天津市郊区冬季大气边界层风、温场结构与特征

利用天津市郊区探空观测资料,对该地区冬季大气边界层内的风场、温度场结构与特征进行研究.结果表明,测试期间风向随着高度增加呈顺时针旋转, 由东风、东南风逐渐右转,转为西南风、西风,遵循Eckman螺线的规律;不同高度层风速日变化规律不同.一般来说,在较低高度风速白天变大,夜晚变小,而较高处则相反;接地逆温大约在20:00开始生成,随着时间的增加,逆温逐渐加强,平均逆温厚度在02:00达到最大值;混合层高度在早晨厚度较薄,午后混合层厚度较厚,有利于污染物的扩散;天津市市区10m和100m高度层风速的日变化规律与郊区相同,200m高度层风速日变化规律不同;市区与郊区相比,不同高度层风速随着时间起伏变化较小.     

草海国家级自然保护区冬季主要水鸟群落结构与生境的关系

于2011年12月至2012年2月对草海湿地国家级自然保护区冬季主要水鸟进行调查,结果表明:(1)共记录草海主要越冬水鸟30种,隶属于6目10科17属,区系上以古北型与全北型居多;(2)雁形目水鸟种类与数量均占优势,白骨顶(Fulica atra)、赤颈鸭(Anas penelope)、斑头雁(Anser indicus)、赤麻鸭(Tadorna ferruginea)、赤膀鸭(Anas strepera)5种水鸟优势度均达10%以上,黑颈鹤(Grus nigricollis)和灰鹤(Grus grus)等珍稀水鸟也具一定的种群数量;(3)5种草海典型生境栖息的水鸟种类与数量存在显著差异(Kruskal-Wallis H Test:n=30,!2=16.1893,P=0.003),浅水区是水鸟多样性最丰富的区域,多样性指数(H'=1.079)和均匀性指数(J'=0.804)均最高,而耕地最低(H'=0.345;J'=0.493);(4)群落聚类显示,草海主要水鸟可分为7类伴生群落,不同群落在不同生境中分布存在一定差异。     

外源葡萄糖对麦秸厌氧发酵产沼气的影响

为进一步阐释混合厌氧发酵的内在机制,在中温(35±1)℃条件下,以麦秸为原料,以葡萄糖为外源易分解有机碳,采用批式发酵方式,进行了葡萄糖不同添加量和不同添加方式对秸秆厌氧发酵产沼气影响试验。结果表明,在试验初始添加葡萄糖可提高日产气量,但葡萄糖添加量太少对提高秸秆总固体(TS)产气量无促进作用,当葡萄糖添加量为秸秆TS质量的6%时获得最大秸秆TS产气量,为303.13 m L·g-1,继续增加葡萄糖添加量,秸秆TS产气量反而降低;在秸秆厌氧发酵日产气量下降阶段一次性或者分次添加葡萄糖对促进秸秆厌氧发酵产沼气均无效果,仅在试验初始一次性添加秸秆TS质量6%的葡萄糖时对秸秆厌氧发酵产沼气有促进作用,秸秆TS产气量较对照提高9.24%;添加葡萄糖对秸秆厌氧发酵过程产气中甲烷含量无明显影响,但提高累积产气中甲烷平均含量,且在日产气量下降后添加葡萄糖的效果更好,但这种促进效果与对照间差异并不显著。综合以上结果,在试验初始一次性添加秸秆TS质量6%的葡萄糖可以获得最佳的产气效果。     

Metsulfuron‐methyl soil persistence and mobility in winter wheat and following green manure crops

