Genetic variability in triticale x bread wheat derivatives under normal and phosphorus stress regimes

Twenty six hexaploid triticale (X Triticosecale Wittmack) X bread wheat (Triticum aestivum L. em Thell) derivatives, along with 2 bread wheat and 2 triticale checks, were grown in normal and P-stress environments. Spikes/plant and grain yield/plant, followed by peduncle length, Were the most sensitive to phosphorus deficiency, which also caused a delay in heading and maturity. The heritability and genetic advance for grain yield/plant were high in the stress environment, reflecting the effectiveness of direct selection. The 1000-grain weight, grains/spike and plant height were the important traits for phenotypic selections in both the environments.     

Stability of some quality traits in bread wheat (Triticum aestivum) genotypes

This study was carried out in order to determine some quality traits such as thousand grain weight (TGW), hectoliter weight (HW), grain protein content (GPC), Zeleny sedimentation volume (ZSV) and stability of quality traits of 25 bread wheat genotypes. The experiment was conducted at seven environmental conditions during 2 growing periods (2003-2004 and 2004-2005) using randomized complete block design with four replicates. The ANOVA showed that out of the total sum of squares, 48.4, 28.0 and 23.6% for TGW, 71.4, 14.9 and 13.7% for HW, 54.4, 23.0 and 22.6% for GPC, 44.7, 41.7 and 13.6% for ZSV was attributable to E, G and G x E interaction effects, respectively. Thousand grain weight, hectoliter weight, grain protein content and Zeleny sedimentasyon volume of genotypes changed from 34.5 to 41.4 g, from 76.5 to 80.4 Kg, from 11.49 to 13.37% and from 22.1 to 46.0 ml, respectively. Seven stability parameters, covering a wide range of statistical approaches, were used so as to predict the genotypes. The study of genotypic stability showed that Bezostaya and advanced lines numbered 11 and 24 had high stability for quality traits and proved to be the best within the pool of the studied genotypes. Also, 8 and 17 numbered genotypes demonstrated high stability for TGW, HW, GPC and HW, GPC and ZSV, respectively.     

Female egg investment in relation to male sexual traits and the potential for transgenerational effects in sexual selection

Life-history theory predicts that individuals should increase their reproductive effort when the fitness return from reproduction is high. Females mated with high-quality males are therefore expected to have higher investment than females mated with low-quality males, which could bias estimates of paternal effects. Investigating the traits females use in their allocation decisions and the aspects of reproduction that are altered is essential for understanding how sexual selection is affected. We studied the potential for differential female allocation in a captive population of a precocial bird, the Chinese quail, Coturnix chinensis. Females paired with males with large sexual ornaments laid larger, but not more, eggs than females paired with males with small sexual ornaments. Furthermore, female egg mass was also significantly positively affected by male testis size, probably via some unknown effect of testis size on male phenotype. Testis size and ornament size were not correlated. Thus, both primary and secondary male sexual traits could be important components of female allocation decisions. Experimental manipulation of hormone levels during embryonic development showed that both male and female traits influencing female egg size were sensitive to early hormone exposure. Differences in prenatal hormone exposure as a result of maternal steroid allocation to eggs may explain some of the variation in reproductive success among individuals, with important implications for non-genetic transgenerational effects in sexual selection.Communicated by C. Brown     

Fecundity and survival in relation to resistance to oxidative stress in a free-living bird

Major life history traits, such as fecundity and survival, have been consistently demonstrated to covary positively in nature, some individuals having more resources than others to allocate to all aspects of their life history. Yet, little is known about which resources (or state variables) may account for such covariation. Reactive oxygen species (ROS) are natural by-products of metabolism and, when ROS production exceeds antioxidant defenses, organisms are exposed to oxidative stress that can have deleterious effects on their fecundity and survival. Using a wild, long-lived bird, the Alpine Swift (Apus melba), we examined whether individual red cell resistance to oxidative stress covaried with fecundity and survival. We found that males that survived to the next breeding season tended to be more resistant to oxidative stress, and females with higher resistance to oxidative stress laid larger clutches. Furthermore, the eggs of females with low resistance to oxidative stress were less likely to hatch than those of females with high resistance to oxidative stress. By swapping entire clutches at clutch completion, we then demonstrated that hatching failure was related to the production of low-quality eggs by females with low resistance to oxidative stress, rather than to inadequate parental care during incubation. Although male and female resistance to oxidative stress covaried with age, the relationships among oxidative stress, survival, and fecundity occurred independently of chronological age. Overall, our study suggests that oxidative stress may play a significant role in shaping fecundity and survival in the wild. It further suggests that the nature of the covariation between resistance to oxidative stress and life history traits is sex specific, high resistance to oxidative stress covarying primarily with fecundity in females and with survival in males.     

