滴灌调控土壤水分对马铃薯生长的影响

研究了滴灌灌溉频率和土壤水势对马铃薯生长和水分利用效率的影响。研究结果表明，滴灌灌溉频率和土壤水势对土壤水分的分布有很大影响，灌水频率越低，灌水前的表层土壤干燥的范围越大，灌水后的土壤湿润范围越大；控制滴头下面20 cm处土壤水势明显影响到50 cm深度以上的土壤水势，20 cm深度处土壤水势越高，50 cm深度范围内的平均土壤水势越高；土壤表面土壤水势越低，以滴头为中心形成的干燥范围越大。当土壤基质势低于-45 kPa时，马铃薯的块茎膨大率会迅速下降，总产量、商品薯产量和水分利用效率高低顺序为：-25 kPa>-35 kPa>-15 kPa>-45 kPa>-55 kPa。不同灌溉频率下马铃薯的总产量、商品薯产量和水分利用效率的高低顺序为：1天1次>2天1次>3天1次>4天1次>6天1次>8天1次。就华北地区而言，采用滴灌对马铃薯进行灌溉，土壤基质势以-25 kPa左右为好，灌水频率以每天1次最优。     

Effects of canopy interception on energy conversion processes in a Chinese fir plantation ecosystem

The functions of canopy interception on energy conversion processes in a Chinese fir plantation ecosystem were studied with the aid of long-term observation data in Huitong. The results showed that the absorbed, penetrated and reflected amounts of solar radiation were, respectively, 2.5543 × 10⁹ J/(m²·year) (absorption rate of 0.827), 2.5306 × 10⁸ J/(m²·year) (penetration rate of 0.082), and 2.7432 × 10⁸ J/(m²·year) (reflection rate of 0.091) by the canopy. The conversion of net solar radiation to latent heat in the process of evaporation from canopy interception amounted to 6.3695 × 10⁸ J/(m²·year) (accounting for 22.9% of total ecosystem net radiation and 30.4% of ecosystem evaporation), which was an important part of the budget of the energy system. Canopy interception consumed kinetic energy of raindrops in overcoming resistance of branches and leaves, which collected raindrops, followed with the conversion of potential energy in raindrops to kinetic energy with falling raindrops. In general, the diameter of raindrops from the canopy is larger than that of the raindrops above the canopy as a result of the collection effort by the canopy. The kinetic energy of raindrops from the canopy, therefore, was higher than that of raindrops in the atmosphere. The drop-size distribution from the canopy was affected by the structure of the canopy layer rather than the amount of precipitation and precipitation intensity. The canopy had no important nor efficient effects on decreasing the kinetic energy of raindrops in our case study with a first branch height of 7 m and precipitation amounts over 3 mm. However, the canopy would play a key role in decreasing kinetic energy of raindrops in two cases, that of a small amount of precipitation and one of heavy precipitation intensity, in which the canopy could intercept the largest amount of precipitation in the former condition and the canopy could scatter bigger raindrops to smaller raindrops with striking leaves in the case of heavy precipitation. __________ Translated from Scientia Silvae Sinicae, 2007, 43(2): 15–20 [译自: 林业科学]     

长穗颈不育系协青早eA(1)的选育

目前推广的籼型不育系存在着较严重的包颈现象 ,限制了繁种和制种产量的提高 .通过直接辐射诱变保持系协青早 B,获得其高秆隐性突变体协青早 e B( 1) ,再转育成不包颈不育系协青早 e A( 1) ,使不育系不仅解除包颈现象 ,且能保持原不育系的优良农艺性状和产量性状 .用协青早 e A( 1)组配的杂种 F1代与不含 eui基因的协青早 A的杂种 F1代无显著差异 ,并具一定增产潜力 .该不育系已于 1999年 9月通过了福建省教委组织的技术鉴定     

华北次生林结构调整研究

以华北天然次生林为对象 ,对其主要类型的结构、质量、数量特点进行分析 ,找出现存的问题 .以河北省五道河林场的天然次生林为例 ,提出了结构调整的原则 ,用持续经营的思想和层次分析法 (AHP)对林种和树种结构进行了优化配置     

Identification of Anti-TNFα VNAR Single Domain Antibodies from Whitespotted Bambooshark (Chiloscyllium plagiosum)