A procedure has been developed for the analysis of metsulfuron‐methyl in the soil of field crops. The soil extracts are cleaned by repeated TLC, and metsulfuron‐methyl is simultaneously separated from its soil metabolites. Metsulfuron‐methyl is transformed by diazomethane into its N,N ‘‐dimethyl derivative which in the GC (electron capture detection) and GC‐MS apparatus is transformed into a benzisothiazole compound which is measured with great sensitivity. The sensitivity limit is 0.3 μg metsulfuron‐methyl kg^‐1 dry soil. The results of the chemical analyses are confirmed by bioassays using sugar beet as test plant. Metsulfuron‐methyl was measured in the soil of two winter wheat crops after post‐emergence application in the spring of 6 g metsulfuron‐methyl ha^‐1. In the 0–8 cm surface soil layer, the metsulfuron‐methyl soil half‐life was 78 days in 1997, and 67 days in 1998. During crop, metsulfuron‐methyl remained in the 0–8 cm surface soil layer. There, it was at a maximum concentration and herbicide efficiency in a 2 cm‐thick soil layer. This maximum concentration soil layer progressively moved down during crop, attaining the 4–6 cm surface soil layer at crop end. After the winter wheat harvest at the end of July, and the rotary‐tilling of the 0–10 cm surface soil layer before sowing of the green manures, 27% of the metsulfuron‐methyl initial dose still remained in the 0–10 cm surface soil layer. This residue progressively disappeared, and was no more detected at the middle of November. It had no, or only very low inhibiting effect on the growth of the green manures. Thus there is no concern about the possible phytotoxicity of persistent metsulfuron‐methyl soil residues towards the following crops, when metsulfuron‐methyl is applied at the rate of 6 g a.i.ha^‐1.     

Relationships between volatile organic compounds with an emphasis on terpene compounds and genetic matrix in inoculated and non-inoculated winter wheat cultivars

In the present study, we focus on the analysis of the volatile organic compound (VOC) contents in the grain of a representative set of winter wheat cultivars grown in Central Europe. The cultivars were grown in control conditions or were inoculated with the fungus Fusarium culmorum. In the analysed samples, hydrocarbons, alcohols, aldehydes and ketones, aromatics, terpenes and others were found. Among them, results for terpenes seem particularly important. The discriminant analysis allowed complete separation of the quality groups of wheat based on VOCs. Simultaneously, a genetic matrix was created based on the genetic distance between the wheat cultivars and the Mantel test was used to compare it with the VOC matrix. The analysis revealed relationships between the genetic matrix and the overall VOCs, as well as terpenes. The obtained results indicate a significant relationship between microorganisms that exist in the environment, genetic features of plants and VOCs formed in the grain.     

Magnetic particles precipitated onto wheat husk for removal of methyl blue from aqueous solution

Magnetic particles prepared via co-precipitation and impregnated onto wheat husk (MN-WH) were used for the removal of methyl blue (MB) from aqueous solution. Experiments were conducted in a batch mode for optimization regarding pH, contact time, adsorbent dose, initial dye concentrations, and temperature. Maximum adsorption (98%) was achieved at pH 5. The adsorption data were fitted into pseudo-first, pseudo-second, intraparticle diffusion, and Elovich equation revealing that adsorption followed pseudo-second-order kinetics. The four most common isotherm models, i.e. the Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich (D–R), were used to evaluate the data, with the best fit to a Langmuir isotherm (R² = 0.996), followed by a Freundlich isotherm (R² = 0.995), indicating monolayer adsorption of MB on the surface of MN-WH. Thermodynamic parameters calculated from the Van't Hoff equation revealed that the adsorption is exothermic (ΔHº = ?19.7 kJ mol^?1).     

Persistence of the sulfonylurea herbicide iodosulfuron-methyl in the soil of winter wheat crops

On four winter wheat fields grown on soils of different textures in Belgium, 10?g a.i.?ha^?1 of the sulfonylurea herbicide iodosulfuron-methyl-sodium was applied post-emergence in the spring. A procedure was developed for the analysis in field soils of iodosulfuron-methyl 1 and of its metabolites iodosulfonamide 2 and iodosaccharin 3 with a sensitivity limit of 0.3?µg of equivalents of iodosulfuron-methyl 1 kg^?1 dry soil. GC and GC-MS was used after purification of the soil extracts by repeated TLC, and methylation. The results of the chemical analyses were confirmed by means of bioassays using sugar beet as test plants. On a winter wheat crop grown on sandy loam soil of pH 6.2 at Melle, iodosulfuron-methyl-sodium 1 was applied at the beginning of April. The iodosulfuron-methyl 1 soil half-life in the 0–10?cm surface soil layer was 60 days. At the end of June, the sum of the concentrations of the metabolites 2 and 3 in the 0–10?cm surface soil layer attained a maximum corresponding to 27% of the applied dose. Green manures were sown after the harvest of the wheat at the end of August. No phytotoxicity at all was observed during the growth of the green manures, in spite of the very low residues of iodosulfuron-methyl 1 remaining in soil in September and October. At the mid of November, iodosulfuron-methyl 1 and its metabolites 2 and 3 were no more detected in soil. On three other winter wheat crops grown on clay soils of pH of about 8 at Leke, Gistel and Zevekote, iodosulfuron-methyl-sodium 1 was applied at the beginning of May. The soil half-life of iodosulfuron-methyl 1 in the 0–10?cm surface soil layer was between 30 and 44 days. Since the application and until the mid of November, in all the trials made on sandy loam or clay soils, iodosulfuron-methyl 1 (and its metabolites 2 and 3 in the trial made on sandy loam soil) were never detected in the 10–15 and 15–20?cm surface soil layers, indicating their low mobilities in the field soils.     