Sperm allocation in relation to male traits, female size, and copulation behaviour in freshwater crayfish species

Sperm competition is a well-recognised agent in the evolution of sperm and ejaculate structure, as well as variation in female quality. Models of the evolution of ejaculate expenditure predict that male body condition, female fecundity and the risk and intensity of sperm competition may be the ultimate factors shaping optimal ejaculate size. We investigated sperm allocation in Austropotamobius italicus, a freshwater crayfish exhibiting a coercive mating system and external fertilisation, in relation to male and female traits and copulation behaviour under laboratory conditions. We found that mating males were sensitive to female size and produced larger ejaculates when mating with larger females, which were more fecund in terms of number of eggs produced. We found no evidence for female egg production being sperm-limited, as the number of eggs was not dependent on male sperm expenditure. Copulation duration and number of ejaculations reliably predicted the amount of sperm transferred, and both these behavioural measures positively covaried with female body size. These results indicate that male freshwater crayfish can modulate their sperm expenditure in accordance with cues that indicate female fecundity. In addition, a novel finding that emerged from this study is the decrease in sperm expenditure with male body size, which may either suggest that large, old male crayfish are better able than small males to economise sperm at a given mating to perform multiple matings during a reproductive season, or that they experience senescence of their reproductive performance.     

The nature of the photosynthate in natural phytoplankton populations in relation to light quality

The relative concentrations of a variety of organic compounds in phytoplankton from different depths of the photic zone of Saanich Inlet and Indian Arm, British Columbia, Canada, were determined. In surface phytoplankton the greatest proportion of ¹⁴C in newly-formed organic compounds was in the ethanol-soluble fraction irrespective of the light intensity. The proportion of the label in the insoluble fraction increased with depth. Within the ethanol-soluble fraction the relative importance of carbohydrates decreased and amino acids increased with depth. Experiments in Indian Arm indicated that these observed changes were in response to light quality rather than intensity. The percentage release of dissolved organic carbon as a percentage of total fixation decreased with depth and was directly related to the size of the ethanol-soluble fraction.     

低磷胁迫下云南稻形态性状的氮肥反应

采用盆栽试验每份材料栽2桶,每盆装4 kg低磷酸性红壤(速效磷2.53 mg·kg-1、速效氮156.7 mg·kg-1和pH=6.03),设置不施氮肥(速效氮156.7 mg·kg-1)和施氮肥(速效氮490.0 mg·kg-1)两种处理对539份云南稻核心种质17个形态性状及其相对指标,研究低磷胁迫下云南稻形态性状的氮肥效应结果表明:总体上低磷胁迫下云南稻核心种质籼稻氮效反应明显比粳稻敏感;按氮反应相对指标将云南稻种17形态性状划分为氮反应的强敏感、中敏感、弱敏感和不敏感型四种类型;揭示了低磷胁迫下云南稻种氮高效鉴定指标以相对穗干质量和相对总干质量为主,相对穗长、秆干质量、地上干质量、根干质量和茎蘖数可作为参考指标,其中穗干质量为氮反应的强敏感型,总干质量、地上干质量、秆干质量和茎蘖数属中敏感型,根干质量属弱敏感型和穗长属不敏感型.另外,低磷胁迫下云南稻种8个对氮反应敏感相对性状无论是在539份云南稻核心种质及其籼粳亚种间,还是在五个稻作区间总趋势是一致的;既证实了该文提出的低磷胁迫下8个氮反应敏感指标性状是十分可靠的,又揭示了低磷胁迫下5大稻作区氮反应的生态差异和土攘类型多样性是云南成为亚洲栽培稻籼粳分化中心之一的驱动力.     

