镧素对镰刀菌Fusarium solani及其致病酶的影响

采用琼脂平板生长速率法及液体培养基培养测定了La对镰刀菌Fusarium solani的抑制作用和毒力,并测定了其对病菌胞外的果胶酶、蛋白酶和纤维素酶等几种致病酶活性的影响。结果表明,随着La2O3浓度升高,对病菌菌丝生长的抑制作用增强,对病菌的EC50和EC95分别为278.2和552.0 mg/L;在一定浓度范围内,La提高了单位量菌丝所产生3种致病酶的活性,但由于菌丝生长受到抑制,除蛋白酶外,病菌胞外致病酶果胶酶和纤维素酶的总量或总活性受到了抑制,降低了病菌的致病力。     

植物对虫害的系统获得性抗性及抗虫与抗病信号途径间的相互作用

受病原体感染后,植物会获得一种持久广泛的抗性,称为系统获得性抗性,受到昆虫侵害时也会获得类似的系统获得性抗性.植物系统抗虫与抗病信号分子不同,前者是茉莉酸(JA)、甲基茉莉酸(Me-JA)或系统素,而后者是水杨酸(SA).SA介导的系统抗病信号途径与JA等介导的系统抗虫信号途径并非完全独立,而是存在所谓的"交叉对话",但"交叉对话"结果是相互促进还是抑制仍不清楚.植物系统抗性信号及其互作研究无疑会完善植物保护策略.     

四硫代碳酸钠对蔬菜根病的防治效果及对土壤生物学性状的影响

为明确四硫代碳酸钠(sodium tetrathiocarbonate,STTC)在蔬菜根病防治上的应用价值及制定应用技术,本研究通过室内瓶土熏蒸法,进行了STTC对病菌的室内毒力测定;用温室盆栽法,进行植前熏蒸处理,测定土壤中病菌数量的变化和对病害的防效,同时进行植后熏蒸处理,测定药剂处理点和根际处病菌数量的变化;通过土壤施药后随即移栽幼苗的方法,评价药剂对蔬菜幼苗的安全性;通过室内模拟田间熏蒸条件,测定药剂不同浓度和熏蒸时间对土壤中主要微生物类群数量和主要土壤酶活性的影响。结果显示STTC对辣椒疫霉病菌Phytophthora capsici、黄瓜枯萎病菌Fusarium oxysporumf.sp.cucumerinum、茄子黄萎病菌Verticillium dahliae、番茄立枯病菌Rhizoctonia solani和蔬菜菌核病菌Sclerotinia sclerotiorum均有较好的杀灭活性,LD50分别为3.956、4.241、5.222、5.457和6.197mg/kg;80g/m2 STTC移植前处理对辣椒疫霉病和黄瓜枯萎病的防效可分别达到91.01%和82.51%;浓度低于900μg/mL的STTC对当日熏蒸后移栽的3叶期辣椒、黄瓜、番茄、白菜和油菜幼苗均表现安全;在辣椒和黄瓜生长期穴施1 200μg/mL STTC能有效减少土壤中辣椒疫霉病菌和黄瓜枯萎病菌的数量;土壤中微生物类群数量监测结果表明,在0.1~50.0μg/g浓度范围内,STTC对土壤真菌有强烈抑制作用,对土壤细菌和放线菌为先抑制后促进。对土壤酶活性测定结果表明,当STTC用量为0.1、1.0、5.0、10.0和50.0μg/g时,对土壤脲酶和蔗糖酶的活性表现为先抑制后促进,对蛋白酶的活性表现为在STTC低浓度时活性增加,高浓度时为先抑制后增加。综合结果表明,STTC用于经济作物生产中的土壤熏蒸具有安全、有效和施用简便的特点,或可广泛使用。     

菜籽饼发酵菌株筛选研究

本研究对利用菜籽饼的菌株筛选，发酵后产品质量变化及影响发酵的主要因素进行了分析，结果表明：ｙ＿１、ｙ＿２、ｙ＿５是发酵利用菜籽饼优良的３个非互为拮抗的菌株，且三菌株混合发酵比单一菌株发酵效果好，其混合发酵可提高蛋白质含量１２％左右，硫代葡萄糖苷降低了１５．１６～１８．９０μｍｏｌ／ｇ，降解率达６０％～８０％，发酵后产品含有１７种氨基酸，氨基酸总量为４５．５４％，优于山东滕县以豆饼为主生产的活性高蛋白饲料。且发现供氧及原料加水量是影响菜籽饼发酵的主要因素，原料加水７０％有利于菜籽饼发酵顺利进行。     