湖泊底泥土地利用对土壤中重金属铅、铜形态影响

采用田区试验研究了田间种植冬小麦条件下,底泥土地利用前后土壤中重金属铅、铜的形态演变及小麦各器官中铅、铜的富集。结果表明,随着底泥施用量的增加,土壤中重金属铅、铜的可交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态、残渣态均有不同程度的增加,本试验所有处理中,可交换态铅的质量分数范围为0.02~0.10 mg·kg-1,碳酸盐结合态铅的质量分数范围为0.04~0.24 mg·kg-1,铁锰氧化物结合态铅质量分数为0.41~1.88 mg·kg-1,有机物结合态铅质量分数范围为1.23~4.92 mg·kg-1,残渣态铅质量分数范围为4.82~23.66 mg·kg-1;各处理与对照相比,可交换态铜质量分数增加了40.00%~200.00%,碳酸盐结合态铜质量分数增加了36.84%~363.16%,铁锰氧化物结合态铜质量分数增加了7.17~45.15%,有机结合态铜质量分数增加了7.98%~62.61%,残渣态铜质量分数增加了0.12%~9.69%,各处理的残渣态铅、铜质量分数均较高。随着底泥用量增加,小麦根系、茎叶、籽粒中铅、铜质量分数均呈增加趋势,植株对重金属铅、铜的富集顺序为根系>茎叶>籽粒,铜的富集系数均大于铅。小麦籽粒产量、茎叶生物量及地上部生物量随着底泥施用量的增加,均出现了先增加后减少的现象,当小麦籽粒产量达到最大值时,籽粒中铅、铜质量分数未超出我国相应标准,依此确定底泥环境安全施用量为3051.29 t·hm-2。     

外源NO对不同冬春性小麦花后光合生理的影响

为利用一氧化氮（NO）调节作用实现小麦（Tritivum aestivum L.）高产优质之目的,本试验在网室盆栽条件下,以冬春性不同的2个小麦品种（弱春性偃展4110和半冬性周麦18）为试验材料,研究了不同浓度外源NO供体——SNP处理对花后小麦光合生理特性及成熟期产量构成因素的影响。结果表明,不同浓度SNP处理对2种小麦旗叶叶面积、RWC、可溶性糖、总叶绿素含量、WUE、千粒质量、穗粒质量等均有不同程度的促进作用;与对照相比,低浓度SNP（0.075～0.15 mmol.L-1）明显降低2种小麦旗叶枯叶/绿叶值（Y/G）,而高浓度（0.30 mmol.L-1）处理则使Y/G值上升。综合分析：本试验条件下,外源NO对半冬性品种周麦18的调控效果优于弱春性品种偃展4110;周麦18以0.30 mmol.L-1SNP处理、偃展4110以0.15mmol.L-1SNP调控对小麦增产较为明显。     

铬胁迫下不同品种小麦萌发和内源激素的变化

采用K2(CrO4)3溶液,设5个浓度,对3种不同抗性的小麦品种(新麦19、矮抗58和豫麦18)进行萌发期胁迫处理,研究了幼苗的发芽势、发芽率、根长、芽长及内源激素含量的变化.结果表明:(1)随着铬浓度的增加,发芽势、发芽率和芽长均基本呈"先升后降"趋势;(2)同一浓度铬处理下,发芽率、发芽势和芽长从大到小的顺序依次为:新麦19、矮抗58、豫麦18,根长从大到小的顺序为:豫麦18、新麦19、矮抗58;(3)150 mg L-1的铬胁迫下,IAA与ABA在小麦幼苗、幼根中含量降低,在籽粒中含量升高,其中新麦19籽粒和根芽中ABA含量均高于其他品种的;(4)不同浓度铬胁迫下,IAA/ABA值在新麦19中最低,变化幅度最小,新麦19表现出较强的抵抗铬胁迫能力.图3表1参20