPQ)显著下降,光系统Ⅱ实际光化学量子产量(ΦPSII)和表观电子传递效率(ETR)显著增加,而对光化学淬灭系数(q P)无显著影响;此外,谷子株高、茎粗和小穗数分别增加3.41%、13.28%和13.11%;而叶重、茎重、千粒重、单株粒数和产量无显著变化,穗重和地上部分生物量分别显著下降12.8%和7.44%;大气CO_2浓度升高后,谷子灌浆期和收获期玉米螟(Ostrinia furnacalis)发生数量显著增加。大气CO_2浓度升高将有利于谷子的生长发育,但会增加玉米螟危害。     

外源放线菌对谷子生长和成熟期根际可培养微生物的影响

为研究外源放线菌对谷子生长及成熟期根际可培养微生物的影响，本研究通过盆栽和田间试验分析施加放线菌微白黄链霉菌（Streptomyces albidoflavus，T4）和密旋链霉菌（Streptomyces pactum，Act12）后成熟期谷子生物量、产量形成指标及根际可培养微生物结构组成的差异，并对谷子生长与根际微生物之间相互关系进行分析。结果表明，①T4促进了盆栽和田间试验中谷子生物量的增加，而T4和Act12也使田间试验中单株谷子籽粒干重和产量增加了13.7%～22.6%。②对于根际微生物，T4处理使培养箱盆栽试验中谷子根际可培养细菌（B）、真菌（F）、放线菌（A）及微生物总数量增加了29.5%～56.9%。T4和Act12使室外盆栽试验中根际真菌数量分别提高了73.3%和222.0%，A/F和B/F降低了34.7%～72.4%。③相关分析表明，成熟期谷子茎叶干重、单株谷子籽粒干重与根际B、F、A和总微生物数量显著正相关（r = 0.748～0.971，P < 0.01），而与A/F和B/F显著负相关（r = -0.764 ～ -0.906，P < 0.01）。综上，供试放线菌通过调整根际可培养微生物群落结构促进了谷子生长，增加了谷子产量。因此，通过外源施加放线菌优化根际可培养微生物群落结构是谷子促生增产的可行途径之一。     

Nuclear DNA content estimations in wild olive ( Olea europaea L. ssp. europaea var. sylvestris Brot.) and Portuguese cultivars of O. europaea using flow cytometry

Olive tree (Olea europaea L.) is an economically important woody fruit crop widely distributed in the Mediterranean regions. In this work the genome size of six Portuguese cultivars of olive (O. europaea ssp. europaea var. europaea) and wild olive (O. europaea spp. europaea var. sylvestris) was estimated for the first time. The nuclear DNA content of O. europaea cultivars ranged between 2.90 ± 0.020 pg/2C and 3.07 ± 0.018 pg/2C and the genome size of wild olive was estimated as 3.19 ± 0.047 pg/2C DNA. These results suggest a low intraspecific variation at least among the studied cultivars and between them and wild olive. This is not in accordance with previous results in some Italian cultivars where high genome size heterogeneity was found. The methodology presented here seems appropriate for genome size estimations within this genus and opens good perspectives for a large screening of estimation of nuclear DNA content among O. europaea cultivars and Olea species that could clarify this issue.     

杂交苏丹草(Sorghum bicolor×S.sudanense)修复DDT污染土壤效果研究

采用盆栽试验,研究了杂交苏丹草吸收和富集DDT的规律及其对DDT污染土壤的修复效果。结果表明:①土壤中添加高浓度的DDT,对杂交苏丹草的生物量没有显著影响,说明杂交苏丹草对DDT有耐受能力;②杂交苏丹草对DDT及其主要降解产物都有吸收,在旺盛生长期,植株中DDT的累积速率也较快;③杂交苏丹草根系中DDT及其主要降解产物的浓度是茎叶中相应组分浓度的4.81~10.32倍,质量比在0.57~1.55倍之间;④杂交苏丹草从土壤中吸收DDT占添加量的11.3%,而在其生长期间,土壤中DDT消失量为56.0%。     

Genetic diversity within and among landraces of pearl millet (Pennisetum glaucum) under farmer management in West Africa

The influence of farmer management on pearl millet landrace diversity was determined by evaluating variation in individual farmers' populations from two villages in north-eastern Nigeria. The variability within and between landrace samples was estimated using variation at 163 amplified fragment length polymorphism marker (AFLP) loci. The data indicated that individual farmers' husbandry practices result in the isolation of their own group of ideotypes each in their own unique genetic backgrounds, thereby rendering landrace names inappropriate as indicators of a generic genetic identity. The implications of these findings for sampling strategies for genebanks and regional genetic evaluations are discussed.     

