模拟增温与UV-B 辐射增强对云杉种子萌发和幼苗生长的影响

臭氧层损耗导致的地球表面UV-B辐射增强以及温室气体增多引起的气候变暖是当今两大全球环境问题。UV-B辐射增强和气候变暖对陆地植物和生态系统产生深远影响，并已成为全球变化研究的重要议题。作为世界第三极的青藏高原，UV-B 辐射增强以及气候变暖现象尤为突出。本试验所在林区是青藏高原东缘的主要林区，具有大面积的亚高山人工针叶成熟林，在全球变化背景下该森林的天然更新潜力如何是急待回答的重要问题。基于此，本研究围绕森林树种的种子和幼苗这一更新的重要阶段，开展了气候变暖、UV-B辐射增强和联合胁迫对云杉种子萌发及幼苗定居影响的研究，旨在全球变化背景下，探讨全球变暖、UV-B 辐射增强和联合胁迫是否对西南地区大面积人工亚高山针叶林更新的种子萌发和幼苗定居阶段产生影响。 本文以青藏高原东缘亚高山针叶林主要树种云杉为研究对象，研究云杉种子萌发及幼苗的生长和生理对UV-B辐射增强与气候变暖的响应。采用UV-B荧光灯（UV-lamp）来模拟增强的UV-B 辐射，此外，采用开顶式有机玻璃罩（OTCs）来模拟气候变暖。本试验包括四个处理：（1）大气UV-B 辐射+大气温度（C）；（2）大气UV-B 辐射+模拟气候变暖（W）；（3）增强的UV-B辐射+大气温度（U）；（4）增强的UV-B辐射+模拟气候变暖（U+W）。 根据本试验结果，UV-B辐射增强对云杉种子萌发没有显著影响，它对萌发云杉幼苗的影响主要体现在幼叶展开以后。根据两年的试验结果，增强的UV-B辐射降低了云杉幼苗抗氧化酶活性，降低了抗氧化物质的含量，此外，造成了膜质的过氧化，表现为MDA在针叶中的积累。增强的UV-B照射处理萌发云杉幼苗两年后，幼苗的生长受到显著抑制。我们的结果显示，OTCs分别提高了空气（10 cm）和土壤（5 cm）温度1.74℃和0.94 ℃。增温显著地促进了云杉种子提前萌发，提高了萌发速率和萌发比率，而且，明显地促进了幼苗的生长，表现为株高和生物量累积的显著增长。此外增温还有利于云杉幼苗根的伸长生长以及生物量的累积，这可以使云杉幼苗更好地利用土壤中的水分和营养元素。 根据本试验结果，温度升高显著地促进了增强UV-B辐射下云杉萌发幼苗的生长，这说明，温度升高缓解了UV-B辐射增强对云杉萌发幼苗的负面影响。这种缓解作用可能是温度升高对UV-B辐射增强处理下幼苗的抗氧化系统活性改善的结果。温度升高还缓解了高UV-B辐射对云杉幼苗根生长的抑制作用，这也可能是增温缓解伤害的原因之一。此外，根据我们的试验结果，增温与UV-B辐射增强联合作用（U+W）下云杉萌发幼苗的生长状况好于大气温度与大气UV-B辐射联合（C）处理，表现为株高、地径、根长和生物量积累均高于C处理，因此可以推断，UV-B辐射增强与气候变暖同时存在对萌发幼苗在两年之内的生长没有产生抑制作用，也就是说，气候变暖的缓解作用完全弥补了UV-B辐射增强的有害作用。 同样，增强的UV-B辐射显著影响了云杉幼苗的光合作用，表现为净光合速率（Pn）和表观量子效率（Φ）的提高，此外，根据我们的试验结果，它还造成了PSII的光抑制。增强的UV-B辐射显著抑制了云杉幼苗对营养元素的吸收，表现为大量营养元素、碳、钙、镁和锌含量的降低，但是，它却显著促进了铁在植株体内的积累。增温显著地提高了净光合速率，但是，它对光系统II（PSII）的光化学效率影响不大。温度升高缓解了UV-B增强对云杉幼苗光合作用的伤害，表现为净光合速率、表观量子效率以及PSII光化学效率的提高。此外，温度升高还缓解了UV-B辐射增强对离子吸收的抑制作用。 Enhanced UV-B radiation due to the reduction of O3 layer and global warming induced by increased greenhouse gases in the air have become the two pressing aspects of global climate changes. Moreover, enhanced UV-B radiation and warming have profound and long-term impacts on terrestrial plants and ecosystems, and the studies focusing on the two factors have attracted many attentions. Qinghai-Tibetan Plateau is the third in elevation in the world, and enhanced UV-B radiation and climate warming are especially prominent in this region. Our research located in the main forest belt in the eastern Qinghai-Tibetan Plateau where large areas of subalpine coniferous forests distributed. Based on that, we carried out a research to study the effects of enhanced UV-B radiation and climate warming on seed germination and seedlings growth of seedlings which are the important basic stage in forest regeneration. This research was arranged by a complete factorial design and included two factors (UV-B radiation and temperature) with two levels. The UV-lamps were used to manipulate the supplemental UV-B radiation and open-top chambers (OTCs) were adopted to increase temperature. The four treatments were: (1) C, ambient UV-B without warming; (2) U, enhanced UV-B without warming; (3) W, ambient UV-B with OTCs warming; (4) U+W, enhanced UV-B with OTCs warming. The main results were exhibited as follows: 1. Based on our results in this research, OTCs increased temperature on average 1.74℃ in air (10 cm above ground) and 0.92 ℃ in soil (5 cm beneath ground). Furthermore, OTCs also slightly reduced soil moisture and relative air humidity, however, the differences was not statistically significant. 