差分分层暗原色先验去雾法

针对烟尘和雾霾等恶劣户外环境下视频图像严重退化的问题,结合大气散射模型和暗原色先验去雾的原理,针对原始算法中暗区域扩张的缺点,提出一种区分图像景深边界的方法。此方法通过对像素求差分能够将不同景深的像素点区分,进而分别求出不同景深图像的透射率,从而达到快速、准确地恢复图像的目的。实验结果表明,这种方法能够具有更高的处理速度和图像细节,更接近实时去雾的要求。     

PPR‐B‐31: a new maintainer allele in the male‐fertility restorer gene of radish (Raphanus sativus) Ogura cytoplasm

The PPR‐B gene is responsible for male‐fertility restoration of the Ogura‐type male‐sterile radish plants, and it is located in the complex Rfo locus in the vicinity of similar PPR‐A gene and PPR‐C pseudogene. The aim of this study was to identify PPR‐B alleles and understand the structure of the Rfo locus in radish breeding lines. Five lines of radish with normal male‐fertile cytoplasm were tested. The entire PPR‐B gene was amplified, sequenced and allelic PPR‐B sequences were identified. The results indicated that the maintainer lines 7, 15 and 21 contained a non‐restoring form of PPR‐B protein. A unique PPR‐B was found in lines 24/15 and 31 that are restorer and maintainer lines, respectively. The substitutions might be responsible for the loss of a restoring function of the PPR‐B‐31 allele. Amplification of the PPR‐A/PPR‐B and PPR‐B/PPR‐C intergenic regions allowed to identify rearrangements within Rfo locus. Obtained results confirm the wide allelic variation within the Rfo locus, as well as high genetic complexity of the fertility restoration mechanism in radish.     

Chromosomal location of fertility restoring genes for ‘wild abortive’ cytoplasmic male sterility using primary trisomics in rice

Summary Identification and location of fertility restoring genes facilitates their deployment in a hybrid breeding program involving cytoplasmic male sterility (CMS) system. The study aimed to locate fertility restorer genes of CMSWA system on specific chromosomes of rice using primary trisomics of IR36 (restorer), CMS (IR58025A) and maintainer (IR58025B) lines. Primary trisomic series (Triplo 1 to 12) was crossed as maternal parent with the maintainer line IR58025B. The selected trisomic and disomic F₁ plants were testcrossed as male parents with the CMS line IR58025A. Plants in testcross families derived from disomic F₁ plants (Group I crosses) were all diploid; however, in the testcross families derived from trisomic F₁ plants (Group II crosses), some trisomic plants were observed. Diploid plants in all testcross families were analyzed for pollen fertility using 1% IKI stain. All testeross families from Group I crosses segregated in the ratio of 2 fertile: 1 partially fertile+partially sterile: 1 sterile plants indicating that fertility restoration was controlled by two independent dominant genes: one of the genes was stronger than the other. Testcross families from Group II crosses segregated in 2 fertile: 1 partially fertile+ partially sterile: 1 sterile plants in crosses involving Triplo 1, 4, 5, 6, 8, 9, 11 and 12, but families involving triplo 7 and triplo 10 showed significantly higher X² values, indicating that the two fertility restorer genes were located on chromosome 7 and 10. Stronger restorer gene (Rf-WA-1) was located on chromosome 7 and weaker restorer gene (Rf-WA-2) was located on chromosome 10. These findings should facilitate tagging of these genes with molecular markers with the ultimate aim to practice marker-aided selection for fertility restoration ability.     

Fertility restoration of new CMS sources in sunflower (Helianthus annum L.)

The development of commercial sunflower hybrids based on new CMS sources is of special interest for reducing the potential risk of vulnerability to pathogens and for increasing genetic diversity. From 263 test crosses involving nine new CMS sources, i.e. ANL1, ANL2, MAX1, PEF1, PET2, ANN1, ANN2, ANNS and ANN4, five lines were selected as potential restorers for PEF1, PET2 and ANN4. In test crosses between all nine CMS sources and these five restorer lines evaluated in 2 years, seven fully restored hybrids could be identified. These hybrids, based on ANL1, ANL2, MAX1, PEF1, PET2, and ANN4, showed good agronomic performance for plant height, days to flowering, maturity and oil content. Segregation analyses of the F2 populations indicate that a single dominant restorer gene was sufficient to restore pollen production of hybrids based on ANL2, PEF1 and PET2. For restoration of ANN4, two dominant complementary genes are required. In restoration of fertility in the crosses of ANL1 and MAX1 investigated, two dominant genes are involved each of which on its own allows the production of fertile plants.     

