Response to the Views and Opinions of Maningat,Seib, and Bassi Regarding McCleary et al (2013)

Phosphate cross‐linked starch, referred to as resistant starch 4 (RS₄) is hydrolyzed much more rapidly under physiological conditions (i.e., pH 6, 37°C, pancreatic α‐amylase) than under the conditions used in AOAC dietary fiber method 985.29/AACC International Approved Method 32‐45.01 (the Prosky method), in which samples are incubated with thermostable bacterial α‐amylase at 95–100°C. For this reason, the author concludes that the Prosky method overestimates the dietary fiber content of these materials. A more accurate estimate of dietary fiber content is obtained with AOAC Method 2009.01/AACCI Approved Method 32‐45.01.     

青海不同林分土壤微生物群落结构(PLFA)

  目的  明确三江源高寒湿地微生物群落结构特征以及植被和土壤理化特性对三江源高寒湿地微生物群落特征的影响。  方法  以三江源地区典型高寒湿地为研究对象,采用磷脂脂肪酸（Phospholipid fatty acid, PLFA）法,探究土壤微生物群落结构特征及其调控因子。  结果  三江源地区高寒湿地的总PLFA为84.76 ± 38.03 nmol g⁻¹,其中革兰氏阳性菌、革兰氏阴性菌、真菌、放线菌、丛枝菌根真菌和其他PLFA分别为14.98 ± 6.21、17.77 ± 8.17、2.60 ± 1.60、4.22 ± 2.38、1.84 ± 1.22和43.41 ± 21.06 nmol g⁻¹。土壤微生物群落结构受到植被生物量和土壤理化特性的共同影响,而气候因素对其影响相对较弱。放线菌与土壤全氮、土壤湿度、硝态氮和地下生物量呈正相关关系;总PLFA、细菌还与总氮和铵态氮呈正相关关系,与土壤容重呈负相关关系;革兰氏阳性菌与总氮、土壤湿度、铵态氮、硝态氮、地下生物量和土壤有机碳呈正相关关系;革兰氏阴性菌与土壤湿度、铵态氮、硝态氮和地下生物量呈正相关关系;而丛枝菌根真菌和真菌受到生物量与土壤理化特性的影响相对较小。  结论  植物和土壤理化特性的共同作用是调控三江源高寒湿地微生物群落结构的重要因素,这有利于更深入地理解陆地生态系统生物地球化学循环。     

Does specialization explain rarity and decline among British bumblebees? A response to Goulson et al.

Recent studies of British bumblebees have proposed a seemingly simple explanation for the decline in some species: that greater dietary specialization among the rarer species has put them at greater risk. However, comparisons of dietary specialization require: (1) that bees have access to the same dietary options among which to make their choices; (2) that the differing relative breadths of dietary choices made are not obscured by the differing sample sizes among bee species. Using one of the few suitable data sets, I find no evidence for a relationship between, on the one hand, rarity or declines in British bumblebees and, on the other, their dietary breadths, the strengths of their dietary preferences, or their proboscis lengths (which influence dietary choices). In contrast, there is support for a relationship between rarity or declines within Britain and the sizes of species’ European ranges, particularly when these measures are adjusted to represent their ranges near sea level. Adjusted range sizes may reflect overall niche breadth and perhaps climatic and habitat specialization. This is not to say that climate change is the driving factor for declines or that changing food-plant availability is unimportant, but that climatic and habitat specialization may be a better indicator of risk of decline, which deserves further study.     

耕地与粮食安全战略: 藏粮于土, 提高中国土地资源的综合生产能力

  目的  根据耕地质量等别差异及其空间特性,科学合理地划定具有空间调控与引导作用的耕地保护分区。  方法  将山东省133个区（县）耕地质量等别作为空间变量,采用自然断点法分析耕地质量空间分布,运用空间自相关的方法分析山东省耕地自然等、利用等、经济等的空间聚集关系,从而进行耕地空间分区。  结果  ①山东省耕地自然等、利用等、经济等平均等别分别为6.67、8.30、9.53,耕地质量总体较优,空间上呈现“西高东低”的特征。②山东省耕地质量呈现显著的空间集聚特征,耕地质量自然等、利用等及经济等的空间集聚性呈递增趋势。③基于农业区位理论、空间极化理论,统筹考虑耕地质量空间内在联系与现实需求,将全省耕地划分为核心保护区、综合重构区、重点改良区、优先提升区4个耕地保护区并提出了相应耕地保护方案。  结论  山东省耕地质量空间差异性显著,可以利用空间集聚特征与农业区位来确定耕地保护分区与保护方案。     

