Effects of pre‐ and post‐treatment with ethephon on gum formation of peach gummosis caused by Lasiodiplodia theobromae

Peach gummosis, caused by Botryosphaeria spp. fungi, is the process of gum accumulation and exudation in plants. Ethephon (2‐chloroethylphosphonic acid) has profound effects on plants, including enhanced production of secondary metabolites and regulation of plant diseases. This study investigates the effects of application of ethephon before and after inoculation with Lasiodiplodia theobromae on gum formation. Gum formation was promoted by ethephon treatment prior to pathogen inoculation, but inhibited by ethephon applied after the pathogen. The inhibitory effect was counteracted by 1‐methylcyclopropane, which is an ethylene signal inhibitor. 1‐methylcyclopropane also promoted gum formation. Exposure of three isolates of Botryosphaeria to ethephon inhibited mycelial growth. Both treatment methods increased the sugar content at 12 and 24 h post‐inoculation (hpi). However, the sucrose, glucose and fructose contents were significantly higher in shoots with ethephon post‐treatment (application of ethephon after the pathogen inoculation) than those in shoots with ethephon pre‐treatment (application of ethephon prior to pathogen inoculation) at 48 and 72 hpi. The expression of two putative senescence‐related genes, SEN2 and SEN4, were significantly enhanced in pre‐ and post‐treated shoots with ethephon at 24, 48 and 72 hpi. Ethephon application also up‐regulated expression of the pathogenesis‐related protein PR4 while down‐regulating PR1a and PR10. The results show that ethephon has a dual function in regulating gum formation by affecting both the peach shoots and the pathogen.     

桃胶枸杞新型营养果冻的研制

[目的]调配研制出适合高血脂人群食用的桃胶枸杞新型营养果冻。[方法]以桃胶和枸杞为主要原料,采用单因素和正交试验优化制作桃胶枸杞营养果冻的最佳配方条件。[结果]试验得出,对果冻口感影响最大的是吉利丁粉的添加量,其次是柠檬酸钠的添加量,混合汁的添加量和白砂糖的添加量影响较小。在试验范围内,最佳配方为吉利丁粉4%,混合汁(桃胶汁∶枸杞汁=1∶2)30%,白砂糖3%,柠檬酸钠0.15%。[结论]研制出的桃胶枸杞果冻颜色橙红,风味独特,营养丰富,可给高血脂人群提供更多饮食选择,市场前景广阔。     

高酰基结冷胶发酵生产工艺优化研究

通过单因素及正交试验对高酰基结冷胶的摇瓶发酵培养基进行了优化,得到了高酰基结冷胶生产工艺中的最佳发酵培养基配方。结果表明:优化后的高酰基结冷胶发酵配方为:蔗糖2.75%,鱼蛋白胨0.25%,KH2PO40.10%,CaCO30.12%。50 L罐发酵试验结果表明,发酵液粘度为20 000 cp,纯胶收率达1.55%以上。该结果可为提高高酰基结冷胶的产胶率提供参考。     

粒粒黄桃汁饮料果粒悬浮性的研究

以黄桃作为饮料的主要原料,通过单因素试验确定果胶、黄原胶、羧甲基纤维素钠在粒粒黄桃汁饮料中的最佳使用方案,通过正交实验,确定果胶、黄原胶、羧甲基纤维素钠的最优复配比例及最优用量。结果表明:果胶∶黄原胶∶羧甲基纤维素钠最优复配比为2∶4∶7,最优用量为每100g饮料添加果胶0.075g,黄原胶0.150g,羧甲基纤维素钠0.2625g。     

供氮水平对枫香种源幼苗生长及氮、磷吸收利用的影响

在砂培条件下研究枫香6个种源幼苗对不同氮素水平的响应差异,结果表明:苗木生物量、根冠比和氮磷吸收量及利用率在不同氮水平间、同一氨水平内不同种源间及氮水平与种源间的交互作用,均存在极显著差异,随着供氮水平的降低,枫香各种源大体呈生物量减小、根冠比增大、氮磷吸收量减少,氮利用率上升和磷利用率下降的变化趋势,尤其在缺氮时,变化幅度剧增.当由标准氮水平增加到丰氮水平时,不同种源的反应不一,无一定变化规律.在6个种源中,南昌和南丹种源在各氮素水平上均保持较大的生物量,但对缺氮的反应较为强烈,更适宜较高的氮素供应条件.延平种源在低氮、缺氮水平上具有较大的生物量,较高的氮磷吸收量和利用率,是对低氮耐受力较强的种源.     

