Nitrogen and potassium mineralization from winery solid waste composts in sandy and sandy loam soils

This study aimed at quantifying nitrogen (N) and potassium (K) released from winery solid waste (WSW) composts during laboratory incubation to address deficiency in two texturally distinct soils. Composts had 4, 10, 20, 30, 40% (w/w) of filter materials (FMs) mixed with grape marc and pruning canes. The composts were mixed with the soils at equivalent rate of 200 kg N ha^?1 and incubated for 42 days. Quantitatively higher (p < 0.05) ammonium N content was recorded in sandy than sandy loam soil during the incubation duration while exchangeable K was increased in K-deficient sandy soil. Cumulative total mineralized N (TMN) measured during the incubation duration ranged from 59 mg kg^?1 to 672 mg kg^?1 depending on compost type and soil texture while a 10-fold increase in compost FMs content resulted in 144% and 139% increases in cumulative mineralized K in sandy and sandy loam textured soil, respectively. Percent N mineralized from the composts relative to the amount applied during the incubation duration was less than 54% reflecting the composts and soils inherent characteristics. The high ammonium N and K mineralized suggests that farmers must be cautious in utilizing these composts for field crops production due to the potential environmental risks.     

薇甘菊最新研究进展

薇甘菊（Mikania micrantha H.B.K）是现今全球最为关注的恶性杂草之一。其因入侵性极强、生态幅宽和化感作用明显等特征,能够迅速占据生态位,使入侵地的植物无法生存。综述了薇甘菊生物学特征、生态学特征、入侵假说和防治现状。     

湖南省晚稻施钾效应及土壤速效钾丰缺指标研究

[目的]研究钾肥对晚稻产量、经济效应的影响,建立湖南省晚稻土壤速效钾的丰缺指标。[方法]2005~2008年在湖南省湘北、湘中-湘东及湘南3个地区的稻田土壤上共布置159个钾肥晚稻田间试验。[结果]晚稻施钾有明显的增产及增收效应,3个地区晚稻施钾平均增产803~871 kg/hm2,平均增产率为13.1%~13.7%;施钾平均增加利润704.01~798.39元/hm2,平均产投比1.94~2.31。施钾增产趋势及经济回报均随土壤速效钾含量的提高而减缓或降低。晚稻种植体系中,湘北区土壤速效钾＂低＂、＂中＂、＂高＂丰缺指标分别为〈45.8、45.8~143.0和〉143.0 mg/kg;湘东-湘中区分别为〈42.9、42.9~125.2和〉125.2 mg/kg;湘南分别为〈38.8、38.8~139.1和〉139.1 mg/kg。[结论]湖南省晚稻种植体系中,严重缺钾土壤较少,土壤钾素主要为中等水平,8%左右的土壤速效钾含量较高。     

Actinomycin V Induces Apoptosis Associated with Mitochondrial and PI3K/AKT Pathways in Human CRC Cells

Actinomycin (Act) V, an analogue of Act D, presented stronger antitumor activity and less hepatorenal toxicity than Act D in our previous studies, which is worthy of further investigation. We hereby report that Act V induces apoptosis via mitochondrial and PI3K/AKT pathways in colorectal cancer (CRC) cells. Act V-induced apoptosis was characterized by mitochondrial dysfunction, with loss of mitochondria membrane potential (MMP) and cytochrome c release, which then activated cleaved caspase-9, cleaved caspase-3, and cleaved PARP, revealing that it was related to the mitochondrial pathway, and the apoptotic trendency can be reversed by caspase inhibitor Z-VAD-FMK. Furthermore, we proved that Act V significantly inhibited PI3K/AKT signalling in HCT-116 cells using cell experiments in vitro, and it also presented a potential targeted PI3Kα inhibition using computer docking models. Further elucidation revealed that it exhibited a 28-fold greater potency than the PI3K inhibitor LY294002 on PI3K inhibition efficacy. Taken together, Act V, as a superior potential replacement of Act D, is a potential candidate for inhibiting the PI3K/AKT pathway and is worthy of more pre-clinical studies in the therapy of CRC.     

