作物群体受光结构与作物生产力研究

植物体内的干物质中,９０％～９５％直接或间接地来自光合作用,作物群体进行光合作用的能源是太阳辐射能,从获得太阳能的观点出发,农业就是“通过高等植物发展光能利用效率的产业”［８］。叶子作为光合作用的主要器官,其光环境的优劣对光能利用效率和作物生产力起着...     

Soil Health,Crop Productivity,Microbial Transport,and Mine Spoil Response to Biochars

Biochars vary widely in pH, surface area, nutrient concentration, porosity, and metal binding capacity due to the assortment of feedstock materials and thermal conversion conditions under which it is formed. The wide variety of chemical and physical characteristics have resulted in biochar being used as an amendment to rebuild soil health, improve crop yields, increase soil water storage, and restore soils/spoils impacted by mining. Meta-analysis of the biochar literature has shown mixed results when using biochar as a soil amendment to improve crop productivity. For example, in one meta-analysis, biochar increased crop yield by approximately 10 %, while in another, approximately 50 % of the studies reported minimal to no crop yield increases. In spite of the mixed crop yield reports, biochars have properties that can improve soil health characteristics, by increasing carbon (C) sequestration and nutrient and water retention. Biochars also have the ability to bind enteric microbes and enhance metal binding in soils impacted by mining. In this review, we present examples of both effective and ineffective uses of biochar to improve soil health for agricultural functions and reclamation of degraded mine spoils. Biochars are expensive to manufacture and cannot be purged from soil after application, so for efficient use, they should be targeted for specific uses in agricultural and environmental sectors. Thus, we introduce the designer biochar concept as an alternate paradigm stating that biochars should be designed with properties that are tailored to specific soil deficiencies or problems. We then demonstrate how careful selection of biochars can increase their effectiveness as a soil amendment.     

基于GIS的黄土丘陵沟壑区作物生产潜力模拟研究

从YIELD模型的来源、输入文件及基本参数,模型中作物生产力计算各个子模型以及计算流程4个方面作了简单的叙述,以黄土丘陵沟壑区典型小流域晋西狼窝沟为例,在地理信息系统（GIS）技术十,应用YILD模型对该流域的作物生产潜力进行了模拟,并从作物类型,地类,耕作措施及气候条件4个方面对影响该流域作物产量的因素进行了分析。结果表明,该模型对不同作物的模拟产量在总体上与实体产量基本相符合,表明模型可以应用于黄土丘陵沟壑区的作物产量模拟之中,对于不同地类来说,坝地的土壤水分和以力条件明显高于梯田和坡耕地,因而坝地的模拟产量地高于梯田和坡地,但三者之间的差距没有实测产量显著,耕作措施是提高作物生产力的有效途径,对地膜覆盖,梯田以及施肥等耕作措施的模拟产量表明,这3种耕作措施均能有效的物生产力;其产量提高率均平均在85％以上,其中以施肥对作物的增产作用最大,增产率高达95％,,这与实测产量资料基本一致;气候条件是影响作物生产的直接因素,模拟结果表明模型对降水量和温度等气候条件十分敏感,不同年份降水量和温度的差异将直接导致作物生产力的显著不同。对YIELD模型的模拟结果分析表明,该模型可以有效地应用于黄土丘陵沟壑区的作物生产潜力研究。     

Bee Species Diversity Enhances Productivity and Stability in a Perennial Crop

Wild bees provide important pollination services to agroecoystems, but the mechanisms which underlie their contribution to ecosystem functioning—and, therefore, their importance in maintaining and enhancing these services—remain unclear. We evaluated several mechanisms through which wild bees contribute to crop productivity, the stability of pollinator visitation, and the efficiency of individual pollinators in a highly bee-pollination dependent plant, highbush blueberry. We surveyed the bee community (through transect sampling and pan trapping) and measured pollination of both open- and singly-visited flowers. We found that the abundance of managed honey bees, Apis mellifera, and wild-bee richness were equally important in describing resulting open pollination. Wild-bee richness was a better predictor of pollination than wild-bee abundance. We also found evidence suggesting pollinator visitation (and subsequent pollination) are stabilized through the differential response of bee taxa to weather (i.e., response diversity). Variation in the individual visit efficiency of A. mellifera and the southeastern blueberry bee, Habropoda laboriosa, a wild specialist, was not associated with changes in the pollinator community. Our findings add to a growing literature that diverse pollinator communities provide more stable and productive ecosystem services.     

