扰流风机降温对奶牛泌乳性能和免疫功能的影响

为研究奶牛舍采用扰流风机降温对奶牛泌乳性能和免疫功能的影响,该研究选择结构和饲养管理相同的两栋泌乳牛舍,检测安装风机（风机舍）和不安装风机（对照舍）对不同时期奶牛泌乳性能、淋巴细胞凋亡率、血液理化指标及免疫相关基因mRNA表达的影响,并分析奶牛泌乳性能、免疫性能指标与等温指数（equivalent temperature index for cattle,ETIC）之间的相关性。结果表明：1）安装风机改善了舍内温热环境,整个试验期风机舍的平均ETIC较对照舍降低了3.52 ℃,有效缓解了奶牛的热应激。2）风机舍的产奶量和4%标准乳在试验中、后期均显著高于对照舍（P<0.05）,且风机舍的乳脂率较对照舍也表现出显著性提高（P<0.05）。3）安装风机改善了热应激条件下奶牛的免疫功能。与对照舍相比,风机舍奶牛血液中淋巴细胞数量在试验中、后期显著增加（P<0.05）,并降低了淋巴细胞的早期凋亡率（P<0.05）,淋巴细胞中促凋亡因子Bax的mRNA表达量及其血清浓度在试验后期均表现出显著性降低（P<0.05）,抗凋亡因子Bcl-xl的mRNA表达量（P<0.01）及其血清浓度（P<0.10）在试验中、后期表现出增加趋势。此外,风机舍的血清白细胞介素-12（Interleukin-12, IL-12）和免疫球蛋白G（Immunoglobulin G, IgG）浓度较对照舍也表现出显著性增加（P<0.05）。4）从各项指标之间的相关分析得出,乳蛋白率、淋巴细胞数量与ETIC均呈显著负相关关系（P<0.05）,淋巴细胞BAK mRNA表达、血清IL-6浓度与ETIC呈显著正相关关系（P<0.05）。 可见,安装扰流风机可改善舍内温热环境,有效缓解夏季奶牛的热应激,提高奶牛生产性能和免疫功能。     

精氨酸对绵羊胴体品质、肉质特性及瘤胃细菌组成的影响

瘤胃细菌在绵羊骨骼肌脂肪酸沉积中起着重要作用。为研究精氨酸对绵羊胴体品质、肉质特性和瘤胃细菌组成的影响,探究瘤胃细菌变化与脂肪酸沉积之间的关系,利用宏基因组测序、气相色谱技术分析绵羊补饲精氨酸后瘤胃细菌组成和肌肉脂肪酸谱的变化,建立两者间的关联性。选取16只健康且体质量相近的3月龄绵羊,随机分为对照组（基础饲粮）和精氨酸组（基础饲粮+1%精氨酸）,进行90 d的饲养试验。结果表明,与对照组相比,精氨酸组绵羊的背膘厚显著降低（P<0.05）,背最长肌的亮度（L^*）值、黄度（b^*）值及剪切力值均显著减小（P<0.05）,红度（a^*）值显著增加（P<0.05）。精氨酸组背最长肌十五烷酸、十七烷酸和十七碳烯酸的含量显著低于对照组（P<0.05）,二十四碳烯酸、α-亚麻酸、二十二碳六烯酸和n-3多不饱和脂肪酸的含量显著高于对照组（P<0.05）;精氨酸组n-6/n-3多不饱和脂肪酸的比值显著降低（P<0.05）。宏基因组分析显示,补充精氨酸显著提高了瘤胃中梭菌属、月形单胞菌属、瘤胃球菌属和密螺旋体属的丰度（P<0.05）,降低了丁酸弧菌属、副拟杆菌属、解琥珀酸菌属、甲烷短杆菌属和Butyrivibrio proteoclasticus的丰度（P<0.05）。此外,精氨酸组瘤胃中丁酸的含量显著增加（P<0.05）。关联性分析显示,丁酸弧菌属与n-3多不饱和脂肪酸呈显著负相关（P<0.05）与饱和脂肪酸呈显著正相关（P<0.05）;脂肪酸含量对肉的色泽和pH值有较大的影响。综上所述,精氨酸通过降低瘤胃氢化菌的数量,减少氢化的发生,促进肉中有益脂肪酸沉积,进而改善羊肉品质。研究结果为今后通过饲粮营养干预靶向调控瘤胃细菌提高羊肉品质提供参考。     

