生物固氮研究新进展

生物固氮是一项具有重大应用前景的基础研究,进入90年代以来,生物固氮的研究又有了许多新的进展: 一、固氮酶结构、固氮基因研究及高效固氮菌的培育 搞清生物固氮酶的结构和模仿生物固氮的过程,对生物固氮研究的突破有着重要意义。最近美国科学家在对固氮酶的结构研究方面取得重要进展,他们利用X光晶体学手段,已基本揭示出固氮酶内一种重要蛋白质的结构,对另外一种蛋白质的结构分析也已接近完成。固氮酶实际上是由两种不同蛋白质组成的二聚物,两种蛋白质中较小的一种为铁蛋白,另一种为铁——钼蛋白。美国加州理工学院的道格等人最近完成了对铁蛋白结构的分析,分辨率达3.0埃。他们的分析表明,铁蛋白的结构极不寻常,它看上去就     

大豆施用钼肥增产效果显著

大豆是对钼较为敏感的作物，对钼的需要量也相对多些，在大豆上施用钼肥具有显著增产效果。一、钼肥的作用钼可以促进大豆根系发育，增强根系对养分的吸收能力，提高植株的耐旱力；钼可以增强固氮酶的活性，提高根瘤菌固定空气中游离氮分子的能力，     

南阳市耕地速效钼含量状况及钼肥的合理施用

钼是植物不可缺少的微量元素之一，豆科作物含钼较多。其生理功能主要是氮素代谢中，钼是固氮酶的组成成分，必须有钼参加，固氮酶才有固氮活性，与豆科作物共生的根瘤菌固氮时，钼必不可少，所以豆科作物对钼较敏感。钼能促进磷及其它矿质养分的吸收和代谢，又是硝酸还原酶的组成成分，缺钼时植物若以硝态氮为氮源时会引起硝酸盐积累，减少蛋白质合成，影响植物正常生长。     

大豆施用钼肥的效果及方法

正钼是一种微量元素,大豆是对钼较为敏感的作物,对钼的需要量比其它作物高出100倍。钼可以促进大豆根系发育,增强根系对养分的吸收能力,并提高植株的耐旱力;钼可以提高固氮酶的活性,提高根瘤菌固定空气中游离氮分子的能力,对大豆氮素代谢有重要作用,可增加蛋白质含量;大豆施用钼肥促进植株对磷的吸收、分配和转化,进而促进开花结荚,增加粒数、粒重。据有关试验表明,适当施些钼肥,可使大豆增产10%以上。     

钼肥对紫云英的增产试验

紫云英绿肥是早稻的主要肥源之一。绿肥丰产主要靠根瘤菌的固氮作用,钼是固氮酶的组成成分之一。国外试验,钼肥对羽扇豆、苜蓿、三叶草,均有增产作用,但对紫云英绿肥的增产作用的研究尚少。为探索微量元素钼与紫云英产量的关系。1974年秋,在长沙县开慧公社开明大队红林坝坵(低产田),面积约1.5亩,进行了紫云英接种根瘤菌和拌钼肥的试验。     

钼在植物体中的生理作用

钼(Mo)是植物必需的矿质元素之一,在植物体内有着重要的生理作用。它作为硝酸还原酶和固氮酶的组分参与植物的氮素代谢,同时还参与光合作用、磷素代谢和某些重要复合物的形成。     

钼肥对紫云英的增产试验

紫云英绿肥是早稻的主要肥源之一。绿肥丰产主要靠根瘤菌的固氮作用,钼是固氮酶的组成成分之一。国外试验,钼肥对羽扇豆、苜蓿、三叶草,均有增广作用,便对紫云英绿肥的增产作用的研究尚少。为探索微量元素钼与紫云英产量的关系。1974年秋,在长沙县开慧公社开明大队红林坝蚯(低产田),面积约1.5亩,进行了紫云英接种根瘤菌和拌钼肥的试验。采用钼肥拌种同时拌根瘤菌的方法,三个处理重复二次,每处理2分地。三个处理是:未     

