温热带玉米种质改良的现状与趋势分析

本文概括了国内外温热带玉米种质改良的现状 ,并结合热带种质的遗传成分、地理起源、温热带种质间的杂优关系 。

基于温带和热带玉米群体全基因组选择和杂种优势候选位点的鉴定

基于187份种质资源材料的全基因组重测序数据开发了120 583个高质量SNP变异位点,通过这些位点可以将具有不同遗传背景的187份玉米种质划分为两大类群,分别为包含100份材料的温带亚群和包含87份材料的热带亚群。通过对温带和热带玉米群体选择信号的遗传分化分析,检测到3 664个受到选择的位点。选取187份材料中已报道能在温/热亚群形成杂种优势的135份代表性自交系,其中75份来自温带玉米自交系,60份为热带玉米系,基于两大杂种优势群进行杂种优势性状的全基因组关联分析(GWAS),结果鉴定出2 407个杂种优势候选位点不均匀分布在玉米10条染色体上。整合选择信号检测和GWAS分析结果,共识别出1 153个受到选择的杂种优势相关位点,其中,619个位点与26个已报道的杂种优势相关QTLs一致。功能注释发现与候选位点紧密连锁的324个候选基因大部分都具有功能,其中包含61个重要的转录因子。根据GO富集分析发现这些候选基因主要参与了很多对杂种优势形成有贡献的关键生化代谢途径,包括氮化合物代谢、叶酸代谢、糖酵解、发育过程的负调控及转录调控等重要生物学途径。

基于玉米50K芯片分析鲜食玉米温-热带杂种优势模式及其育种利用

利用基于Illumina平台的玉米MaizeSNP50(50K)芯片对90份鲜食玉米自交系材料进行SNP基因分型,获得11100个高质量SNP变异位点。通过这些位点可以将具有不同遗传背景的90份鲜食玉米资源划分为四大类群,分别为热带糯玉米群(31份)、热带甜玉米群(15份)、温带糯玉米群(11份)、温带甜玉米群(33份),并对其群体遗传结构进行PCA分析,二者结果与自交系谱系来源保持一致。以上述温、热优势群划分结果为依据,现已知15个自主选育鲜食玉米品种的组配模式为温、热带优势群间杂交,且各品种在农艺性状、品质、抗性等方面均表现出较强的杂种优势,该温-热杂优模式为今后鲜食玉米品种选育提供了新方向。

Comparison of Major Nutrient Release Patterns of Quercus liaotungensis Leaf Litter Decomposition in Different Climatic Zones

Leaf litter decomposition of liaotong oak (Quercus liaotungensis Koize) under temperate, subtropical and tropical forests was examined using a litter bag technique. Decomposition rates and release dynamics of nutrients Ca, Cu, Fe, K, Mg, Mn and P were observed separately at all three sites for I to 2 a periods. The leaf litter mass loss of liaotong oak was simulated with Olson's exponential model. Significant differences of leaf litter mass loss were found in forests of all three climate zones. Litter decomposition was accelerated with the increase of both annual mean precipitation and temperature. Our results agreed with other studies demonstrating that litter decomposition processes were greatly affected not only by soil organisms (including soil fauna and microorganisms), but also by chemical factors. These chemical factors were important for controlling the release of nutrients, especially elements of Fe and Mn. We also found that Fe and Mn content increased in semi-decayed leaf litter as litter mass decreased. This result was presumably due to chelating process which accumulated soil Fe and Mn ions into the decomposing litter. In conclusion, our study allowed us to determine the classification of the characteristics of different nutrient release patterns.

Temperature Dependence of the Energy-Band Structure for the Holstein Molecular-Crystal Model

We study the influences of the temperature on the energy-band structure for the Holstein molecular-crystal model. We show that the energy-band width and the energy-gap width of a solid are relevant to both the interaction between an electron and thermal phonons and to thermal expansion. For a one-dimensional Li atom lattice chain, under the chosen parameters,the width of the ls and 2s energy bands narrows as the temperature increases and the energy-gap width between the two bands widens. These results agree qualitatively with those observed experimentally. Studying temperature dependence of the energy-band structure is of great importance for understanding optical and transporting characteristics of a solid.

Vegetation-Climate Relationship and Its Application in the Division of Vegetation Zone in China

Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes.