水分和CO2对玉米光合性能及水分利用率的影响

利用环境生长室探讨不同CO₂浓度和土壤水分亏缺处理下玉米植株生物量、气孔形态与分布特征、叶片气体交换参数、叶绿素荧光参数等生长及生理指标的变化规律。以‘郑单958’ 玉米品种为试材,利用环境生长室设置2个CO₂浓度和4个土壤水分梯度对玉米进行CO₂浓度和水分处理。结果表明：1）不同程度土壤水分亏缺均显著降低玉米地上生物量（P<0.05）,但CO₂浓度升高增加了轻度水分亏缺条件下玉米地上生物量（P<0.01）和总生物量（P<0.01）。2）大气CO₂浓度升高导致轻度和中度水分亏缺条件下玉米的净光合速率（P_n）分别提高15.8%（P<0.05）和25.7%（P=0.001）,而CO₂浓度升高却降低了玉米叶片蒸腾速率（P<0.001）和气孔导度（P<0.001）,最终导致玉米瞬时水分利用效率均显著提高（P<0.001）。3）不同水分处理对玉米叶片气孔密度和单个气孔形态特征均造成显著影响（P<0.01）。因此,大气CO₂浓度升高可以增加轻度水分亏缺条件下玉米叶片氮含量、叶片非结构性碳水化合物含量和光合电子传递速率,从而提高玉米植株的生物量累积以及叶片碳同化能力和水分利用效率。研究结果将为深入理解气候变化背景下玉米对大气CO₂浓度升高和土壤水分亏缺的生理生态响应机制提供科学依据。     

控释掺混肥对麦玉轮作体系农田温室气体排放和硝态氮残留的影响

为阐明控释肥对冬小麦-夏玉米轮作体系作物产量、温室气体排放和硝态氮残留的影响,该研究以郑单958（夏玉米）和济麦22（冬小麦）为供试材料,设不施氮对照（CK）、常规施氮（FFP）、优化施氮（OPT）、含30%控释尿素的控释掺混肥（夏玉米）和含50%控释尿素的控释掺混肥（冬小麦）（CRBF1）、含50%控释尿素的控释掺混肥（夏玉米）和含70%控释尿素的控释掺混肥（冬小麦）（CRBF2）共5个处理,对比分析了不同处理的冬小麦、夏玉米及周年产量、温室气体排放和土壤硝态氮残留的差异。结果表明,施氮可显著提高麦玉轮作系统单季和周年作物产量（P<0.05）。与FFP相比,CRBF1和CRBF2处理的夏玉米、冬小麦和周年产量分别提高了1.4%～3.0%、1.9%～3.4%和1.6%～3.1%（P>0.05）。施氮显著增加了麦玉轮作体系的土壤N₂O和CO₂的周年排放（P<0.05）。CRBF1和CRBF2处理的土壤N₂O周年排放总量较FFP处理显著降低了27.7%～34.6%（P <0.05）。施氮显著增加了麦玉轮作体系的周年全球增温潜势（GWP）（P<0.05）。CRBF1和CRBF2处理的周年GWP较FFP处理降低了4.2%和5.7%,其中CRBF2处理差异显著（P<0.05）。施氮降低了麦玉轮作体系的周年温室气体排放强度（GHGI）。CRBF1和CRBF2处理的周年GHGI较FFP处理降低了5.6%～8.6%（P>0.05）。与FFP相比,CRBF1和CRBF2处理的100~200 cm土层硝态氮残留降低30.6%～34.3%（P<0.05）,减少了硝态氮淋失风险。综上所述,控释掺混肥在稳定作物产量、减少温室气体排放和土壤硝态氮残留方面具有积极作用,研究结果可为麦玉轮作体系的轻简高效氮肥管理提供数据支持和理论支撑。     

