活性氧化及其清除剂诱导抗病作用与影响膜脂过氧化作用的关系

细胞内外 AOS的快速增加可导致膜脂过氧化 ,甚至直接损伤核 DNA和失活蛋白质 ,造成细胞丧失生活能力〔2〕,诱导抗氧化防卫基因、植保素合成基因和与系统获得抗性 (SAR)细胞内外 AOS的快速增加可导致膜脂过氧化 ,甚至直接损伤核 DNA和失活蛋白质 ,造成细胞丧失生活能力〔2〕,诱导抗氧化防卫基因、植保素合成基因和与系统获得抗性 (SAR)有关的基因的表达以及诱导程序性细胞死亡〔3〕。百草枯 (PQ)是一种特异性的 O·2 产生剂。我们的研究表明 ,PQ在导致 O·2 产生的同时 ,也使 SOD活性增加 ,并诱导了对稻白叶枯菌的系统抗性。而 O…     

红掌抗热性研究初探

通过不同浓度的６－ＢＡ、ＧＡ３、ＳＢＮ（苯甲酸钠）处理３２℃高温胁迫下的红掌叶片及苞片,发现三者均明显降低了细胞膜透性并提高ＰＯＤ活性及花青素含量。三者的最佳浓度分别为５,２０和５０ｍｇ／Ｌ。     

Introgressive hexaploid oats from the Avena abyssinica (♀) × A. sativa hybrid: performance, grain lipids and proteins

A fertile hexaploid oat plant was obtained after several generations of selection for seed set and plant type from a colchicine-produced decaploid hybrid, Avena abyssinica(2n = 4x = 28, AABB) × A. sativa (2n = 6x = 42, AACCDD). The selected line proved to be stably fertile and in many characteristics equal or superior to the hexaploid parent. The grain protein fractions showed two qualitative differences from those of the pollen parent and several differences from the maternal parent. The fractionating extraction used was new for oats. The fatty acid composition of grains of the hybrid derivative was similar to that of the pollen parent, but different from that of the maternal parent. The maternal parent (A. abyssinica) had a relatively high 16:0 fatty acid content (ca. 20.5 mol%) compared with the level of the hexaploid parent and the hybrid derivation (ca. 17.5 mol% each) in field-grown grain. However, in grain produced in the greenhouse, the hexaploids had ca. 20.5 mol% of 16:0 fatty acid and a decrease in 18:1 fatty acid, whereas seed of the A. abyssinica parent showed only a slight increase (ca.21.5 mol%) in 16:0 fatty acid. These and other responses statistically significant may be due to adaptation to temperature conditions being wider in the hexaploids than in the East-African A. abyssinica. A new method of grain lipid extraction was introduced and showed good reproducibility. The derived hexaploid oat can be crossed with A. sativa for breeding purposes and due to its early maturity might also have direct use in northern or high-altitude cultivation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Physiological and Biochemical Responses of Hexaploid and Tetraploid Wheat to Drought Stress

An experiment was conducted to investigate the physiological and biochemical responses of two hexaploids viz., C 306 (water stress tolerant) and Hira (water stress susceptible), and two tetraploids, HW 24 (Triticum dicoccum) and A 9‐30‐1 (Triticum durum) wheat genotypes to water stress under pot culture condition. Water stress was imposed for a uniform period of 10 days at 50, 60 and 70 days after sowing (DAS) and observations were recorded at 60, 70 and 80 DAS. Total dry matter and plant height were recorded at harvest. Water stress caused a decline in relative water content (RWC), chlorophyll and carotenoid content, membrane stability and nitrate reductase activity and increased accumulation of proline at all stages and abscisic acid (ABA) at 80 DAS in all the genotypes. Both the tetraploids showed a lower reduction in RWC and highest ABA accumulation under water stress. Among the hexaploids Hira showed the most decline in RWC and the lowest ABA accumulation. The tetraploids also showed comparatively higher carotenoid content and membrane stability, closely followed by C 306, while Hira showed the minimum response under water stress. Nitrate reductase activity and chlorophyll content under irrigated conditions were highest in Hira but under water stress the lowest per cent decline was observed in C 306, followed by HW 24, A 9‐30‐1, and Hira. Proline accumulation under water stress conditions was highest in hexaploids C 306 and Hira and lowest in tetraploids HW 24 and A 9‐30‐1. Tetraploids HW 24, followed by A 9‐30‐1 maintained higher plant height and total dry matter (TDM) under water stress and also showed a lower per cent decline under stress than hexaploids C 306 and Hira. From the results it is clear that proline accumulation did not contribute to better drought tolerance of tetraploids than hexaploids. It is also apparent that water stress tolerance is the result of the cumulative action of various physiological processes, and all the parameters/processes may not be positively associated with the drought tolerance of a particular tolerant genotype.     

