气候暖干化背景下环渤海地区旱涝时空响应

[目的]在全球变暖背景下,为深入认识环渤海地区区域响应特征,进而制定防灾减灾政策,提高旱涝灾害应变能力。[方法]利用环渤海地区60个气象台站1961—2012年的实测气温、降水资料,采用线性趋势法、Mann—Kendall检验以及空间插值法揭示环渤海地区气候的时空变化特征;应用Z指数旱涝等级标准和区域旱涝指标分析该区域旱涝灾害的时空响应特征。[结果](1)环渤海地区近52a气候总体呈现暖干化趋势,年平均气温显著上升,增温速率为0.25℃/10a,且于1988年前后发生增温突变;年平均气温南高北低,大部分地区呈增温趋势,且南北增温程度差异不大。(2)降水量呈减少趋势,下降速率为10.37mm/10a;降水自东南向西北递减,沿海多于内陆,差异逐渐减小;(3)1988年后,环渤海地区旱涝灾害频率明显增加,其中旱灾显著增加,涝灾略有减少;空间上旱灾比例高于涝灾,且呈现出明显的干旱趋势。[结论]环渤海地区气候对全球气候变化有所响应,尤其是旱涝灾害,表现出一定的区域特征。     

宁夏旱涝灾害对气候变化的响应

利用宁夏回族自治区20个气象站自建站以来到2012年共52 a的降水数据资料,运用趋势线、滑动平均等数理分析方法对宁夏52 a以来的降水变化特征进行了分析,并应用降水Z指数和正负20%的降水距平指标对宁夏的旱涝灾害特征进行了分析。最后基于信息预测理论的对称性及可公度法,对宁夏未来的旱涝灾害进行了趋势判断。结果表明:(1)宁夏52 a年降水量以8.57 mm/10 a的速度递减,从20世纪90年代起干旱化趋势明显。(2)宁夏旱涝灾害交替发生,旱涝出现的频率为32.7%和28.7%,降水正常年份仅占38.5%。(3)宁夏旱涝灾害的发生具有显著对称性周期特征,未来发生旱灾的可能年份是2014和2015年,发生涝灾的可能年份是2017年。     

气候暖干化背景下东北地区旱涝时空演变特征

[目的]从旱涝灾害角度探讨气候变化对东北地区的影响,以期充分利用气候资源,为农业领域应对气候变化的对策措施提供理论依据。[方法]统计东北地区1956—2012年50个气象台站的逐月气温、降水资料,通过样条插值法、Mann—Kendall检测及Z指数方法对该区降水及旱涝时空演变特征进行分析。[结果](1)近57a东北地区气候整体呈现暖干化的趋势;(2)半湿润区增温幅度最大,达0.34℃/10a,湿润区相对较低,为0.25℃/10a。半湿润区降水减少趋势最为明显,为-8.82mm/10a。(3)东北全区、半干旱区、半湿润区Z指数变化一致,呈现出"涝—旱—涝—旱"的演变特征。(4)大涝频率高值中心分布于小兴安岭北部和三江平原、嫩江流域北部等;大旱频率高值中心集中分布于东北地区西部。[结论]东北地区气候暖干化的趋势给该区农牧业带来不利影响,受旱地区应及时启动干旱预警紧方案,开展抗旱工作。     

1959-2009年秦岭山地气候变化趋势研究

以秦岭山地39个气象站点1959—2009年近50a来的气温、降水资料为基础,分析研究了秦岭南北坡半个世纪气温与降水的变化趋势及特征。结果表明:(1)近50a来研究区气温总体上呈增加趋势,北坡气温倾向率为0.24℃/10a,南坡为0.15℃/10a;20世纪80年代中期以后,年均温呈极显著的增加趋势,特别是北坡地区气温倾向率高达0.74℃/10a,1993年后秦岭地区气候暖化趋势显著。(2)近50a来除夏季季均气温呈微弱的减少趋势外,研究区春、秋、冬3季均温均呈极显著的上升趋势(p<0.01),尤以冬、春两季平均气温上升更为显著;但1983—2009年27a间秦岭夏季气温呈上升趋势。(3)在50a尺度内秦岭北坡年均降水量在增加,而南坡年均降水量在减少,导致南北降水量差值减少;但近15a来秦岭南北坡年均降水量均有所增加,且北坡降水量增加速度更快(230.4mm/10a),说明秦岭北坡地区气候有暖湿化趋势。     

