Occurrence of two localMegastigmus species parasitic on the eucalyptus gall waspLeptocybe invasa in Israel and Turkey

Two localMegastigmus species were found to be parasitoids on the invasive Eucalyptus gall waspLeptocybe invasa Fisher & La Salle in Turkey and Israel.Megastigmus sp, from Israel is a larval and pupal parasitoid ofL. Invasa. Both species are biparental. Features showing morphological differences between them are presented. The biology, distribution and potential efficiency as biological control agents are discussed.     

干旱荒漠区荒漠锦鸡儿种群繁殖对策研究

通过调查荒漠锦鸡儿(Caragana roborovskyi)灌丛的繁殖倾向、克隆生长特性及分株特征,研究荒漠锦鸡儿的繁殖特点并探讨其适应干旱荒漠环境的机制。结果表明:荒漠区荒漠锦鸡儿既可以进行无性繁殖,又可以进行有性繁殖,且无性繁殖所占的比例(95.8%)明显高于有性繁殖(4.2%)。荒漠锦鸡儿由根萌蘖产生无性系分株,其克隆生长构型为游击型。综合分析认为,荒漠锦鸡儿通过游击型克隆繁殖和发达的根系适应荒漠区的干旱贫瘠环境,使其成为荒漠区的优势种。     

Laboratory experiments on nematodes from natural CO2 springs reveal species-specific tolerance to extreme CO2 concentrations

This study focuses on the CO₂-tolerance of soil nematodes from natural CO₂ springs (mofette fields). In laboratory experiments, we compared survival, reproduction, activity and reactivation of a CO₂-sensitive species with a CO₂-tolerant species. Both species survived even 100% CO₂, but in an inactive state. The higher the CO₂ concentration the more individuals entered inactivity. We found significant differences between the two species: more adults of the CO₂-tolerant species maintained activity and reproduction at higher CO₂ concentrations. Moreover, reactivation after inactivity was faster. Together with a higher juvenile mortality of the CO₂-sensitive species, these interspecific differences are conclusive to explain the niche separation of the two species that was observed in the mofette field.     

Contribution of autochthonous maize populations for adaptation to European conditions

Early vigor, earliness and cold tolerance are the main potential contributions of European maize (Zea mays L.) for breeding programs for adaptation to areas with short growing seasons and cold springs. The objective of this research was to determine the potential contributions of populations from different European regions to breeding for adaptation. Six Spanish and six French maize populations differing on variability for earliness, vigor and cold tolerance were crossed in a complete diallel without reciprocals. The populations and their crosses were evaluated in the field and in a cold chamber. Minimum temperatures were the main environmental trait affecting genotype × environment interaction, probably due to the cold sensitivity of the genotypes with the best performance in the field. The best population cross, based on specific heterosis for adaptation-related traits in the field, was Viana × Rastrojero, but this cross was cold sensitive. Tuy × Lazcano should be the best choice for a breeding program for adaptation, based on performance in the field and cold tolerance. As conclusions, there was variability for earliness, vigor and cold tolerance among the populations and crosses involved in this study, being tolerant to cold conditions the populations with medium growing cycle originated in areas with short growing seasons. The highest yielding crosses were cold sensitive.     

近年来我国粮食生产的时空格局变化及其对策研究

从我国粮食生产总量,3种主要粮食作物（小麦、玉米和水稻）产量的时空变化,以及我国粮食生产重心的空间迁移等角度,阐述了我国粮食生产的时空格局变化规律,探讨其原因所在,并提出了相应的策略和建议。     

海北高寒草甸矮嵩草色素及抗氧化物质动态分析

对海北高寒草甸优势种矮嵩草色素以及多种抗氧化物质的含量分析研究,结果表明,矮嵩草（Kobresiahumilis）对其生存的环境有极其强的适应能力,对矮嵩草草甸的生产力的维持具有积极作用。矮嵩草的叶绿素a、b和总叶绿素含量6,7月份达到最大;Chlb／（a＋b）有微弱的下降趋势,Car／Chl（a＋b）有明显的下降趋势;O2-含量的变化呈现下降趋势,与抗坏血酸含量的变化是负相关;叶黄素循环组分玉米黄质于505nm波长处最大吸收峰在6月和7月达到最大,与叶绿素及光强的变化趋势相吻合;SOD的含量却呈现非规律变化。     