Geographic distribution of Waxy gene SNPs and indels in foxtail millet, Setaria italica (L.) P. Beauv.

To elucidate diversity and evolution of the Waxy gene in foxtail millet, Setaria italica, we analyzed sequence polymorphism of Waxy gene in 83 foxtail millet landraces collected from various regions covering the entire geographical distribution of this millet in Europe and Asia. We found a unique geographic distribution pattern at the sequence level of gene haplotypes and also found a large diversity in East Asian landraces. We also found a higher degree of genetic polymorphism in a non-waxy phenotype than in other low amylose types, supporting the hypothesis that low amylose types recently originated from non-waxy type.     

Geographical variation of nuclear genome RFLPs and genetic differentiation in foxtail millet, Setaria italica (L.) P. Beauv.

Sixteen RFLP loci in 62 landraces were assayed to study geneticdifferentiation in foxtail millet, Setariaitalica (L.) P. Beauv. Among 52 bands, 47 werepolymorphic among foxtail millet landraces. A dendrogram constructedbased on RFLPs was divided into five major clusters (clusterI–V). Clusters I and II contained strains mainly from EastAsia. Cluster III consisted of strains from subtropical and tropicalregions in Asia such as Nansei Islands of Japan, Taiwan and thePhilippines and India and cluster IV consisted of some strains fromEast Asia, a strain from Nepal and a strain from Myanmar. Cluster Vcontained strains from central and western regions of Eurasia such asAfghanstan, Central Asia and Europe. Chinese landraces wereclassified into four clusters. These results indicate that foxtailmillet landraces have differentiated genetically between differentregions and that Chinese landraces were highly variable.     

Soil microbial attributes along a chronosequence of Scots pine (Pinus sylvestris var. mongolica) plantations in northern China

Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies have simultaneously considered these two factors. In this study, we measured soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil basal respiration (SBR) rate, and potential extracellular enzyme activity (EEA) in soil to a depth of 60 cm under 10-, 30-, and 40-year-old Scots pine (Pinus sylvestris var. mongolica) stands (Y10, Y30, and Y40, respectively) in plantations in northern China in 2011. Soil water content (SWC), soil pH, soil organic carbon (SOC), and soil total nitrogen (STN) were also measured to explore their effects on soil microbial indices across different stand ages and soil depths. Our results showed that SMBC, SMBN, and the SBR rate were generally higher for the Y30 stand than for the Y10 and Y40 stands. Potential EEA, except forα-glucosidase, decreased significantly with increasing stand age. Soil organic carbon,STN, SWC, and soil pH explained 67%of the variation in soil microbial attributes among the three stand ages. For the same stand age, soil microbial biomass and the SBR rate decreased with soil depth. Lower microbial biomass, lower SBR rate, and lower EEA for the mature Y40 stand indicate lower substrate availability for soil microorganisms, lower soil quality, and lower microbial adaptability to the environment. Our results suggest that changes in soil quality with stand age should be considered when determining the optimum rotation length of plantations and the best management practices for afforestation programs.     

Livestock predation by endangered African wild dogs (Lycaon pictus) in northern Kenya

Most large mammalian carnivores are in global decline, principally due to conflict with livestock farmers. Because endangered African wild dogs (Lycaon pictus) range widely, often beyond the boundaries of protected areas, they may be particularly exposed to lethal control by farmers, even where nominally protected by reserves. Hence, effectively conserving wild dogs demands resolution of their conflicts with farmers. We investigated livestock depredation by African wild dogs living outside protected areas in northern Kenya. Scat analysis confirmed the distribution of depredation events reported by local farmers, indicating that farmer reports - collated by local Community Liaison Officers - gave a reasonably good index of the true pattern of depredation. Although livestock were abundant throughout the study area, depredation was exceedingly uncommon (approximately one attack per 1000 km² per year) and the costs of tolerating wild dogs were very low (US $3.40/wilddog/year) where wild prey remained, even at low densities. However, where wild prey were seriously depleted, wild dogs killed livestock repeatedly, and the cost of sustaining them rose to US $389/wilddog/year. Hence, although wild dogs had a negligible economic impact in the region, their impact was locally severe. Conservation activities for wild dogs are most likely to be successful if targeted at areas where wild prey remain, and where traditional herding practices have been retained.     

