杜鹃花介质干燥技术研究

[目的]研究介质法对杜鹃花干燥的效果。[方法]用介质食盐和河沙对杜鹃花进行包埋干燥处理,同时探讨了不同浓度蔗糖液及浸泡时间对杜鹃花干燥的影响,测定各处理杜鹃花失水率、重量变化、感观分值等品质指标,以确定杜鹃花干花的制作方法。[结果]从河沙、食盐包埋干燥处理杜鹃花鲜重变化及感观评分来看,8 h为最佳烘烤时间,且河沙包埋效果优于食盐包埋。从不同浓度蔗糖液浸泡干燥处理后的杜鹃花失水率及感观评分来看,1.0%蔗糖液浸泡12 h效果最好。[结论]1.0%蔗糖液浸泡12 h后河沙包埋烘烤8 h得到的杜鹃干花观赏效果最好。     

脱水速率和灌浆速率对玉米收获期子粒含水量的影响

以黑龙江省极早熟和早熟玉米种植区域两对收获期含水量差异显著的玉米主栽品种及其亲本自交系为试材,极早熟玉米种植区域品种为德美亚2号和克玉17,早熟玉米种植区域品种为德美亚3号和哲单37,对比调查子粒含水量动态变化、灌浆速率、生理成熟前后脱水速率等,分析与收获期子粒含水量的关系。结果表明,收获期含水量低的德美亚2号和德美亚3号,与同熟期含水量高的克玉17和哲单37相比,均提前3 d达到生理成熟期,此时期两对杂交种间子粒含水量均无显著差异,灌浆速率平均快0.12 g/d,灌浆时间缩短3 d,各自的母本自交系间呈现出同样的变化;生理成熟后德美亚2号和德美亚3号与克玉17和哲单37相比,随着子粒脱水速率的加快,子粒含水量差异逐渐增大,收获期差异达到极显著水平,父母本自交系间也具有同样的表现。玉米收获期子粒含水量与生理成熟后子粒脱水速率和子粒灌浆速率均呈极显著和显著负相关,相关系数分别为-0.767和-0.589。     

不同脱水剂对杂交水稻制种种子质量及基因表达的影响

种子脱水干燥是杂交水稻制种过程的一个重要环节,种子自然脱水速率慢,遇雨天还易引起成熟期推后和穗发芽等问题。利用脱水剂快速降低种子水分对种子安全生产有重要意义。本研究以Y两优689杂交水稻品种为材料,比较不同脱水剂对其制种种子脱水及种子质量的影响。11种脱水剂均能加快种子成熟后期脱水,7号和9号脱水剂喷施后5 d,种子水分分别下降4.6%和3.6%,且对种子千粒重、发芽和幼苗生长无不良影响,种子可溶性蛋白、可溶性糖、ABA和GA3含量则显著高于对照。种子室温贮藏6个月后,与对照相比,7号、8号和9号脱水剂处理对种子发芽和幼苗生长无显著影响,7号和9号脱水剂处理的种子可溶性蛋白含量、α-淀粉酶活性、ABA含量与对照无显著差异。7号比9号的脱水效果好,可作为Y两优689的脱水剂。种子贮藏前,7号、8号和9号脱水剂处理能提高种子中OsNECD1和OsNCED2基因的表达,降低OsGA2ox1的表达;而种子贮藏6个月后,OsNECD1和OsNCED2表达量下降,OsCYP707A5和OsGA2ox1表达量上升。这表明经过6个月贮藏,脱水剂处理对种子ABA合成相关基因和GA3分解相关基因表达的影响减弱,同时OsCYP707A5的高表达导致种子ABA含量减少,可能是种子贮藏后萌发力提高的主要原因。     

Gender Differences–Induced Changes in Serum Hematologic and Biochemical Variables in Mangalarga Marchador Horses After a Marcha Gait Competition

The aim of this study was to investigate whether marcha exercise results in changes in serum hematologic and biochemical variables and whether this condition differs in male and female horses. Thirty-five Mangalarga Marchador horses, 18 males and 17 females were included in the study. Blood samples were obtained before and immediately after a marcha competition. Samples were used for measurement of hematocrit (HCT), hemoglobin concentration (HGB), red blood cell (RBC), total and differential white blood cell (WBC), total protein (TP), albumin (Alb), aspartate aminotransferase (AST), gamma glutamyltransferase (GGT), creatine kinase (CK), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatinine (Crea), and urea (BUN) levels. Data were submitted to analysis of variance using the SAS statistical program, and means were compared by the Tukey test (P < .05). In both males and females, RBC, HCT, AST, and GGT activity increased in response to exercise, but there were no significant differences between genders. In females, significant increases in TP, BUN, Crea, CK, and LDH levels were detected after the marcha gait, but no such changes were detected in males. Total WBC concentrations increased in response to the exercise in both, males and females; however, there were no differences between genders. Plasma HGB, Alb, and ALP levels after marcha gait did not differ in both genders. Marcha exercise–induced significant hematologic and biochemical changes in serum of Mangalarga Marchador horses, independently of gender. However, females presented more blood changes after marcha gait. Gender differences should be taken into consideration in experiments with athletic horses.     

