Latitudinal and seasonal variation in reproductive effort of the eastern fence lizard (Sceloporus undulatus)

Geographic variation in life‐history traits among populations of wide‐ranging species is influenced by both spatial and temporal aspects of the environment. Rarely, however, are the effects of both aspects examined concurrently. We collected gravid female lizards (Sceloporus undulatus) from northern (Indiana), central (Mississippi) and southern (Florida) populations, spanning nearly the full latitudinal range of the species, to examine amongpopulation differences in strategies of reproductive energy allocation. Adult females from the southern population were smaller, and produced fewer and smaller eggs in their first clutches than did females from the more northern populations. Southern females were more likely to produce a second clutch, and second clutches were smaller than first clutches for females from the 2 northern populations. Together these trends eliminated population differences in overall reproductive output after accounting for body size. The trend for greater reproductive energy to be allocated to first clutches at higher latitudes, and to later clutches at lower latitudes is corroborated by published data from field studies on multiple populations. Distributing reproductive effort by producing more clutches of smaller eggs may be an adaptive response to the long season available for egg incubation and lizard activity in sub‐tropical southern environments. In contrast, allocating greater resources to early reproduction may enhance maternal fitness in the relatively short activity seasons that characterize more northern sites.     

PRRSV山西株ORF5和Nsp2基因序列分析

采用RT-PCR方法对2009—2011年山西省分离的5株猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome virus,PRRSV）的ORF5和Nsp2（2503～3269nt）基因进行克隆和测序,并对其基因序列和推导的氨基酸序列与国内外毒株进行了同源性分析。序列分析结果显示,5株分离株Nsp2基因与国内分离的PRRSV变异株（JXA1、HuN、HUN4、HUB1）的序列同源性最高,为96．8％～98．2％,且缺失位置一致,均存在2个位点30个氨基酸缺失;ORF5基因大小为603bp,编码200个氨基酸,第13、151位均为具有强毒特性的精氨酸（R）,137位为丝氨酸（S）,表明这5株均为野毒株,与国内分离的PRRSV变异株（JXA1、HuN、HUN4、HUB1）毒株的序列同源性最高,为96．5％～98．0％。结果表明,山西省内目前流行的PRRSV为Nsp2缺失30个氨基酸的变异毒株。     

准噶尔盆地地表反照率时空变化特征及其影响因素分析

地表反照率变化影响地表辐射收支与能量平衡,从而对区域和全球气候产生影响。以准噶尔盆地为研究对象,利用MODIS卫星遥感数据产品MOD09A1反演地表短波反照率,结合气象数据和植被指数分析准噶尔盆地2001—2018年荒漠草地地表反照率时空变化特征及其影响因素。结果表明:准噶尔盆地地表反照率空间分布地域差异明显,地表反照率年均值为0.303,整体呈东北高、西南低的特点;其年际变化速率呈减少趋势,平均每年为1.4×10^-4,减少面积约占总面积的52.8%;四季空间分布变化明显,春、夏、秋三季空间分布相似,冬季值最高(0.551),夏季最低(0.203)。准噶尔盆地东北缘的阿尔泰山地表反照率年内变化较为剧烈;生长季归一化植被指数(NDVI)值大小为:夏季>秋季>春季。准噶尔盆地整体地表反照率与NDVI呈负相关,大部分区域与平均气温呈负相关,与降水呈正相关,且相关性大小依次为气温>NDVI>降水。MODIS反演结果与地面实测值之间存在显著的相关性(R²=0.8908,P<0.01),均方根误差为0.014。为了解准噶尔盆地陆面特征,客观评价全球气候变化下干旱区陆面变化及其正负反馈响应机制提供一定的理论依据。     

Assessing the response of dryland barley yield to climate variability in semi-arid regions,Iran

Precipitation and temperature are the most abiotic factors that greatly impact the yield of crop, particularly in dryland. Barley, as the main cereal is predominantly cultivated in dryland and the livelihood of smallholders depends on the production of this crop, particularly in arid and semi-arid regions. This study aimed to investigate the response of the grain yield of dryland barley to temperature and precipitation variations at annual, seasonal and monthly scales in seven counties of East and West Azerbaijan provinces in northwestern Iran during 1991-2010. Humidity index (HI) was calculated and its relationship with dryland barley yield was evaluated at annual and monthly scales. The results showed that the minimum, maximum and mean temperatures increased by 0.19°C/a, 0.11°C/a and 0.10°C/a, respectively, while annual precipitation decreased by 0.80 mm/a during 1991-2010. Climate in study area has become drier by 0.22/a in annual HI during the study period. Negative effects of increasing temperature on the grain yield of dryland barley were more severe than the positive effects of increasing precipitation. Besides, weather variations in April and May were related more to the grain yield of dryland barley than those in other months. The grain yield of dryland barley was more drastically affected by the variation of annual minimum temperature comparing with other weather variables. Furthermore, our findings illustrated that the grain yield of dryland barley increased by 0.01 t/hm² for each unit increase in annual HI during 1991-2010. Finally, any increase in the monthly HI led to crop yield improvement in the study area, particularly in the drier counties, i.e., Myaneh, Tabriz and Khoy in Iran.     