不同类型叶面肥对日光温室越冬番茄风味品质的影响

为解决日光温室冬季低温弱光导致的番茄品质下降问题,该研究以 “184”番茄为试材,采用高效液相色谱法、顶空固相微萃取法与气相色谱-质谱联用（Gas Chromatography-Mass Spectrometry,GC-MS）等技术,研究5种不同类型叶面肥对番茄果实糖酸组分及挥发性物质种类和含量的影响。结果表明：喷施硒元素液体肥显著提高了白熟期、成熟期和完熟期番茄果实蔗糖和葡萄糖的含量（P < 0.05）,硅元素液体肥显著增加了白熟期、转色期和成熟期番茄果实蔗糖的含量,氨基酸液体肥显著提高了这三个时期番茄葡萄糖含量（P < 0.05）。喷施硒元素液体肥和鱼蛋白水溶肥显著降低了成熟期番茄α-酮戊二酸、柠檬酸和苹果酸含量（P < 0.05）。 硒元素液体肥显著提高了白熟期和转色期番茄糖酸比,分别较CK增加了15.32%和12.15%（ P < 0.05）。GC-MS结果显示,各处理成熟期番茄果实共检测到71种挥发性物质,包括20种醛类、9种酮类、17种醇类、5种酯类、10种烃类和10种其他类物质。各处理中醛类含量最多,酯类含量最少。5种叶面肥均可提高醛类含量,其中硅元素液体肥处理较对照显著增加21.89%（P < 0.05）。 所有被检测出的挥发性物质包含了9种特征香气成分,主要分为花香、果香和青香3种类型,硒元素液体肥、硅元素液体肥和海藻精水溶肥处理分别较对照显著提高番茄的特征香气成分总含量7.93%、17.68%和8.33%（P < 0.05）。综上,叶面喷施硒元素和硅元素液体肥可提高番茄果实糖组分,增加挥发性醛类物质和特征香气成分,对番茄风味品质提升效果显著,可在日光温室越冬番茄生产中推广应用。研究结果为设施番茄高品质栽培提供了数据支撑和实践参考。     

长期保护性耕作对坡耕地黑土有机碳组分的影响

为对比长期保护性耕作模式与传统耕作模式对黑土有机碳组分的差异化,揭示长期保护性耕作对侵蚀退化黑土质量的恢复作用。基于典型黑土坡耕地连续15 a保护性耕作长期定位田间试验,设置免耕保护性耕作（NT）和旋耕传统耕作（CT）2个田间耕作试验,并实行玉米-大豆轮作模式,测定并分析了两种耕作措施下土壤有机碳及其不同碳组分随土壤剖面的垂直分布及变化特征。结果表明：连续实施15 a的NT与CT相比分别显著提高0～5和>5～10 cm土层的土壤有机碳质量分数（29.54%和22.38%）（P<0.05）,碳储量（31.11%和27.34%）（P<0.05）,全氮质量分数（53.74%和37.60%）（P<0.05）,表层土壤碳氮质量分数提升显著（P<0.05）,深层土壤碳氮质量分数变化不显著;以>5～10 cm土层土壤颗粒有机碳（69.85%）、0～5 cm土层的土壤轻组有机碳（130.81%）和0～5、>5～10 cm土层土壤微生物量碳（85.59%和59.53%）的提升为主,并且对深层土壤有机碳组分也产生一定的积极影响;耕作效应对于土壤团聚体稳定性指标影响显著（P<0.05）,并且土壤团聚体稳定性指标对于SOC质量分数提升也起到了关键作用。研究表明,与传统耕作相比,连续实施15 a保护性耕作,增加的有机碳以活性有机碳为主。长期的保护性耕作对恢复退化农田黑土质量及土壤固碳均具有重要意义。     