A Study of Fructification Quantitative Characteristics of Spartina alterniflora Lossel in Mangroves

[Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflora in Mangroves conservation zone located at Hepu of Guangxi being taken as experimental material, its morphological and quantitative characteristics, as well as the weight of 100 full seeds at maturity stage in three different growth conditions（ clay, loam and sand） were studied. [ Results] The results showed that Spartina alterniflora had the best growth pattern in the loam. The morphological factors of fructification of S. altemiflora grown in sand were larger then in others. In the three growth conditions the order of quantitative characteristics of fructification of S. alterniflora was clay 〉 sand 〉 loam and the seeds in spikelet at top position were more maturity than those at the button position. [ Conclusion] In good condition, the Spartina altemiflora growth was vigor but the ratio of seed-setting was low.

Study on the Characteristics of Florescence and Pollen in Lagerstroemia speciosa

[ Objective] To study the characteristics of florescence and pollen in Lagerstroemia speciosa. [ Method ] The process of flower opening and pollen tube germination of Lagerstroemia speciosa was observed and the pollen viability was determined through in vitro germination. [ Result] Sepals of L. speciosa started to diverge at 4：30 am, at 7： 00 am petals flatten up, anther diverged, and the stigma secreted a large number of mucus, it was the best time for artificial pollination. Boric acid and sucrose had a great effect on in vitro pollen germination of L. speciosa, the combination which made highest rate of pollen germination, was sucrose 150 g/L ＋ boric acid 20 mg/L ＋ CaCI2 10 mg/L. Through the fluorescence microscope, it was known that four hours after flowering, a lot of pollen grains germinated on the stigma, six hours after flowering, lots of pollen tubes entered the style and reached to 1/4 length of the style, 12 hours after flowering, pollen tubes concentrated into a beam forward, and reached to 1/2 length of the style, 24 hours after flowering, lots of pollen tubes entered the ovary in a beam and then fertilized and produced seeds. [ Conclusion] The results provide some basis for utilizing L. speciosa to breed.

A review of recent studies on extreme heat in China

This paper reviews recent studies on extreme high temperatures in China during summer. The focus is on the variation in extreme heat and tropical nights（i.e. high temperature at night）, and the factors of influence. Potential research topics in the future are also discussed.

A New Approach for Classifying Two Types of El Nio Events

In recent decades, the typical E1 Nifio events with the warmest SSTs in the tropical eastern Pacific have become less common, and a different of E1 Nifio with the wannest SSTs in the central the east and west by cooler Pacific, which is flanked on SSTs, has become more frequent. The more recent type of E1 Nifio was referred to as central Pacific E1 Nifio, warm pool E1 Nifio, or dateline E1 Nifio, or the E1 Nifio Modoki. Central Pacific E1 Nifio links to a different tropical-to-extratropical teleconnection and exerts different impacts on climate, and several clas- sification approaches have been proposed. In this study, a new classification approach is proposed, which is based on the linear combination （sum or difference） of the two leading Empirical Orthogonal Functions （EOFs） of tropi- cal Pacific Ocean sea surface temperature anomaly （SSTA）, and the typical E1 Nifio index （TENI） and the central E1 Nifio index （CENI） are able to be derived by projecting the observed SSTA onto these combinations. This classification not only reflects the characteristics of non-orthogonality between the two types of events but also yields one period peaking at approximate two to seven years. In particular, this classification can distin- guish the different impacts of the two types of events on rainfall in the following summer in East China. The typi- cal E1 Nifio events tend to induce intensified rainfall in the Yangtze River valley, whereas the central Pacific El Nifio tends to induce intensified rainfall in the Huaihe River valley. Thus, the present approach may be appropriate for studying the impact of different types of E1 Nifio on the East Asian climate.

Remote impacts from the tropical Indian Ocean on haze pollution in January over the Yangtze River Delta

Haze events in the Yangtze River Delta(YRD)region have recently been occurring more frequently and with dramatic damages inflicted on human and ecosystem health.In this study,observational analyses and numerical experiments are used to investigate the meteorological conditions associated with haze pollution,with the main emphasis on the impacts of the preceding sea surface temperature(SST)in the tropical Indian Ocean(TIO).The results show that the December SST in the TIO has a significant positive correlation with the number of haze days in January over the YRD,especially during 1999–2017.In December,the positive SST anomalies in the TIO heat the overlying air,and then in the following January provoke a Matsuno–Gill-like pattern and a series of Rossby wave–like trains in the upper troposphere,transmitting signals to the YRD and downstream through the Sea of Japan and Aleutian Islands.The cyclonic anomalies in the YRD seem to significantly weaken the East Asian jet stream by means of anomalous easterlies,and subsequently affect the climate in the region.Near the surface,the increased surface air temperature and southerly winds,along with the decreased surface wind speed,accompanied by influences from upstream areas,are conducive to the occurrence of haze.These observational results were also reproduced well in CESM-LE simulations.