川滇地区气候特征与旱涝灾害变化趋势分析

以川滇地区70个气象观测站点1961-2011年的降水、气温资料为基础,采用线性回归、M-K突变检验、反距离加权空间插值、小波变换等方法,分析了川滇地区近51a来气候变化特征和旱涝灾害趋势。结果表明:(1)近51a来川滇地区气温总体上呈增加趋势,气温倾向率为0.21℃/10a,增温趋势系数高达0.71,气温存在极其显著的长期增温趋势。川西高原年平均气温最低,云南省南部地区气温最高,海拔高度是影响该区气温空间差异的重要因素。(2)近51a来川滇地区降水量总体上呈减少趋势,平均递减率为10.76mm/10a。受西南季风与海拔高度的影响,降水量在空间分布上差异极大,川西高原与四川盆地西南周边地区降水量相对较少,四川盆地降水相对丰富,滇西南地区降水量最为充沛。(3)川滇地区气候暖干化趋势明显,分别在1997和1999年发生了增温和降水量减少的突变,旱涝灾害存在10~15a和28a的周期振荡,该区涝灾向旱灾转化的趋势明显。     

阿拉善荒漠地区近50年气候变化的多时间尺度分析

利用阿拉善地区1961—2005年的气温、降水实测资料,分析了不同时间尺度下年平均气温、年降水量序列变化的周期和突变点,揭示了阿拉善地区近50a气候变化的多时间尺度特征,并根据主周期对未来气温和降水变化进行预测。结果表明：阿拉善地区的气温在20世纪80年代开始大幅度上升,突变点在1986年。80-90年代降水量很少,为干旱期,年降水量的突变点为1980年。根据气温和降水小波变换的主周期预测：未来阿拉善地区的气温可能升高,降水可能减少,即气候有暖干化的趋势。     

全球变化背景下新疆和田地区近半个世纪极端气温变化特征分析

对新疆和田地区1960—2013年的极端气温进行研究,以期为该区短期气候预测、生态环境安全以及灾害控制提供科学依据。通过累计距平法、滑动平均、一元线性回归趋势法、Mann-Kendall突变检验法及Morlet小波分析法,对该地区极端气温变化特征进行了分析,以探讨该地区气温变化的事实。结果表明:近54年来和田地区极端低温、极端高温分别以0.48℃/10a(p0.01)和0.19℃/10a(p0.01)的速率呈明显的上升趋势。极端低温自60年代以来呈现波动上升趋势;极端高温变化幅度较大,自60年代前期下降后波动上升,70年代后期至80年代初下降,之后波动上升,90年代末以来先下降后波动上升。极端低温、高温四季呈明显的上升趋势,均为秋季变化幅度最大,对年变化的贡献最大。年均极端高温在1997年发生突变,年均极端低温突变现象不明显。该区极端气温上升明显,向暖湿化方向发展。     

近50年来疏勒河上游气候变化及其对地表径流的影响

以1961—2010年疏勒河上游山区气温、降水和径流数据为基础,采用Mann—Kendall和R/S分析法,在年、季节尺度上研究了气温、降水和径流的变化特征,并采用多元线性回归分析法揭示了径流变化的主控因素。研究结果表明,近50a来研究区年均气温上升趋势显著且持续性极强。20世纪60—70年代气温偏低,1986年以后快速上升,并在1990年左右发生暖突变。降水量在研究时段内增加趋势明显且持续性较强。20世纪60—70年代降水偏少,80年代开始偏多,90年代偏少,1998年左右发生由少到多的突变。研究区气候在20世纪80年代中期由暖干向暖湿转型,受气候变化影响上游地区径流量显著增加,其年际和季节变化特征与降水变化相似。冬季和秋季径流变化主要受地下水影响,而春季和夏季径流变化主要受降水和冰雪融水的控制。     