基于主成分分析的饲料级磷酸盐理化特性评价

该研究旨在探究不同饲料级磷酸盐理化特性指标的差异,分析其相关性,找出关键理化特性指标,并建立饲料级磷酸盐的评价体系。选取常用的5种磷酸氢钙、4种磷酸二氢钙和3种磷酸一二钙为试验材料,测定分析水分、比表面积、滑动摩擦角、休止角、松散密度、振实密度、压缩度、吸水性指数、水溶性指数及溶胀度等理化特性指标,运用主成分分析法精简理化特性指标,并计算各样品的综合得分。结果表明：1）不同饲料级磷酸盐理化特性存在一定差异,也存在不同程度的相关性。饲料级磷酸盐的休止角与比表面积呈极显著正相关（r=0.919,P<0.01）;压缩度与休止角呈极显著正相关（r=0.926,P<0.01）;溶胀度与吸水性指数呈极显著正相关（r=0.930,P<0.01）、与水溶性指数呈极显著负相关（r=-0.987,P<0.01）。2）运用主成分分析,提取了3个有效主成分,累积方差贡献率达到88.27%,确定休止角、比表面积、松装密度、压缩度及水溶性指数为关键的理化特性指标。饲料级磷酸盐理化特性得分排序由大到小依次为磷酸氢钙、磷酸一二钙、磷酸二氢钙,粒状磷酸盐得分较低。综合分析,从饲料级磷酸盐的理化特性考虑,为改善多元化配方的加工性能和颗粒饲料质量,可优先选用磷酸氢钙,研究为不同饲料级磷酸盐在饲料中的应用提供数据基础及参考依据。     

中国北方地区不同滴灌方式节水增产效应的Meta分析

为了探明中国北方地区地下滴灌（subsurface drip irrigation,SSDI）与地表滴灌（surface drip irrigation,SDI）节水增产效应的差异,该研究以SDI作为对照,采用Meta分析定量分析了不同条件下SSDI对作物产量和水分利用效率的影响。结果表明,与SDI相比,SSDI可使作物总体增产6.66%（P<0.05）,水分利用效率提高9.34%（P<0.05）,净效益增加6.94%（P<0.05）;SSDI在西北和华北地区均能提高作物产量和水分利用效率;当年均降雨量不大于400 mm时,SSDI能显著提高作物产量;当土壤容重大于1.5 g/cm³,灌水施肥频率大于6次,滴灌带埋深为15～25 cm,滴头流量介于1.5～2.5 L/h时,更有利于发挥SSDI优势,节水增产效果显著。研究可为中国北方地区SSDI的推广应用提供理论参考。     

氮肥和品种及种植密度对春玉米机械化收获性状及产量的影响

机械化收获是提高农业生产效率的重要措施，但机械化收获受倒伏、籽粒脱水特性和收获籽粒含水率等的影响。为探讨春玉米形态结构与抗倒伏性之间的关系、籽粒脱水进程和收获籽粒含水率对品种、施氮量和种植密度的响应，该研究以先玉335和陕单609为试验材料，设置0、180和225 kg/hm² 三个氮肥水平、6.5×10⁴和8.5×10⁴ 株/hm² 两个种植密度，通过2 a大田试验研究品种、种植密度和氮肥对株高、茎粗、穗位系数、抗折强度、弯曲力矩、倒伏系数、灌浆末期籽粒脱水速率、收获籽粒含水率、产量和生物量等的影响。结果表明：不施氮条件下，株高和茎粗对倒伏系数影响较大；施氮条件下，倒伏系数主要受弯曲力矩、抗折强度和株高影响。施氮显著降低陕单609的倒伏系数（P<0.05），施氮处理下陕单609的株高和茎粗较不施氮处理分别增加8%～21%和26%～45%，抗折强度和弯曲力矩分别增加157%～277%和72%～114%，倒伏系数降低30%～47%。施氮可降低籽粒脱水速率，推迟脱水进程，显著增加收获籽粒含水率（P<0.05）。施氮处理籽粒含水率较不施氮处理提高7%～9%。高密度处理收获籽粒含水率比低密度处理低3%（P<0.05）。先玉335的籽粒脱水速率快，收获籽粒含水率比陕单609低7%（P<0.05）。与不施氮处理相比，施氮处理产量和生物量分别显著提高92%和63%（P<0.05）。与低密度处理相比，高密度处理产量显著增加12%（P<0.05）。综上所述，春玉米的倒伏性、灌浆后期籽粒脱水速率及收获籽粒含水率受品种特性影响，也受施肥、栽培措施和气候条件的显著影响。选育籽粒脱水快的品种、适当增加种植密度并合理统筹氮肥施用量可以提高春玉米机械化收获适宜性。     

