Influence of intra-row cruciferous surrogate weed growth on crop yield in organic spring cereals

In Northern Europe, inter-row hoeing has become a popular tactic for controlling weeds in organic cereals. Hoeing is highly effective and can be implemented from crop emergence until stem elongation to maintain a nearly weed-free inter-row zone. However, hoeing has a lesser effect on weeds growing in the intra-row zone, where crop–weed proximity results in heightened competition. In the hoed cereal system, it is investigated whether tall-growing, competitive, cruciferous weeds in the intra-row zone affect crop biomass, yield and thousand kernel weight (TKW). An additive experimental design is employed to enable the fitting of rectangular hyperbolas, describing and quantifying the effects of increasing intra-row surrogate weed density on crop growth parameters. Regressions were studied under the influence of crop (spring barley and spring wheat), row spacing (narrow [12.5 or 15.0 cm] and wide [25.0 cm]) and nitrogen rate (50 and 100 kg NH₄-N/ha). Cruciferous surrogate weeds were found to impact crop yield and quality severely. For example, ten intra-row plants/m² of surrogate weed Sinapis alba reduced grains yields by 7%–14% in spring barley and by 7%–32% in spring wheat with yield losses becoming markedly greater in wheat compared to barley as weed density increases. Compared to wheat, barley limited yield and quality losses and suppressed intra-row weed growth more. Row spacing did not have a consistent effect on crop or weed parameters; in one of six experiments, the 25 cm row spacing reduced yields and increased intra-row weed biomass in wheat. Nitrogen rate did not affect crop or weed parameters. Results warrant the implementation of additional tactics to control intra-row weeds and limit crop losses.     

种植密度对2个青稞品种抗倒伏及秸秆饲用特性的影响

种植密度是影响青稞抗倒伏和秸秆饲用特性的重要因子。以抗倒伏品种昆仑14号和倒伏品种门源亮蓝为试验材料,比较研究种植密度对这2个品种生长发育、抗倒伏特性和秸秆饲用特性的影响。结果表明,种植密度对2个品种的抗倒伏和秸秆饲用特性的影响存在差异。随着种植密度的增加,昆仑14号根长、根体积、根数和根干重先增后降,茎粗和壁厚依次下降;门源亮蓝根系和茎秆相关指标则随种植密度增大而下降。昆仑14号抗倒伏相关指标先增后降,但整个生育期未发生倒伏;门源亮蓝各指标均显著降低,诱发倒伏现象提前发生,致使倒伏率增大、倒伏程度加剧。昆仑14号茎秆中性洗涤纤维、酸性洗涤纤维、半纤维素、纤维素和木质素等化学成分含量随密度增加先增后降,门源亮蓝各成分含量呈下降趋势,相对饲喂价值随密度增加呈现增高的趋势。综合抗倒伏特性与秸秆饲用特性,昆仑14号最佳种植密度为375×104株hm~(-2),门源亮蓝粮饲兼用时适宜密度为300×104～375×104株hm~(-2)。     

Effects of seedbed properties on crop emergence: 3. Effects of firming of seedbeds with various sowing depths and water contents

Abstract

Extensive experiments were carried out in shallow plastic boxes placed directly on the ground in the field to study the effects of seedbed properties on the emergence of various crops in a cool temperate climate. In a group of experiments with barley (Hordeum vulgare L.), we studied the effects on crop emergence of firming (slight compaction) of the seedbed, simulating the recompacting effects of rolling after sowing or press wheels on the seed coulters. Most of the experiments were carried out without irrigation after sowing. The firming usually had a slightly positive effect on emergence when the water content in the surface layer at sowing was below the wilting point. When the water content in the surface layer was higher, firming often reduced emergence drastically, particularly with deep sowing and in coarse-textured soils. The main reason for negative effects was harmful hardening of the surface layer when the more firm seedbed gradually dried out. When irrigation kept the seedbed continuously moist, the negative effect of firming was almost eliminated. Very high initial water content in the basal layer tended to delay surface layer drying and hardening, and to reduce the negative effect of firming. Firming only slightly influenced the evaporative water losses from the soil. In contrast to the results presented here, previous field trials with cereals have usually resulted in more positive effects of rolling after sowing. This indicates that other effects than firming, such as modification of sowing depth and reshaping of the soil surface, are other important effects of rolling.     

大麦条纹病侵染对大麦叶片蛋白组的影响

大麦条纹病由麦类核腔菌(Pyrenophora graminea)引起,是一种世界性病害.为进一步探索条纹病与大麦(Hordeum vulgare)的相互作用,以大麦品种甘啤6号和Issto为实验材料,在接种麦类核腔菌(代号DWC)7和21d后提取叶片蛋白,运用2-DE和质谱分析技术研究条纹病菌侵染后叶片蛋白质组学的变化.结果显示,与对照相比,甘啤6号和Isotta差异表达量在1.4倍以上的蛋白点28个,其中在甘啤6号中表达上调的蛋白点4个,下调的6个,诱导表达的2个,抑制表达的2个;在Isotta中,表达上调的蛋白点3个,下调的4个,诱导表达的4个,抑制表达的3个.质谱鉴定分析发现,表达上调的蛋白包括二磷酸核酮糖羧化酶A(2号蛋白点)、肌动蛋白(9号蛋白点)、核糖体再循环因子(ribosome-recycling factor,RRF)(10号蛋白点)、ATP合酶γ链(11和27号蛋白点)、琥珀酸脱氢酶(辅酶q)黄素蛋白亚基(15号蛋白点)和假定蛋白(26号蛋白点):表达下调的包括过氧化物还原蛋白(4号蛋白点)、1,5-二磷酸核酮糖羧化酶大亚基(ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit,RuBisCo)(3、5、12、14、16和18号蛋白点)、ATP合酶CF1α亚基(13号蛋白点)、Ycf3蛋白(17号蛋白点)和α-1,4葡聚糖蛋白合酶(alpha-1,4-glucanprotein synthase,UTPG)(28号蛋白点);诱导表达蛋白包括假定蛋白(6号蛋白点)、脂氧合酶2(lipoxygenase 2,LOX2)(7号蛋白点)、捕光叶绿素a/b结合蛋白质(light harvesting chlorophyll a/b-binding protein,LHCP)(19号蛋白点)、3-磷酸甘油酸激酶(3-phosphoglycerate kinase,PGK)(20号蛋白点)、凝集素(21号蛋白点)和ATP合酶γ链(22号蛋白点);抑制表达的蛋白包括RuBisCo(1、8、24和25号蛋白点)和二磷酸核酮糖羧化酶小链(ribulose bisphosphate carboxylase small chain,RuBPCase)(23号蛋白点)等.按照其功能分类,这些差异表达蛋白点分别参与了光合作用、蛋白质生物合成、植物防卫反应、能量代谢和细胞信号转导、细胞结构和纤维素生物合成等生理功能.这些差异表达蛋白可能与大麦响应条纹菌侵染过程有关,研究结果有助于从蛋白质水平揭示不同抗性大麦品种抗条纹病的抗性机制.     

