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.     

Variation within improved cultivars and landraces of lucerne in Central Italy

Summary A variety must be distinguishable, uniform, stable and of sufficient productivity to be officially registered. In Italy landraces of lucerne are still widely used because they are characterized by a good persistence and productivity in their area of origin and adaptation.The landrace from Casalina (20 km south of Perugia, Central Italy) has higher dry matter production than many other commercial cultivars. The objective of this paper was to measure the variation of the landrace Casalina and compare it with that of the commonest cultivars available on the market and with some lines selected from the landrace Casalina.The experiment consisted of 11 entries: Casalina, two selections from Casalina (one for high seed yield and one for frequent cuttings), the registered landrace Italia Centrale and 7 registered cultivars. Each entry was represented by 80 genotypes transplanted in the field 60×40 cm apart in a randomized block design with 4 replications. In 1991 the following characters were recorded on a single plant basis: time of first flowering, height, number of shoots and dry matter yield at the first harvest, time of second flowering, leafiness, height, number of shoots and dry matter yield at the second harvest, height, number of shoots and dry matter yield at the third and fourth harvest. Height, number of shoots and dry matter yield at the first harvest, dry matter at the second and third harvest were recorded during the 1992 season.Casalina was as variable as the other entries in 77% of the comparisons; it was more variable in 8% of the comparisons and less variable in 15% of the comparisons. In conclusion, the variation of landrace Casalina is equal to or less than that of registered varieties so that it could be directly registered at the National Registry of Varieties.     

Forest responses to climate change in the northwestern United States: Ecophysiological foundations for adaptive management

Climate change resulting from increased concentrations of atmospheric carbon dioxide ([CO₂]) is expected to result in warmer temperatures and changed precipitation regimes during this century. In the northwestern U.S., these changes will likely decrease snowpack, cause earlier snowmelt, increase summer evapotranspiration, and increase the frequency and severity of droughts. Elevated [CO₂] and warmer temperatures may have positive effects on growth and productivity where there is adequate moisture or growth is currently limited by cold. However, the effects of climate change are generally expected to reduce growth and survival, predispose forests to disturbance by wildfire, insects, and disease; and ultimately change forest structure and composition at the landscape scale. Substantial warming will likely decrease winter chilling resulting in delayed bud burst, and adversely affect flowering and seed germination for some species. The extent of these effects will depend on the magnitude of climate change, the abilities of individual trees to acclimate, and for tree populations to adapt in situ, or to migrate to suitable habitats. These coping mechanisms may be insufficient to maintain optimal fitness of tree populations to rapidly changing climate. Physiological responses to climatic stresses are relatively well-understood at the organ or whole-plant scale but not at the stand or landscape scale. In particular, the interactive effects of multiple stressors is not well known. Genetic and silvicultural approaches to increase adaptive capacities and to decrease climate-related vulnerabilities of forests can be based on ecophysiological knowledge. Effective approaches to climate adaptation will likely include assisted migration of species and populations, and density management. Use of these approaches to increase forest resistance and resilience at the landscape scale requires a better understanding of species adaptations, within-species genetic variation, and the mitigating effects of silvicultural treatments.     

食用菌产业如何适应低碳经济的发展趋势

在环境压力和哥本哈根会议精神的影响下,低碳化必然成为今后社会与经济的发展趋势。现今,食用菌原辅材料与能源价格不断攀升,食用菌产业面临着严峻的挑战,但同时也蕴育着新的机遇。如何提升产业的整体水平,适应低碳经济的总体趋势,是目前食用菌行业急需解决的问题。就该行业目前的实际状况,笔者根据自身的实践与经历,提出了一套切实可行的低碳技术与策略,以期能对同行提供一些有益的参考,推动食用菌事业的健康发展。     

碱茅（Puccinellia tenuiflora）对盐胁迫及渗透胁迫的适应性反应

盆栽条件下对碱茅在等渗的盐（ＮａＣｌ）及渗透胁迫（ＰＥＧ模拟）下的生长，水分含量，离子（Ｋ＋、Ｎａ＋）吸收与选择性以及渗透反应进行了比较研究。结果表明，在－０．０１～－１．５ＭＰａ渗透势范围内，随渗透势降低植株的干重及水分含量均迅速降低，ＰＥＧ胁迫比等渗的ＮａＣｌ胁迫下降幅更大。ＮａＣｌ及ＮａＣｌ＋ＰＥＧ胁迫下，随溶液渗透势的降低（或ＮａＣｌ浓度的增大）植株Ｎａ＋浓度，Ｎａ＋／Ｋ＋及对Ｋ＋（相对于Ｎａ＋）的选择性均迅速增大，而Ｋ＋浓度未显著变化。植株Ｎａ＋主要是被动吸收的结果，而Ｋ＋则是主动的选择性吸收的结果。植株渗透势随胁迫溶液渗透势降低而线性降低，ＮａＣｌ胁迫下植株渗透势约比等渗的ＰＥＧ胁迫下低－０．１４～－０．２０ＭＰａ。ＮａＣｌ胁迫下，当渗透势高于－０．９ＭＰａ时，植株渗透势的降低（渗透反应）主要可归于由Ｎａ＋积累引起的渗透调节与脱水；渗透势－０．９～－１．５ＭＰａ时，渗透调节可解释植株渗透反应的７２％～７８％（其中，由Ｎａ＋引起的渗透调节占总渗透调节的５６％～７３％），脱水可解释２２％～２８％。ＰＥＧ胁迫下，当溶液渗透势高于－０．７ＭＰａ时，植株的渗透反应主要是脱水引起的；渗透势－０．７～－１．５     