中国南北方植物对土壤加固机制的差异性

为深入分析植物对土壤加固的影响效益和机制,该研究选取重庆缙云山地区和陕西延安黄土丘陵区种植一年的乔木（火炬树、榆树）和灌木（荆条、酸枣）,该测定其根系形态、力学参数和土壤的抗剪强度,通过RBM_w模型计算根系固土效益,综合评估不同植物种的固土效能和贡献度。结果表明：2地种植的物种平均根直径的差异不显著（P > 0.05）,重庆种植的乔木(火炬树、榆树)的根长、分叉数和根尖数显著高于延安,灌木未出现显著差异（P < 0.05）。根系的抗拉强度与直径都符合负幂函数关系,其中平均抗拉强度最大的为荆条。除荆条外,同种植物根系的抗拉强度并未因不同地区的种植产生显著差异。4个植物种根系的固土效率为0.65～4.12 kPa,各物种间存在显著差异（P < 0.05）。重庆2种乔木种植下的根土复合体有效黏聚力高于裸地（约10%）,灌木种植下则普遍略低于裸地。除酸枣外,种植于重庆的4种植物的根系固土作用和效率都显著的高于延安（P < 0.05）。研究结果可为不同地区固土护坡的树种选择提供理论依据。     

Effect of the novel low molecular weight hydrolyzed chicken sternal cartilage extract, BioCell Collagen, on improving osteoarthritis-related symptoms: a randomized, double-blind, placebo-controlled trial

Osteoarthritis (OA) is a significant source of pain and disability. Current medical and surgical treatments can be costly and have serious side effects. The aim of this randomized, double-blind, placebo-controlled trial was to investigate the tolerability and efficacy of BioCell Collagen (BCC), a low molecular weight dietary supplement consisting of hydrolyzed chicken sternal cartilage extract, in the treatment of OA symptoms. Patients (n = 80) in the study had physician-verified evidence of progressive OA in their hip and/or knee joint. Joint pain had been present for 3 months or longer at enrollment, and pain levels were 4 or higher at baseline as assessed by Physician Global Assessment scores. Subjects were divided into two groups and administered either 2 g of BCC or placebo for 70 days. Other outcome measurements included visual analogue scale (VAS) for pain and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores taken on days 1, 35, and 70. The tolerability profile of the treatment group was comparable to that of the placebo. Intent-to-treat analysis showed that the treatment group, as compared to placebo, had a significant reduction of VAS pain on day 70 (p < 0.001) and of WOMAC scores on both days 35 (p = 0.017) and 70 (p < 0.001). The BCC group experienced a significant improvement in physical activities compared to the placebo group on days 35 (p = 0.007) and 70 (p < 0.001). BCC was well tolerated and found to be effective in managing OA-associated symptoms over the study period, thereby improving patient's activities of daily living. BCC can be considered a potential complement to current OA therapies.     

共培养对土壤重金属污染植物修复的调控作用

A co-culture of two plant materials, Astragalus sinicus L., a leguminous plant with concomitant nodules, and Elsholtzia splendens Naki-a Cu accumulator, along with treatments of a chelating agent (EDTA), root excretions (citric acid), and a control with E. splendens only were used to compare the mobility of heavy metals in chelating agents with a co-culture and to determine the potential for co-culture phytoremediation in heavy metal contaminated soils. The root uptake for Cu, Zn, and Pb in all treatments was significantly greater (P < 0.05) than that of the control treatment. However with translocation in the shoots, only Cu, Zn, and Pb in plants grown with the EDTA treatment and Zn in plants co-cropped with the A. sinicus treatment increased significantly (P < 0.05). In addition, when a co-culture in soils with heavy and moderate contamination was compared, for roots in moderately contaminated soils only Zn concentration was significantly less (P < 0.05) than that of heavily contaminated soils, however, Cu, Zn, and Pb concentrations of shoots were all significantly lower (P < 0.05). Overall, this "co-culture engineering" could be as effective as or even more effective than chelating agents, thereby preventing plant metal toxicity and metal leaching in soils as was usually observed in chelate-enhanced phytoremediation.     