Effect of rice variety on methane emission from an Indonesian paddy field

Variations in CH₄ emission from a Sumatra paddy field in which 8 popular modern varieties in Indonesia were grown were compared in the 1994/1995 rainy season. Total amounts of CH₄ emitted during the period of rice growth were in the ranges of 32.6-41.7 and 51.3–64.6 g CH₄ m^-2 for the plots amended with chemical fertilizer only and those amended with both rice straw and chemical fertilizer, respectively. The mean CH₄ emission rate was highest in the plot with the variety Bengawan solo and lowest in the plots with the varieties Atomita-4 and Way seputih among the plots which received chemical fertilizer, while highest in the plot with Way seputih and lowest in the plot with Bengawan solo among the plots amended with both rice straw and chemical fertilizer. The increase in the mean CH₄ emission rates by rice straw application was higher for the plots planted with Way seputih (1.98 times) and Atomita-4 (1.77 times) than for the plots with Bengawan solo (1.23 times) and IR-64 (1.35 times). The plots with Walanai and Cisanggarung recorded intermediate mean emission rates and the increase in CH₄ emission by rice straw application was also intermediate (1.57–1.64 times). It was noteworthy that Way seputih and Atomita-4 were derived from the variety Cisadane, Bengawan solo and IR-64 from the variety IR-54, and Walanai and Cisanggarung from the varieties IR-36 and Pelita 1-1, respectively.

The amounts of CH. emitted for 1 kg grain production ranged from 53 (Atomita-4) to 74 (Kapuas and Walanai) and from 89-93 (IR-64, Bengawan solo, and Atomita-4) to 121 (Kapuas) g CH₄ kg^-1 of grain for the plots amended with chemical fertilizer and those amended with rice straw and chemical fertilizer, respectively.     

Genotypic variation in Fe concentration of barley grain

Abstract

Iron deficiency in humans is the most prevalent micronutrient deficiency worldwide. To screen for high Fe cultivar, genotypic variation in Fe concentration of barley grain was investigated in two collections of barley: 274 standard varieties selected at the Barley Germplasm Center of the Research Institute for Bioresources, Okayama University (SV) and 135 varieties from the Barley Core Collection of Americas (BCCAM). The Fe concentration of barley grain showed large variation, ranging from 24.6 to 63.3 mg kg^?1 in SV, from 21.0 to 83.0 mg kg^?1 in BCCAM barleys. The Fe concentration was not affected by the key characters of barley varieties, kernel row types, and hulled or hull-less. The Fe concentration was also not related to the place of origin of the barley variety. About 90% of total Fe was localized in the grain without hull. These results provide fundamental data for breeding Fe-rich cultivars and for studying the mechanisms involved in genotypic variation in Fe concentration.     

Diurnal variations in absorption and translocation of a ferrated phytosiderophore in barley as affected by iron deficiency

The release of phytosiderophore (PS) from roots of Fe-deficient graminaceous plants follows a distinct diurnal rhythm with maximum release rates occurring usually 3 to 4 hours after the onset of light. However, it remains to be determined whether absorption of the PS-Fe³⁺ complex shows a diurnal rhythmicity similar to that of PS release, Barley plants grown with or without 10 µM FeEDTA for 7 days were fed with ferreted PS (10 µM labelled with ⁵⁹Fe) at 4-h intervals to study the diurnal variations in the absorption and transloca tion of ⁵⁹Fe, The absorption of ⁵⁹Fe, irrespective of the Fe nutritional status of the plants, was higher during the day and lower during the night but did not show any peak throughout the day-night cycle. On the other hand, the translocation of ⁵⁹Fe into shoots of Fe-deficient plants was lower than that of Fe-sufficient plants, while the Fe nutritional status of the plants did not affect the absorption of ⁵⁹Fe by roots, The formation of root apoplastic ⁵⁹Fe was lower during the day and higher during the night, regardless of the Fe nutritional status of plants. Our results showed that the absorption of the PS-Fe³⁺ complex by roots did not follow the PS release pattern.     