施肥对毛白杨生长量、叶片氮(N)、磷(P)、钾(K)含量及蒸腾作用、气孔阻力影响的研究

对二年生三倍体毛白杨进行了施肥试验,分析了不同施肥水平、不同生长月份以及不同无性系对胸径、树高生长量和叶片N、P、K含量的影响,及其在生长季的变化规律,蒸腾作用和气孔阻力的不同生长月份和日变化情况。结果表明,不同施肥水平和生长月份对生长量和叶片N、P的含量有极显著影响;不同的无性系对K的含量有极显著的影响;在生长季毛白杨生长量与叶片N、P、K含量的变化规律相吻合;不同生长月份以及一天内不同时间,蒸腾速率和气孔阻力均存在极显著差异;蒸腾速率和气孔阻力日进程呈单峰曲线,高峰出现在中午。     

不同供钾水平对茶树幼苗叶片光合作用的影响

以10月龄扦插"瑞香"茶苗[Camellia sinensis(L.)O.Kuntze cv.Ruixiang]为试验材料,通过沙培试验,设5个K浓度(0、100、200、600、2 000μmol/L),每周施肥3次,处理后24周,利用LI-6400便携式光合作用测定仪进行测定。结果表明,缺钾时茶树叶片CO2同化速率、气孔导度、水分利用率等都显著下降,而胞间CO2浓度显著增加;缺钾条件下茶树生物量、叶片钾含量、叶绿素等都显著下降。当供钾浓度为0、100μmol/L时(叶片钾含量6.63 mg/g、6.85 mg/g),茶树出现缺钾症状。     

K亚群禽白血病病毒gp85单因子血清的制备及其特异性鉴定

为了制备一种快速特异性识别K亚群禽白血病病毒(ALV-K)的单因子血清,本试验将ALV-K接种DF1细胞,提取感染细胞DNA作为模板,PCR扩增1 005 bp ALV-K-gp85和510 bp ALV-K-gp85(fragment)基因.将其正确的阅读框插入表达载体pET-28a(+)中,转化大肠杆菌BL21(Rosetta)菌株中表达.将表达蛋白常规免疫昆明白小鼠制备抗血清.结果表明成功获得39.85和22.01 ku的重组融合蛋白,且具有良好的免疫原性.间接免疫荧光试验(IFA)结果表明两血清均可与ALV-K反应,而不与ALV-A、ALV-B和ALV-J反应.本试验首次研制获得能特异性识别ALV-K的单因子血清,为K亚群禽白血病的快速检测奠定了基础.     

氮磷钾调控对苜蓿生产影响的研究进展

科学合理施肥是增加苜蓿产量和提高苜蓿品质的关键环节。总结了氮磷钾素营养调控对苜蓿生产的影响,并针对河北省苜蓿生产现状及存在的问题,从施肥方面提出了增加产量、提高品质和保护生态环境的对策。     

EXOGENOUS APPLICATION OF POTASSIUM DIHYDROGEN PHOSPHATE CAN ALLEVIATE THE ADVERSE EFFECTS OF SALT STRESS ON SUNFLOWER

A greenhouse experiment was conducted to examine whether foliarly applied potassium + phosphorus (K + P) in the form of monopotassium phosphate (KH₂PO₄) could mitigate the adverse effects of salt stress on sunflower plants. There were two levels of root-applied salt [0 and 150 mM of sodium chloride (NaCl)], and varying levels of KH₂PO₄ [(NS (no spray), WS (spray of water), 5 + 4, 10 + 8, 15 + 12, and 20 + 16 mg g^?1 K + P, pH 6.5] applied foliarly to 18-day old non-stressed and salt stressed sunflower plants. Salt stress adversely affected the growth, yield, photosynthetic capacity, and accumulation of mineral nutrients in the sunflower plants. However, varying levels of foliar applied KH₂PO₄ proved to be effective in improving growth and yield of sunflower under salt stress. The KH₂PO₄ induced growth in sunflower was found to be associated with enhanced photosynthetic capacity, water use efficiency and relative water contents.     

间作环境中小麦氮钾养分吸收利用与干物质累积的动态变化特征*

 采用田间试验研究了小麦蚕豆间作环境对小麦氮钾养分吸收利用及小麦产量的影响。研究表明：小麦蚕豆间作在小麦干物质累积和产量上较单作具有明显优势。在常规施氮水平下，间作小麦生物量较单作小麦高30.6%，产量较单作增加了12.8%。在抽穗期至乳熟期，小麦茎、叶、穗氮含量和小麦穗钾含量均表现出间作第1行＞间作第3行＞单作，但收获时间作小麦茎叶钾含量呈低于单作趋势。小麦氮、钾养分累积量为间作第1行＞单作＞间作第3行。