Physicochemical Properties Related to Quality of Rice Noodles

Eleven rice genotypes with diverse Rapid Visco Analyzer (RVA) pasting characteristics were evaluated for their physicochemical and gel textural characteristics relative to their suitability for making rice noodles. Apparent amylose content (AC) was highly correlated with swelling power (r = -0.65, P < 0.05), flour swelling volume (FSV) (r = -0.67, P < 0.05), noodle hardness (r = 0.74, P < 0.01), gumminess (r = 0.82, P < 0.01), chewiness (r = 0.74, P < 0.01), and tensile strength (r = 0.72, P < 0.05). Solubility showed an inverse relationship with the pasting parameters and noodle rehydration, and a positive relationship with cooking loss, noodle hardness, and gumminess. FSV and most of the pasting parameters were negatively correlated with noodle hardness. RVA parameters and textural parameters of gels formed in the RVA canister were well correlated with actual noodle texture and may, therefore, be used for predicting rice noodle quality during early screening of genotypes in breeding programs.     

Swelling Index of Glutenin Test. I. Method and Comparison with Sedimentation,Gel‐Protein,and Insoluble Glutenin Tests

Molecular weight distribution of wheat proteins is primarily responsible for the viscoelastic properties of flour dough. Furthermore, the amount of SDS insoluble proteins (mainly high molecular weight glutenin) plays the major role. We have developed a simple test to determine the swelling power of glutenin (swelling index of glutenin or SIG) for predicting dough properties and end‐use quality. Flour samples (40 mg) were hydrated in distilled water and then allowed to swell in nonreducing solvents (SDS, lactic acid, or mixtures of the two) followed by low speed centrifugation. The SIG was calculated as the weight of the residue divided by the original sample weight. The SIG test was compared with the results from other small‐scale tests for 20 flour samples. SIG tests showed highly significant correlations with the gel protein and insoluble glutenin test (r ≥ 0.85, r ≥ 0.93, P < 0.001, respectively) and significant correlations with SDS and Zeleny sedimentation tests (r ≥ 0.74, r ≥ 0.72, P < 0.001, respectively). The swelling capacity of glutenin depended on swelling time and mixing intensity in nonreducing solvents. Swelling curves obtained from SIG values versus different swelling time can be divided into three distinct stages: swelling, swollen, and breakdown. These stages may reflect soluble and insoluble glutenin contents and quality among different cultivars. SIG test values for short swelling time and low mixing intensity were significantly correlated to gel protein content and SDS‐sedimentation values (r = 0.96, r = 0.90, P < 0.001, respectively). SIG test values for long swelling time and high mixing intensity were significantly correlated to insoluble glutenin content (r = 0.96, P < 0.001). The difference of swelling condition (time and mixing intensity) among these small‐scale methods is the reason for their different correlations with insoluble glutenin content. Because large numbers of samples can be analyzed in a short time with excellent reproducibility, the SIG test may be a useful screening test in a breeding program, predicting the quantity and quality of insoluble glutenin.     

Size Distribution and Properties of Wheat Starch Granules in Relation to Crumb Grain Score of Pup‐Loaf Bread

Twelve hard winter wheat flours with protein contents of 11.8–13.6% (14% mb) were selected to investigate starch properties associated with the crumb grain score of experimentally baked pup‐loaf bread. The 12 flours were classified in four groups depending on the crumb grain scores, which ranged from 1 (questionable‐unsatisfactory) to 4 (satisfactory). Flours in groups 1, 2, 3, and 4 produced breads with pup‐loaf volumes of 910–1,035, 1,000–1,005, 950–1,025, and 955–1,010 cm³, respectively. Starches were isolated by a dough handwashing method and purified by washing to give 75–79% combined yield (dry flour basis) of prime (62–71%) and tailing (7–16%) starches. The prime starch was fractionated further into large A‐granules and small B‐granules by repeated sedimentation in aqueous slurry. All starches were assayed for weight percentage of B‐granules, swelling power (92.5°C), amylose content, and granular size distribution by quantitative digital image analysis. A positive linear correlation was found between the crumb grain scores and the A‐granule sizes (r = 0.65, P < 0.05), and a polynomial relationship (R² = 0.45, P < 0.05) occurred between the score and the weight percentage of B‐granule starch. The best crumb grain score was obtained when a flour had a weight percentage of B‐granules of 19.8–22.5%, shown by varietal effects.     

