Seasonal critical concentration and relationships of leaf phosphorus and potassium status with biomass and yield traits of soybean

Analysis of uppermost fully expanded leaves is useful to detect a deficiency of mineral nutrients such as phosphorus (P) and potassium (K) in soybean. Although, the leaf P or K status aids in fertilizer management, information on nutrient seasonal relationships with growth and yield traits at maturity are limited. To investigate this, soybean was grown under varying P or K nutrition under ambient and elevated CO₂ concentrations. Results show significant relationships of the relative total biomass and yield‐related traits with the foliar P and K concentrations measured several times in the season across CO₂ levels. However, the relationships established earlier in the season showed that the growth period between 25 and 37 d after planting (DAP), representing the beginning of flowering and pod, respectively, is the best for leaf sampling to determine the foliar P or K status. The leaf P and K status as well as the critical leaf P (CLPC) and K (CLKC) concentrations for traits such as seed yield peaked around 30 DAP (R2 stage) and tended to decline thereafter with the plant age. The CLPC and CLKC of seed yield indicate that the leaf P and K concentration of at least 2.74 mg g^?1 and 19.06 mg g^?1, respectively, in the uppermost fully expanded leaves are needed between 25 and 37 DAP for near‐optimum soybean yield. Moreover, the greatest impact of P and K deficiency occurred for the traits that contribute the most to the soybean yield (e.g., relative total biomass, seed yield, pod and seed numbers), while traits such as seed number per pod, seed size, and shelling percentages were the least affected and showed smaller leaf critical concentration. The CLPC or CLKC for biomass and seed yield was greater under elevated CO₂ 24–25 DAP but varied thereafter. These results are useful to researchers and farmers to understand the dynamics of the relationship of pre‐harvest leaf P and K status with soybean productivity at maturity, and in the determination of suitable growth stage to collect leaf samples.     

基于悬空压裂法的油菜角果抗裂角力测试试验

为寻求出油菜角果不易炸裂的优良品种,在分析已有油菜角果抗裂角力测试方法优缺点的基础上,采用悬空压裂法在WDW-300型万能试验机上对不同品种油菜角果的抗裂角力进行了试验研究,分析油菜品种、角果大小、角果含水率、角果成熟度等因素对油菜角果抗裂角力的影响。结果表明:加载速度为10 mm/min时,载荷随位移的增加先迅速上升,在得到一个峰值力后瞬间下降,呈曲线变化状态,峰值即为角果的抗裂角力。试验测得了28个品种油菜角果抗裂角力范围为0.898～3.035 N,同一品种的油菜角果含水率越高,角果尺寸越小时抗裂角力越小。油菜角果大小差异明显时,同一品种角果尺寸大其抗裂角力大;品种相同含水率不同时,含水率大的角果抗裂角力大。该试验也为研究油菜角果抗裂角力提供了一种新的测定方法,操作简单、快捷。     

IDENTIFICATION OF GROUNDNUT (ARACHIS HYPOGAEA L.) CULTIVARS TOLERANT OF SOIL SALINITY

Field screening of 83 groundnut cultivars was undertaken for two seasons to assess their tolerance of salinity based on plant mortality and yield attributes. During the dry season, soil salinity of 4 dS m^?1 at sowing and 6–7 dS m^?1 21–98 days after sowing (DAS) caused high mortality without seed formation in any cultivars, however, at salinity 4.5 dS m^?1 during sowing and 3.5–3.0 dS m^?1 15–80 DAS during wet season, 61 cultivars produced seed. The cultivars ‘VRI 3’, ‘UF 70–103’, ‘TKG 19A’, ‘S 206’, ‘Tirupati 4’, ‘M 522’, ‘Punjab 1’, ‘BG 3’, ‘Somnath’ and ‘ICGV 86590’, with high plant stand during both the seasons and over 75 g m^?2 seed yield during wet season, were identified salinity tolerant. However, 15 cultivars with more than 50 g m^?2 seed yield were moderately tolerant and 28 cultivars with less than 25 g m^?2 seed yield were sensitive to salinity.     

谷子黄叶色突变体光合特性研究

为解析谷子黄叶色突变体高光合特性机理,以野生型豫谷1号为对照,分析了谷子全生育期黄叶色突变体ylm-1和ylm-2的光合色素、光合速率、气孔特性、荧光参数、光合关键酶活性和产量性状。结果表明,突变体光合色素含量为野生型豫谷1号的50%~60%,强光下突变体光合速率(Pn)较野生型显著提高,且无明显的“午休睡眠现象”;ylm-1和ylm-2气孔导度(Gs)显著增加。荧光参数结果显示,与野生型相比,突变体的光能利用效率和转化效率明显增加,光合关键酶1,5二磷酸核酮糖羧化酶(Rubisco)活性明显降低,而ylm-1和ylm-2磷酸烯醇式丙酮酸羧化酶(PEPCase)和苹果酸酶(NADP-ME)活性分别增加了23.3%、24.4%和12.9%、15.5%。产量相关性状分析表明,突变体单穗质量、穗粒质量及千粒质量较野生型显著增加。本研究结果为谷子高光效及分子标记辅助选择育种提供了重要的理论依据。     

