不同倍性小麦材料对水分和密度条件的响应

以栽培一粒(2n)、栽培二粒(4n)和长武134(6n)为材料在大型活动防雨棚条件下研究不同倍性小麦材料在不同密度和水分条件下的产量适应性变化。结果发现,在两种水分条件下随着染色体倍性从2n→6n的增加,产量、千粒重、水分利用效率(WUE)和收获指数均呈增加趋势,在水分胁迫下各材料穗粒数和穗数则呈降低趋势,而在正常供水下穗粒数则呈增加趋势。在水分胁迫下栽培一粒、栽培二粒和长武134最高产量分别出现在中、低、高密度群体,而同一材料不同密度群体间变异系数分别为6.73%,1.98%,9.07%;不同倍性材料千粒重均随着密度增加而减小,而穗数则逐渐增加,二倍体的穗粒数以中密度最高,四倍体的穗粒数随着群体密度的增加而减小,六倍体则相反;三种材料WUE和收获指数分别以低、高、低密度最高。正常供水下随着染色体倍性从2n→6n的增加,三个倍性材料最高产量分别出现在高、低、低密度群体,而同一材料不同密度群体间变异系数分别为6.01%,17.12%,2.46%;千粒重表现为中密度>低密度>高密度,而穗粒数均以低密度群体最高,二倍体和四倍体以高密度群体最低,六倍体则以中密度群体最低,穗数则随着密度群体增加而增加;二倍体WUE以高...

不同类型作物对干湿交替环境的反应

通过对干湿交替环境下春小麦、马铃薯、大豆和玉米等作物的产量、水分利用效率及光合作用、蒸腾作用、气孔导度等生理变化的研究表明 :( 1 )春小麦和马铃薯在干湿交替环境下可获得与充分供水相当的产量而它们的水分利用效率却显著提高 ,大豆减产幅度较大 ,玉米减产严重 ,其水分利用效率显著低于全湿处理 ;( 2 )浇水后各作物的光合速率、蒸腾速率和气孔导度都有所增加 ,但不同作物增加的幅度不同 ,就是同一作物各指标的增幅也不同 ;( 3)干湿交替环境下同化物的运输模式有利于春小麦籽粒的充实和马铃薯块茎的膨大 ,而不利于玉米产量的形成 ;( 4 )产量不仅决定于营养生长阶段 ,更主要决定于生殖生长阶段。此外 ,还就干湿交替过程中若干生理变化和经济产量形成机制作了初步探讨。

论窖灌农业中水窖的配置模式与窖水高效利用技术

针对黄土高原蓬勃发展的窖灌农业 ,提出3种水窖配置模式 :峁顶光头式 ;路旁葡萄串式和场、院、凹地单点式。为了高效利用水窖集蓄的雨水资源 ,文中推荐自压微灌、外动力加压微灌、坑灌和水肥穴灌等4种窖水高效利用技术。

黄土塬区不同水分条件下冬小麦氮肥效应与土壤氮素调节

在黄土旱塬长期定位研究表明 ,根据小麦生育年降水量施用氮肥 ,将能更好地发挥肥料效益。丰水年、平水年氮肥增产效果极为显著 ,应加大施用量 ;干旱年氮肥效果受抑 ,应减少施用量。氮肥利用率受降水等因素影响 ,年际间变化幅度为 6.4%～ 58.6%。氮肥利用率亦随施用量的增加而降低 ,变化幅度为 2 5.4%～ 42 .9%,且其利用率与施肥利润的高低并不同步。施用有机肥或氮磷有机肥配施、轮作中增加豆科作物 (或牧草 )能有效地调节改善土壤氮素状况

土壤水库和森林植被对水资源的调节作用

以湖南省土地、森林利用状况等有关资料为基础，从土壤和森林对降水形成径流的影响，调节水资源的数量和方式，防洪抗旱减灾方面的作用3个层次，详细地剖析了土壤水库和森林植被对水资源的调节作用。结果指出，土壤水库和森林植被能够调节水资源，其潜力非常大。合理利用土壤水库和森林植被可以蓄水保土减蚀，削减洪峰，减少自然灾害。 关键词：土壤水库；森林植被；水资源

黄土高原降雨空间分布的不均匀性研究

根据黄土高原13条流域的降雨资料，分三种雨型即局地强对流条件引起的小范围、短历时、高强度的局地性暴雨（A型暴雨），峰面型降雨夹有局地雷暴性质的较大范围、中历时、中强度暴雨（B型暴雨），峰面型降雨引起的大面积、长历时、低强度暴雨（C型暴雨）；选用流域面雨量离差系数Cv、流域降雨不均匀系数η和流域最大点与最小点降雨量比值系数α三种指标，分析了次降雨空间分布的不均匀性。