Sensitivity Difference in the Extratropical Atmosphere to Two Types of El Nio Events

A comparison of sensitivity in extratropical circulation in the Northern Hemisphere （NH） and Southern Hemisphere （SH） is conducted through observational analyses and diagnostic linear model experiments for two types of El Ni（n）o events,the traditional El Ni（n）o with the strongest warmth in the eastern tropical Pacific （EP El Ni（n）o） and the El Ni（n）o Modoki with the strongest warmth in the central tropical Pacific （CP El Ni（n）o）.It is shown that CP El Ni（n）o favors the occurrence of a negative-phase Northern Annular Mode （NAM）,while EP El Ni（n）o favors that of the Pacific-North American （PNA） pattern.In SH,both EP and CP El Ni（n）o induce a negative phase Southern Annular Mode （SAM）.However,the former has a greater amplitude,which is consistent with the stronger sea surface temperature （SST） warmth.The difference in the two types of El Ni（n）o events in NH may originate from the dependence of heating-induced extratropical response on the location of initial heating,which may be associated with activity of the stationary wave.In SH,the lack of sensitivity to the location of heating can be associated with weaker activity of the stationary wave therein.

Influences of tropical circulation and sea surface temperature anomalies on extreme heat over Northeast Asia in the midsummer of 2018

A destructive extreme heat attacked Northeast Asia(NEA)in the midsummer of 2018,characterized by the average midsummer Tmax(daily maximum air temperature at 2 m)ranking first during the study period.The current study indicates that the cyclonic anomaly over the western North Pacific(WNP)was an important cause,which presents an anomaly of two standard deviations.The cyclonic anomaly over the WNP was accompanied by anomalous convection,which favored descending and anticyclonic anomalies over NEA through a local meridional cell.The anticyclonic anomaly over NEA corresponds to the northwestward extension of the WNP subtropical high and facilitated the occurrence of extreme heat.The tropical sea surface temperature anomaly(SSTA)presents a La Ni?a decaying episode,but the SSTA over the tropical Pacific and North Indian Ocean was weak in the summer.In contrast,the southeastern tropical Indian Ocean(SETIO)was obviously cool,which was the coolest after detrending.The SETIO cooling triggered a low-level southeasterly anomaly,which turned into a southwesterly after crossing the equator,due to the Coriolis force.The southwesterly anomaly extended eastwards and favored the cyclonic anomaly over the WNP.Meanwhile,the circulation anomalies over the SETIO and WNP were connected via a local meridional cell,with the ascending branch over the WNP.Moreover,the above mechanism also operates for the climate statistics,verifying the robust in?uence of the SETIO SSTA.Considering the consistency of the SETIO SSTA,it could be a potential predictor for the climate over the WNP and NEA.

Rainfall Variability Patterns in West Africa： Case of Cote d＇lvoire and Ghana

This study is focused first on the rainfall variability in C6te d＇Ivoire and in Ghana; second, on the determination of the climatic zones of these areas. Monthly rainfall heights recorded in 43 weather stations from 1964 to 2000 is carried out. This study suggests a sudivision in three climatic zones which are： the littoral zone that borders the tropical Atlantic, the center zone that is located in the central region of both countries, and the northern zone whose seasonal cycle is close to that of the Sahel of West Africa. The study of the interannual variability of the rainfall shows some patterns which are differently influenced by sea surface temperature. Such work could be useful for agricultural activities and to better quantify the role of the vegetation dynamics.

Spatial Distribution of Internal Temperatures in a LGR （Light Green Roof） for Brazilian Tropical Weather

This article aims to assess the spatial distribution of the IST （internal surface temperatures） in the ceiling and DBT （dry bulb temperatures） of a LGR （light green roof） in a test cell. Cover systems known as green roofs have the potential to retain rainwater and help reduce runoff. However, the characteristic considered in this work is the insulation capacity of this kind of coverage. To evaluate the spatial distribution of temperatures in an environment with light green roof, we proposed a new method for acquisition of series of climatological data and temperatures according to spatial and temporal approaches of dynamic climatology. Climatological data were provided by an automatic weather station and temperatures were collected in a test cell with light green roof. The spatial distribution of surface temperatures and internal air temperature （DBT） are based on the concepts of a climatic episode and typical experimental day from the study of the dynamic climatology. The results led to the conclusion that the light green roof has a balanced spatial distribution of the IST and of the internal air temperature （DBT）, i.e., without substantial variations over the day. The new methodology also showed the importance of specifying the location of the sensors and automatic weather station in experimental studies on the thermal behaviour of buildings.