Levels of Protein and Protein Composition in Hard Winter Wheat Flours and the Relationship to Breadmaking

Protein and protein fractions were measured in 49 hard winter wheat flours to investigate their relationship to breadmaking properties, particularly loaf volume, which varied from 760 to 1,055 cm³ and crumb grain score of 1.0–5.0 from 100 g of flour straight‐dough bread. Protein composition varied with flour protein content because total soluble protein (SP) and gliadin levels increased proportionally to increased protein content, but albumins and globulins (AG), soluble polymeric proteins (SPP), and insoluble polymeric protein (IPP) levels did not. Flour protein content was positively correlated with loaf volume and bake water absorption (r = 0.80, P < 0.0001 and r = 0.45, P < 0.01, respectively). The percent SP based on flour showed the highest correlation with loaf volume (r = 0.85) and low but significant correlation with crumb grain score (r = 0.35, P < 0.05). Percent gliadins based on flour and on protein content were positively correlated to loaf volume (r = 0.73, P < 0.0001 and r = 0.46, P < 0.001, respectively). The percent IPP based on flour was the only protein fraction that was highly correlated (r = 0.62, P < 0.0001) with bake water absorption followed by AG in flour (r = 0.30, P < 0.05). Bake mix time was correlated positively with percent IPP based on protein (r = 0.86) but negatively with percent SPP based on protein (r = ‐0.56, P < 0.0001).     

<Emphasis Type="Italic">Erigeron annuus</Emphasis> (L.) Pers., as a green manure for ameliorating soil exposed to acid rain in Southern China

Background, aims, and scope  Increasing soil acidification is a growing concern in southern China. The traditional green manures applied in the fields mostly comprise legumes that tend to accelerate soil acidification. Moreover, acid deposition can act as a source of nitrogen. Hence, we looked for new plant species that would enhance nutrient concentrations when used as green manure and would reduce soil acidity or at least not worsen it. Materials and methods  We studied the use of Erigeron annuus (L.) Pers. for ameliorating acid soil in a pot experiment with simulated acid rain (SAR) treatments (pH 5.8 to 3.0) in an open area in Guangzhou City. The pots were divided into two groups named A and B groups. On day 0, pots of A group were filled with soil and planted with Erigeron annuus seedlings. Pots of B group were only filled with soil as the control. On day 40, seedlings of E. annuus were harvested and buried in the corresponding pots. On day 54, two seeds of Phaseolus vulgaris L. were sown in each pot in both groups. The growth and bean yield of P. vulgaris seedlings were then used to evaluate the effects of E. annuus on acid soil. Plant and/or soil samples were collected on days 0, 40, 54, and 150; corresponding parameters were measured. Results  Results showed that E. annuus could maintain a good growth even on very acid soil. On day 40, the pH decreased significantly (P < 0.0001) in the B group pots without E. annuus compared with the A group. On day 54, after E. annuus was buried as a manure, the soil pH of all A group treatments except the pH 4.0 treatment showed a significant increase compared to day 40 (P < 0.01). At the same time, the application of E. annuus as a manure produced a significant increase of soil K and P (P < 0.001), Ca (P < 0.05), and Mg (P < 0.001) concentrations of all A group SAR treatments compared to their B group counterparts (except control pots for Ca). The soil exchangeable K and available P concentration doubled, and Ca and Mg increased by around 25% in the presence of the E. annuus manure application. Discussion  The higher soil pH in the A group than B group on the day 40 was due to a great absorption of NO₃ ⁻ by the roots of E. annuus. The soil pH increase after E. annuus was applied to the soil of A group was attributed to the release of high amount of K, the mineralization of organic N, and the oxidation of organic acid anions. Nutrient increase in the A group after E. annuus application was mostly the result of the nutrient release during the residue decomposition. The amelioration of the soil was effective as demonstrated by the enhanced growth and bean yield of P. vulgaris seedlings on the manured soil compared to the seedlings grown on a control that was not manured. Conclusions   E. annuus could maintain a good growth in the acid lateritic field soil. Cultivating this plant and applying it to the soil with a rate of 1.6 ton ha⁻¹ doubled the soil K and P concentrations and increased soil exchangeable Ca and Mg concentrations by around 25%. This species would be a good green manure candidate for growing in the acid soils of southern China. Application of E. annuus also has beneficial effects on crop growth through reduced Al toxicity and cation leaching. Recommendations and perspectives  Since E. annuus would improve soil pH and nutrient concentrations with minimum care, it is recommended for treating acid soils with poor yield whenever a low-cost solution is required.     