Zinc-Induced Changes in Growth Characters,Foliar Properties,and Zn-Accumulation Capacity of Pigeon Pea at Different Stages of Plant Growth

Application of zinc (Zn) [50, 100, 200, 300, and 400 μ g zinc sulfate (ZnSO₄)/g of soil] reduced the foliage and the total growth of pigeon pea [Cajanus cajan (Linn.) Huth]. The root-shoot length ratio, varying little with age, was relatively low in the treated plants. Decrease in dry weights of stem and root was more pronounced in the late stages of plant development. The root-shoot dry weight ratio, maximum in the flowering stage, was lower in treated plants than in the control. Number of pods per plant declined, showing a positive correlation with Zn concentration. Net photosynthetic rate, declining with plant age, was significantly low in the treated plants. Density and size of stomata and trichomes, stomatal conductance, intercellular carbon dioxide concentration, quantity of green pigments, nitrate reductase activity, and the nitrate and protein contents in the leaves also declined significantly. Proportion of vascular tissues both in stems and roots increased with plant age with a concomitant reduction of pith and cortex. Under zinc stress, the relative proportion of tissues varied inconsistently. Dimensions of vessel elements and fibers in stems and roots, increasing with the plant age, were always smaller in the treated plants. The vulnerability factor and mesomorphic ratio of treated plants declined, suggesting induction of water stress due to zinc treatments. Accumulation of Zn^{2 +} in different plant parts was considerably high at each developmental stage of the treated plants, and showed a positive correlation with Zn in the soil.     

Phosphorus Use Efficiency of Wheat Genotypes Grown in Calcareous Soils

ABSTRACT

Phosphorus (P) deficiency and low P-use efficiency are induced by soil properties, especially in calcareous soils, which are dominant in semi-arid regions of the world such as the Mediterranean region. Alternative approaches to P fertilization involve exploiting plant genetics in order to achieve more efficient use of P by the growing crop. Accordingly, in a greenhouse pot experiment, we evaluated P-efficiency in wheat genotypes grown in typical calcareous soils in southern Turkey. Ten common local genotypes were grown in six soil series for eight weeks using five P application rates (0, 25, 50, 100, and 200 mg P kg^?1). Dry matter (DM) yield and P content were significantly increased by increasing P rates, with significant differences between soils. Some genotypes performed better under P stress because of better P utilization efficiency. Shoot DM was the most sensitive indicator of genetic variability under P-deficient conditions. Genotypes classified as efficient-responsive (Adana-99, 1014, Golia, Balatilla) had above average DM yield when P was not added, and responded well to P applications; efficient-non-responsive genotypes (Firat-93, Seri-82, Genc-99, Panda) had below average DM yield, but responded to P applications; inefficient-non-responsive genotypes (Fuat Bey and Ceyhan-99) had below average DM yield; and no genotypes were in the inefficient responsive category. Such P response categorization is needed for better breeding programs for nutrient-use efficiency. The study may aid in selecting P-efficient genotypes in low-P soils, especially where little P is used. The use of P-efficient genotypes should be seen as complement to, rather than a substitute for, chemical P fertilization depending on local conditions.     

VARIATION AND INTERRELATIONS AMONG NUTRIENT ELEMENTS IN WHEAT LEAVES USED FOR FORAGE

Dual purpose wheat provides valuable forage resources for cattle in the southern Great Plains during winter. In this study, 96 recombinant inbred lines (RILs) were analyzed for variation in concentrations of 11 mineral elements in leaves. The mean concentration was 133.4 mg kg^?1 for manganese (Mn) and 293 mg kg^?1 for iron (Fe), being much higher than the 30 mg kg ^?1 recommended for each of these two minor mineral elements. Mean concentrations of zinc (Zn) (24.1 mg kg^?1) and copper (Cu) (4.4 mg kg^?1) were much lower than recommended concentrations. A highly significant correlation was detected between major minerals, magnesium (Mg) and calcium (Ca) (r = 0.9272**) and between minor minerals, Fe and nickel (Ni) (r = 0.8905**). Copper had no significant correlation with any minerals except Zn (r = 0.2529*), whereas Zn had significant correlations with all of the tested minerals except Cu, Mn, and Ni. The interrelations between different minerals provided information for effective selection strategy for ideal mineral concentrations in breeding of dual purpose wheat.