The effects of walnut and pine leaves on bread wheat growth and frequence of common weed species in the East-Mediterranean region

A field experiment was carried out to determine the effects of walnut (Juglans regia L.) and pine (Pinus sp.) leaves on bread wheat (Triticum aestivum L.) growth and weed control, during 2001-02 and 2002-03 growing seasons in East Mediterranean region of Turkey. In this research, the treatments were: applications of ground walnut leaves (GWL) and ground pine leaves (GPL) at 19 g/m2 dose at Zadoks-11, applications of 200, 400 and 800 cc/m2 of walnut leaves extract (WLE2, WLE4 and WLE8 respectively), pine leaves extract (PLE2, PLE4 and PLE8 respectively), mixture extract of 200 cc walnut and 200 cc pine (ME), herbicide application (HA) at 8 g/m2 dose at Zadoks-21, and control (C) without any treatment. The results have indicated that the effects of treatments were significant for grain yield (GY), plant height (PH), flag leaf length (FLL), weed number per square meter (WN), but non significant for grain number per head (GN), grain weight per head (GW), 1000 grain weight (1000 GW), flag leaf width (FLW), head number per square meter (HN), vegetative period (VP), grain filling period (GFP) and days to maturity (DM).     

养分管理与农田杂草生物多样性和遗传进化的关系研究进展

施肥被看作是一项潜在降低农田杂草对作物干扰的有效农作管理措施。不同施肥处理可形成具有不同养分状况的土壤条件,而土壤条件的差异是导致杂草生物多样性的重要因素。论证养分管理可显著改变农田杂草发生状况和杂草生物多样性,强调了深入开展不同养分管理模式对农田杂草生物多样性和遗传进化影响研究的重要性,提出了如何利用养分管理措施调节农田杂草,在控制杂草对农业危害的同时,保持一定农田可控杂草生物多样性的科学问题。长期N、P和K平衡配施,可维持杂草群落和杂草种子库的生物多样性与稳定性,兼顾杂草控制和杂草多样性保护,实现平衡施肥的经济效应与生态效应的统一。同时,农业生态系统中不同养分管理措施条件下的地表光辐射变化特征、不同光辐射变化对杂草种群种子萌发及植株建立的影响、优势杂草种群的确定及其生理生态和遗传进化规律是今后研究的重点和难点。     

Nutritional quality of phloem sap in relation to host plant-alternation in the bird cherry-oat aphid

Summary. Host alternation in aphids has been attributed to complementary growth of host plants, or more specifically to seasonal changes in the nitrogen quality of the phloem sap. In this report, seasonal fluctuation of free amino acids in phloem of the winter and summer host plants (Prunus padus, bird cherry and Hordeum vulgare, barley) of Rhopalosiphum padi (the bird cherry-oat aphid) were investigated in the context of aphid growth and behaviour. Phloem was collected from the cut stylets of aphids taken from plants that were grown outdoors. The total concentration of amino acids in P. padus phloem increased between bud break and late flush (spring), decreased in mature leaves (summer), and increased again in early senescent leaves (autumn). In H. vulgare, however, amino acid concentration fluctuated less from seedlings to flowering. Spring aphids from P. padus grew rapidly on this host from bud break to late flush, but died on mature and early senescent leaves. Summer aphids from H. vulgare grew as fast on this host as spring aphids did on flush leaves of P. padus. Sexual females grew more slowly than other generations and nearly as well on mature as on early senescent P. padus leaves. As judged by aphid growth and phloem nitrogen quality, P. padus during spring equals the summer host H. vulgare. However, the lower growth rates of R. padi on mature and senescent leaves of P. padus appear only loosely correlated with phloem amino acid concentrations. Therefore, factors influencing aphid nutrition, or ecology, other than seasonal changes in phloem sap amino acid concentration may explain the existence of host alternation in R. padi.     