Bottlenecks to coral recovery in the Seychelles

Processes that affect recovery of coral assemblages require investigation because coral reefs are experiencing a diverse array of more frequent disturbances. Potential bottlenecks to coral recovery include limited larval supply, low rates of settlement, and high mortality of new recruits or juvenile corals. We investigated spatial variation in local abundance of scleractinian corals in the Seychelles at three distinct life history stages (recruits, juveniles, and adults) on reefs with differing benthic conditions. Following widespread coral loss due to the 1998 bleaching event, some reefs are recovering (i.e., relatively high scleractinian coral cover: ‘coral-dominated’), some reefs have low cover of living macrobenthos and unconsolidated rubble substrates (‘rubble-dominated’), and some reefs have high cover of macroalgae (‘macroalgal-dominated’). Rates of coral recruitment to artificial settlement tiles were similar across all reef conditions, suggesting that larval supply does not explain differential coral recovery across the three reef types. However, acroporid recruits were absent on macroalgal-dominated reefs (0.0 ± 0.0 recruits tile^?1) in comparison to coral-dominated reefs (5.2 ± 1.6 recruits tile^?1). Juvenile coral colony density was significantly lower on macroalgal-dominated reefs (2.4 ± 1.1 colonies m^?2), compared to coral-dominated reefs (16.8 ± 2.4 m^?2) and rubble-dominated reefs (33.1 ± 7.3 m^?2), suggesting that macroalgal-dominated reefs have either a bottleneck to successful settlement on the natural substrates or a high post-settlement mortality bottleneck. Rubble-dominated reefs had very low cover of adult corals (10.0 ± 1.7 %) compared to coral-dominated reefs (33.4 ± 3.6 %) despite no statistical difference in their juvenile coral densities. A bottleneck caused by low juvenile colony survivorship on unconsolidated rubble-dominated reefs is possible, or alternatively, recruitment to rubble-dominated reefs has only recently begun. This study identified bottlenecks to recovery of coral assemblages that varied depending on post-disturbance habitat condition.     

Increased Productivity of a Cover Crop Mixture Is Not Associated with Enhanced Agroecosystem Services

Cover crops provide a variety of important agroecological services within cropping systems. Typically these crops are grown as monocultures or simple graminoid-legume bicultures; however, ecological theory and empirical evidence suggest that agroecosystem services could be enhanced by growing cover crops in species-rich mixtures. We examined cover crop productivity, weed suppression, stability, and carryover effects to a subsequent cash crop in an experiment involving a five-species annual cover crop mixture and the component species grown as monocultures in SE New Hampshire, USA in 2011 and 2012. The mean land equivalent ratio (LER) for the mixture exceeded 1.0 in both years, indicating that the mixture over-yielded relative to the monocultures. Despite the apparent over-yielding in the mixture, we observed no enhancement in weed suppression, biomass stability, or productivity of a subsequent oat (Avena sativa L.) cash crop when compared to the best monoculture component crop. These data are some of the first to include application of the LER to an analysis of a cover crop mixture and contribute to the growing literature on the agroecological effects of cover crop diversity in cropping systems.     

植物生物反应器研究现状、瓶颈及策略

近10年,植物作为重组蛋白生产系统是生命科学中研究最活跃领域之一。植物系统具有低成本、安全和易规模化优势,其表达生物活性药用蛋白能力已被许多研究所证实;同时,植物药用蛋白产品还表现出潜在的市场和广阔应用前景。鉴于此,回顾了植物生物反应器兴起,介绍了植物表达系统和重组蛋白研究现状,综述了植物生物反应器面临瓶颈问题、解决对策和未来一段时间内研究热点;在展望植物生物反应器前景同时,对我国研究现状、与国外差距和未来发展应采取策略进行了讨论。     

Crop Response to Fertilizers

The response–function approach to the effects of fertilizerson crop yield is discussed. The problem is first consideredin general terms and expressions are derived for the maximumyield, the economic yield and the utilization efficiencies orrecovery factors. It is described how the use of a compoundfertilizer modifies the method. The theory is then applied tothe inverse polynomial function, which is used to describe theresponse to various levels of nitrogen, phosphorous and potassiumfertilizers; the response equation is modified to allow forthe depressive effects of high nitrogen levels on yield. Next,a numerical example is given in which the results are appliedto summer cabbage, and the most profitable fertilizer treatmentsare calculated. Finally, the application of the model acrossdifferent soils and different crops is briefly discussed. crop yield, fertilizers, mathematical model, optimal application     