坡改梯的水土保持效益研究

主要研究了坡耕地、新梯田、老梯田的各种水土保持指标,对比分析坡改梯后的水土保持效果。研究结果表明,坡改梯后土壤水分、土壤贮水量、地表径流量、入渗性能、土壤物理性状等指标都得到明显的改善。     

The Luke et al. method for determining multipesticide residues in fruits and vegetables: collaborative study

Ten laboratories analyzed unfortified and fortified samples of lettuce, tomatoes, and strawberries for organochlorine and organophosphorus pesticides by applicable portions of the comprehensive multipesticide method of Luke et al. The 3 crops were fortified with 6 pesticides, alpha-BHC, dieldrin, chlorpyrifos, acephate, omethoate, and monocrotophos, each at 3 levels per crop. Included in the 54 fortifications were 16 pairs of blind duplicates: same pesticide, crop, and level. Recoveries were calculated by area comparisons with known reference materials, using the responses obtained from 2 separate element-specific gas chromatographic (GC) systems. The organochlorine pesticides were chromatographed on a methyl silicone column and detected with a Hall 700A electrolytic conductivity detector, and the organophosphorus pesticides were determined with a flame photometric detector after being chromatographed on a specified DEGS column material. Chlorpyrifos was quantitated on both GC systems. Mean recoveries ranged from 82.6% for acephate fortified at 0.5000 ppm in strawberries to 118.1% for 0.0636 ppm fortification of chlorpyrifos in lettuce. Interlaboratory coefficients of variation ranged from 4.0% for 0.6360 ppm fortification of chlorpyrifos in tomatoes to 17.8% for the 0.0636 ppm chlorpyrifos level in lettuce. The procedure features essentially no cleanup before GC and proved comparable to existing multiresidue methods for pesticides of the class types studied, as evidenced by the intra- and interlaboratory measurements of precision and recoveries obtained. The method with the 2 GC systems has been adopted official first action.     

Collaborative study of an extension of the Mills et al. method for the determination of pesticide residues in foods.

Fifteen laboratories collaboratively determined parathion, o,p'-DDT, p,p'-DDT, and p,p'-DDE in kale, and lindane, dieldrin, heptachlor epoxide, and p,p'-DDE in eggs, using electron capture gas-liquid chromatography (potassium chloride thermionic detector for parathion). Pesticide levels ranged from 0.033 ppm heptachlor epoxide to 3.32 ppm p,p'-DDT. Mean recoveries (+/- standard deviations) were: parathion 91+/-15%, o,p'-DDT 99+/-8%, P,P'-DDT 97+/-8%, lindane 94+/-4%, dieldrin 106+/-8%, heptachloro epoxide 106+/-5%, p,p'-DDE 94+/-8% in eggs and 101+/-9% in kale. The methods have been adopted as official first action.     

Aluminium and uptake of base cations by tree roots: A critique of the model proposed by Sverdrup et al.

Sverdrupet al. (1992) proposed a model intended to evaluate effects of soil solution (Ca²⁺+Mg²⁺/Al³⁺ ratios on the uptake of Ca²⁺ and Mg²⁺ (here called base cations=BC) by tree roots. They considered the adsorption of BC on exchange sites on root surfaces to be a major step, and the competition between Al³⁺ and BC for exchange sites on roots to be crucial. Although this may certainly affect the rates of uptake, it will not exclude base cations from entering the root cells through ion channels or by carriers. Above all, the model overlooks important gradients in the rhizosphere, e.g. pH-gradients and root exudates, which have profound influences on the speciation of Al. One should instead consider modifying existing models accounting for processes in a buffered soil medium and handling gradients in the rhizosphere (e.g. Nye and Tinker, 1977). This would also require considerations on mycorrhizas and possible changes in the capacity for uptake of certain ions, which could be induced by deficiencies.     

Comment on the comment by Amthor et al. on “Appropriate experimental ecosystem warming methods” by Aronson and McNulty

In a recent comment on the paper by Aronson and McNulty (2009) about “Appropriate experimental ecosystem warming methods by ecosystem, objective, and practicality”, Amthor et al. (2010) state that infrared lamps do not warm open-field plots by the mechanism expected with global warming. While this statement is correct, in the aftermath of their comment, confusion exists about how warming with infrared heaters can be related to global warming. This comment illustrates how infrared heating at “constant temperature rise” relates in a quantitative way to anticipated global warming. Amthor et al. (2010) also state that changes in vapor pressure gradient from leaf to atmosphere are an issue with infrared heating, but this problem can be minimized with supplemental irrigations in controlled amounts. Therefore, “constant temperature rise” infrared warming experiments with supplemental irrigations are a viable T-FACE (temperature free-air controlled enhancement) that can be used in combination with CO₂-FACE to produce conditions more representative of future open-fields than can be done with chambers with their many known artifacts.