大豆病虫害防治技术

一、大豆生长需要的微量元素及施用 大豆正常生育需要一些微量元素,其中较为重要的有钼、硼、锌、锰等。钼是大豆根瘤固氮酶的组成成分,是固氮菌正常生命活动不可缺少的成分。硼在大豆生命活动中也很重要,缺棚大豆根系发育不好,根瘤着生不好,失去固氮能力。所以对于微量元素也必须注意。     

甘氨酸钼与硼配施对黄瓜幼苗生长发育的协同作用研究

以黄瓜幼苗为研究材料,初步研究了新型络合钼肥——甘氨酸钼与硼酸对黄瓜幼苗生长发育的协同作用。结果表明:在2 mg/L甘氨酸钼处理组中,黄瓜幼苗的生物量、叶绿素含量、根系活力及保护性酶活性等各项生理指标均随着硼酸配施用浓度的增加而增大;在4 mg/L甘氨酸钼处理组中,黄瓜幼苗被检测的各项生理指标呈现出先升后降的变化趋势,其中,以T5处理组(4 mg/L Gly-Mo+10 mg/L B)的协同效果最佳,与其他各处理差异显著。     

甘氨酸钼与硼配施对黄瓜幼苗生长发育的协同作用研究

以黄瓜幼苗为研究材料,初步研究了新型络合钼肥——甘氨酸钼与硼酸对黄瓜幼苗生长发育的协同作用。结果表明:在2 mg/L甘氨酸钼处理组中,黄瓜幼苗的生物量、叶绿素含量、根系活力及保护性酶活性等各项生理指标均随着硼酸配施用浓度的增加而增大;在4 mg/L甘氨酸钼处理组中,黄瓜幼苗被检测的各项生理指标呈现出先升后降的变化趋势,其中,以T5处理组(4 mg/L Gly-Mo+10 mg/L B)的协同效果最佳,与其他各处理差异显著。     

氯化锰和钼酸对盐渍地棉花幼苗生长耐盐性影响的研究

为了开发利用盐渍土地,给棉花的抗盐栽培提供理论依据。试验研究氯化锰(MnCl2.4H2O)和钼酸(H2MoO4.H2O)浸种对盐渍地棉花幼苗生长耐盐性的影响。通过对幼苗长度、根系活力、幼苗叶片叶绿素含量、过氧化物酶(POD)活性的测定,结果显示:氯化锰和钼酸混合液对棉花幼苗的耐盐性有显著影响,其中以1 000mg/L的MnCl2.4H2O+200 mg/L的H2MoO4.H2O混合液,效果最佳。     

不同H_5亚型禽流感灭活苗对鸡H_5N_1株的免疫效力试验

采用H5N2和H5N1两种类型的禽流感(A I)油乳灭活疫苗免疫鸡群对高致病性A I流行株H5N1A IV的攻毒保护效力进行了比较。结果表明:在同等免疫剂量条件下,H5N2和H5N1油乳灭活苗对鸡群具有相似或同等的免疫效力,均能抵抗对高致病性A IH5N1流行株的攻击;A I母源抗体对灭活苗免疫具有一定的干扰作用。     

ABA上调水稻叶片中OsHsf基因的表达

运用半定量PCR方法研究了ABA和H_2O_2诱导水稻热激转录因子基因OsHsfA4a和OsHsfA2的表达情况。结果表明:ABA和H_2O_2均能上调水稻OsHsfA4a和OsHsfA2基因的表达,分别在4 h处理时间内产生2个表达高峰;H_2O_2清除剂和抑制剂预处理试验证明,ABA对水稻OsHsf基因的诱导作用是通过ABA诱导产生的H_2O_2而实现的。     

Cytochemical localization of H_2O_2 in pigment glands of cotton(Gossypium hirsutum L.)