HEC和AAM添加剂对提高黄土集流效率的试验研究

基于西北地区黄土资源丰富、地形复杂、外源材料运输困难的实际状况 ,提出将 HEC(High Strength andWater Stability Earth Consolidator)和 AAM(Active Aluminate Mixture)材料添加剂与黄土混掺 ,以期提高其集流效率。通过室内人工降雨模拟试验 ,探讨了典型黄土与 HEC和 AAM材料添加剂分别混掺后集流效率和性能的变化过程。同时 ,对照其它几种集雨材料 ,对不同雨强、雨量及坡度下的起流历时、集流效率和材料性能进行了比较。结果表明 :黄土与 HEC和 AAM添加剂混掺后形成的黄土复合集流材料具有较强的抗拉、抗压能力 ,不同雨强和雨量等级范围均具有较高的集流效率 (>78% ) ,已达到混凝土的集流效果 ,其成本仅为混凝土的 1/ 3～ 1/ 2。

Relationships between precipitation, soil water and groundwater at Chongling catchment with the typical vegetation cover in the Taihang mountainous region, China

Vegetation cover plays an important role in the process of evaporation and infiltration. To explore the relationships between precipitation, soil water and groundwater in Taihang mountainous region, China, precipitation, soil water and water table were observed from 2004 to 2006, and precipitation, soil water and groundwater were sampled in 2004 and 2005 for oxygen-18 and deuterium analysis at Chongling catchment. The soil water was sampled at three sites covered by grass (Carex humilis and Carex lanceolata), acacia and arborvitae respectively. Precipitation is mainly concentrated in rainy seasons and has no significant spatial variance in study area. The stable isotopic compositions are enriched in precipitation and soil water due to the evaporation. The analysis of soil water potential and isotopic profiles shows that evaporation of soil water under arborvitae cover is weaker than under grass and acacia, while soil water evaporation under grass and acacia showed no significant difference. Both delta O-18 profiles and soil water potential dynamics reveal that the soil under acacia allows the most rapid infiltration rate, which may be related to preferential flow. In the process of infiltration after a rainstorm, antecedent water still takes up over 30% of water in the topsoil. The soil water between depths of 0-115 cm under grass has a residence time of about 20 days in the rainy season. Groundwater recharge from precipitation mainly occurs in the rainy season, especially when rainstorms or successive heavy rain events happen.

Study on mechanism of interaction between Eu3+ and microperoxidase-11

The interaction mechanism between Eu3+ and microperoxidase-II (MP-11) in the aqueous solution was investigated using the UV-vis absorption spectroscopy, cyclic voltammetry and electrospray ionization mass spectrometry. It was found that one Eu3+ ion can coordinate with two carboxyl oxygen of two propionic acid groups of the heme group in the MP-11 molecule, leading the increase in the nonplanarity of the porphyrin ring and exposure degree of Fe(III) in the heme group. Therefore, the reversibility of the electrochemical reaction and the electrocatalytic activity of MP-11 for the reduction of oxygen are increased.

Promoter effect of La3+ on the electrochemical reaction of microperoxidase-11

The effect of La3+ on the electrochemical behavior and structure of heme undecapeptide-microperoxidase-11 (MP-11)-in the aqueous solution was investigated using cyclic voltammetry, circular dichroism (CD) and UV-vis absorption spectrometry. It was found for the first time that La3+ would promote the electrochemical reaction of MP-11 at the glassy carbon (GC) electrode. This is mainly due to the fact that La3+ would induce more beta-turn and alpha-helical conformations from the random coil conformation of MP-11 and increase the non-planarity of the heme.

Direct decomposition of NO over the mixed oxide catalysts Nd_(2-)Sr_xNiO_(4±λ)

The nitrogen oxides (NO_x) are serious pollutants in earth's atmosphere in the sensethat they are one of the main sources to cause the acid rain. The removal of NO_x is oneof the key research topics in the protection of environmen.

The variation of upper ocean structure and paleoproductivity in the Kuroshio source region during the last 200 kyr