适应二氧化碳肥效作用的农业技术潜力分析

从育种、耕作与栽培三个方面分析了适应CO2肥效作用的农业技术潜力措施.在育种方面,采用综合运用育种理论和育种技术培育新品种,改善作物生理和生态性状来适应大气中CO2含量升高;在耕作制度上,采用调整作物播期、改变当前多熟制边界、调整水作和旱作作物、C3作物和C4作物的播种面积和区域布局等措施;在栽培措施上,采用调节作物冠层温度、改善灌溉条件、保持土壤肥力和养分以及综合防治病虫草害和极端天气灾害等综合措施.扬长避短,兴利除弊,采取主动适应CO2肥效作用的策略,最大限度发挥作物产量潜力.     

Effects of Solution Nitrogen and Plant Density on Annual Grass Seed Biochemistry and Progeny Phenotypic Plasticity

Abstract

Cogenerational phenotypic plasticity compensation to nutrient limitations and shoot densities (light limitation) among individual plants of the same species could provide an increased fitness. Planting density varying between 4 and 16 plants per container and solution nitrogen varying between 5 and 19 mM were used to test phenotypic plastic responses in oat (Avena sativa cv. Montezuma) seed biochemistry and the resulting progeny. Seed Kjeldahl nitrogen (N), magnesium (Mg), and both albumin–globulin (l M NaCl soluble) and prolamin–glutelin (residue) protein fractions were affected by a solution N × plant density interaction. Phosphorus (P) content was influenced by both treatment variables. The protein fractions, P, N, and Mg, in seeds from parent treatments were generally highest in the two higher planting densities. The contents of N, P, Mg, and the prolamin–glutelin fraction were highest at mid‐N (9 mM), except for the 16 plants per container where they were maximal at high‐N (19 mM). In contrast, the albumin–globulin fraction responded linearly to N availability. Seeds per plant decreased while seed weights increased, as plant density increased. The seed content of N, albumin–globulin, prolamin–glutelin, P, and Mg were all negatively associated with the number of seeds per plant. Germination rates of progeny were inversely related to parent plants N treatment. Progeny from the treatment plants (seeds × germination percent) were inversely related, over a five‐fold range, to parent density. Progeny shoot/root ratios (S/R) were directly influenced by the N treatment of parent plants, with progeny from the highest parent N treatment having the highest S/R. Seed N and P content and the prolamin–glutelin protein fraction concentration were correlated with progeny SR. Seed weight was negatively correlated with progeny S/R. Annual grass seed numbers and weights and the allocation of several seed constituents are environmentally influenced by plant density and solution N. These seed biochemical and physiological effects result in a reproductive fitness change and a cogenerational phenotypic plasticity influenced progeny fitness (S/R attribute).     

高等植物非生物胁迫适应的分子生理机制

在综述高等植物非生物胁迫适应的分子生理机制、转基因改良及其局限的基础上,对今后植物抗性生理研究及分子改良研究中方法论创新以及新技术的综合应用进行了探讨。     

"黑土型"退化草地人工植被披碱草属三种牧草的适应性评价

对引入达日县和玛沁县“黑土型”退化草地的三种披碱草属牧草的生长情况,分别进行了4年和3年的观测。结果表明,这些牧草的越冬率均接近100%,抗寒性很强,适应性随栽培年限延长而提高。总的生长发育规律是生长前期地上植物增加速度较快,到抽穗期达到最大值,后逐渐下降。生育期随栽培年限延长而缩短,随海拔增高而延长。三种牧草第2年单位面积平均干草产量约1 100g/m2,垂穗披碱草和短芒老芒麦单位面积平均种子产量约330g/m2。是“黑土型”退化草地上建植人工植被的优良草种。