The freezing characteristics of wheat at ear emergence

Wheat is occasionally exposed to freezing temperatures during ear emergence and can suffer severe frost damage. Few studies have attempted to understand the characteristics of freezing and frost damage to wheat during late development stages.

It was clearly shown that wheat appears to have an inherent frost resistance to temperatures down to −5 °C but is extensively damaged below this temperature. Acclimation, whilst increasing the frost resistance of winter wheat in a vegetative state was incapable of increasing frost resistance of plants at ear emergence. It is proposed that the ability to upregulate frost resistance is lost once vernalisation requirement is fulfilled.

Culms and ears of wheat were able to escape frost damage at temperatures below −5 °C by supercooling even to as low as −15 °C and evidence collected by infrared thermography suggested that individual culms on a plant froze as independent units during freezing with little or no cross ice-nucleation strategies to protect wheat from frost damage in the field appear to revolve around avoiding ice nucleation.     

北京藜麦适应性栽培研究进展及展望

藜麦营养全面,植株转色后花色艳丽,观赏期长达40d左右,且耐旱、耐寒,是一种集多功能为一体的新兴保健食粮。北京市自2015年引种藜麦,在适宜种植区、适宜品种筛选、营养品质检测、抗逆稳产栽培技术探索、菜品开发和技术示范等方面开展了大量工作。北京藜麦适应性栽培研究表明,藜麦在海拔≥300m、年均气温≤12.5℃、年均积温≤4802.0℃·d、年均光照强度≥2268.7lx的区域可正常成熟;“陇藜1号”、“陇藜3号”、“红藜1号”和“红藜2号”4个品种表现优良;藜麦米富含蛋白质,特别是“红藜1号”和“红藜2号”蛋白含量高达19.6%~20.0%;围绕栽培、农机、植保三大关键环节集成的藜麦抗逆稳产栽培技术体系在京郊示范应用面积为453.33hm²,应用率达100%;与一茬籽粒玉米相比,藜麦增收3.77万元/hm²。但区域发展不平衡、生产效率低和没有享受政策性农业保险等因素制约了藜麦在北京的持续健康发展。今后,应从加大政策和财政支持、提高藜麦机械化生产水平及建立健全相关标准制度等方面着手,做大做强北京藜麦产业,让藜麦的“小生产”能够在“大市场”中找到“微需求”,卖出好价钱。     

Cold acclimation of winter and spring peas: carbon partitioning as affected by light intensity

Like most plants, pea (Pisum sativum L.) becomes tolerant to frost if it is first exposed to low non-freezing temperatures, a process known as cold acclimation. Cold acclimation is a complex process involving many physiological and metabolic changes. Two spring dry peas, two winter dry peas and one winter forage line were exposed to cold temperature in a controlled environment in two experiments, one using low light intensity and the other regular light intensity. Plants were harvested throughout the experiment and dry matter accumulation, water content, soluble and insoluble sugar concentrations were determined from shoot and root samples. Cold acclimation did not occur when temperatures were low if light intensity was low, even in winter peas. In contrast, with regular light intensity, the winter peas acquired more freezing tolerance than spring peas and a close relationship was found between the soluble sugar concentration of leaves just before the frost and the degree of freezing tolerance obtained by the different genotypes. Relationships between freezing tolerance and carbon partitioning between shoot and roots are discussed.     

PAM施用深度对盐碱胁迫下藜麦生长及生理指标的影响

以陇藜4号为试验材料，采用根管土柱栽培试验，设置轻度(S1,3g/kg)、中度(S2,5g/kg)和重度盐碱胁迫(S3,7g/kg)以及土壤调理剂聚丙烯酰胺(PAM)施用深度0～10(PAM₀)、10～20(PAM₁₀)、20～30(PAM₂₀)和0～30cm(PAM₃₀)的完全随机试验组合，以土壤中不加盐碱和PAM为对照组(S0)，共计13个处理组合，研究PAM施用深度对不同盐碱胁迫条件下藜麦生长及生理指标的影响。结果表明，盐碱胁迫处理和PAM施用深度处理均会对藜麦的形态指标和生理指标造成显著影响：在合理施用PAM的前提下，与对照相比，轻度盐胁迫反而更有利于藜麦的生长，甚至中度盐胁迫下藜麦生长也没受到显著影响，表明藜麦具有较强的耐盐性。当盐碱胁迫达到重度(S3)时，虽然不同PAM施用浓度对藜麦生长有一定影响，但与对照相比，盐碱胁迫均显著抑制了藜麦地上部的生长；不同盐碱胁迫条件下不同PAM施用方式对藜麦生长及生理指标的影响均表现为PAM₀处理的效果最佳。隶属函数结果表明，不同处...     

Growth and Physiological Responses of Quinoa to Drought and Temperature Stress

Quinoa (Chenopodium quinoa Willd.), traditionally called the mother of grains, has the potential to grow under high temperatures and drought, tolerating levels regarded as stresses in other crop species. A pot experiment was conducted in a climate chamber to investigate the potential of quinoa tolerance to increasing drought and temperature. Quinoa plants were subjected to three irrigation and two temperature regimes. At low temperature, the day/night climate chamber temperature was maintained at 18/8 °C and 25/20 °C for high temperature throughout the treatment period. The irrigation treatments were full irrigation (FI), deficit irrigation (DI) and alternate root‐zone drying (ARD). FI plants were irrigated daily to the level of the pot's water‐holding capacity. In DI and ARD, 70 % water of FI was applied either to the whole pot or to one side of the pot alternating, respectively. The results indicated that plant height and shoot dry weight significantly decreased by ARD and DI compared to FI treatment both at low and at high temperatures. However, plants in ARD treatment showed significantly higher plant height and shoot dry weight compared to DI especially at higher temperature, which is linked to increased xylem ion content. Higher quinoa plant growth in ARD was associated with increase in water‐use efficiency (WUE_i) due to higher abscisic acid concentration and higher nutrient contents compared to DI. From results, it can be concluded that quinoa plant growth is favoured by high temperature (25/20 °C) and ARD is an effective irrigation strategy to increase WUE in drought prone areas.     