厄尔尼诺/拉尼娜事件对山西省南部地区气候的影响

根据1961年以来的气温和降水资料,结合小波分析和发生的厄尔尼诺/拉尼娜事件,分析了1961年以来山西省南部地区气温和降水的变化趋势、周期以及厄尔尼诺/拉尼娜(El Nino/Southern Oscillation,ENSO)事件对山西省南部地区气温、降水量以及旱涝灾害的影响。研究结果表明,1961年以来山西省南部年平均气温总体呈波动式上升,上升速率为0.34℃/10a,而年平均降水量总体呈下降趋势,下降速率为23.4mm/10a。小波周期分析显示,山西省南部气温变化的周期约为3,8,20和25a,降水量变化的周期约为3和7a。厄尔尼诺年山西省南部年平均气温升高,降水量显著减少,而拉尼娜年气温下降,降水量略有增加。该区在厄尔尼诺年易发生旱灾,而拉尼娜年易发生涝灾,且旱涝灾害多分别发生在连续性的厄尔尼诺年和拉尼娜年。     

气候变化对宁夏自治区中卫市环香山地区气候生产潜力的影响

根据宁夏回族自治区中卫市兴仁气象站1961-2008年逐月气温、降水数据,采用Miami和Thornthwaite Memorial模型模拟了中卫市环香山地区气候生产潜力及其变化。结果表明:(1) 环香山地区气候向"暖干型"方向变化,年平均气温呈明显上升趋势,降水量变化波动大,呈逐年递减的趋势;(2) 温度生产潜力逐年增加,降水生产潜力和气候生产潜力呈波动中减少的趋势;(3) 气候生产潜力与年平均降水量具有着极其显著的线性相关关系,与年平均气温没有明显的相关性,温度生产潜力分别是降水生产潜力和气候生产潜力的2.79和2.35倍,说明降水条件是制约环香山地区气候生产潜力的关键因子;(4) 对未来气候进行情景模拟分析,结果表明环香山地区气候主要以"暖干型"气候为主,这对当地农业生产极为不利,需大力发展节水农业技术以保证农业生产。     

Agricultural potential of Mediterranean grain and forage legumes: Key differences between and within Vicia species in terms of phenology, yield, and agronomy give insight into plant adaptation to semi-arid environments

