杜仲叶中绿原酸稳定性研究及沉降试验

研究了绿原酸的稳定性并进行了沉降试验,结果表明,绿原酸在温度小于60℃保持4 h以下及酸性、室内闭光的条件下比较稳定,而在碱性、强光照射下不稳定;同时,沉降剂(cjh∶cjj=1∶3)使用不利于杜仲叶中有效成分绿原酸的提取,造成绿原酸1%的损失。     

乳酸对酵母凋亡及某些相关基因表达的影响

采用终浓度为200、250、300 mmol.L-1的乳酸作用酵母细胞200 min,同时,采用终浓度为250mmol.L-1的乳酸分别作用酵母细胞120、200、260 min后,通过DAPI染色、PI染色和TUNEL染色法检测酵母细胞的凋亡。结果表明,随着乳酸终浓度的增加,酵母的死亡率随之增加。死亡的细胞出现DNA断裂和染色质凝聚现象,但没有显示膜损伤,所以乳酸引起的酵母细胞死亡是以凋亡的形式进行。200 mmol.L-1乳酸处理酵母200 min,可引起约不到30%的凋亡,当终浓度增加到300 mmol.L-1时,凋亡率可达80%以上,乳酸引起的死亡率和凋亡率具有剂量依赖性,但无时间依赖性。RT-PCR检测结果表明,随着凋亡程度的增加,Fis1、Bir1、SOD1、SOD2基因的表达随之降低。     

细叶百合鳞茎冷藏过程中核酸及蛋白质的变化

以细叶百合为试材,通过冷藏(5℃)解除鳞茎休眠,研究了细叶百合鳞茎解除休眠过程中核酸及可溶性蛋白质的变化规律。结果表明,冷藏过程中顶芽与鳞茎盘中核酸含量发生了明显的变化,顶芽中DNA、RNA含量及RNA/DNA比值在鳞茎冷藏36 d时变化最为明显,贮藏36 d是内外鳞片DNA及核酸总含量的转折点;顶芽和鳞茎盘冷藏0~36 d内可溶性蛋白质的含量升高,鳞茎不同部位可溶性蛋白质含量在冷藏48 d后迅速降低也是鳞茎开始解除休眠的重要体现。     

大豆皂苷Bb乙二胺衍生物的制备

天然的皂苷分子结构不一定表现出免疫佐剂活性的最佳状态,为获得不同皂苷结构修饰衍生物,研究选用碳二亚胺法,借助于乙二胺衍生物的氨基,使大豆皂苷单体Bb分别与β-苯丙酸、L-脯氨酸发生缩合反应,将亲脂性的,带正电荷的、亲水性的化合物基团分别连接到大豆皂苷C-3-O位的葡萄糖醛酸羧基上,形成不同程度亲水、亲脂性的衍生物。分别使用分析及制备型HPLC分离纯化制备的衍生物,并利用傅立叶红外光谱、质谱等方法鉴定衍生物结构。研究结果形成了不同结构的衍生物,可用于后续的大豆皂苷结构与免疫佐剂活性的研究。     

多菌灵有机酸盐防治柑橘贮藏期病害的初步研究

以多菌灵可湿粉为对照,试验了多菌灵柠檬酸盐、酒石酸盐和草酸盐对柑橘贮藏期病害的毒力和药效。多菌灵草酸盐效果最好,对柑橘蒂腐病菌的毒力是多菌灵的２．９４倍,用含有效成分９００ｍｇ／ｋｇ的药液浸泡处理的柑橘,常温贮藏３０￣８０ｄ,药效均达８０％以上。     

甜菜渣提取果胶后剩余残渣的利用

对甜菜渣提取果胶后剩余残渣的利用，提出了两条有效途径：一是采用物理方法制取食物纤维。残渣经水反复洗涤，用无水乙醇脱水后，在不同温度下真空干燥。结果表明在较低温度下可得到白色无毒的食物纤维。二是将残渣氧化制备草酸。通过对不同催化剂催化效果的研究，结果表明用Ｖ２Ｏ５—Ｆｅ２（ＳＯ４）３—ＡｇＮＯ３作催化剂，草酸的产率较高且重现性好。     