Designing resilient and sustainable grasslands for a drier future: Adaptive strategies,functional traits and biotic interactions

In many regions of the world, such as Southern Europe and most Mediterranean areas, the frequency and magnitude of droughts and heat waves are expected to increase under global warming and will challenge the sustainability of both native and sown grasslands. To analyze the adaptive strategies of species, genotypes and cultivars, we aim both (i) to understand the composition and functioning of natural grasslands and (ii) to propose ideotypes of cultivars and optimal composition for mixtures of species/genotypes under water deficit and high temperatures. This review presents a conceptual framework to analyze adaptive responses of perennial herbaceous species, starting from resistance to moderate drought with growth maintenance (dehydration avoidance and tolerance of lamina) to growth cessation and survival of plants under severe stress (dehydration avoidance and tolerance of meristems). The most discriminating functional traits vary according to these contrasting strategies because of a trade-off between resistance to moderate moisture deficit and survival of intense drought. Consequently it is crucial to measure the traits of interest in the right organs and as a function of soil water use, in order to avoid misleading interpretations of plant responses. Furthermore, collaboration between ecologists, eco-physiologists, and agronomists is required to study the combination of plant strategies in natural grasslands as only this will provide the necessary rules for species and cultivars or ecotypes assemblage. This ‘agro-ecological’ approach aims to identify and enhance functional complementarity and limit competition within the multi-specific or multi-genotypic material associated in mixtures since using plant biodiversity should contribute to improving grassland resistance and resilience.     

Breeding for adaptation to drought and heat in cowpea

Accomplishments in breeding for adaptation to drought and heat are reviewed based upon work with the indeterminate grain legume species cowpea. Plant traits and some crop management methods are examined that influence adaptation to rainfed production in the drought-prone, semiarid tropical Sahelian zone of Africa. Drought escape, drought resistance, delayed-leaf-senescence, and varietal intercrops are examined. In addition, adaptation to the heat that can detrimentally impact irrigated production in the hot, subtropical arid zone of California is evaluated. Heat tolerance during reproductive development, electrolyte leakage, membrane thermostability, some aspects of crop management including date of sowing, and chilling tolerance during emergence including the beneficial effects of a dehydrin protein are considered. Methods for breeding cowpeas with adaptation to drought and heat are described that have been effective.     

分子筛改性催化乳酸丁酯制备农药中间体丙烯酸酯的合成研究

[目的]在改性分子筛的作用下,研究了以乳酸丁酯为原料催化制备农药中间体丙烯酸酯的工艺。[方法]考察了K、Ca、La等金属离子改性的NaX、NaY、ZSM-6、ZSM-8等沸石分子筛对乳酸丁酯脱水制备丙烯酸酯的影响。[结果]K/ZSM-6改性分子筛对该脱水过程具有较高的选择性和转化率。最佳反应温度为380℃,空速为3h-1,甲醇与乳酸丁酯的摩尔比为2.0,转化率达到100%,丙烯酸及其酯的总选择性达到了64.3%。     

烫漂工艺对脱水菠菜品质影响的研究

本文主要对影响脱水菠菜成品的颜色及组织状态的烫漂工艺条件进行了试验研究，其研究结果表明，最佳条件是：烫漂液小苏打浓度是0．5％，烫漂温度为60℃，烫漂时间为1．5min。     

氧含量急剧变化对冷血脊椎动物氧化压力的影响

氧气对大多生物体至关重要,但是氧气能转变为活性氧从而对机体产生毒性。多种冷血脊椎动物可耐受自然条件下产生的氧化压力,如某些鱼、蛙、龟和蛇等。综述了缺氧/低氧耐受性动物在环境、代谢产生供氧不足时的应对方式。对比这些动物的应对方式后发现了某些抗氧化能力提高的规律。机体一般采用关键抗氧化酶的酶活增强、谷胱甘肽含量增多来抵御氧化压力。