Mulching with branches of an indigenous shrub (Guiera senegalensis) and yield of millet in semi-arid Niger

Crop residues from millet production in southwest Niger are limited for their utilization as mulch because of many other uses. Thus, branches of an indigenous shrub (Guiera senegalensis J.F. Gmel.) were tested with a randomised block design for their effect on millet (Pennisetum glaucum L.) yield. Pearl millet was planted in 1995 and 1996 on a luvic Arenosol in southwest Niger. Three treatments were applied: control, 1000 kg ha⁻¹ dry matter Guiera-mulch and 2000 kg ha⁻¹ dry matter Guiera-mulch. Mulched plots had 68–94% higher millet yields compared to the control. Differences in soil properties before the treatments were applied, explained a high variability within the treatments. Significant differences of soil properties between blocks led to a distinction of infertile and fertile blocks. In infertile plots with 1000 kg ha⁻¹ Guiera-mulch, millet yield was higher than in plots with 2000 kg ha⁻¹ Guiera-mulch. Due to the many uses of Guiera senegalensis by the local farmers, an application of 1000 kg ha⁻¹ Guiera-mulch, at least on infertile soils, seems a good possibility to increase millet production.     

Morphological characterization of seeds of three Australian wild Citrus species (Rutaceae): Citrus australasica F. Muell., C. inodora F.M. Bailey and C. garrawayi F.M. Bailey

The comparative morphology of the seeds of three Australian Citrus species, C. australasica C. inodora and C. garrawayi, was studied. Their seed characteristics were broadly similar to those of the cultivated species of the genus, when observed under light and scanning electron microscopy. Citrus garrawayi differed in seed shape (rounded to triangular) and seed coat morphology (i.e., thicker with longer epidermal protrusions) from C. australasica and C. inodora (rounded surface with flat underside in shape). The well-developed minute epidermal protrusions on the seed coat of C. garrawayi were more similar to those in the cultivated species, C. × sinensis and C. × aurantium. In contrast, the surface topography of C. australasica and C. inodora seeds was more like that of the cultivated species, C. × aurantifolia and C. × limon. Seed morphology, especially surface topography, was found to be a useful tool for taxonomic identification in Australian wild citrus.     

Oleaster (var. sylvestris) and subsp. cuspidata are suitable genetic resources for improvement of the olive (Olea europaea subsp. europaea var. europaea)

The olive belongs to Olea, a complex genus and to a species with six subspecies. Subsp. europaea includes both the cultivated olive and the oleaster, the wild ancestor of the olive. Little is known on the phenotype of fruits from subsp. cuspidata. We aimed to compare europaea and cuspidata trees for oil content and composition and to verify whether natural hybrids may exist between the two subspecies. Specimens were from Kenya and putative natural hybrids between cuspidata and europaea were from Stellenbosch (South Africa). Cultivar and oleaster trees were sampled in France (continental and Corsica), Italy (Continental and Sardinia) and Tunisia. We have examined the fruit (drupe) structure between subsp. cuspidata and europaea and extracted oil from the pulp, seed and total drupe. Comparison for oil content was made between the cultivated olive and the oleaster and some cuspidata trees from Kenya. A few of cuspidata individuals from Botanical gardens do not enable phenotyping for oil content and composition. Oil composition analyses were performed for the main fatty acids to compare the three taxa. We used microsatellite markers at 11 loci to compute genetic distances between cuspidata, oleaster and cultivar trees and to reveal eventual hybrids. The SSR polymorphisms were huge between the two subspecies and they revealed that putative hybrids were true hybrids sampled around olive orchards. The whole comparison of oil content shows that olive cultivars display higher oil content than the subsp. cuspidata and that the oleaster trees are intermediate, whereas for oil composition of the drupe, cuspidata from Kenya shows less oleic acid than europaea. However, the cuspidata trees show seed oil composition similarities with the other two taxa. The discussion deals with possible reasons to explain the differences and of the possible uses of these taxa for breeding both the olive and brown olive. H. Hannachi and H. Sommerlatte have equal contribution in the article.     