In order to identify key adaptive traits which affect productivity in Mediterranean grain and forage legumes and simultaneously determine the agricultural potential of a wide range of Vicia species, germplasm collected from the wild throughout the eastern Mediterranean was grown under semi-arid conditions in Tel Hadya, Syria (313 mm growing season rainfall). These included species currently in use in Mediterranean agriculture, such as V. sativa L., as well as those more widely used in the past-such as V. ervilia L., but also a broad selection from Section Narbonensis (B. Fedtsch. ex Radzhi) Maxted, including V. narbonensis L, V. johannis Tamamsch., V. hyaeniscyamus Mout., V. serratifolia Jacq., and V. kalakhensis Khattab et al. V. faba, a near relative of the taxa in Section Narbonensis, was included as a domesticated control. Where applicable, a representative range of subspecies was used. Accessions were chosen from a wide range of habitats in terms of latitude (31.02–40.72 decimal^o), longitude (27.1–43.17 decimal^o), altitude (20–1510 m), rainfall (180–1700 mm/yr) and soil depth (5–50 cm) in order to maximise diversity within species. Agricultural potential was determined by measuring seed, hay and biological yield, as well as agronomic traits such as harvest index, standing crop height, and seed size. The comparative influence of phenology and key agronomic traits such as plant habit and seed size on productivity varied tremendously between species, depending on their reproductive strategies. In V. sativa and V. ervilia, the smaller seed species which rely on long vegetative phases and growing seasons to accumulate sufficient biomass to set seed, and in which there was comparatively little agronomic variation, phenology had a large impact on yield. In early emerging taxa such as V. ervilia and V. s. subsp. sativa, with built-in long vegetative phases and growing seasons, seed yield was negatively correlated with flower ing (r = –0.86 to –0.88), whereas the opposite was the case for later emerging taxa such as V. s. subsp. nigra (L.) Ehrh. (r = 0.95). Within V. narbonensis and relatives, the larger seeded Vicia species which rely on more conservative reproductive strategies where high seedling vigour associated with large seeds enables the species to enter reproductive phases relatively early, phenology had a much smaller impact on yield than did variation of key traits such as seed weight, plant habit and pod shattering. Among the undomesticated germplasm harvest indices ranged from 0.09–0.31, hay yields from 0.1–3.4 t/ha, seed yield from 0–2.0 t/ha, and dry matter at maturity from 1.6–6.5 t/ha. Sub-specific taxonomy was crucial in determining agronomic potential. V. narbonensis var. aegyptiaca Kornhuber ex Asch. et Schweinf. showed the most potential, combining an upright habit, large seeds (212 mg) and tendency to retain intact pods after maturity, with the highest yield, harvest index and crop height of all the wild Vicia species. V. sativa subsp. sativa, V. ervilia and V. narbonensis var. narbonensis were less productive, but still showed agricultural potential. The smaller seeded V. narbonensis, var. affinis, var. jordanica H. Schäf. and var. salmonea (Mout.) H. Schäf., and their close relatives V. johannis, V. hyaeniscyamus, V. serratifolia and V. kalakhensis have little to offer Mediterranean agriculture on the basis of poor agronomy.     

Collection and preliminary evaluation of native turfgrass accessions in Italy

Despite a raising interest on turfs in Italy, all theavailable varieties of this kind in the Country are of foreign origin, and areoften poorly adapted to the prevailing climatic conditions. This prompted tobegin a collection activity of indigenous turfgrass species, with the ultimategoal of identifying promising materials for future breeding based on localgenetic resources. The collection was carried out in three areas of Italy, viz.the northern Po Plain, the coastal region of Liguria, and the island of Sardiniathat are characterised, respectively, by subcontinental, warm temperate, andtypical Mediterranean climate. Altogether, 141 sites were visited, yielding 226accessions belonging to eight species of potential interest for turfs:Poa pratensis, Poa trivialis,Festuca rubra, Festuca arundinacea,Lolium perenne, Agrostis stolonifera,Agrostis tenuis, and Cynodon dactylon,this last being a warm-season grass. Poa pratensis andCynodon dactylon were mostly collected in northern Italyand Sardinia, respectively, whereas Festuca arundinacea andLolium perenne were rather ubiquitous. The collection sitesranged from 0 to 1040 m asl, but sites over 750 m wereonly visited in the inner part of Sardinia. All the accessions, collected aswhole plants, were transplanted at Lodi, northern Italy, where they are beingevaluated. Their preliminary evaluation for traits of importance for turf use,such as sward colour and overall quality, highlighted the great variation andthe occurrence of interesting accessions in all species. Other characters wererecorded, bearing specific importance in individual species, and in all casespromising accessions were identified. The germplasm of Festucarubra, Festuca arundinacea, and Loliumperenne proved highly infected by endophytic (symbiotic) fungi of thegenus Neotyphodium.     