干旱胁迫对文心兰抗氧化酶活性和渗透调节物质含量的影响

以切花文心兰＂黄金2号＂（Oncidium Gower Ramsey‘Gold 2’）幼苗及成熟苗为材料,用盆栽控制浇水模拟干旱的方法,对不同程度干旱胁迫下其叶片抗氧化酶活性和渗透调节物质含量的变化进行研究。结果表明,文心兰＂黄金2号＂具有一定的耐旱性。随着干旱胁迫程度的加深,文心兰幼苗及成熟苗的相对含水量和相对电导率变化慢、幅度小,超氧化物歧化酶（SOD）和过氧化物酶（POD）活性能保持一定水平,渗透调节物质可溶性糖和脯氨酸含量持续上升,表明文心兰＂黄金2号＂对干旱胁迫具有较强的适应能力。     

Early life history traits of the gold-eye rockfish, Sebastes thompsoni, in relation to successful utilization of drifting seaweed

The gold-eye rockfish Sebastes thompsoni lives in association with drifting seaweed during the early developmental period. Early life history traits of the gold-eye rockfish were studied by means of otolith analysis of larvae and juveniles associated and unassociated with drifting seaweed in the waters off southern Sanriku, Tohoku, northern Japan, from 1993 to 1995.␣Daily growth increments and the existence of an extrusion check were confirmed by both a series of tetracycline marking experiments and an analysis of the relation between the number of increments and the number of days after extrusion. Larvae and juveniles associated with drifting seaweed occurred from late May to late July, with a peak in late June, showing the same seasonal fluctuation in abundance as drifting seaweed. Larvae seemed to associate with drifting seaweed after aggregation to surface slick areas. Body size at the commencement and the end of the seaweed-associated period was estimated at 18 and 50 mm total length, respectively. Growth rates were low until the beginning of the association with seaweed; thereafter they became high but declined towards the end of seaweed-associated life. Larvae and juveniles born later grew faster than those born earlier. This tendency was detected both before and during the association with drifting seaweed. Although the season of abundant drifting seaweed was about 2␣months shorter, and occurred 2 months later, than the extrusion season of the gold-eye rockfish from early February to early June, this seemed to be compensated by the growth variation dependent on birth month. Early life history traits of the gold-eye rockfish are discussed in relation to the successful utilization of drifting seaweed. Received: 3 August 1997 / Accepted: 24 March 1998     

Response of peroxidase and catalase to acid rain stress during seed germination of rice, wheat, and rape

Seed germination of plants with various acid-resistance display different responses to acid rain. To understand the reason why such differences occur, the effects of simulated acid rain (pH 2.5–5.0) on the activities of peroxidase (POD) and catalase (CAT) during seed germination of rice (O. sativa), wheat (T. aestivum), and rape (B. chinensis var. oleifera) were investigated. Results indicated that the maximum change in activities of CAT and POD by acid rain treatment with different acidity and time in relation to the referent treatment without acid rain, was in the order: rice (28.8%, 31.7%) < wheat (34.7%, 48.3%) < rape (79.3%, 50.0%). The pH level for which the treatment with acid rain did not cause significant difference (p < 0.05) was in the order: rice (3.5).wheat (4.0).rape (5.0). Moreover, the change in activity of POD was higher than that of CAT, which showed that POD was more sensitive to acid rain stress than CAT. The difference in the ability of POD and CAT in removing free radicals was one reason why the germination indexes of these three species behaved differently.     

Response of non-enzymatic antioxidative mechanisms to stress caused by infection with Fusarium fungi and chemical protection in different wheat genotypes

The aim of this study was to assess the effect of infection with Fusarium fungi and chemical protection on the contents of phenolic acids and antioxidative potential of extracts from grains of 23 wheat genotypes. Based on chemical analyses including abiotic factors such as weather conditions and the location of the plantation, the authors attempted to clarify non-enzymatic antioxidative response mechanisms to two different stressors in 23 wheat genotypes. Based on chemical analysis, it was found that mass infection with fungi from the genus Fusarium induces defence mechanisms of the plant, which results in an increased production of phenolic acids, mainly those, which are substrates for the production of acids exhibiting antimicrobial action. This mechanism is confirmed by the analyses of antioxidant activity, which also increases significantly during fungal infection, connected with the production of mycotoxins. In the course of chemical plant protection, significant changes were observed in the production of phenolic acids. Even if antioxidant activity was not higher in comparison to the control, an increased production of certain phenolic acids was recorded, which suggests stimulation of the resistance system of the plant, at a simultaneous complete response of antioxidative mechanisms, as it takes place during fungal infection.     

