麦草碱木质素基环氧树脂的合成

以麦草碱木质素为原料,在碱性条件下,与环氧氯丙烷发生反应,生成木质素基环氧树脂,采用红外光谱对其结构进行定性分析,通过盐酸—丙酮测定环氧当量对其进行定量分析。考察了环氧氯丙烷的量,氢氧化钠的用量,反应温度和反应时间对环氧当量值的影响。单因素试验结果得出合成环氧树脂的条件为:环氧氯丙烷与碱木质素的质量比为12∶1,每克木质素用氢氧化钠(质量分数20%)5mL,反应温度80℃,反应时间3h。此时环氧值最大,为0.3623。     

In vitro protein digestibility of different grow‐out stages of spotted rose snapper (Lutjanus guttatus,Steindachner, 1869)

The aim of this study was to compare in vitro protein digestibility between two groups of fish, at early (21 g) and late stages (400 g) of spotted rose snapper Lutjanus guttatus, to evaluate the degree of hydrolysis (DH) and total amino acid release (TAAR) using crude extracts from stomach, pyloric caeca and intestine of 13 protein ingredients including marine, animal and plant meals. Degree of hydrolysis and TAAR were measured by a pH‐Stat method, and the PAGE‐Zymogram was also used as complementary technique. Differences in DH were found between both grow‐out stages mainly in the alkaline hydrolysis phase. Fish and squid meals (marine sources) had the highest DH and TAAR, followed by porcine meat and poultry meal by‐products from recycling sources, and soybean and canola meals (plant sources), which represent better protein sources for use in practical diets. Stomach zymograms showed two pepsin isoforms in both grow‐out stages. Pyloric caeca and intestine zymograms showed five bands with proteolytic activity in the early grow‐out stage, whereas four additional bands were found in late grow‐out stage. Alkaline proteases were identified as serine and metalloproteases. Thus, L. guttatus presents an ontogenetically differentiated digestive enzyme pattern that modifies the DH and TAAR of different protein sources.     

Wound‐healing potential of curcumin in the carp,Labeo rohita

In this investigation, the effect of dietary administration of curcumin on the healing of skin wound in fish, Labeo rohita, has been reported. Fish were divided into three groups: control group (fish without skin wound), sham group (fish with skin wound without curcumin treatment) and curcumin‐treated group (fish with skin wound and subjected to dietary administration of 1% curcumin). Experiments were conducted for 30 days to assess the healing of skin wounds at different time intervals using scanning electron microscopy, histology, and mucopolysaccharide and enzyme histochemistry. In the curcumin‐treated group, healing of skin wounds was found to be enhanced than in the sham group as indicated by early restoration of morphology of the surface layer of epithelial cells; the density of the mucous goblet cells; the density of club cells in epidermal layer; and early granular tissue formation, collagen deposition and tissue remodelling in dermal layer. Furthermore, peroxidase and catalase enzyme activity showed increased endogenous defence system in the curcumin‐treated group compared with the sham group. It could be concluded that dietary administration of curcumin is beneficial in rapid healing of skin wounds in fish. Early healing of wounds could be considered to prevent the invasion of pathogens and to maintain the integrity of the surrounding tissue.     

软化病感染家蚕的碱性磷酸酶活力测定及病理学研究

为了研究感染软化病的家蚕碱性磷酸(ALKP)的活力并研究酶组织病理学,通过ALKP活力测定证实感染黑胸败血病的软化病家蚕ALKP,活力变化的规律与正常家蚕相似而单位更低．石蜡切片显示感病家蚕丝腺组织内充满丝胶类物质,家蚕吐丝结茧受阻．用冰冻切片法以ALKP反应底物对病蚕的丝腺组织进行活性测定,显示出感病家蚕的丝腺内外膜均呈现较强的酶反应,暗示了膜上活跃的磷酸转运系统．而脂肪体内的某些部位也呈现出点状深着色,证明脂肪体内含有ALKP,合成组织．     

Hydrolysis of triasulfuron,metsulfuron‐methyl and chlorsulfuron in alkaline soil and aqueous solutions