Properties of Starch Noodles as Affected by Sweetpotato Genotype

Starch was extracted from 14 sweetpotato genotypes from the Philippines. The Rapid Visco-Analyzer (RVA) viscoamylographs of the starches showed Type A pasting curves, characterized by a high pasting peak followed by a high degree of shear-thinning. The major difference among genotypes was in the sharpness of the peak, with some showing a very sharp peak while others showed a broad peak. This difference was related to time from onset of pasting to peak viscosity, and to stability ratio (holding viscosity/peak viscosity), which were also highly correlated (r = 0.84, P < 0.01) to each other. Stability ratio was also correlated to noodle firmness (r = 0.95, P < 0.01), rehydration (cooked weight) (r = -0.89, P < 0.01), and swelling volume of the starch (r = -0.62, P < 0.05). The amylose content was correlated significantly only to peak viscosity (r = -0.84, P < 0.01). Significant differences in texture and cooking quality of the starch noodles produced from the different genotypes was found. It was shown that the RVA viscoamylographs could be used to detect differences in pasting characteristics of sweetpotato starch which are related to quality of noodle produced.     

紫外辐射对9个昆虫病原线虫品系存活率和致病力的影响

为探明紫外辐射对昆虫病原线虫（entomopathogenic nematodes,EPN）的作用,以甘肃省分离得到的昆虫病原线虫为研究材料,用室内模拟生测法,测定了经20 W、40 W紫外线辐射后,斯氏属（Steinernema feltiae,S.kraussei）和异小杆属（Heterorhabditis brevicaudis,H.megidis）4种昆虫病原线虫9个品系的存活率,并以大蜡螟（Galleria mellonella）为供试昆虫,采用改良的ONE ON ONE法,测定了其对大蜡螟的致病力。结果表明：经UV-B辐射后供试的9个昆虫病原线虫品系存活率未发生显著变化（P>0.05）。20 W紫外辐射30 min后,S.feltiae 0639C和0663TD 2品系对大蜡螟的致病力提高,其中S.felitiae 0639C致病力显著升高（P<0.05）,侵染32 h后,寄主昆虫死亡率由13.3%升高到73.3%;S.felitiae 0661YM品系的致病力显著降低（P<0.05）,侵染32 h后,寄主昆虫死亡率率由66.7%降低到0;其余各品系致病力均无显著变化。不同辐射时长和辐射强度对S.felitiae 0639C和0663TD引起寄主昆虫死亡的时间有影响,较对照组而言,经辐射预处理后,2品系线虫引起寄主昆虫死亡的时间均提前,其中S.felitiae 0639C随着辐射强度的增大引起寄主昆虫开始死亡时间提前,而S.felitiae 0663TD随着辐射强度增加引起寄主昆虫开始死亡时间延后。不同紫外辐射时长对S.felitiae 0663TD和S.felitiae 0639C致病力无显著影响,30 min、60 min、90 min、120 min辐射处理之间差异不显著（P>0.05）。研究表明,9个供试昆虫病原线虫品系均对UV-B辐射具有一定的耐受能力;20 W UV-B辐射30 min,能刺激S.felitiae 0663TD和S.felitiae 0639C侵染和致死寄主昆虫;一定的辐射时长内（120 min）,辐射时长对S.felitiae 0663TD和S.felitiae 0639C的致病力无影响。