Assessment of storage protein variation in relation to some morphological characters in a sample of Spanish landraces of common wheat (Triticum aestivum L. ssp. aestivum)

Fifty nine Spanish landraces of common wheat belonging to differentagrotypes were evaluated with four morphological spike characters and 11 seedprotein loci in order to study the level of agreement between the agrotypeclassification and the morphological and biochemical variation of the wheats. Asa result of the work 22 new gliadin alleles were found and 12 of them werecatalogued. Multivariate and cluster analysis performed on the two sets of data(morphological plus biochemical and biochemical only) showed that there was aclear relationship between seed protein composition and the wheat classificationfor the agrotypes Barbilla, Candeal andNegrete. For the other groups, agrotype classification was notconsistent with the variation for biochemical characters although, some allelesin common were found except for the Jeja type. Morphologicaltraits revealed that they could be useful as first step in discriminating amongagrotypes. In contrast, biochemical markers showed that genetic variation amongaccessions was higher than among agrotypes. The protein lociGli-B1,Gli-A2,Gli-D2 andGli-A1 were shown to be the mostpolymorphic and useful in discriminating between the accessions studied.     

Development of EST-SSR in foxtail millet (<Emphasis Type="Italic">Setaria italica</Emphasis>)

The development of EST-SSR in foxtail millet (Setaria italica) for polymorphism and transferability study was reported here. From 1213 EST sequences, 30 SSRs were obtained and primers were designed for 26 SSRs. Among them, four pairs of SSR primers amplified polymorphic products in 12 foxtail millet cultivars and one accession of Setaria viridis, a wild relative of foxtail millet, with 10 alleles detected for the four loci and 2.5 alleles per locus. In addition, ten SSR markers could be transferred to other nine Gramineae species. The putative functions of 11 ESTs containing polymorphic and transferable SSRs were also identified.     

Detecting hybridization in wild (Coturnix c. coturnix) and domesticated (Coturnix c. japonica) quail populations

Two subspecies of Coturnix coturnix have allopatric distributions in Europe, Maghreb and western Asia (the Common quail C. c. coturnix), and in eastern Asia (the Japanese quail C. c. japonica), except for sympatric breeding areas in the Baikal (Russia) and Kentei (Mongolia) regions, where they could hybridize. Japanese quails have been reproduced in captivity for centuries and domesticated. Massive releasing of Japanese domesticated quails, or hybrids, in west European countries might threaten with hybridization the gene pool of wild quail populations. Here, we used mitochondrial (mtDNA) and nuclear DNA markers (microsatellites), and Bayesian admixture analyses aiming to assess subspecies distinction and identify hybrids in wild and captive-reared quails. A phylogenetic tree identified two major mtDNA clades, corresponding to the two subspecies, and allowed detecting 12 hybrids in wild Common quails sampled in Spain. Additional hybrids were identified in wild quails sampled in Spain, Italy and Senegal using microsatellite markers. Wild quails sampled in Mongolia showed japonica mtDNAs, but their microsatellite genotypes were admixed, suggesting that Common and Japanese quails can hybridize in nature. Some captive-reared stocks of Japanese quails were also admixed. Introgression of domesticated Japanese quail genes in wild Common quail populations might affect the phenotypic expression of functional traits, as body size, feather colours, sexual calls and migratory behaviours. Hence, restocking with captive-reared non-native quails should be banned.     

Testing of rye-specific markers located on 1RS chromosome and distribution of 1AL.RS and 1BL.RS translocations in Turkish wheat (Triticumaestivum L., T.durum Desf.) varieties and landraces

Rye (Secale cereale L.) is a valuable source for alien chromosome translocations in wheat breeding, due to its capability to grow and sustain under harsh environmental conditions. Wheat germplasm with 1AL.1RS and 1BL.1RS wheat-rye chromosome translocations have been used worldwide by breeders. Determining 1AL.1RS and 1BL.1RS translocations in wheat is therefore of important practical value for wheat improvement. In this study, nine rye-specific markers detecting the rye chromosome 1RS in wheat background were evaluated. The markers PAWS5/S6, SCM9 and O-SEC5′-A/O-SEC3′-R amplified specific bands associated with 1AL.1RS and 1BL.1RS translocations. These three markers therefore provide a quick and reliable tool to identify and to discriminate these two wheat-rye translocations in wheat background. Six out of nine rye specific markers were subsequently used to determine the frequency of these translocations in commonly grown bread and durum wheat cultivars from Turkey. One hundred seven wheat cultivars and landraces were molecularly screened. Among them, only 4% (‘Seri-82’, ‘Yıldız-98’, ‘Tahirova’, and ‘Osmaniyem’) harbor the 1BL.1RS translocation whereas the 1AL.1RS translocation was not found. The information provided here will contribute to the creation of new Turkish wheat populations with a larger genetic diversity necessary for future requirements.     

