高校构建学习实践科学发展观长效机制的基本要求

高校要构建学习实践科学发展观长效机制,应该着力完善高校发展的价值取向,建立正确的价值评价体系;同时,在中国特色社会主义理论体系教学中突出科学发展观;最后,在科学发展观教育实践中,处理好矛盾的普遍性和特殊性的关系。     

国内外柑桔黑斑病研究进展

为了更好地了解和掌握柑桔黑斑病,笔者就国内外柑桔黑斑病研究进展进行较全面的综述。该病害自发现以来,其研究不断深入,至今已报道了4种症状类型,病原菌分类地位经历了数次变更,基于ITS的分子检测技术极大提高了病原菌检测的准确性,化学防治仍是主要防治手段,但还有一些问题如病原菌的潜伏侵染机制未研究清楚。目前柑桔黑斑病已扩散分布于南非、亚洲、澳洲、南美等地,危害表现日益严重,被欧美地区列为重要的检疫性病害,引起了相关部门的重视。     

柑橘木虱的防治技术研究进展

防治柑橘木虱是柑橘黄龙病综合防控的关键措施。本文主要阐述了柑橘木虱的防治技术手段,包括田间管理、化学防治、生物防治等,并且探讨了柑橘木虱防治的发展趋势,旨在为防治柑橘木虱及防控柑橘黄龙病提供理论参考和技术支撑。     

基于复杂系统的柑橘产业链脆弱性研究

中国是柑橘生产大国,然而,在以2008年四川广元蛆柑事件为代表的一系列外部事件的冲击下,柑橘产业链表现出较强的脆弱性,研究柑橘产业链的脆弱性对于柑橘产业的发展具有重要的意义。产业链是一个复杂系统,对于产业链脆弱性的研究是一个全新的、值得进行深入研究的领域。文章以复杂系统的脆性模型为基础,以产业链脆弱性的内涵及概念为切入点,分析产业链脆弱性的影响因素,提炼其脆性因子,并构建出柑橘产业链脆弱性的评价指标体系。     

长期水分胁迫下氮、钾对夏玉米叶片光合特性的影响

采用2 种不同夏玉米基因型（陕单9号,抗旱品种;陕单911,不抗旱品种）的盆栽试验,研究了长期水分胁迫下氮、钾对各生育期叶片净光合速率、蒸腾速率、胞间二氧化碳浓度和叶绿素含量的影响,旨在从光合生理特性揭示这些因子的抗旱机理。结果表明,长期水分胁迫下叶片净光合速率、蒸腾速率、胞间二氧化碳浓度（除成熟期）和叶绿素含量显著降低,不抗旱品种降幅更甚。抗旱品种的净光合速率和叶绿素含量大于不抗旱品种,而蒸腾速率和胞间二氧化碳浓度则相反。两品种苗期光合作用较弱,净光合速率和叶绿素含量均较低,抽雄期达到高峰。施氮能不同程度降低水分胁迫下玉米叶片的蒸腾速率,增加叶绿素含量,提高净光合速率,从而减缓水分胁迫对光合作用的伤害。随氮肥用量增加,不抗旱品种净光合速率和叶绿素含量显著升高,蒸腾速率和胞间二氧化碳浓度明显降低,两种氮肥用量间有显著差异;抗旱品种在低氮用量时效果显著,但高低氮用量间无显著区别。钾对受水分胁迫的玉米表现出比氮肥更突出的效果。相反,在适量供水条件下,氮钾肥的作用明显下降。以上结果表明,适当用量的氮、钾肥,可以有效地改善水分胁迫下作物叶片的光合特性,从而增强作物的抗旱性。     

Woodpeckers as reliable indicators of bird richness, forest health and harvest

Woodpeckers (family Picidae) show promise as indicators of avian diversity in forests because their populations can be reliably monitored, and their foraging and nesting activities can positively influence the abundance and richness of other forest birds. A correlation between woodpecker richness and richness of forest birds is known to exist at the landscape scale, but uncertainty remains whether this correlation occurs at the smaller stand-level spatial scales where forest management activities take place. We used data collected under a diverse range of forest types, harvest treatments, and forest health conditions during a long-term study of bird communities in interior British Columbia, Canada, to examine two basic questions: (1) at the level of individual forest stands, is woodpecker richness correlated with bird richness (measured as richness of all other bird species)? and (2) do woodpecker richness and bird richness have similar habitat correlates? Bird richness was positively correlated with woodpecker richness (β = 0.59, SE = 0.22, 95% CI = [0.14 1.03]). Richness of both woodpeckers and all other birds were positively correlated with tree species richness and negatively correlated with density of pines, and the effect for forest harvest type was similar for both measures of avian richness (uncut < partial harvest < clearcut with reserves). The effect of density of lodgepole pines killed by mountain pine beetles differed between the two richness measures, being positive for woodpecker richness and negative for forest bird richness. We conclude that the richness of woodpeckers is indeed correlated with the richness of other birds at the stand-level, and can serve as a reliable indicator of overall bird richness in most forest stands and conditions, except during insect outbreaks when differential responses by woodpeckers and the rest of the avian community may decouple the relationship between bird richness and woodpecker richness.     

