基因工程技术的发展及其在农作物上的应用

对基因工程技术的发展历程进行了概述,总结了不同的转基因方法;对基因工程技术在农作物上的应用进行了阐述;分析了转基因技术目前存在的问题,并对其发展前景进行了展望。     

冬小麦秸秆还田对夏玉米生长发育及产量的影响

【目的】探讨不同品种冬小麦秸秆、秸秆覆盖量和覆盖方式对夏玉米生长发育和产量的影响。【方法】于2012年在陕西关中一年两熟典型地区,采用随机区组设计,选用小偃22和小偃216 2个冬小麦品种秸秆,设秸秆混入耕层、秸秆带状覆盖、秸秆全面覆盖3种秸秆还田方式,以及4 500,7 500和10 500kg/hm2 3个秸秆还田量,以秸秆不还田为对照,于夏玉米幼苗期和发育中期测定株高、茎粗、次生根数、叶片颜色、单株干质量,并于成熟期测定株高、穗位高及产量构成因素,研究各处理对夏玉米生长发育及产量的影响。【结果】2012年夏玉米播种后由于较长时期干旱少雨,冬小麦秸秆覆盖的保墒作用大于其化感作用,各秸秆还田处理夏玉米生长发育及产量总体优于对照。在2个小麦品种秸秆中,以小偃216秸秆对夏玉米诸性状的表现较好;在3种秸秆还田量中,以7 500kg/hm2秸秆还田量较为适宜;3种秸秆还田方式中,则以秸秆带状覆盖方式对夏玉米生长发育影响较小;在此组合下,夏玉米幼苗和植株生长健壮,成熟期产量最高。【结论】对夏玉米进行秸秆覆盖时,以冬小麦秸秆覆盖量为7 500kg/hm2的带状覆盖方式最好。     

超级杂交稻干物质生产特点与产量稳定性研究

 【目的】探明超级杂交稻在不同种植地点和不同施肥量条件下的产量表现及干物质生产特点。【方法】于2004～2005年在湖南省桂东、长沙、衡阳、南县和永州5个地点进行大田试验,按照N﹕P2O5﹕K2O为1﹕0.5﹕1的比例,设置3种施肥量处理（135、180、225 kg N•ha-1）,田间采用随机区组排列,4次重复,以超级杂交稻组合准两优527和两优293为试验材料。【结果】超级杂交稻收获产量以桂东点产量最高,地点间差异显著,其中准两优527平均为7 492.3～12 209.2 kg•ha-1,两优293为6 984.0～11 679.5 kg•ha-1。产量构成因子和干物质生产量的地点间变化与收获产量一致,但在同一地点的不同施肥量处理间收获产量和干物质生产量差异均不显著。收获产量与单位面积穗数、结实率和千粒重表现为正相关,而与每穗粒数表现为负相关。【结论】超级杂交稻存在适宜的种植区域,且在施肥量为135～225 kg N•ha-1的范围内,施肥量不是超高产栽培的限制因子。超级杂交稻的库容量大,提高结实率和粒重是获得超高产的可能途径。     

猴头菌不同生长发育期粗蛋白、粗多糖含量及水溶性粗多糖体外免疫活性

测定猴头菌(Hericium erinaceus)华中猴头菌株不同生长发育期子实体中的粗蛋白、粗多糖和水溶性粗多糖中β-葡聚糖含量,并研究不同生长发育期子实体粗多糖体外刺激巨噬细胞产生NO的活性变化规律.结果表明,供试菌株不同生长发育期子实体的粗蛋白、粗多糖和β-葡聚糖含量以及粗多糖体外刺激巨噬细胞产生NO的活性均存在显著或极显著差异,随着生长发育的进行,猴头菌子实体中粗蛋白含量总体上呈下降的趋势(小菌剌期比前一时期有所增加),而多糖含量则总体呈上升趋势(小菌刺期比后一时期高),β-葡聚糖含量呈先快速上升后平稳的趋势;分裂期粗多糖在浓度500 μg/mL时对RAW264.7释放NO的促进作用较强.     

辽宁省粮菜主产区农村饮用水硝酸盐污染状况研究

为了解农村饮用水硝酸盐污染情况,2005-2008年连续4年7次采集辽宁省粮食、蔬菜主产区农户井水样品1307个,利用TU-1810DASPC紫外可见光光度计测定了硝酸盐含量。结果表明,粮食、蔬菜主产区农村饮用水硝酸盐含量平均值为18．96mg·L^-1,大于20mg·L^-1的样品占32．08％。保护地蔬菜产区农户饮用水硝酸盐含量平均值为21．26mg·L^-1,个别的蔬菜种植户地下水硝酸盐含量达到396．67mg·L^-1。水稻产区农村饮用水硝酸盐含量平均值为20．62mg·L^-1,玉米产区农户饮用水硝酸盐含量为17．8mg·L^-1。受硝酸盐污染的水井占监测水井总数的百分比分别为：昌图县34．52％、开原市49．63％、铁岭县38．92％、新民市52．68％、辽中县39．82％黑山具3242％和北镇市32．99％．     