Mortality of eggs and third instar larvae of Anastrepha ludens and A. obliqua with insecticidal controlled atmospheres at high temperatures

The in vitro mortality of eggs and third instar larvae of Anastrepha ludens and A. obliqua was determined after exposure to 21 treatments of air or controlled atmospheres (CA) at high temperatures and 50% RH. Air at 44°C for 160 min caused very low mortality, which increased significantly by CA. Higher temperatures caused a more rapid kill. One hundred percent mortality was achieved for third instar larvae of both species in air or CA at 48°C for 220 min. A 100% mortality of eggs of A. ludens was achieved in air at 51°C for 240 min or in CA at 52°C for 240 min, and 100% mortality of eggs of A. obliqua was achieved in air or in CA at 55°C for 240 min. A. obliqua was slightly more tolerant than A. ludens, and eggs were more tolerant than third instar larvae in both species. CA had a synergistic effect at <50°C, but was slightly less effective than air at higher temperatures. Low O₂ concentrations were more effective than high CO₂ levels. The mean estimated temperatures for 50, 99 and 99.9968% mortality (LT₅₀s, LT₉₉s, LT_99.9968s) of eggs of A. obliqua (the most tolerant) exposed to 0 kPa O₂+50 kPa CO₂ for 240 min were 49.4, 54.8 and 60.9°C, respectively. We conclude that dry hot air at ≥44°C and 50% RH in CA (0 kPa O₂+50 kPa CO₂), for 160 min or longer, is effective in increasing mortality of eggs and third instar larvae of A. ludens and A. obliqua.     

新疆伊犁河谷藜麦产业发展的SWOT分析

藜麦作为早期从南美引进的特色杂粮作物,近几年已在我国18个省（区）推广应用,有望发展成为一特色的新兴产业。采用SWOT分析法对新疆伊犁河谷藜麦产业发展的优势、劣势、机会和威胁进行分析,以充分掌握和了解其产业现状、存在问题及发展方向,为今后伊犁河谷藜麦产业发展提供理论依据。结果表明,伊犁河谷藜麦产业发展的优势大于劣势,既有机遇,也有挑战：可利用藜麦耐旱、耐盐碱、耐寒等特性以及可作为粮饲兼用作物,扩大种植规模;坚持以市场为中心,制定相应的政策,加大财政投入,积极引导农民合理种植。通过发挥产品开发和“互联网+农业”等产业优势,拓市场、引人才、建基地、强科技、抓产业,必能实现伊犁河谷藜麦产业可持续发展,进而促进产业结构调整、推动精准扶贫、乡村振兴及生态环境保护。     

H2O2对吸胀冷害下花生种子萌发的影响

为探明H₂O₂浸种对吸胀冷害下花生种子萌发和生理代谢的影响,选择豫花9326和豫花37为材料,用50mmol/L H₂O₂进行低温（5℃）浸种,以灭菌水低温浸种为对照,进行发芽试验。结果表明,与对照相比,处理后豫花9326的发芽势、发芽率和发芽指数分别提高了31.25%、18.52%、50.53%,豫花37分别提高了14.58%、3.64%、36.13%,种子电导率分别显著降低了47.67%和23.67%,其中豫花9326发芽相关指标增长比例高于豫花37。与对照相比,用H₂O₂处理的豫花9326在萌发的第0、4、6天丙二醛含量分别降低了0.22%、7.05%和32.55%,可溶性糖含量分别显著提高了48.27%、53.42%和52.29%,可溶性蛋白含量分别显著增加了59.66%、13.04%和43.76%,脱落酸（ABA）含量呈先降低后升高的变化趋势,赤霉素（GA）含量和GA/ABA比值均呈显著增长的趋势。H₂O₂浸种可能是通过维持种子细胞膜的完整性、增加可溶性物质含量以及调控内源激素含量,来提高花生种子对吸胀冷害的抗性,从而提高发芽率、发芽势和发芽指数。本研究可为花生萌芽期耐寒性的调控技术提供方法和理论依据。     

藜麦活性成分研究进展

藜麦是苋科藜属一年生双子叶植物,作为一种营养价值突出的功能性健康食品,不仅富含多酚、黄酮、皂苷、多糖、多肽、蜕皮激素等活性成分,还含有丰富的维生素、必需氨基酸、矿物质(K、P、Mg、Ca、Zn、Fe)等营养物质,具有均衡补充营养、增强机体功能、抗氧化、降血糖、降血脂、抗炎、提高免疫、防治心血管疾病以及抗菌抗溃疡等生理活性,尤其适于高血糖、高血压、高血脂、心脏病等慢性病人群及婴幼儿、孕产妇、儿童、学生、老年人等人群食用。藜麦因其全面的营养价值和食用功能特性,且优于大多数谷物,成为适宜人类食用的全营养食品。本文综述藜麦的活性成分及其生理功能作用,并展望其在食品工业中的发展前景,旨在对藜麦产业、食品保健和医药研发等领域提供重要的参考价值。