Identification of QTLs associated with salinity tolerance at late growth stage in barley

Salinity is a major abiotic stress to barley (Hordum vulgare L.) growth and yield. In the current study, quantitative trait loci (QTL) for yield and physiological components at the late growth stage under salt stress and non-stress environments were determined in barley using a double haploid population derived from a cross between CM72 (salt-tolerant) and Gairdner (salt-sensitive). A total of 30 QTLs for 10 traits, including tiller numbers (TN), plant height, spikes per line (SPL), spikes per plant (SPP), dry weight per plant, grains per plant, grain yield, shoot Na⁺ (NA) and K⁺ concentraitions (K) in shoot, and Na⁺/K⁺ ratio (NAK), were detected, with 17 and 13 QTLs under non-stress and salt stress, respectively. The phenotypic variation explained by individual QTL ranged from 3.25 to 29.81%. QTL flanked by markers bPb-1278 and bPb-8437 on chromosomes 4H was associated with TN, SPL, and SPP under salt stress. This locus may be useful in the breeding program of marker-assisted selection for improving salt tolerance of barley. However, QTLs associated with NA, K, and NAK differed greatly between non-stress and salt stress environments. It may be suggested that only the QTLs detected under salt stress are really associated with salt tolerance in barley. D. Xue and Y. Huang contributed equally to the article.     

大麦与簇毛麦杂交有性过程的研究

簇毛麦花粉粒在大麦柱头上的萌发,花粉管在花柱中的生长以及双受精过程均基本正常,但受精过程的时间以及胚和胚乳初期发育的过程,均较自交的缓慢。授粉后36～48小时,杂交合子进行第一次有丝分裂,形成两个细胞的原胚。授粉后8天,多数杂交原胚的细胞开始解体。授粉后5～6小时,杂交的初生胚乳核进行第一次有丝分裂。授粉后6天,胚乳游离核开始解体,比原胚败育早。因此在授粉后6～7天将尚未败育的杂交原胚进行离体培养也许是较为合适的时期。     

普通卷甲虫的抗寒性研究

[目的]研究普通卷甲虫的抗寒性,为进一步预测下一年虫口发生提供参考资料。[方法]对2000只普通卷甲虫的体长、体宽、鲜重等生物学特征进行了测定,并对每一个体进行了不同低温强度及持续时间的冷冻培养。[结果]在低温条件下,卷甲虫的死亡率与培养温度和培养时间,以及在相同条件下雌、雄虫死亡率之间都具有明显的相关性,呈直线回归关系;一定的低温条件下,培养时间愈长,死亡率越高;在一定的培养时间下随着低温强度加大,死亡率明显升高。但在不同的培养条件下,卷甲虫的死亡率与它们的体长、体重都无明显相关性。[结论]普通卷甲虫的抗寒性与该地区年最低气温的变化相关联。     

宁夏海原小茴香发展现状及前景展望

介绍了小茴香在宁夏的分布、生物学特性、化学成分及其产业现状;分析了目前制约海原小茴香发展的主要问题;展望了未来海原小茴香产业发展的潜力及前景。     

重金属对大麦幼苗膜脂过氧化及脯氨酸和可溶性糖含量的影响

采用室内水培法,研究了不同浓度(1、10、50、100mg·L-1)Cd2 、Pb2 、Hg2 、Ni2 胁迫对大麦幼苗根膜脂过氧化水平及脯氨酸、可溶性糖含量的影响。结果表明,不同浓度重金属均可诱导根细胞膜透性增大,随着重金属浓度的增加,根外渗液的相对电导率和丙二醛(MDA)含量逐渐增大,二者与重金属浓度呈正相关。重金属胁迫下,脯氨酸含量呈先降后升的变化趋势。根内可溶性糖含量的变化随重金属浓度的增加逐渐下降。4种重金属中以Cd2 对膜脂过氧化水平(MDA)和可溶性糖含量的影响最大,而Pb2 、Ni2 对脯氨酸含量的影响最为明显。     

高粱在畜禽日粮中的应用研究

高粱的抗旱性强，比玉米的生长环境条件更宽广。随着玉米、小麦等能量原料价格的高涨，为了降低成本，提高产品竞争力，很多大型饲料企业开始从国外进口高粱。然而，由于高粱中含有丹宁，与玉米相比，用高梁作为饲料原料降低了非反刍动物对能量和其它养分的消化利用率。文章就目前高粱在非反刍动物营养中的研究应用进行了总结。