Programmed cell death(PCD) plays a critical role in the development of plant pigment glands, while H_2O_2, which is a kind of reactive oxygen species(ROS) produced by the aerobic metabolism of cells, acts as an important signal in this process. Here, we investigated the temporal and spatial dynamics of accumulated H_2O_2 in pigment glands of Gossypium hirsutum L. with 3,3-diaminobenzidine(DAB) staining, 2',7'-dichlorodihydrofluorescein diacetate(DCFH2)-DA fluorescent labeling and Ce Cl3 cytochemical localization techniques. The results showed that the pigment glands of G. hirsutum could generate H_2O_2, and the amount and localization of H_2O_2 varied at different developmental stages. At the early developmental stage, a small amount of H_2O_2 accumulated in the vacuole membrane of pigment gland cells. At the intermediate stage, a large number of H_2O_2 appeared in the vacuole membrane, while cell walls started to accumulate a small amount of H_2O_2. When pigment gland cell degraded, H_2O_2 mainly accumulated on the chloroplast envelope membrane of inner sheath cells. With the degradation of the sheath cells, H_2O_2 was detected in cell wall and the membrane of secretory vesicles which contains the preliminary contents of pigment gland. With the pigment glands completely maturation, H_2O_2 would disappeared. The accumulation sites of H_2O_2 are consistent with the process of PCD of individual gland cells, which started from the degradation of intracellular membrane and ended with the degradation of cell walls. Thus H_2O_2 probably plays an important role in the development of pigment glands. In addition, the development of pigment glands and the generation of H_2O_2 are not associated with the light, and no H_2O_2 was detected in the secretions of pigment glands.     

双氧水对鼻咽癌细胞生长特性的影响及其机制的初步研究

目的:观察H2O2对人低分化鼻咽癌细胞(CNE-2Z)生长、增殖能力的影响,并探讨其可能机制。方法:用M TT及平板克隆形成实验、W estern B lot等检测H2O2诱导CNE-2Z后增殖能力、EGR-1、p53、p16、Cyclin D1的表达。结果:不同浓度H2O2可不同程度地抑制CNE-2Z细胞的生长增殖能力,同一时间点各实验组细胞抑制率相比差异有统计学意义,抑制率与H2O2浓度间表现出明显的剂量-效应关系。平板克隆形成实验的抑制率较M TT更明显。CNE-2Z无EGR-1、p16蛋白表达,可见p53、Cyclin D1蛋白表达;诱导培养后EGR-1、p53、Cyclin D1蛋白表达明显增加。结论:一定浓度的H2O2能抑制CNE-2Z细胞生长,其作用可能与EGR-1及p53蛋白表达增强有关;Egr-1基因在CNE-2Z中具有可诱导性,在肿瘤治疗中有一定的应用前景。     

In-depth observations of fermentative hydrogen production from liquid swine manure using an anaerobic sequencing batch reactor

In this study,experiments were designed to reveal in-depth information of the effect of pH and hydraulic retention time(HRT)on biohydrogen fermentation from liquid swine manure supplemented with glucose using an Anaerobic Sequencing Batch Reactor(ASBR)System.Five values of HRT(8,12,16,20,and 24 h)were first tested and the best HRT determined was further studied at five p H levels(4.4,4.7,5.0,5.3,and 5.6).The results showed that for HRT 24 h,there was a dividing H_2 content(around 37%)related to the total biogas production rate for the ASBR System running at p H 5.0.When the H_2 content went beyond 37%,an appreciable decline in biogas production rate was observed,implying that there might exist an H_2 content limit in the biogas.For other HRTs(8 through 20 h),an average H_2 content of 42%could be achieved.In the second experiment(HRT 12 h),the highest H_2 content(35%)in the biogas was found to be associated with p H 5.0.The upswing of p H from 5.0 to 5.6 had a significantly more impact on biogas H_2 content than the downswing of p H from5.0 to 4.3.The results also indicated good linear relationships of biogas and H_2 production rates with HRT(r=0.9971 and0.9967,respectively).Since the optimal ASBR operating conditions were different for the biogas/H_2 production rates and the H_2 yield,a compromised combination of the running parameters was determined to be HRT 12 h and pH 5.0 in order to achieve good biogas/H_2 productions.     