Control of pitch pine seed germination and initial growth exerted by leaf litters and polyphenolic compounds

We investigated the influence of three concentrations of water extracts of three leaf litter species (pitch pine, huckleberry and white oak) and a mixture of all litters on the germination of pitch pine seeds and initial seedling growth in a microcosm experiment. All three plant species are important components of the pine barrens ecosystems in New Jersey, where it has been seen that pine seedling recruitment occurs only after stand replacing fire or in disturbed sites, where surface organic soil horizons and leaf litter have been removed. Leaf litter extracts did not influence seed germination, but significantly reduced seedling growth at high concentrations. There was little difference between the leaf litter species in growth suppression. As charcoal is a natural residue on the forest floor following fire, its influence on growth suppression was examined; it has been shown to immobilize polyphenols. Charcoal removed the inhibitory effect of leaf litter extracts and allowed the fertilizer effect of nutrients leached from the leaves to enhance seedling growth, particularly at the higher concentration of litter extract used. Responses to litter extracts were compared to four pure phenolic compounds, catchecol, p-coumaric acid, p-hydroxybenzoic acid and tannic acid. None of these compounds suppressed pine seedling growth, suggesting that these phenolics are not allelopathic to pine seedlings. The results are discussed in the context of fire as a driving factor in these oligotrophic and seasonally dry ecosystems and the interactions between nutrient supply and allelopathic chemistry of different leaf litters.     

Phylogenetic relationships of Actinidia and related genera based on micromorphological characters of foliar trichomes

The phylogenetic relationships within the genus Actinidia and among 3 allied genera Clematoclethra, Saurauia, and Sladenia have been very controversial. In order to understand the systematic implication of foliar trichomes in those genera, the micromorphological characteristics of foliar trichomes from 34 taxa were examined by means of light microscopy and scanning electron microscopy (SEM). The observed micromorphological characteristics were classified into eight main types. A phylogenetic analysis of Actinidia and related genera based on 15 micromorphological characters of foliar trichomes was conducted using Wagner parsimony method and Sladenia celastrifolia, Rhododendron hybridum and R. simsii as a complex outgroup. In the resulting phylogenetic tree, Actinidia is shown to be a monophyletic group, and Clematoclethra and Saurauia form another monophyletic group. This study also presents the phylogenetic relationships among 4 sections within the genus Actinidia: the monophyly of sect. Leiocarpae and of sect. Strigosae, and polyphyly of sect. Maculatae and of sect. Stellatae.     

Effects of mixing radiata pine needles and understory litters on decomposition and nutrients release

A microcosm experiment was conducted to understand the impacts of mixing radiata pine (Pinus radiata D. Don) needle litter and understory (gorse—Ulex europaeus L., broom—Cytisus scoparius L., bracken—Pteridium aquilinum L., and lotus—Lotus pedunculatus L.) litter materials on decomposition and nutrient release dynamics. Mixing of pine needle litter with understory litter material had significant impacts on both the rate of decomposition and nutrient release patterns of pine litter as well as that of the understory species. Incubation in microcosms over 10 months resulted in significantly lower mass loss of radiata pine needle litter mixed with broom and lotus litters (35.8±8.4 and 41.3±0.8%, respectively) than pure pine needle litter (63.5±2.3%). Mixing with pine needle litter significantly increased the mass loss of broom (53.1±6.1%) compared to that of pure broom (30.2±1.0%). Significant transfers of nutrients, especially of magnesium and potassium, were observed in litter mixture treatments. Concentration of K in litter materials was found to be the most limiting factor for the decomposing microorganisms in the present study. The findings of this study suggest that management of understory litter composition via weed control could be used to manipulate carbon turnover and nutrient release in the forest floor. Also, initial selection of understory species will be important and could be managed.     