采前高浓度赤霉素处理对贵妃芒果色泽发育的抑制效应

以10年生贵妃芒果树为实验材料,研究不同浓度（0、0.5g/L、1.0g/L、2.0g/L、3.0g/L）赤霉素（GA3）处理果树对采后芒果果实色泽变化的影响。于果树的盛花期、幼果期和果实膨大期三次进行GA3喷洒处理。结果表明：与对照组相比,不同浓度的赤霉素处理对果皮色度a*值均具有明显影响,浓度越高,抑制a*值增大的效果越显著;赤霉素处理可以显著抑制果皮叶绿素(Chl)的降解,降低类胡萝卜素及花青素的合成;高浓度赤霉素对叶绿素酶（Chlase）、查尔酮异构酶(CHI)活性增加、5-氨基乙酰脱氢酶(ALAD)活性的降低具有明显的抑制效果。综上表明：采前GA3处理可以抑制采后贵妃芒果果皮色泽的转变, 浓度越高对果皮转色的抑制效果越显著。     

不同施磷量对油菜新品种产量的影响

通过田间试验,研究磷肥与油菜产量、品质和植株形态之间的关系,确定油菜高产、优质、高效的磷肥施用量。不同油菜品种磷肥用量试验的结果表明:①每公顷施纯磷360kg的处理,中双9号,每公顷产量达3301.65kg,中油杂2号,产量达到最大值,每公顷产量3781.95kg。②一次分枝对产量影响最大,二次分枝、主花序的贡献相对要小得多。③随着施磷量的增加单位面积有效角果数呈增长的趋势。     

大荚型抗锈菜豆新品种选育

利用极早熟品种春丰四号和抗锈病品种鉴 - 7配制并选育而成的菜豆新品系 5 - 4 - 2 - 4、6 - 1- 8- 1、6 - 1- 2 - 1,株高 30 0 cm,第一花节位 3～ 5节 ,荚形扁圆 ,荚长 2 2～2 5 cm,最长荚可达 30 cm。中早熟类型 ,优质 ,抗锈病。该品系在天津地区种植适应性很强 ,可以春秋双季栽培     

Quality characteristics in raw and smoked fillets of Atlantic salmon, Salmo salar, fed high-energy diets

Atlantic salmon, Salmo salar , were fed four levels of dietary fat (256, 308, 346 and 389 g kg⁻¹ of diet) for 138 days, with the purpose of studying quality characteristics in raw and smoked fish fillets. Dietary fat levels up to 346 g kg⁻¹ resulted in increased fat content of the raw fillets. The dietary fat levels had a less systematic effect on perceived fatness of the smoked fillets and caused a trend towards better odour and flavour. The fat content of raw fillets was significantly ( P ≤ 0.05) correlated to lower smoke odour, greater rancid flavour, fatness, and a yellower hue of the smoked fillets. Astaxanthin levels of the raw fillets varied between 6 and 11 mg kg⁻¹ of fillet and were significantly ( P ≤ 0.05) correlated with greater intensity of smoke odour, lower off-odour, and less whiteness, greater colour intensity and a redder hue of the smoked fish. It is proposed that salmon fillets can be graded according to weight, fat content and colour values prior to smoking to obtain more standardized quality characteristics of the final product after processing.     

马氏珠母贝两个不同地理种群的形态性状

在“珍珠贝育种规划（Pearl Oyster Breeding scheme,POBs）”中,马氏珠母贝的两个地理种群——印度养殖种群和三亚野生种群正在作为两个基础群（Basic population）建立专门化品系,通过杂交获得杂种优势,构建杂交配套系以培育优良品种。从形态上看,印度养殖种群体个体大,而三亚野生种群体个体小;三亚野生种群的壳宽系数为0．18,大于印度养殖种群的0．15,三亚野生种群的贝体外形较凸,而印度养殖种群的贝体外形扁平。三亚野生种群的壳重指数（25．30）大于印度养殖群体（18．80）。通过成像色度检测分析系统分析,每个种群都有自己的颜色特征值——三刺激值和颜色参数;比较两个种群颜色参数Lab时表明,三亚野生种群贝壳珍珠质颜色的明度（L）大于印度养殖种群,色品比印度养殖种群更偏向绿色（-a）和黄色（b）,印度养殖种群色品偏向蓝色和红色。两个种群间贝壳珍珠质的色差（△XEab）为10．69,属于大色差,感觉强烈。