应用热释光剂量测定法检测农作物活体叶片~(14)C同化物输出的研究

在~(14)CO_2饲喂植物叶片后,以CaSO_4(Dy)-TEFLON热释光片,贴于饲喂叶片上检测0.5至1小时,用圆产FJ-377热释光剂量仪(北京核仪器厂)读取TL值(热释光读数值),说明热释光片对~(14)C释放的β能量具有一定响应性。使用FJ-377热释光剂量仪时,热释光片以φ5.5×0.4mm的检测效果优于φ8.0×0.5mm。热释光剂量测定法(TLD)的检测与液闪法测定比较,两者结果一致,TL值与dpm/cm_2呈极显著相关(r=0.94,P<0.01)。取大豆、葡萄为材料,经多次连续检测TL值,观察TL值下降(或递增)百分率以估计~(14)C同化物的输出与输入情况。实践证明,应用TLD较液闪法简便、快速,适于在田间活体植株上多点测试。     

Acute phase proteins in cattle after exposure to complex stress

Stressors such as weaning, mixing and transportation have been shown to lead to increased blood concentrations of acute phase proteins (APP), including serum amyloid A (SAA) and haptoglobin, in calves. This study was therefore undertaken to assess whether SAA and haptoglobin levels in blood mirror stress in adult cattle. Six clinically healthy Holstein cows and two Holstein heifers were transported for four to six hours to a research facility, where each animal was housed in solitary tie stalls. Blood samples for evaluation of leukocyte counts and serum SAA and haptoglobin concentrations were obtained before (0-sample) and at 8, 24 and 48 hours after the start of transportation. Upon arrival the animals gave the impression of being anxious, and they appeared to have difficulty coping with isolation and with being tied on the slippery floors of the research stable. Serum concentrations of SAA and haptoglobin increased significantly in response to the stressors (P < 0.01 and 0.05 at 48 hours, respectively). Additionally, the animals had transient neutrophilia at 8 and 24 hours (P < 0.05). In conclusion, the results of the study suggest that SAA and haptoglobin may serve as markers of stress in adult cattle.     

Transport stress in matrinxã, Brycon cephalus (Teleostei: Characidae), at different densities

Matrinxã, Brycon cephalus, is a nativeteleost fish from the Amazon Basin, and is of economic importance forcultivation for food and sport in Brazil. Mortality losses due to handling andtransport of this stenohaline freshwater species are common. The effects oftransportation at different densities on the biochemical stress responses ofmatrinxã (mean weight 1 kg) were examined. Fish weresubjected to three different transport densities (100, 200, and 300 kgm^–3) for four h in water with added salt (0.6%). Thefish were bled at departure (baseline level), arrival (immediately aftertransportation) and at 24 and 96 h after arrival (recoveryperiod).Blood glucose, cortisol, sodium, chloride, potassium and ammonia were used asstress bioindicators. No mortality was observed and no alterations in plasmacortisol were registered. However, blood glucose and ammonia levels increasedand serum sodium and plasma chloride decreased on arrival for the fishtransported at the highest densities. These stress responses were transient andthe concentrations returned to baseline levels within 24 h. Thisstudy showed that matrinxã can be transported at densities as high asthose tested in the present study, at least under the conditions employed inthis study. A recovery period of at least 24 h is stronglyrecommended.     