A core from the source region of the Kuroshio warm current (east of the Luzon Island) was analyzed using several proxies in order to study the variability of the Western Pacific Warm Pool (WPWP) during the last two glacial-interglacial cycles. Primary productivity (PP) variations were deduced from variations in the coccolith flora. Primary productivity was higher during glacial periods (the end of Marine Isotope Stage [MIS] 3, some periods in MIS 2 and 6), and decreased during interglacial periods (MIS 7, MIS Se and probably MIS 5c-5d), with the lowest PP in MIS 5e. variations in the delta C-13 difference in benthic and bulk carbonate, thus in the vertical gradient of delta C-13 in dissolved inorganic carbon (Delta delta C-13(c). (wuellerstorfi-N. dutertrei) and Delta delta C-13(c.) (wuellerstorfi-coccolith)) Coincided With the PP Changes, showing that export productivity was low during interglacial periods (MIS 7, MIS 5e and Holocene) and high during glacial periods (MIS 6, probably MIS 5c-5d, late MIS 4 and late MIS 3). Comparison of foraminiferal carbonate dissolution indicators and PP changes reveals that nannofossil assemblage in core Ph05-5 is not sensitive to carbonate dissolution intensity. The depth of the thermocline (DOT) was estimated from planktonic forminiferal assemblages, and was relatively greater during interglacial periods (MIS 7, MIS 5e, probably MIS 5c and Holocene) than during glacials (middle MIS 6, probably MIS 5b and 5d, some periods in MIS 4, MIS 3 and MIS 2). Good coherence between the paleoproductivity records and the DOT suggests that the DOT changes could be the primary control factor in changes of paleoproductivity, and the glacial high productivity in the Kuroshio source region could be associated with a global increase of nutrient concentration in the intermediate waters that upwelled into the photic zone. The low CO2 values derived for intervals of high productivity and a relatively shallow DOT suggest that the changes in biological productivity and DOT in the equatorial Pacific could have modified atmospheric CO2 concentrations. High Sea Surface Temperatures (SSTs) during the warm MIS 5e in combination with intensified monsoonal rain fall could have resulted in a more intense stratification of the upper waters, resulting in low nutrient supply to the surface waters and a resulting decrease in productivity. (C) 2010 Elsevier B.V. All rights reserved.

A nitrogen budget of the Changjiang river catchment

Based on 1997-1998 field investigations in the Changjiang river mouth, rain sampling from the river's upper reaches to the mouth, historical data, and relevant literature, the various sources of Total Nitrogen (TN) and Dissolved Inorganic Nitrogen (DIN) in the Changjiang river catchment and N transport in the Changjiang river mouth were estimated. The export fluxes of various form of were mainly controlled by the river runoff, and the export fluxes of NO3-N, DIN and TN in 1998 (an especially heavy flood year) were 1438 103 tonnes (t) yr(-1) or 795.1 kg km(-2) yr(-1) 1746 10(3) t yr(-1) or 965.4 kg km(-2) yr(-1) and 2849 10(3) t yr(-1) or 1575.3 kg km(-2) yr(-1), respectively. The TN and DIN in the Changjiang river came mainly from precipitation, agricultural nonpoint sources, N lost from fertilizer and soil, and point sources of industrial waste and residential sewage discharge, which were about 56.2% and 62.3%, 15.4% and 18.5%, 17.1% and 14.4%, respectively, of the N outflow at the Changjiang river mouth; maximum transport being in the middle reaches.

青藏高原高山植物麻花艽的传粉生态学研究

对青藏高原东部麻花艽(Gentiana straminea)海北居群的传粉生态学进行了3a连续的观察和实验。试验表明自然去雄、人工自交和杂交处理均结实，而人工去雄套袋和自然套袋不结实。麻花艽自交亲合，但必须依赖传粉媒介才能完成授粉过程，不存在无融合生殖。野外捕捉到14种访花昆虫，它们分别属于2个纲，7个目，8个科。观察和分析了各种昆虫的访花行为后，认为苏氏熊蜂(Bombus sushikini)是麻花艽有效而稳定的传粉者。测量表明麻花艽花蜜通道的深度和苏氏熊蜂的舌长基本吻合。苏氏熊蜂的访花频率在lO：00～12：00，13：00～15：00和16：00～18：OO时间段没有差别，单花的访花频率为0．005次／(花·rain)。和其它高山植物相比，青藏高原高山植物麻花艽的访花频率较高。熊蜂传粉和高频率的访花维持了麻花艽在极端寒旱的青藏高原环境下的有性生殖。此外，高频率的访花对于维持该地区高山植物的生殖保障具有重要的现实意义，但是否具有普遍性，还有待研究更多的高山代表类群。

青藏高原矮嵩草草甸种子库的初步研究

The seed bank of Kobresia humilis meadow in Qing- Zang Plateau was preliminaryly studied and the relationships among seed bank , seed rain and above-ground vegetation were compared and analysed.The results showed that there were 23 species in the seed bank in both of green up and withering stage. In species composition of the seed bank ,Ranunculaceae and Leguminosae were dominant ,while the percentage of Cyperaceae and Gramineae were lower. The percentage of K. humilis seeds was relatively lower with 0. 97 % in green up stage and 1. 97 % in withering stage. The species composition of the seed bank correlated with that of the seed rain ( r = 0. 7505 , P < 0. 01) ,and there were 18 common species which was 78. 3 %of species of the seed bank. Only 41. 81 %of above-ground vegetation species presented in the seed bank. The seed numbers of the dominant plant species in vegetation were smaller , with lower percentage in the seed bank. Therefore , the dominant vegetation of K. humilis et al. mainly depended on vegetative reproduction to maintain and strengthen. From vegetation to the seed bank in green up stage ,the species diversity decreased by 9. 94 %. It implied that the seed bank was the source of vegetation regeneration , but also a mechanism of preserving species diversity of the plants.