黄原胶溶液模拟消化污泥流动性能分析

为污泥消化反应器流场的可视化研究提供可行性方法,该文根据同流体流动相似准则分别从密度和流变学特性来分析黄原胶透明溶液作为常规消化污泥相似溶液的可行性。采用质量法和流变仪分别测量不同浓度污泥和添加KCl的黄原胶溶液的密度及流变特性。结果表明15 g/L添加KCl的黄原胶溶液与95%含水率污泥在密度不具有显著性差异的前提下具有相似的流变特性,流变曲线的决定系数分别为R2=0.995 3(动力黏度)、R2=0.893 5(剪切应力),均为典型的假塑性非牛顿流体。混合试验表明2种流体中示踪剂浓度的变化规律相似且均在40 min后趋于平衡浓度50 mg/L。等同性分析表明,在显著性水平α=0.05时,2种流体中以流变特性和密度为参数的双侧t检验不具有显著性差异,符合同流体流动相似准则。故添加KCl的黄原胶溶液可以作为污泥的透明相似溶液,为污泥等不透明生物质流体厌氧消化的模拟及可视化研究奠定基础。     

Improvement in growth and alkaloid content of Rauwolfia serpentina on application of organic matrix entrapped biofertilizers (Azotobacter chroococcum,Azospirillum brasilense and Pseudomonas putida)

The field experiment was conducted to study the effect of conventional chemical fertilizer (urea),conventional biofertilizers (charcoal based) and organic matrix entrapped biofertilizer; (OMEB: a consortium of Azotobacter chroococcum, Azospirillum brasilense and Pseudomnas putida entrapped with clay soil, neem leaves, and cow dung in ratio of 1:1:1 and 15% saresh (plant gum of Acacia sp.) in various doses on growth parameters of Rauwolfia serpentina in terms of root length, shoot length, number of leaves, number of roots and fresh and dry weight of roots and shoots. Replacement of conventional chemical fertilizer by the consortium of biofertilizers (un-entrapped) increased plant growth in a dose dependent manner up to triple dose of the recommended dose (RD) of biofertilizers (1.80 kg ha-1). This increase in plant growth was not up to the level which appeared in the application of RD of urea. Entrapment of the same biofertilizers in an organic matrix mentioned above enhanced the plant growth similar to that observed for urea. The percentage increase of 9.57 and 7.54 in fresh weight (FW) and 11.93 and 11.12% in dry weight (DW) of shoot and 17.94 and 37.87% in FW of roots and 31.90 and 50.08% in DW of roots were recorded in 75 days old plant by the application of OMEB- triple dose over the conventional biofertilizers triple dose and recommended dose of urea. Conventional biofertilizers enhanced the availability of nitrate, nitrite and phosphate in the roots and leaves of the plant over application of urea as well as conventional biofertilizers. This formulation also increased alkaloid contents of in the roots of this plant. Microbial population of soil was also improved indicating enhanced soil fertility with application of OMEB. The results indicate that replacement of chemical fertilizers with microbial biofertilizers is possible with application of higher dose of biofertilizers entrapped into the organic matrix for the cultivation of medicinal plants like R. serpentina.     

阿拉伯胶的性质研究

探讨阿拉伯胶的一些主要性能。试验表明,阿拉伯胶的溶解性较好;随着阿拉伯胶浓度的增加,黏度亦增大;pH值变化时,阿拉伯胶黏度几乎保持恒定;同时阿拉伯胶有较好的保持香气的能力。     

循环干燥对尾巨桉木材弦向干缩性影响的研究

采用人工模拟大气湿度变化规律,对尾巨桉木材进行循环干燥;利用傅立叶红外光谱揭示循环干燥对尾巨桉木材干缩影响的内在因素,探索尾巨桉木材弦向干缩率在循环干燥中的变化规律,旨在寻求降低尾巨桉木材胀缩性的新途径,为尾巨桉木材干燥和实木加工提供新的理论依据。     

松脂贮存过程的褐变作用及漂洗方法

以含有松树皮、木质和松针叶等杂质的松脂为原料，水为溶剂进行松脂加工过程褐变作用和漂洗方法的研究。考察了不同水质、温度、时间、松脂粒度及更换漂洗水质对松脂贮存和漂洗过程褐变作用的影响，比较了漂洗和未漂洗松脂在熔解过程中的非酶褐变作用。结果表明采用细菌总数为110000个／L的河水贮存松脂，产生严重的褐变作用，导致松香产品颜色加深，松节油也夹带臭味；而用无菌或灭菌蒸馏水保养松脂，在室温下可贮存24个月、冷沸水可贮存12个月、自来水可贮存9个月，松脂的颜色基本不变；当贮存温度低于10℃时，抑制了松脂褐变作用的进行；松脂粒度小于10mm和更换水质的方法，有利于提高松脂所含杂质的浸提速率；新鲜松脂漂洗与否对熔解过程非酶褐变的影响不大。由于采用无菌或灭菌水质保养和漂洗松脂，延长了松脂的贮存时间，因此松脂厂可变季节性生产为全年生产，从而提高了生产装备的利用率和产量。