白雪公主水培试验研究

以天南星科植物白雪公主为试材,采用水培法经不同浓度的吲哚乙酸（IAA）处理,进行诱导水生根系试验,然后用诱导的水生根系材料进行营养液培养。结果表明：采用低浓度IAA、短时间浸泡处理可有效促进水生根系生长。20mg/L的IAA浸泡1d处理后的白雪公主插条表现出生根快、持续生根时间长、生根量多、根系长、生根率高等优点,是水培白雪公主插条最适宜的处理浓度。KC营养液最适合白雪公主的生长,各项生长指标都达到最佳。     

Carbon Sequestration in Soil Humic Substances Under Long-Term Fertilization in a Wheat-Maize System from North China

The changes in humic substances （HS） is fundamental in detecting soil carbon sequestration mechanisms in natural and cultivated environments. Based on a long-term trial, the amounts of water dissolved substances （WSS）, humic acid （HA）, fulvic acid （FA） and humin （HU） were determined to explore the impact of long-term fertilization on HS. Increases in the amounts of WSS, HA, FA and HU were significant different among the treatments with manure. A significant correlation was found between the increased soil organic carbon （SOC） and HS （R^2=0.98, P〈0.01）. The change in the E4/E6 ratio was significantly correlated with the increased SOC （R2=0.88, P〈0.01）, HA （R^2=0.91, P〈0.01）, FA （R^2=0.91, P〈0.01） and HU （R^2=0.88, P〈0.01）. The cluster was mainly divided into two parts as manure fertilization and inorganic fertilization, based on the increases in HA, FA and HU. These results suggest that long term fertilization with manure favours carbon sequestration in HS and is mainly stabilized as HU, while the HA becomes more aliphatic. We conclude that increases in SOC can be linked to changes in the molecular characteristics of HS fractions under long term fertilization.     

Soil Quality Assessment of Acid Sulfate Paddy Soils with Different Productivities in Guangdong Province,China

Land conversion is considered an effective measure to ensure national food security in China, but little information is available on the quality of low productivity soils, in particular those in acid sulfate soil regions. In our study, acid sulfate paddy soils were divided into soils with high, medium and low levels based on local rice productivity, and 60 soil samples were collected for analysis. Twenty soil variables including physical, chemical and biochemical properties were determined. Those variables that were significantly different between the high, medium and low productivity soils were selected for principal component analysis, and microbial biomass carbon (MBC), total nitrogen (TN), available silicon (ASi), pH and available zinc (AZn) were retained in the minimum data set (MDS). After scoring the MDS variables, they were integrated to calculate a soil quality index (SQI), and the high, medium and low productivity paddy soils received mean SQI scores of 0.95, 0.83 and 0.60, respectively. Low productivity paddy soils showed worse soil quality, and a large discrepancy was observed between the low and high productivity paddy soils. Lower MBC, TN, ASi, pH and available K (AK) were considered as the primary limiting factors. Additionally, all the soil samples collected were rich in available P and AZn, but deficient in AK and ASi. The results suggest that soil AK and ASi deficiencies were the main limiting factors for all the studied acid sulfate paddy soil regions. The application of K and Si on a national basis and other sustainable management approaches are suggested to improve rice productivity, especially for low productivity paddy soils. Our results indicated that there is a large potential for increasing productivity and producing more cereals in acid sulfate paddy soil regions.     

植物蛋白乳酸菌饮品储存过程中乳酸菌的变化规律

以嗜热链球菌FJAT-7928、干酪乳杆菌FJAT-7929为菌株,以黄豆为基质,发酵得到植物蛋白乳酸菌饮品,研究其在4℃保存条件下菌落数以及酸度和pH值的变化。结果表明,保存30d内,两菌种混合发酵植物蛋白乳酸菌饮品的乳酸菌可高达到3.5×109 cfu.mL-1,高于单独发酵的植物蛋白乳酸菌饮品中的活菌数。混合发酵植物蛋白乳酸菌饮品的最终酸度为109.0°T,pH值为3.58;FJAT-7929单独发酵植物蛋白乳酸菌饮品最终酸度为114.0°T,pH值为3.65;FJAT-7928植物蛋白乳酸菌饮品酸度为60.0°T,pH值4.09。4℃保存3种发酵处理的植物蛋白乳酸菌饮品,30d内乳酸菌活菌数和酸奶的理化性质基本稳定。