长江流域生态修复工程的意义及对策

长江流域幅员辽阔 ,自然条件优越 ,水土保持生态建设已引起全社会各界的高度重视。充分发挥生态的修复能力 ,大面积迅速恢复植被和改善生态系统 ,正是顺应时代要求 ,从根本上解决长江流域水土流失防治步伐缓慢这一重大问题的最为有效途径。长江流域大部分地区雨量充沛 ,气候温和 ,植被类型繁多 ,大部分地区植物可全年生长 ,十分有利于植物的繁衍和生态的自我修复。多年的实践表明 ,发挥生态自我修复能力的主要对策是全面规划 ,采取科学的退耕还林、还草 ,实行封禁治理 ,合理解决好农村燃料、饲料和木材等问题 ,积极营造适应生态修复的外部环境和条件     

云南省砚山县石漠化区域植被修复的物种配置研究

[目的]对石漠化区域人工植被恢复的物种配置方案进行研究,为恢复石漠化地区的生态服务功能,遏制水土流失提供技术支撑。[方法]通过对砚山县不同等级石漠化区域的植被进行实地调查,选取并查明无明显石漠化、潜在石漠化和轻度石漠化3类小区域植物群落结构特征及各物种在群落中的地位。[结果]清香木、栓皮栎是乔木层优势种,火棘、野花椒是灌木层优势种,茅草为草本层优势种,葛藤为藤本植物优势种,它们均具有极为重要的生态价值和经济价值。[结论]结合当地实际情况,提出采用各层乡土优势种并结合引进物种山葡萄等进行石漠化山地乔灌草藤搭配为适合人工植被修复的物种配置方案。     

黄土高原植被恢复与建设的理论和技术问题

黄土高原地区植被恢复与建设是我国重大的生态工程,有巨大的战略意义。主要论述了植被恢复与建设中存在的科学理论和技术问题,以期在植被恢复与建设实践中,能用理论做科学指导,使技术得以充分持续地推广和应用,使植被恢复与建设产生明显的效果。     

土地利用总体规划中生态退耕规划标准指标体系构建与应用

生态退耕规划标准是新一轮土地利用总体规划编制过程中确定生态退耕布局和规模的准则和依据。针对目前生态退耕规划仅从改善生态环境的单一目标出发，而忽视生态退耕对区域粮食安全、经济发展影响的情况，该文以河北省为例，根据整体性、综合协调、科学和可操作性的原则，构建了生态退耕规划标准指标体系；并以河北省下辖11个行政市为评价单元，应用层次分析法进行河北省生态退耕区域评价；应用最小人均耕地面积的概念，确定生态退耕规模。根据评价单元各因素和综合得分情况，河北省可划分为重点、次重点和一般生态退耕区。预计到2020年河北省生态退耕总规模约为61.09×10⁴ hm²。     

Regrowth forests on abandoned agricultural land: A review of their habitat values for recovering forest fauna

Human land use has modified the structure and function of terrestrial landscapes throughout much of the world, with cropping and livestock grazing the major drivers of landscape change. In many tropical, sub-tropical, temperate and Mediterranean regions, regrowth forests regenerate naturally on abandoned agricultural land if human disturbance declines. With the exception of some tropical forest literature, the broader ecological and conservation literature has largely ignored the potential of regrowth forests to facilitate passive landscape restoration and the recovery of fauna communities in fragmented agricultural landscapes. This paper addresses this deficiency by reviewing the available global evidence of fauna recovery in regrowth forest from 68 papers, identifying the main gaps in current knowledge, and providing directions for further research. The majority of reviewed studies focus on regrowth in tropical regions, which often contain large areas of mature forest. Species’ utilisation of regrowth forest is highly variable and is particularly influenced by land-use history, an important determinant of the structural and compositional characteristics of regrowth forests. While site-scale (<1 ha) forest structure and floristic diversity were frequently studied, only 11 studies considered the spatial configuration and context of habitat patches and just two studies explicitly considered landscape structure. Based on this review, six key research questions are posed to direct future research on this important issue. We conclude that a broader perspective of the role of regrowth forest in the landscape is required if we are to realise the potential benefits of regrowth forest for passive landscape restoration and fauna conservation and recovery.     

The Swedish liming programme

To mitigate the acidification problem in surface waters the Swedish government is funding a liming programme. Limestone or dolomite powder has been applied to acidified waters since 1976 and on a large scale since 1982. In most projects, limestone is applied directly to the lake, but in several cases supplementary liming is carried out on wetlands and in streams using dosers or other techniques. At present 7,500 Swedish lakes and more than 11,000 kilometers of streams are limed repeatedly with a total of some 200,000 tonne of limestone every year. In 1994 about US$ 25 million was invested by the Swedish government in the liming programme. The biological objective of the liming operations is to detoxify the water so that the natural fauna and flora can survive or recolonize. The chemical aim is to raise the pH above 6.0 and the alkalinity above 0.1 meq/l, which gives an acceptable buffering capacity. In addition, dissolved metals will be deposited after liming, thus reducing their toxicity. Overdosing must be avoided, with natural softwater characteristics being the objective. The chemical and biological effects in water of the liming operations are encouraging. The Swedish liming programme has so far resulted in restoration in 80–90% of the limed surface waters. The fauna often shows an initial dominance by a few species but diversity increases with time, In general, flora and fauna in limed waters show a great resemblance to those in waters not acidified. An undesired effect of liming is significant changes in mosses and lichens after wetland liming.