基于主成分回归的黑龙江省粮食生产能力影响因素分析

针对当前的粮食安全问题,结合黑龙江省的情况,将影响粮食单产与粮食种植面积的指标综合考虑,由于指标较多和相互间可能的相关性,故先利用主成分分析将多个影响指标综合成少数具有代表性地反映所有影响因素的几个指标来代替,再建立回归模型来进行定量分析。该方法有效地避免了回归分析中的变量相关的问题,提高了拟合的精度和效用。     

Effect of Water and Rice Straw Management Practices on Soil Organic Carbon Stocks in a Double-Cropped Paddy Field

ABSTRACT

Water and rice straw (RS) management practices can potentially affect the accumulation of soil organic carbon (SOC) in agricultural soils. Field experiments were conducted in two consecutive rice-growing seasons (wet and dry) to evaluate SOC stocks under different water (continuous flooding [CF], alternate wetting and drying [AWD]) and RS management practices (RS incorporation [RS-I], RS burning [RS-B], without RS incorporation and burning [WRS]) in a double-cropped paddy field. RS-I under AWD had higher volumetric water content than the same RS management under CF at tillering in both growing seasons. Total SOC was significantly higher under AWD at tillering in both wet and dry seasons and after harvesting in the dry season compared with CF. The same trend was also observed for C:N ratio at tillering and after harvesting in the dry season. RS-B plots had lower SOC stocks than RS-I and WRS plots across most of the measuring periods regardless of the growing seasons. SOC stocks were 33.09 and 39.31 Mg/ha at RS-B and RS-I plots, respectively, in the wet season, whereas the respective values were 21.45 and 24.55 Mg/ha in the dry season. Incorporation of RS enhanced SOC stocks under AWD irrigation, especially in the dry season before planting. Soil incorporation of RS in combination with AWD could be a viable option to increase SOC stocks in the double-cropped rice production region as it is strongly linked with soil fertility and productivity. However, the environmental consequences of RS incorporation in irrigated lowland rice production system should be taken into consideration before its recommendation for paddy field on a large scale.     

The effect of lime levels on the growth of beans and maize and nodulation of beans in three tropical acid soils

Abstract

A study to investigate the effect of lime on dry matter yield of maize (Zea mays) and beans (Phaseolus vulgaris) and nodulation of beans grown in three tropical acid soils (two humic Nitosols and one humic Andosol) was carried out in a greenhouse. The soils ranged from 4.2 to 5.0 in pH; 1.74 to 4.56 in %C; 21.0 to 32.0 meq/100g in CEC; 5.10 to 8.10 meq/100g in exchange acidity; 0.60 to 3.20 meq/100g in exchangeable (exch.) Al and 0.13 to 0.67 meq/ 100g in exch. Mn.

Exchange acidity and exch. Al decreased with increasing levels of lime in the three soils. Exchangeable Al was reduced to virtually zero at pH 5.5 even in the soils which had appreciable initial amounts. Exchangeable Mn also decreased with increasing levels of lime in the two Nitolsos. Exceptional results, however, were obtained with the Andosol where exch. Mn increased ten‐fold with the first level of lime and then decreased with subsequent levels.

In all the soils, mean dry matter yield of beans and maize, and mean nodule dry weight of beans generally increased significantly with increasing lime levels up to pH value of 6.0. The dry matter yield of beans and maize, and nodule weight of beans, however, decreased progressively with increasing lime levels beyond pH 6.0 value. pH range of 5.5 to 6.0 was considered optimum for the growth of maize and beans, and nodulation of beans in these soils.     

Effect of tillage and crop on arbuscular mycorrhiza colonization of winter wheat and triticale under Mediterranean conditions

Large‐scale inoculation with arbuscular mycorrhizal fungi (AMF) is generally impractical in most regions and we have little understanding of the factors that determine inoculation success. Nevertheless, the ability to take full advantage of indigenous AMF for sustainable production needs to be developed within cropping systems. We used part of a long‐term field experiment to understand the influence of tillage and the preceding crop on AMF colonization over the growing season. Arbuscular mycorrhiza colonization rate was more affected by treatment (tillage or the combination of crop and preceding crop) than by the total number of AMF spores in the soil. Conventional tillage (CT) had a statistically significant negative effect (P ≤ 0.05) on spore numbers isolated from the soil, but only in the first year of study. However, the AMF colonization rate was significantly reduced by CT, and the roots of wheat, Triticum aestivum, L, cv. Coa after sunflower, Helianthus annuus L., were less well colonized than were those of triticale, X Triticosecale Wittmack, cv. Alter after wheat, but the affect of tillage was more pronounced than was the effect of crop combination. Under no‐till there was a significant increase in AMF colonization rate throughout the sampling period in both wheat and triticale, indicating that the extraradical mycelium previously produced acted as a source of inoculum. In general, triticale showed greater AMF colonization than wheat, despite the preceding crop being less mycotrophic. Under these experimental conditions, typical of Mediterranean agricultural systems, AMF colonization responded more strongly to tillage practices than to the combination of crop and preceding crop.