The hydrolysis of triasulfuron, metsulfuron‐methyl and chlorsulfuron in aqueous buffer solutions and in soil suspensions at pH values ranging from 5.2 to 11.2 was investigated. Hydrolysis of all three compounds in both aqueous buffer and soil suspensions was highly pH‐sensitive. The rate of hydrolysis was much faster in the acidic pH range (5.2–6.2) than under neutral and moderately alkaline conditions (8.2–9.4), but it increased rapidly as the pH exceeded 10.2. All three compounds degraded faster at pH 5.2 than at pH 11.2. Hydrolysis rates of all three compounds could be described well with pseudo‐first‐order kinetics. There were no significant differences (P = 0.05) in the rate constants (k, day⁻¹) of the three compounds in soil suspensions from those in buffer solutions within the pH ranges studied. A functional relationship based on the propensity of nonionic and anionic species of the herbicides to hydrolyse was used to describe the dependence of the ‘rate constant’ on pH. The hydrolysis involving attack by neutral water was at least 100‐fold faster when the sulfonylurea herbicides were undissociated (acidic conditions) than when they were present as the anion at near neutral pH. In aqueous buffer solution at pH > 11, a prominent degradation pathway involved O‐demethylation of metsulfuron‐methyl to yield a highly polar degradate, and hydrolytic opening of the triazine ring. It is concluded that these herbicides are not likely to degrade substantially through hydrolysis in most agricultural alkaline soils. © 2000 Society of Chemical Industry     

巯基坡缕石-硫酸锰复配对碱性土壤镉污染钝化阻控效应

为探讨巯基坡缕石（MPAL）和硫酸锰（MnSO₄）复配处理对碱性土壤镉（Cd）污染钝化阻控效应,以河南省Cd污染小麦土作为供试土壤,进行了土壤单施MPAL、单施MnSO₄及MPAL和MnSO₄复配施用的为期30 d的土壤老化培养实验。结果表明：土壤孔隙水中Mn含量主要受外源MnSO₄添加剂量的影响,受MPAL添加量影响较小。随着外源MnSO₄添加剂量的增加,土壤DTPA-Mn含量显著升高,但DTPA-Cd含量与空白对照（不添加MPAL和MnSO₄）间并无显著差异。MnSO₄和MPAL复配施用对碱性土壤Cd的钝化效果优于单施MPAL和单施MnSO₄处理,其中,MPAL和MnSO₄复配处理、单施MnSO₄及单施MPAL处理对土壤Cd的最大钝化率分别为57.7%、19.2%和41.8%。在所有复配处理中,添加0.025% MnSO₄对MPAL钝化Cd无显著影响或存在一定的活化作用,而添加0.1%~0.2% MnSO₄对MPAL钝化Cd具有促进作用,在较高剂量MnSO₄对MPAL钝化Cd呈促进作用的情况下,MnSO₄对0.01% MPAL作用最大,随着MPAL添加剂量的增加,这种促进效应逐渐降低。研究表明,MPAL与MnSO₄合适剂量复配处理可以高效固定土壤Cd,是适用于修复碱性农田Cd污染土壤的良好方法。     

尿素与多效唑配施对苯磺隆胁迫下土壤酶活性的影响

通过盆栽试验,采用三因素完全随机设计,研究尿素、多效唑配施对苯磺隆胁迫下土壤脲酶、碱性磷酸酶、蛋白酶活性的影响。结果表明:不同浓度苯磺隆对土壤脲酶活性表现为抑制—激活作用,抑制和激活作用均随着苯磺隆浓度的增大而增强,第60 d激活率是对照的2.83倍;低浓度苯磺隆对碱性磷酸酶表现为激活—抑制—激活作用,高浓度苯磺隆表现为抑制—激活作用,第60 d极显著地高于对照,是对照的2.49倍;低浓度苯磺隆对蛋白酶活性表现为激活—抑制作用,高浓度苯磺隆表现为抑制—激活作用;尿素、多效唑(除B1N1处理对蛋白酶的影响外)配施可减弱苯磺隆对土壤脲酶、碱性磷酸酶和蛋白酶活性的抑制作用,大多数处理表现为抑制—激活作用,在处理结束时(第60 d),脲酶和碱性磷酸酶仍极显著地高于对照。     

重新被“激活”的土壤无机碳研究

荒漠区植被稀疏、土壤有机碳含量低,在全球碳循环研究中,一直被忽略。但2006年前后,若干研究显示干旱荒漠区具有潜在的碳汇功能,一直被认为是死碳的土壤无机碳开始受到关注,长期被忽视的干旱荒漠区无机碳碳循环重新进入人们的视野。后续的研究显示,土壤中的溶解性无机碳并非来自土壤本身的碳酸盐,而是来自土壤空气或大气,是现代碳循环的一个重要环节。土壤温度的变化改变了CO2在土壤溶液中的溶解度,催生出一个日出夜进的"无机呼吸"过程。这个"无机呼吸"过程在广义干旱、盐碱土区普遍存在;在土壤生物过程微弱的荒漠区,可以主导地-气界面的碳交换。盐碱土改良过程中溶解性无机碳的淋洗,更可以直接形成储存于地下咸水层的无机碳汇。总之,在生命过程微弱的干旱荒漠区,无机碳过程可以主导地-气界面碳交换与碳汇的形成:尽管这里起关键作用的不是土壤碳酸盐,而是土壤中的溶解性无机碳。     