Tumor necrosis factor α (TNFα), an important clinical testing factor and drug target, can trigger serious autoimmune diseases and inflammation. Thus, the TNFα antibodies have great potential application in diagnostics and therapy fields. The variable binding domain of IgNAR (VNAR), the shark single domain antibody, has some excellent advantages in terms of size, solubility, and thermal and chemical stability, making them an ideal alternative to conventional antibodies. This study aims to obtain VNARs that are specific for mouse TNF (mTNF) from whitespotted bamboosharks. After immunization of whitespotted bamboosharks, the peripheral blood leukocytes (PBLs) were isolated from the sharks, then the VNAR phage display library was constructed. Through phage display panning against mTNFα, positive clones were validated through ELISA assay. The affinity of the VNAR and mTNFα was measured using ELISA and Bio-Layer Interferometry. The binding affinity of 3B11 VNAR reached 16.7 nM. Interestingly, one new type of VNAR targeting mTNF was identified that does not belong to any known VNAR type. To understand the binding mechanism of VNARs to mTNFα, the models of VNARs-mTNFα complexes were predicted by computational modeling combining HawkDock and RosettaDock. Our results showed that four VNARs’ epitopes overlapped in part with that of mTNFR. Furthermore, the ELISA assay shows that the 3B11 potently inhibited mTNFα binding to mTNFR. This study may provide the basis for the TNFα blockers and diagnostics applications.     

石羊河流域气候变化对参考作物蒸发蒸腾量的影响

根据甘肃省气象局石羊河流域的6个气象站近50年的观测资料，应用1998年FAO最新推荐的Penman-Monteith公式计算了50年各月参考作物蒸发蒸腾量ET₀，分析了ET₀的月际变化和年际变化特征，除武威与肃南站ET₀呈逐年显著减少趋势外，其他各站的ET₀值均表现为逐年增加趋势，各个站ET₀ 20世纪90年代较80年代均有明显增加，说明气候变化对ET₀的影响较大；并分析了平均气温、平均最高气温、年日照时数、平均风速、平均相对湿度、年降水量、年蒸发量、海拔高度与ET₀的相关性，各站ET₀与平均相对湿度相关性最好；石羊河流域ET₀空间变化也较大，从山区到绿洲平原ET₀多年平均值呈递增趋势。     

稳定振动条件下梨的振动损伤研究

通过梨的振动试验，研究了稳定振动条件下，振动加速度、振动频率对梨的损伤影响，分析了梨振动至失去商品性时的振动次数N与损伤能量的关系，探讨了在相同振动加速度、不同频率下梨振动至失去商品性时的振动次数N1、N2与振动圆频率ω1、ω2的关系。试验结果表明，振动加速度越大，梨越容易产生损伤；在相同加速度条件下，振动频率越小，梨越容易产生损伤。     

Implication of Echinochrome A in the Plasticity and Damage of Intestinal Epithelium

The diverse therapeutic feasibility of the sea urchin-derived naphthoquinone pigment, Echinochrome A (Ech A), has been studied. Simple and noninvasive administration routes should be explored, to obtain the feasibility. Although the therapeutic potential has been proven through several preclinical studies, the biosafety of orally administered Ech A and its direct influence on intestinal cells have not been evaluated. To estimate the bioavailability of Ech A as an oral administration drug, small intestinal and colonic epithelial organoids were developed from mice and humans. The morphology and cellular composition of intestinal organoids were evaluated after Ech A treatment. Ech A treatment significantly increased the expression of LGR5 (~2.38-fold change, p = 0.009) and MUC2 (~1.85-fold change, p = 0.08). Notably, in the presence of oxidative stress, Ech A attenuated oxidative stress up to 1.8-fold (p = 0.04), with a restored gene expression of LGR5 (~4.11-fold change, p = 0.0004), as well as an increased expression of Ly6a (~3.51-fold change, p = 0.005) and CLU (~2.5-fold change, p = 0.01), markers of revival stem cells. In conclusion, Ech A is harmless to intestinal tissues; rather, it promotes the maintenance and regeneration of the intestinal epithelium, suggesting possible beneficial effects on the intestine when used as an oral medication.     

不同采收期对猕猴桃香气成分的影响

采用顶空固相微萃取法(Headspace Solid-Phase Micro-Extractions,HS-SPME),提取美味猕猴桃品种"米良1号"不同采收期果实的香气成分.经气相色谱-质谱联机分析,在10月18日、28日的果实中分别检测出51种、48种香气成分,占各自总峰面积的97.75%和98.36%.果实香气成分主要以酶类、醇类、醛类为主.在两种采收期果实中,除酯类物质呈下降趋势外,醇类、醛类、羧酸类及酮类等香气物质都呈上升趋势.