HPLC法快速检测记忆缺失性贝毒软骨藻酸

采用高效液相色谱法测定贝类食品中的记忆缺失性贝毒软骨藻酸。软骨藻酸经适当甲醇水提取,经过阴离子柱净化,用高效液相色谱仪进行检测,外标法定量方法。方法定量限为200μg/kg,回收率大于88.0%。该方法操作简单、快速、准确、灵敏、适用性强,能满足贝类食品中软骨藻酸的测定。     

Importance of chlorogenic acid on the oxidative potential of potato tubers of two German cultivars

Summary Two German cultivars differing in blackspot susceptibility were grown in pots in 1998 and 1999 under control and water stress conditions. Blackspot susceptibility of the tubers was defined as oxidative potential. The effect of free tyrosine, cysteine, phenylalanine, chlorogenic and ascorbic acid on the oxidative potential was analyzed. A high concentration of ascorbic acid led to a decrease in the oxidative potential after harvesting in 1998. No correlation was found between oxidative potential and free tyrosine, phenylalanine or cysteine, respectively. Chlorogenic acid content increased during storage and gave a significant correlation with discoloration, showing that it can have an effect on the oxidative potential of the tuber greater than previously thought. Supplementing freeze-dried potato samples with pure chlorogenic acid increased the oxidative potential. Oxidative potential seems to depend on a series of chemical compounds, and their content is affected by factors including annual variations, cultivar, water availability and storage.     

受黄色镰刀菌侵染的马铃薯薯块的抗氧化酶、细胞壁防御酶及StLTPa1基因的表达特性

黄色镰刀菌Fusarium culmorum为黑龙江省马铃薯干腐病主要致病菌,干腐病可以导致马铃薯在窖藏过程中发生腐烂,影响薯块的商品价值和食用价值,为进一步研究马铃薯干腐病的发生和防治,本研究采用黄色镰刀菌对不同抗性的马铃薯块茎进行侵染,对病原菌侵染过程中薯块的抗氧化酶及细胞壁降解酶变化及病程相关基因的表特性进行了研究。结果表明,当黄色镰刀菌侵染块茎时,块茎中的可溶性蛋白和丙二醛(malondlaldehyde,MDA)含量,超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)活性、几丁质酶(chitinase)和β-1,3-葡聚糖酶(β-1,3-glucanase)活性都呈现不同程度的上升趋势。非特异性脂质转移蛋白基因StLTPa1表达量随着黄色镰刀菌的侵染时间呈波动性,在植物防御反应中发挥一定的作用。     

浙江省山区河道护坡乔木植物枫杨耐淹性研究

[目的]对浙江省山区河道护坡植物枫杨进行耐淹性研究。[方法]分别测定生长在河岸和河道水流中的枫杨叶片的气孔导度和膜保护酶活性。[结果]枫杨树种在淹水条件下气孔导度比旱生条件下增加了52.89%,SOD和POD活性分别减少了17.1%和25.8%,MDA含量增加了18.48%。[结论]枫杨植株在山区河道消落带中具有较强的耐淹性。     

采用响应曲面法优化甘草饮片中甘草酸的超声提取工艺

根据Box-B ehnken的中心组合实验设计原理,在单因素试验的基础上,采用三因素三水平的响应曲面分析法,建立了甘草饮片中甘草酸超声提取的二次多项数学模型,并以甘草酸提取率为响应值作响应面和等高线,考察了浸泡时间、超声时间和液固比对甘草酸超声提取的影响。结果表明,甘草酸超声提取的优化工艺条件为:浸泡时间151.3 m in,超声时间48.8 m in,液固比10.2 mL/g;在此工艺条件下,甘草酸提取率为21.06%。     

Variation in the storage proteins of peas in relation to sulphur amino-acid content

Summary A cellulose acetate electrophoretic technique has been used to characterise the storage proteins present in pea seeds in order to try and determine the proportions of proteins present which are enriched in sulphur amino-acids. Some of the eight varieties examined were shown to differ in their proportions of the various storage proteins. When the proteins were separated and estimated quantitatively and also characterised by their sub-unit composition, it was shown that cellulose acetate electrophoresis of crude protein extracts or of whole globulins did not give the degree of resolution required. The procedures which have to be undertaken in order to obtain this information are considered, and the difficulties of incorporating them into a plant breeding programme discussed.