Effect of agroforestry woody species on earthworm activity and physicochemical properties of worm casts

The effects of five agroforestry woody species (Dactyladenia barteri, Gliricidia sepium, Leucaena leucocephala, Senna siamea andTreculia africana) on the surface aasting activity ofHyperiodrilus africanus were studied in an Alfisol (Oxic Paleustalf) in southwestern Nigeria. Casting activity under the woody species decreased in the following order:Dactyladenia sp. (26.4 Mg ha^-1 year^-1)>Gliricidia sp. (24.4 Mg ha^-1 year^-1)>Treculia sp. (22.9 Mg ha^-1 year^-1)>Leucaena sp. (18.6 Mg ha^-1 year^-1)>Senna sp. (18.3 Mg ha^-1 year^-1). These differences in casting activity were partly explained by microclimatic effects. Irrespective of the woody species, the worm casts were higher in clay and silt contents, bulk density, water-stable aggregates, pH, organic C, exchangeable cations, effective cation exchange capacity, and extractable P levels than the corresponding surface soils. The woody species did affect the physicochemical properties and P sorption of the worm casts. The content of water-stable aggregates of worm casts decreased in the following order:Dactyladenia sp.>Treculia sp.>Senna sp.>Leucaena sp.>Gliricidia sp. Large differences in extractable P levels were observed.Senna sp. was associated with the highest extractable P level (11.5 mg kg^-1) andTreculia sp. the lowest (4.9 mg kg^-1). P sorption was highest on worm casts underDactyladenia sp. and lowest on those underTreculia sp. Without fertilizer application, there were no significant differences in the dry weight of maize grown in the different worm casts. With NPK applications, the dry weight of maize grown in worm casts associated withTreculia sp. was significantly lower than that of maize grown in the other worm casts, mainly due to the low extractable P level. Despite a high organic C and exchangeable K status, maize grown in the worm casts still responded significantly to N and K applications. The N uptake by maize grown in worm casts associated withTreculia sp. was lower than that in the other treatments.     

Allelic diversity of HMW and LMW glutenin subunits and omega-gliadins in French bread wheat (Triticum aestivum L.)

Wheat endosperm storage proteins, namely gliadins and glutenins, are the major components of gluten. They play an important role in dough properties and in bread making quality in various wheat varieties. In the present study, the different alleles encoded at the 6 glutenin loci and at 3 -gliadin loci were identified from a set of 200 hexaploid wheat cultivars grown primarily in France using SDS PAGE. At Glu-A1, Glu-B1 and Glu-D1, encoding high molecular weight glutenin subunits (HMW-GS), 3, 8 and 5 alleles were observed respectively. Low molecular weight glutenin subunits (LMW-GS) displayed similar polymorphism, as 5 and 11 alleles were identified at loci Glu-A3 and Glu-B3 respectively. Four alleles were observed at Glu-D3 loci. Omega-gliadin diversity was also very high, as 7, 13 and 9 alleles were found at Gli-A1, Gli-B1 and Gli-D1, respectively. A total of 147 (or 149) patterns resulted from the genetic combination of the alleles encoding at the six glutenin loci (or Glu-1 and Gli-1 loci). Although Glu-1 and Glu-3 loci were located on different chromosome arms and were theoretically independent, some associations were revealed due to pedigree relatedness between some French wheat cultivars. The usefulness of allelic identification of LMW-GS together with HMW-GS and gliadins for future genetic and technological wheat improvement is discussed.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.     

Genetic Diversity within and Between Populations of Lathyrus genus (Fabaceae) Revealed by ISSR Markers

In order to evaluate the genetic diversity in Lathyrus genus, the Inter Simple Sequence Repeats method (ISSR) was exploited in five populations. These consisted of two cultivated species belonging to section Lathyrus (L. sativus L. and L. cicera L.) and a wild one belonging to the section Clymenum (L. ochrus DC.). Two 3′anchored ISSR primers and two unanchored ones, generated a total of 60 useful polymorphic DNA bands. Our data provide evidence of high molecular polymorphism at the intra- and the inter-specific levels showing that both wild and cultivated forms constitute an important pool of diversity. Moreover, among the generated DNA bands, a 500 bp band, totally absent in the banding patterns of the section Clymenum, appears to be a molecular marker of section Lathyrus. Results provided for lineage and suggest recent origin of these species that might have evolved from a common ancestor producing both L. ochrus species and the two other species L. sativus and L. cicera. These relationships support previous studies based on morphological variation and molecular analysis.