国家自然科学基金资助农作物生物技术研究项目现状与展望

近年来,我国农作物生物技术研究和应用取得了很大进展。自然科学基金作为资助自然科学基础性研究的重要渠道之一,资助了大量有关农作物生物技术研究的课题。本文介绍了国家自然科学基金从重大项目、重点项目和面上项目三个层次上资助农作物生物技术研究项目的情况,分析了我国农作物生物技术研究中存在的问题,并展望了国家自然科学基金未来资助农作物生物技术研究的几个重要方面。     

Welcome to the Swamp: Addressing Community Capacity in Ecohealth Research and Intervention

The standpoint from which this article is written is that of development practitioners who work fairly continuously with community transformation processes, and with their peers in many disciplines who are trying to stimulate and support such processes. Drawing on three case examples, the authors put forward four lessons for an ecosystems approach to health development work. First, health and natural resource management professionals, and the technical solutions they create, cannot, by themselves, solve many of the problems communities face. To be effective, solutions have to address a complex set of variables that may be largely invisible to professionals from outside the communities. Creating a map of the human and natural systems within which a particular human health issue arises is often an important first step. Second, another reason why professionals cannot solve complex health challenges on their own is that, in the end, many of the solutions must be implemented by community people from the inside out. Therefore the “map” needs to include human dynamics and community capacity. Third, identifying and assessing the specific capacities that a community needs to address particular health determinants is therefore an important part of health development work. It is critical that community capacity assessment is not undertaken in the abstract, but rather in a way that links capacity assessment with real, ongoing work and through a participatory process that builds understanding and commitment within the community, and identifies clear pathways for future action. Finally, outside professionals working with a community contribute to its capacity to address critical health challenges, not only because of the technical knowledge and skills they bring, but also through the characteristics and attitudes they exhibit. It is therefore important that professionals build their own capacity to role model effective community practice.     

Wood Bioenergy and Soil Productivity Research

Timber harvesting can cause both short- and long-term changes in forest ecosystem functions, and scientists from USDA Forest Service (USDA FS) have been studying these processes for many years. Biomass and bioenergy markets alter the amount, type, and frequency at which material is harvested, which in turn has similar yet specific impacts on sustainable productivity. The nature of some biomass energy operations provides opportunities to ameliorate or amend forest soils to sustain or improve their productive capacity, and USDA FS scientists are leading the research into these applications. Research efforts to sustain productive soils need to be verified at regional, national, and international scope, and USDA FS scientists work to advance methods for soil quality monitoring and to inform international criteria and indicators. Current and future USDA FS research ranges from detailed soil process studies to regionally important applied research and to broad scale indicator monitoring and trend analysis, all of which will enable the USA to lead in the sustainable production of woody biomass for bioenergy.     

Lab to Farm: Applying Research on Plant Genetics and Genomics to Crop Improvement

Over the last 300 years, plant science research has provided important knowledge and technologies for advancing the sustainability of agriculture. In this Essay, I describe how basic research advances have been translated into crop improvement, explore some lessons learned, and discuss the potential for current and future contribution of plant genetic improvement technologies to continue to enhance food security and agricultural sustainability.

This article is part of the PLOS Biology Collection “The Promise of Plant Translational Research.”

     

Crop responses to climatic variation

The yield and quality of food crops is central to the well being of humans and is directly affected by climate and weather. Initial studies of climate change on crops focussed on effects of increased carbon dioxide (CO2) level and/or global mean temperature and/or rainfall and nutrition on crop production. However, crops can respond nonlinearly to changes in their growing conditions, exhibit threshold responses and are subject to combinations of stress factors that affect their growth, development and yield. Thus, climate variability and changes in the frequency of extreme events are important for yield, its stability and quality. In this context, threshold temperatures for crop processes are found not to differ greatly for different crops and are important to define for the major food crops, to assist climate modellers predict the occurrence of crop critical temperatures and their temporal resolution. This paper demonstrates the impacts of climate variability for crop production in a number of crops. Increasing temperature and precipitation variability increases the risks to yield, as shown via computer simulation and experimental studies. The issue of food quality has not been given sufficient importance when assessing the impact of climate change for food and this is addressed. Using simulation models of wheat, the concentration of grain protein is shown to respond to changes in the mean and variability of temperature and precipitation events. The paper concludes with discussion of adaptation possibilities for crops in response to drought and argues that characters that enable better exploration of the soil and slower leaf canopy expansion could lead to crop higher transpiration efficiency.     