不同混凝剂强化混凝处理富磷废水实验研究

对富磷污水进行混凝除磷研究,以出水总磷为评价指标,对硫酸铝、氯化铝、硫酸铁、碱式硫酸铁混凝剂进行比较实验。实验表明新型碱式硫酸铁为适合处理富磷污水的混凝剂,且碱式硫酸铁用于处理富磷污水时,去除等量总磷所消耗的药剂更少,利用率更高。     

碱性肥料调节香蕉园土壤酸度及防控香蕉枯萎病的效果

【目的】我国香蕉主产区蕉园土壤酸化严重、 香蕉营养失衡、 巴拿马病（枯萎病）严重泛滥和肆虐,造成香蕉严重减产甚至绝收。中性碱性土壤条件可有效抑制引发巴拿马病（枯萎病）细菌（Fusarium oxysporum f. sp. Cubense）的感染。本研究在长期从事香蕉营养与施肥研究的基础上,研制了碱性肥料,并在海南乐东（香蕉枯萎病重灾区）进行了3年碱性肥料田间试验,研究碱性肥料以及其他肥料与其混合使用在改良蕉园土壤酸性的同时,防控香蕉枯萎病及其营养效果。以期通过施用碱性肥料改善我国蕉园土壤状况,降低枯萎病的发生,促进香蕉增产。【方法】试验采用5因素完全方案,分别为碱性肥料（AF）+长效肥料（CRF）+速效肥料（CCF）、 AF+CRF、 AF+CCF、 CRF+CCF、 CCF 5个处理,每个处理的氮、 磷、 钾总量相等,香蕉整个生育期内施氮（N）、 磷（P2O5）、 钾（K2O）分别为200、 80、 400 g/plant,每个处理重复3次,随机排列。在每次施肥后15~20 d采集表层15 cm的土壤并测定土壤pH值。分别在香蕉孕蕾期、 抽蕾期、 果实膨大期、 收获期调查枯萎病发病率、 病情指数。【结果】土壤pH值分别和香蕉枯萎病发病率、 病情指数间呈极显著的负相关,即土壤酸性越强,香蕉枯萎病越严重;黄叶率和香蕉枯萎病发病率、 病情指数间呈显著或极显著的正相关,说明香蕉枯萎病发病率和病情指数越高,香蕉黄叶数越多,绿叶数越少。通过4次施肥,碱性肥料在香蕉生长期供应适量足量氮、 磷、 钾养分的同时,还能有效地提高土壤pH值,使土壤pH值维持在7.0~7.4之间,并且能有效降低香蕉黄叶率、 发病率和病情指数,对防控香蕉枯萎病有显著效果。从香蕉孕蕾期开始,枯萎病呈现加重趋势,到收获期时香蕉发病最严重,但在这期间碱性肥料能明显降低香蕉枯萎病的发病率。香蕉收获期,常规肥料处理的枯萎病发病率在62%以上,而碱性肥料处理的发病率降低到了18%以下;并且碱性肥料能明显减轻发病香蕉病情,常规对照处理香蕉病情指数达到了21%,而碱性肥料处理的只有5%。香蕉黄叶率从营养期开始逐渐增大,碱性肥料处理香蕉黄叶率显著低于常规对照处理的黄叶率。碱性肥料处理的香蕉经济收获率由对照的56%增加到了72%,每公顷增产13267 kg,单株增产3.43 kg。【结论】碱性肥料增产的原因在于一方面提高了土壤pH值而降低了香蕉枯萎病发病率及其病情指数,减少了香蕉的黄叶数量,使香蕉有较多的绿叶进行光合作用而高产;另一方面香蕉生长期土壤处于中性偏碱环境能有效地抑制尖孢镰刀菌的萌发和致病,而有利于其他有益微生物的生长,从而为香蕉健康生长营造良好的土壤环境。由此可见,应用碱性肥料不仅是改良蕉园土壤酸性、 均衡土壤养分、 平衡香蕉营养的施肥技术,而且是防控香蕉枯萎病的有效措施。