Correlates of abundance and breeding success in the globally threatened Hinde's babbler (Turdoides hindei) and its congener, northern pied babbler (T. hypoleucus)

We investigated the relationship between habitat quality, abundance, group size and breeding success in the threatened Kenyan endemic Hinde's babbler (Turdoides hindei; Family Timaliidae), a co-operative breeder mainly associated with riverine thickets in cultivated areas. At two intensively cultivated sites, significantly more Hinde's babbler groups occurred in areas retaining at least 3% thicket cover, while breeding outcome improved where cover exceeded 9%. Despite previous concerns over low breeding success, the percentage of young birds present (17%, n=424 birds aged) was similar to that of a sympatric congener, the northern pied babbler (T. hypoleucus) (12%, n=162), and comparable with that of two other African congeners. Although breeding outcome was positively correlated with adult group size, there was no evidence that larger groups monopolised more favourable habitat or defended larger territories. Group density showed a positive, non-linear relationship with adjacent cover, levelling out where this exceeded 15-20%. Our findings suggest that even a modest increase in thicket cover may significantly raise the density and productivity of Hinde's babblers at these sites.     

Genetic differences between the two remaining wild populations of the endangered Indian rhinoceros (Rhinoceros unicornis)

The management of rare and endangered species in the wild and in captivity requires an understanding of the characterization of the genetic units within each species and their relationships to each other. The Indian rhinoceros (Rhinoceros unicornis) is an endangered species with a current population size of c. 2800 individuals. We analyzed 26 individuals of known origin kept in captivity and 21 wild ranging individuals of the two remnant large wild populations in Assam (India) and Nepal employing mitochondrial and microsatellite markers to determine whether the two geographically isolated populations show distinct patterns of genetic diversity, and whether the genetic diversity of the populations is influenced by past demographic bottlenecks. We identified 10 different mitochondrial D-loop haplotypes, of which 4 were specific to the Assam population (10 sequences examined) and 6 specific to the Nepal population (19 sequences). Similarly, the microsatellite analysis demonstrated a strong genetic differentiation between the Assam and Nepal populations and allowed to assign each individual to its origin with high confidence. Furthermore, our analyses revealed the occurrence of a bottleneck in the Assam population long before the reported bottleneck in 1908, and it revealed that the Nepal population is a recent (probably post-glacial) colonization. In summary, the extent of genetic divergence between the two remnant R. unicornis populations suggests separate conservation programs (even for captive individuals) as long as the persistence of the entire species is not severely threatened. The microsatellite markers can also be used to determine the origin of confiscated material such as horns.     

大白菜简单序列重复(SSR)和插入/缺失(InDel)标记的开发及通用性分析

为探讨大白菜基因组序列中SSR位点的分布规律并开发SSR引物,利用SSRHunter软件对大白菜A10(16899818～17299817)的DNA序列进行简单序列重复(SSR)位点查找,共得到394个SSRs,平均每1.02kb出现1个SSR。二核苷酸和三核苷酸重复是最主要的SSR类型,分别占79.44%和18.78%。为了提高SSR标记开发的准确性和通用性,对检索得到的含SSR位点的序列进行了同源比对,选取符合条件的15条SSR序列并设计引物;依据Blast过程中发现的在SSR位点不存在差异而在其侧翼序列中存在插入/缺失(InDel)差异的序列,设计了19条InDel引物。用34对SSR及InDel引物在6个大白菜(Brassica rapassp.pekinesis)材料中进行多态性研究,发现28对引物能扩增出理想的PCR产物,有效扩增率为82.35%,其中27对引物具有多态性,多态性比率为79.41%。为验证SSR引物的真实性,随机对4对SSR引物的部分白菜扩增片段进行了测序,发现100%的片段具有相应的SSR位点。28对SSR和InDel引物在甘蓝(B.oleracea)、油菜(B.napus)和萝卜(Raphanus sativus)品种的有效扩增率分别为85.71%、100%和77.78%,说明新开发的SSR和InDel标记具有较好的多态性和通用性。利用6对引物分析了48份十字花科种质的遗传多样性,结果表明48份材料被明显地区分成白菜和甘蓝组、萝卜组、油菜组3大类群,与传统分类一致。大白菜SSR和InDel标记的开发对于十字花科种质亲缘关系及遗传多样性分析具有重要的应用价值。