A CLIMATOLOGY OF EXTRATROPICAL TRANSITION OF TROPICAL CYCLONES IN THE WESTERN NORTH PACIFIC

Based on best-track data and JRA-25 reanalysis,a climatology of western North Pacific extratropical transition (ET) of tropical cyclone (TC) is presented in this paper. It was found that 35% (318 out of 912) of all TCs underwent ET during 1979-2008. The warm-season (June through September) ETs account for 64% of all ET events with the most occurrence in September. The area 120°E-150°E and 20°N-40°N is the most favorable region for ET onsets in western North Pacific. The TCs experiencing ET at latitudes 30°N-40°N have the greatest intensity in contrast to those at other latitude bands. The distribution of ET onset locations shows obviously meridional migration in different seasons. A cyclone phase space (CPS) method was used to analyze the TC evolution during ET. Except for some cases of abnormal ET at relatively high latitudes,typical phase evolution paths-along which TC firstly showed thermal asymmetry and an upper-level cold core and then lost its low-level warm core-can be used to describe the main features of ET processes in western North Pacific. Some seasonal variations of ET evolution paths in CPS were also found at low latitudes south of 15°N,which suggests different ET onset mechanisms there. Further composite analysis concluded that warm-season ETs have generally two types of evolutions,but only one type in cold season (October through next May). The first type of warm-season ETs has less baroclinicity due to long distance between the TC and upper-level mid-latitude system. However,significant interactions between a mid-latitude upper-level trough and TC,which either approaches or is absorbed into the trough,and TC's relations with downstream and upstream upper-level jets,are the fingerprints for both a second type of warm-season ETs and almost all the cold-season ETs. For each type of ETs,detailed structural characteristics as well as precipitation distribution are illustrated by latitude.

Traditional El Nio and El Ni o Modoki Revisited:Is El Nio Modoki Linearly Independent of Traditional El Nio?

The present study revisited the first two leading modes of tropical Pacific sea surface temperature anomalies （SSTA） during the period of 1979-2008. It is suggested that the so-called El Nino Modoki, which is captured by the second mode, exists objectively and exhibits obvious differences from traditional El Nifio, which is captured by the first mode, in terms of its spatial characteristics. Furthermore, the authors found that El Nino Modoki is linearly independent of traditional El Nino; hence, it cannot be described as part of the traditional El Nino evolution, and vice versa.

Movements of the Western Pacific Warm Pool Centroid and Their Relationship to Sea Surface Temperature Changes in Nino Regions

By using monthly historical sea surface temperature (SST) data for the yearsfrom 1950 to 2000, the Western Pacific Warm Pool (WPWP) climatology and anomalies are studied inthis paper. The analysis of WPWP centroid (WPWPC) movement anomalies and the Nino-3 region SSTanomalies(SSTA) seems to reveal a close, linear relation between the zonal WPWPC and Nino-3 regionSSTA, which suggests that a 9° anomaly of the zonal displacement from the climatological positionof the WPWPC corresponds to about a 1℃ anomaly in the Nino-3 region area-mean SST. This studyconnects the WPWPC zonal displacement with the Nino-3 SSTA, and it may be helpful in betterunderstanding the fact that the WPWP eastward extension is conducive to the Nino-3 region SSTincrease during an El Nino-Southern Oscillation (ENSO) event.

Contrasting two spring SST predictors for the number of western North Pacific tropical cyclones

Recent studies have revealed that two boreal spring sea surface temperature （SST） indices have potential to predict the number of western North Pacific （WNP） tropical cyclones （TCs） in the following peak typhoon season （June-October）： the northern tropical Atlantic （NTA） SST, and the SST gradient （SSTG） between the southwestern Pacific and western Pacic warm pool. The interannua[ and interdecadal variations of NTA SST and SSTG and their relationships to the number ofWNP TCs during 1950-2013 were compared. On the interdecadal timescale, SSTG showed better correlation with the number of WNP TCs than NTA SST. The interdecadal variation of NTA SST was closely associated with the Atlantic Multidecadal Oscillation, while that of SSTG was anti-correlated with the Central Pacific （CP） El Nino index at the interdecadal timescale. On the interannual timescale, both NTA SST and SSTG were modulated by two types of El Nino. The NTA SST revealed significant correlations with the number of WNPTCs beginning from the early 1960s; by contrast, SSTG showed significant correlations after the mid-1970s. Co-variability of NTA SST and SSTG existed after the late 1980s, induced by modulation from CP El Nino.The co-variability of these two spring SST predictors increased their prediction skill after the late 1980s, with enhanced correlation between the number of WNPTCs and the two predictors.