成都市园林植物造景特色探析

回顾了成都园林植物造景的发展历史,将其归纳为4个阶段,分别为：①1949～1978年的起步时期,整修扩建了传统纪念性古典园林,新建了武侯祠、桂湖、杜甫草堂等一批公园和街道绿化;②1979～1989年的突破束缚时期,修缮扩建了＂十年动乱＂中被损坏的古典园林,首次编制了绿地规划,开始探索本土化与现代化相结合的园林形式,以植物园、游乐园、塔子山公园、百花潭公园为代表;③1989～1999年的全面振兴时期,形成了府南河环城绿带,并在1996年编制了新一版成都市城市绿地系统规划,以蜀都大道、府南河环城带状公园、新华公园、活水公园为代表;④自2000年起的继往开来时期,以＂建设田园城市＂为目标,城乡统筹,形成了较成熟的绿地规划理念,浣花溪公园、沙河带状公园、三圣花乡、北湖森林公园、非物质文化遗产公园、金沙遗址公园、东湖公园、三环路道路绿带、人民南路道路景观是该时期的代表。从自然特色和文化特色两个层面探讨了成都园林植物造景特色,根据公园绿地、居住区绿地、道路绿地、风景游览绿地4种用地类型进行植物造景调查分析,并提出相应的建设建议,强调努力发掘地域自然文化特征是时代的需求和发展的方向。     

Highly client-oriented breeding,using local preferences and selection,produces widely adapted rice varieties

When explicit measures are taken to account for the needs of clients (farmers and consumers) it results in highly client-oriented breeding. This involves the participation of farmers to specify the design of desirable varieties and, once they are produced, their testing without delay with the target clients in the target environments. The term highly client-oriented breeding (COB) explains the purpose of farmer involvement – the deliberate achievement of a high degree of client orientation – rather than simply explaining the process of farmers participating in plant breeding (participatory plant breeding). Client-oriented breeding is sometimes based on the preferences of relatively few farmers in a small area, so a possible drawback is that it will produce varieties that are too locally adapted. We describe the testing of varieties in the High Barind Tract (HBT) of Bangladesh from a COB programme carried out in Chitwan district, Nepal. The two best lines, Judi 582 and Judi 567, yielded 19–50% more during the T. Aman season and 106% more during the Aus season than check varieties in the HBT. Research to determine farmers’ preferences and adoption consistently showed these varieties were preferred over all available alternatives. The new varieties were broadly adapted as they were superior in all the three rice-growing seasons over varying levels of inputs. This broad adaptation could be explained by the breeding method: the generations were advanced in two contrasting seasons and each generation was grown on a different farmer's field under different management and planting dates. Because the segregating generations were grown under moderate and fluctuating levels of nitrogen, it is to be expected that genotypes with good nitrogen use efficiency will be selected that can also respond to added nitrogen. Overall, the cost-effectiveness of COB was high as it produced widely adapted genotypes from a small breeding programme, and knowledge of farmers’ preferences increased the efficiency of targeting new germplasm.     

Pancreatic and intestinal enzyme activities in rats in response to balanced and unbalanced plant diets

To simulate the effects of nutritionally adequate and inadequate vegetariandiets, rats were fed, for 28 days, an isonitrogenous, isocaloric, amino acidunbalanced cereal diet (CD) deficient in lysine and tryptophan or abalanced cereal-legume diet (CLD). The impact of these diets on enzymesresponsible for digestion of proteins and carbohydrates were measured.Neither experimental diet significantly affected the animal's final weight orfeed consumption in comparison with controls fed a standard mixed dietfrom plant and animal sources. However, during the first three weeks, theweight gain of rats fed the CD was significantly lower (p<0.01;p<0.05) than that of the controls. CD fed rats also had a higher feedefficiency ratio (p<0.05), demonstrating increased feed consumptionper unit of body weight. They also had decreased pancreatic-amylase activity (p<0.05), serum phytolytic and zoolytic-amylase activity (p<0.05) and serum protein level(p<0.05) than the controls. Activity of pancreatic trypsin and intestinalenzymes (sucrase, maltase, aminopeptidase N) were the same as in thecontrols. In rats fed CLD, growth, food consumption, and enzyme activitiesdid not change, however serum protein and glucose levels were higher(p<0.025; p<0.005) than in the controls. It is hypothesized thatdecrease in -amylase activity was mostly related to the tryptophandeficiency in the CD because this enzyme contains the highest amount oftryptophan units among all tested enzymes.     

天山北坡东西部山地野生鸭茅部分生理生化指标分异性的研究

针对不同区域的鸭茅(Dactylis glmerata)对环境的适应性,选取天山北坡东段与西段鸭茅分布的典型区域,研究分析了鸭茅种群植株部分生理生化特征的差异以及这些性状之间的关联.结果表明:天山西段及东段野生鸭茅除叶片相对含水量、脯氨酸(Pro)含量及超氧化物歧化酶(SOD)活性差异不显著外,叶绿素含量、丙二醛(MDA)含量及过氧化物酶(POD)活性在种群间均成差异显著(P＜0.05);进一步分析表明,叶绿素含量、叶绿素a/b比值的大小与分布生境的海拔、年内降水量有关;MDA含量也反映出分布地段的生境差异性与当地降水量有很大关系a研究结果初步揭示了分布地段野生鸭茅居群在相异生境下适应环境的一些信息,可为该地区鸭茅种质资源的评价与新品种选育等提供部分参考数据.     

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。