水稻抽穗期喷施6—BA,ABA对旗叶衰老及同化物运输的影响

探讨了水稻抽穗期喷施6－BA、ABA对旗叶衰老及同化物运输的影响。结果表明：水稻抽穗期喷施6－BA，能延缓旗叶叶片衰老，提高旗叶光合速率及同化物输出能力。抽穗期喷施ABA，对旗叶光合速率、叶面积及叶绿素含量影响不大，主要是增加旗叶鞘糖含量，促进同化物运输。     

冻马哈鱼片/段加工工艺的研究

冷冻马哈鱼片/段,原料从国外进口,加工成品后再销往美国、欧盟、俄罗斯等地区.原料一般有去头去脏,或者带头去脏2种.对于一直从事淡水鱼片(鮰鱼片)加工的企业来说,其积累了丰富的经验,来料加工的这种模式在生产设备的需求和工艺上和其他鱼片加工区别不大,除了在原料的供应和产品质量控制的关注点不同外,利用公司运行的体系,可以将产品的质量控制在最佳范围之内.但在加工过程中,从原料验收到成品形成全过程都可能受到不同程度的污染,因此在加工过程中应严格按照相关操作规范进行生产加工,确保产品质量.     

Comparison of the influences of vegetation stem parameters on hydraulic variables and sediment transport capacity

The hydraulic variables (Hv) and sediment transport capacity (Tc) of overland flow have changed immensely due to large-scale revegetation. However, research comparing the influences of stem parameters (diameter, cover, and arrangement) on Hv and Tc is limited. The objectives of this study were to explore and compare the influences of stem parameters on Hv and Tc. Data on three treatment groups with varying stem diameters, covers, arrangements, flow discharges and slopes were collected in this study. With increasing stem diameter, Hv and Tc increased; Hv included the Reynolds and Froude numbers, flow velocity (v), shear stress (τ), stream power (Ω), and unit stream power (ω). However, the trend of the Darcy-Weisbach friction coefficient (f) was opposite. Hv and Tc were significantly influenced by stem diameter and cover. The effect of stem diameter on Hv and Tc was greater than the effects of cover and arrangement. Stem cover as a variable could not be used to adequately estimate the Tc when there were various stem diameters. A new exponential equation involving stem cover and stem diameter was demonstrated to be an appropriate predictor of Tc. Stem diameter and arrangement had no obvious influence on the relationship between Tc and v, and v as an indicator could explain the effect of stem parameters on Hv and Tc. This result could illustrate why the variables, including v, were able to predict Tc under vegetation stem and litter cover.     

Reduction of energy usage during storage and transport of bananas by management of exogenous ethylene levels

Unripe Australian-grown Cavendish and Lady Finger bananas were stored at 15, 20 and 25 °C in an atmosphere containing 0.001, 0.01, 0.1 and 1.0 μL/L ethylene in air and the green life was determined as the time to reach the respiratory climacteric. As expected, green life increased as the temperature and ethylene concentration decreased. The equation describing the relationship between temperature, ethylene concentration and green life of Cavendish bananas was applied to a five-day 3000 km road transport route from the major tropical production area to the major urban markets. It predicted that bananas transported in the prevailing mean summer temperature of 25 °C would not require refrigeration if the ethylene level did not exceed 0.58 μL/L while transport at the mean winter temperature of 14 °C fruit could withstand a level of about 0.90 μL/L without ripening en route. The equation was also applied to a shipment protocol of 19 days for bananas exported from Central America to southern Europe. This predicted that fruit could be transported without refrigeration if ethylene levels were maintained at 0.04 μL/L during the winter temperature of 17 °C and at 0.002 μL/L at the summer transport temperature of 24 °C. Since a range of technologies are available to maintain such low ethylene levels or reduce the action of ethylene, these findings suggest that the current refrigerated transport of bananas could be minimised or eliminated. The use of higher temperatures in the supply chain would reduce energy consumption with resultant environmental and economic benefits.     

植物对硒的吸收、转运及代谢机制研究进展

硒元素是人和动物必需的微量元素之一，人体缺硒会引发诸多疾病甚至导致死亡。我国是缺硒大国，全国有2/3的人口处于缺硒地区。目前，食物补硒是提高人体摄硒量的最佳途径，同时也决定着食物链中硒的水平。本文从环境角度介绍了植物对土壤中不同硒元素的吸收利用途径，综述了硒在植物体内的转运和代谢机制，为开发富硒农产品提供参考。