From marl to rock powder: On the history of soil fertility management by rock materials

The ancient practice of marling and the recent application of rock powder to soils are interventions into the orogenic energy budget of soils. Both are slow‐release, long‐term fertilizers or better, soil conditioners. Marls and their uses are reviewed by a study of knowledge and practices from the 1st century AD to the 1800s, for rock powders, a review of the recent theoretical and experimental literature is presented. Under pre‐industrial conditions, paucity of energy prevented the wide‐spread use of such materials, today they are marketed as by‐product of industrial operations. For marls and rock powders alike, their positive effect depends to a large extent on the soil matrix to which the minerals are applied, on the cultivar, and the specific type of applied material. Drawing parallels between the two materials, we suggest that the long‐term experience with marls could be used to study the effects of rock powders, as duration of experiments with these is most often too limited to allow conclusions.     

丘陵红壤橘园不同地面管理措施的经济生态效益研究

A three-year experiment was conducted to investigate and compare the economic and ecological benefits of six types of vegetation management measures in citrus orchards of the hilly red soil region of the eastern part of China. Six vegetation treatments, including tillage without herbicide （clean tillage） and no tillage without herbicide （sod culture） and with herbicide paraquat （paraquat）, glyphosate （glyphosate）, glyphosate-glyphosate-paraquat （G-G-P）, and paraquatparaquat-glyphosate （P-P-G）, were applied in the citrus orchards on a clayey red soil with slopes of 8° and 13°and a sandy soil with slope of 25°. The results showed that the sod culture, paraquat, glyphosate, G-G-P, and P-P-G treatments reduced surface runoff by 38.8%, 42.5%, 18.7%, 28.7%, and 37.5%, then the soil-water losses by 55.5%, 51.7%, 39.9%, 46.8%, and 50.0%, and the N, P, and K nutrient losses by 60.3%, 50.2%, 37.0%, 41.8%, and 45.4%, respectively, as compared with the clean tillage treatment. The weed regeneration ratios with the treatments of clean tillage without herbicide, paraquat, glyphosate, G-G-P, and P-P-G were reduced by 55.1%, 67.2%, 30.3%, 36.8%, and 51.2%, respectively, as compared with the sod culture. The sod culture, paraquat, glyphosate, G-G-P, and P-P-G treatments could increase the soil fertility （annual accumulation of N, P, K, and OM） by 7.1%, 6.9%, 5.3%, 6.2%, and 6.6%, respectively, whereas the clean tillage treatment without herbicide reduced soil fertility by 4.4% after the three-year experiment. The citrus fruit yields in the treatments of paraquat, glyphosate, G-G-P, and P-P-G increased by 7%-10%; the soluble solid, total sugar, total acidity, sugar-acid ratio, and single fruit weight of citrus fruits of all treatments except sod culture significantly （P 〉 0.05） exceeded that of the clean tillage treatment. In general, the paraquat treatment showed the best economic and ecological benefits among the six treatments; therefore, it could be regarded as the best available vegetation     

红吼猴粪便沉积物对表层土壤的影响

The short-term influence of dung deposition and the further redistribution of dung by dung beetles were studied under a resting place of the red howler monkey (Alouatta seniculus) living in tropical rainforests of South America. Monkey dung was experimentally clumped on the field in a place used by troops of howler monkeys for resting in the Nouragues Reserve Station, French Guiana. Dung-treated plots were sampled serially over three weeks and compared with controls located in their immediate vicinity. The composition of the soil matrix (top 10 cm) was studied in successive microlayers using an optical method. Under the influence of dung beetle activity, the topsoil became more homogeneous by losing its litter, its content in earthworm faeces increased in the course of time, and surface mineral deposits were penetrated by roots. The results were interpreted in the light of present knowledge on the effects of soil animal activity on plant growth and survival of seedlings.     

春季柑橘幼树生长对红壤水分条件的响应

以第四纪红黏土发育的红壤、2年生宫川温州蜜柑(Citrus unshiu Marc.cv.Miyaga Ma Mase)盆栽幼树为材料,采用土壤水分探头(FDR)实时监测红壤水分含量,控制红壤水分设5个处理:SMC30、SMC45、SMC60S、MC75和SMC90(分别代表红壤相对含水量的30%、45%、60%、75%和90%),研究了红壤水分条件对柑橘幼树根、叶、春梢和横径的影响。结果表明,当红壤水分为SMC75时最适合柑橘幼树生长,且柑橘幼树根、春梢和横径及叶面积、周长、宽生长参数均在此处理时达最大值。幼树根生长指标(根体积、总根长、根上下扫描面积和根表面积)均与红壤水分间呈极显著抛物线相关,叶形态指标(叶面积、叶周长、叶宽、叶长、叶长/宽比值、叶形状因子)以SMC75为界,随着红壤水分的增加或减少,其生长量均受到了一定程度的影响。SMC≤45%,幼树春梢长和横径受到显著抑制。