土壤干旱胁迫对Larrea tridentata叶片膜脂过氧化和保护酶活性的影响

Larrea tridentata是一种亚热带沙漠中常绿的含树脂的灌木,有很高的生态价值和药用价值。在不同土壤干旱胁迫条件下,测量了L.tridentata叶片具有生物学活性物质的含量变化。结果表明,随着土壤水分胁迫的加重,L.tridentata保护酶活性与MDA含量的整体趋势都是先升高,在土壤水势达到-2.415 MPa时,有所下降。L.tridentata体内重要的渗透调节物质脯氨酸的质量分数总体成上升趋势。可见,保护酶及渗透调节对L.tridentata提高自身的抗旱性有重要作用。     

东江干流浮游植物群落结构特征及与水质的关系

2009年7月,调查了东江干流浮游植物的属类组成、密度和生物多样性指数,并将水质理化参数与藻类的群落指标进行相关性分析。47个采样点中共发现7门78属藻类,浮游植物的密度范围在0.72×104~853.86×104 cells.L-1之间。其中蓝藻门、硅藻门、绿藻门和隐藻门占总浮游植物密度的96.12%,优势属为颤藻属、隐藻属、小环藻属、菱形藻属、栅藻属。根据藻类各项指标值显示,东江干流水质良好。相关分析结果表明：浮游植物密度以及属类数均与CODMn及电导率呈极显著的正相关关系（P〈0.01）。并且CCA分析表明CODMn浓度是影响这一区域物种分布格局的重要因素。     

沙芥幼苗叶片解剖结构和光合作用对干旱胁迫的响应

为了了解干旱胁迫对植物光合作用和叶片结构的影响,明确植物光合作用和结构对干旱胁迫的响应,本研究以沙生植物、中国特有种---沙芥为材料,采用Li-6400光合仪和常规石蜡切片法,研究了干旱胁迫下沙芥光合参数、叶片解剖结构的变化,结合前期对沙芥叶片内活性氧物质含量变化的研究,试图阐述沙芥叶片应对干旱胁迫的机制,揭示沙生植物—沙芥在干旱环境中的生存策略,为植物耐旱性提供理论依据。结果表明：随着土壤含水量下降,净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、叶片厚度、上表皮厚度、下表皮厚度呈下降趋势;海绵组织厚度呈先下降后上升的趋势;胞间二氧化碳浓度(Ci)呈上升的趋势;气孔限制值(Ls)、水分利用率(WUE)、栅栏组织和栅栏组织/海绵组织和叶片组织结构紧密度(CTR)呈先先上升后下降的趋势;且在土壤含水量大于39% WHC时沙芥光合和结构受影响较小,在土壤含水量低于39% WHC时,沙芥光合作用受到抑制,而叶片紧密度变大,能够较好的抵御干旱环境。结果表明干旱胁迫下沙芥幼苗叶片光合作用的下降是非气孔因素造成的,且其叶片结构的变化会影响光合作用,光合作用通过产生活性氧对结构也有影响。说明沙芥能够很好的适应中度干旱以上的环境,在重度干旱环境中沙芥通过调节叶片结构以适应环境,这可能是沙芥能够在沙漠地区生存繁殖的原因之一。     

基于综合气象干旱指数（CI）的干旱时空动态格局分析——以甘肃省黄土高原区为例

借助ArcGIS9．3和SPSS数据软件平台,根据甘肃省黄土高原区33个气象站1962-2010实测气象资料,利用综合气象干旱指数（CI）对甘肃省黄土高原区近50年的干旱特征进行了时空分析。首先计算了各站历年逐日的CI指数,统计近50年各站点出现的干旱过程、各时段的干旱事件,在此基础上分析了甘肃省黄土高原区历年各地区干旱发生的覆盖范围、频率和不同等级干旱发生的多年平均天数,揭示了甘肃省黄土高原区干旱发生的时空差异和动态格局。分析结果表明,（1）甘肃省黄土高原区有大范围干旱发生的年份,夏季和秋季较多分别有13、8a,冬季最少,只有3a。（2）从空间尺度来看,甘肃省黄土高原区中兰州一榆中一靖远一带和庆阳北部属于高值区,而岷县、渭源一带属于低值区;106°E以西“临洮．通渭．天水”一带和庆阳东南部是干旱变幅最大的地方。（3）从季节尺度来看,夏季干旱频率和持续日数最多,春季、秋季次之,冬季最少。