两种鸢尾属植物在铝胁迫下的生理反应

采用水培方法,在AlCl_3·6H_2O质量浓度为0(对照)、5、10、15、20、25 mg/L条件下分别培养鸢尾和黄花鸢尾,研究两种鸢尾在铝胁迫下的生理反应.结果表明,AlCl_3·6H_2O质量浓度为10 mg/L时,两种鸢尾的叶绿素含量、类胡萝卜素含量和根系活力均较对照极显著升高;AlCl_3·6H_2O质量浓度高于10 mg/L时,两种鸢尾的叶绿素含量、类胡萝卜素含量和根系活力均随Al~(3+)浓度的增大而下降;AlCl_3·6H_2O质量浓度为5 mg/L时,两种鸢尾叶片内可溶性糖含量显著低于对照,随着AlCl_3·6H_2O质量浓度的增大,可溶性糖含量逐渐上升;AlCl_3·6H_2O质量浓度为0～25 mg/L时,两种鸢尾叶片内丙二醛和游离脯氨酸含量均随Al~(3+)浓度的增大而持续上升.     

转化法处理含砷硫酸废水的研究

A technology of conversion treatment of wastewater containing H_2SO_4 and As by Fes was presented in the light of actual conditions of H_2SO_4 production. Through the two-stage treatment of conversion-neutralization or neutralization-conversion, concentra     

H_2O_2对丙草胺在水体中光解的影响

以高压汞灯和自然光为光源,研究了酰胺类除草剂丙草胺在水体中的光解动态,并以PNDA为探针,初步研究了双氧水对丙草胺光解的影响机理。由于H2O2能通过光解产生羟基自由基,从而对丙草胺表现出显著的光敏化降解作用。在高压汞灯下,H2O2使丙草胺的光解速率提高了1.74~4.55倍,但光敏率随H2O2浓度添加至一定量后而减弱;在太阳光下,H2O2使丙草胺的降解速率提高了33.6~81.58倍,敏化作用却随H2O2添加浓度的升高而增强。     

Foliar application of sodium hydrosulfide(NaHS),a hydrogen sulfide(H_2S) donor,can protect seedlings against heat stress in wheat(Triticum aestivum L.)

Temperature extremes represent an important limiting factor to plant growth and productivity. Low concentration of hydrogen sulfide(H_2S) has been proven to function in physiological responses to various stresses. The present study evaluated the effect of foliar application of wheat seedlings with a H_2S donor, sodium hydrosulfide(NaHS), on the response to acute heat stress. The results showed that pretreatment with NaHS could promote heat tolerance of wheat seedlings in a dose-dependent manner. Again, it was verified that H_2S, rather than other sulfur-containing components or sodion derived from NaHS solution, should contribute to the positive role in promoting wheat seedlings against heat stress. To further study antioxidant mechanisms of NaHS-induced heat tolerance, superoxide dismutase(SOD, EC 1.15.1.1), catalase(CAT, EC 1.11.1.6) and ascorbate peroxidase(APX, EC 1.11.1.11) activities, and H_2S, hydrogen peroxide(H_2O_2), malonaldehyde(MDA), and soluble sugar contents in wheat seedlings were determined. The results showed that, under heat stress, the activities of SOD, CAT, and APX, H_2S, H_2O_2, MDA, and soluble sugar contents in NaHS-pretreated seedlings and its control all increased. Meanwhile, NaHS-pretreated seedlings showed higher antioxidant enzymes activities and gene expression levels as well as the H_2S and soluble sugar levels, and lower H_2O_2, MDA contents induced by heat stress. While little effect was detected in antioxidant enzymes activities and soluble substances contents in pretreated wheat seedlings compared with its control under normal culture conditions(data not shown). All of our results suggested that exogenous NaHS could alleviate oxidative damage and improve heat tolerance by regulating the antioxidant system in wheat seedlings under heat stress.