Exploring the Limits of Crop Productivity : I. Photosynthetic Efficiency of Wheat in High Irradiance Environments

The long-term vegetative and reproductive growth rates of a wheat crop (Triticum aestivum L.) were determined in three separate studies (24, 45, and 79 days) in response to a wide range of photosynthetic photon fluxes (PPF, 400-2080 micromoles per square meter per second; 22-150 moles per square meter per day; 16-20-hour photoperiod) in a near-optimum, controlled-environment. The CO₂ concentration was elevated to 1200 micromoles per mole, and water and nutrients were supplied by liquid hydroponic culture. An unusually high plant density (2000 plants per square meter) was used to obtain high yields. Crop growth rate and grain yield reached 138 and 60 grams per square meter per day, respectively; both continued to increase up to the highest integrated daily PPF level, which was three times greater than a typical daily flux in the field. The conversion efficiency of photosynthesis (energy in biomass/energy in photosynthetic photons) was over 10% at low PPF but decreased to 7% as PPF increased. Harvest index increased from 41 to 44% as PPF increased. Yield components for primary, secondary, and tertiary culms were analyzed separately. Tillering produced up to 7000 heads per square meter at the highest PPF level. Primary and secondary culms were 10% more efficient (higher harvest index) than tertiary culms; hence cultural, environmental, or genetic changes that increase the percentage of primary and secondary culms might increase harvest index and thus grain yield. Wheat is physiologically and genetically capable of much higher productivity and photosynthetic efficiency than has been recorded in a field environment.     

Biological Assessment of Water Pollution Using Periphyton Productivity and Standing Crop in the Linggi River,Malaysia

Many assessments of water pollution in aquatic ecosystem have focused mainly on physical and chemical characteristics. However, until recently, biological aspects have been given little attention. Although physical and chemical methods of assessing water pollution are relatively simple to interpret, biological assessments have many strong merits. Therefore an attempt was made to use periphyton productivity (in terms of biomass ash‐free dry weight, AFDW) and chlorophyll‐a content (measured from periphyton colonized on glass microscope slides) to assess water pollution in the Linggi river. The Linggi River is a tropical lotic system in the country of Malaysia. As a result of increased nutrient enrichment due to sewage and agro‐industrial wastes, analyses of accumulated periphyton on glass slides showed increased biomass AFDW from an unpolluted upstream reach to the highly polluted downstream reach of the river. In contrast to biomass, the chlorophyll‐a content of the accumulated periphyton was not always directly related to the AFDW of the biomass. Though the highly polluted Station 4 showed high biomass AFDW and chlorophyll‐a, due to increased nutrient enrichment. The chlorophyll‐a values at slightly polluted Station 2 were lower than at the unpolluted Station 1. Meanwhile, the mean chlorophyll‐a content observed in Linggi river was relatively high as compared to previous studies carried out in Malaysia. When the Water Quality Index (WQI) was calculated using key chemical parameters linked to organic pollution, there was a significant correlation between chemical parameters, biomass AFDW, and chorophyll‐a. Though the chlorophyll‐a content increased with decreases in the WQI, similar to the biomass AFDW, the chlorophyll‐a values were found to be lower in slightly polluted Station 2 than unpolluted Station 1. Therefore it was not necessary that an increase in the biomass AFDW, due to nutrient enrichment, would always increase the chlorophyll‐a in accumulated periphyton (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

纳米材料在农作物领域的应用及展望

近年来,纳米材料成为农业领域的一个研究热点,受到了国内外学者的广泛关注。纳米材料基于其尺寸小的特点,可以在穿透植物细胞壁后,通过内吞作用被细胞吸收,进而对植物生长产生影响。纳米材料被广泛应用于植物遗传转化、作物生长发育和植物健康等农作物领域,尤其在遗传转化领域,其可作为转化载体与基因编辑技术综合运用,对作物进行遗传改良。基于此,对纳米材料在植物体内的吸收、转运机制及其在农作物领域的应用进展进行了综述,重点探讨了纳米材料在植物遗传转化方面的研究进展,并对其在农作物领域亟待解决的问题和后续发展方向进行了展望,以期为拓宽纳米材料的应用领域提供参考。     

我国农作物QTL定位研究的现状和进展

植物大多数重要的经济性状都是数量性状,研究植物数量性状遗传对植物育种具有十分重要的意义。近十几年来,分子生物学特别是分子标记技术的飞速发展,许多植物高饱和的分子连锁图谱的构建,使得我们可以更深入地进行数量性状的研究。本文综述了近年来我国在农作物数量性状遗传研究方面的进展及发展动态。列举了我国利用DNA分子标记进行数量性状QTL定位的47个实例。总结了控制数量性状的QTL的数目、类别、效应及其互作和 QTL与环境间的互作关系。讨论了当前在该研究领域中存在的问题,展望了该领域的发展前 景。