Oxidative Stress and Antioxidants in Wheat Genotypes: Possible Mechanism of Water Stress Tolerance

The role of plant antioxidant systems in water stress tolerance was studied in three contrasting wheat genotypes. Water stress imposed at different stages after anthesis resulted in an increase in lipid peroxidation and a decrease in membrane stability and chlorophyll and carotenoid contents. The antioxidant enzymes ascorbate peroxidase, glutathione reductase and non-specific peroxidase also increased significantly under water stress. Genotype PBW 175, which had highest ascorbate peroxidase, glutathione reductase and peroxidase activity, had the lowest lipid peroxidation (malondialdehyde content) and highest membrane stability and contents of chlorophyll and carotenoids under water stress, while the susceptible genotype WH 542 exhibited the lowest antioxidant enzyme activity, membrane stability and contents of chlorophyll and carotenoids and the highest lipid peroxidation. Genotype HD 2402 showed intermediate behaviour. It seems that drought tolerance of PBW 175, as represented by higher membrane stability and chlorophyll and carotenoid contents and lower lipid peroxidation, is related to its higher antioxidant enzyme activity.     

膜分离技术及其在乳品工业中的应用

对膜分离技术的发展简史、特点、原理及其装置、流程进行了介绍,并在此基础上综述了膜分离技术在乳品工业中的应用,分析了该技术当前存在的问题,探讨了膜技术的发展前景。     

日光温室黄瓜节水灌溉研究

对比分析了日光温室黄瓜滴灌、膜下沟灌和畦灌 3种灌水方式对温室环境、黄瓜耗水量、产量、品质的影响以及这 3种灌溉方式下温室黄瓜的年产出投入比。结果表明 :日光温室滴灌比畦灌温室内空气相对湿度降低 1 0 %～ 1 5%,冬季地温提高 3～ 8℃ ;黄瓜耗水量减少 4 3 .4 %,灌溉水节约 59.9%;黄瓜增产 3 3 %,产值增加 6.75万元 /hm2 ;黄瓜粗蛋白含量和可溶性糖均高 4 %;提早 1 0 d左右上市 ;年产出投入比高 1 .0 1。膜下沟灌比畦灌使温室内空气相对湿度降低 1 3 %左右 ;黄瓜耗水量减少 1 3 .6%,节约灌溉水 2 0 %;黄瓜产量提高1 3 %,产值增加 3 .1 5万元 /hm2 ;年产出投入比提高 0 .82     

梳角窃蠹的防治研究

梳角窃蠹 ( Ptilinus fuscus Geoffroy) ,亦称梳栉窃蠹 ,属鞘翅目 ( Coleopptera) ,窃蠹科( Anobiidae)。嗜食多种杨 ( Populus spp.)、柳 ( salix spp.)及白榆 ( Ulmus pumila L.)的干材 ,尤以青杨 ( P.cathayana Rehd.)受害最重 ,除钻蛀居室木材外 ,还能寄生于活立木的枯朽枝、干部 ;如云杉 ( Picea spp.)木与杨、柳木混用时 ,也能轻度危害云杉木。据报道国外分布于欧洲、埃及、叙利亚 ,国内分布于青海、辽宁[1] 、甘肃 (兰州、白银、临夏、定西、天水、平凉、庆阳、陇南等8地 (州、市 )的 46县 (市、区 ) ) ,是甘肃省房屋木材构件杨…     

Role of Tween 80 in biobleaching of unbleached hardwood kraft pulp with manganese peroxidase

The role of Tween 80 in biobleaching of unbleached hardwood kraft pulp (HWKP) with manganese peroxidase (MnP) was investigated. Among the surfactants (e.g., Tween 80, Tween 20, CHAPSO) the most significant brightness increase was obtained with Tween 80. Tween 80 and Tween 20 exhibited several effects, such as dispersion of degraded lignin and activation of MnP, that partly contributed to the brightening of HWKP during MnP treatment. However, these characteristics did not explain the most appreciable effect on the brightness increase by Tween 80. Lipid peroxidation of surfactants during MnP biobleaching was determined by measuring the peroxide value (POV). The order of the POV increase was consistent with that of the brightness increase of pulp during MnP treatment in the presence of various surfactants or linolenic acid. However, radicals and peroxides derived from lipid (linolenic acid) peroxidation by lipoxidase hardly brightened the HWKP by themselves. These results suggested that Tween 80 was peroxidized by Mn(III), and that Mn(III) and lipid peroxidation of Tween 80 synergistically brightened HWKP.This study was presented in part at the 43rd lignin symposium, Fuchu, Tokyo, Oct. 26–27, 1998 and the 49th annual meeting of the Japan Wood Research Society, Tokyo, April 2–4, 1999