2. Our results showed that enhanced UV-B had no significant effects on the seeds germination of P. asperata. Enhanced UV-B affected sprouts of P. asperata until the needles unfolded. During two years, enhanced UV-B inhibited the efficiency of the antioxidant defense systems, and as a result, it induced oxidant stress and the accumulation of MDA in needles. After two years of exposure to enhanced UV-B, the growth of P. asperata sprouts was markedly restrained compared with those under ambient UV-B radiation and temperature (C). Warming significantly stimulated the germination speed and increased the germination rate of P. asperata seeds. In the next place, it prominently facilitated the growth of P. asperata sprouts, represented as improvements in stem elongation and biomass accumulation. Furthermore, warming also increased root growth of P. asperata sprouts, which could made sprouts more efficient to use water and nutrient elements in soil. In this research, warming alleviated the deleterious effects of enhanced UV-B on P. asperata sprouts. It markedly stimulated the growth of P. asperata sprouts exposed to enhanced UV-B. The ease effects of warming on the abilities of the antioxidant defense systems might account for its amending effects on growth. After two years of exposure to enhanced UV-B radiation and warming, the growth of P. asperata sprouts was better than those under ambient UV-B radiation without warming (C), which could be seen from the higher plant height, basal diameter, root length and total biomass accumulation compared with C. 3. Enhanced UV-B radiation significantly influenced the photosynthesis processes of two-year old P. asperata seedlings. Our results showed that enhanced UV-B reduced the net photosynthetic rate (Pn) and the apparent quantum efficiency (Φ), and induced photoinhibition of photosynthetic system II (PSII). Enhanced UV-B significantly decreased the concentration of nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and zinc (Zn), however, it increased the accumulation of iron (Fe) in the whole plant of P. asperata seedlings. Warming significantly stimulated Pn of P. asperata seedlings but it had no prominent impacts on the photochemical efficiency of PSII. In our research, warming also alleviated the harmful effects of enhanced UV-B on photosynthesis and absorption of ions of P. asperata seedlings. It increased Pn, Φ and the photochemical efficiency of PSII in seedlings exposed to enhanced UV-B. Moreover, warming also increased the absorption of ions of the seedlings exposed to enhanced UV-B radiation.

不同小麦品种（系）中主要矿质元素的含量比较及与品质的关系

采用微波消解、电感耦合高频等离子体原子发射光谱（ICP-AES）的方法,对62份不同小麦品种（系）中锌、铁、铜、钙、钠和钾的含量进行了测定。同时利用红外线品质测定仪对主要品质指标粗蛋白、湿面筋、沉降值进行了测定。结果表明，不同小麦品种（系）中各种矿质元素的含量存在差异，2006年小麦品种中铁含量变幅为18.55-58.19 ug/g，平均为30.83ug/g ，最高与最低的相差39.64ug/g；锌含量变幅为5.70-25.80 ug/g，平均为15.13ug/g ，最高与最低相差20.10ug/g。2008年小麦品种（系）中铁含量变幅为16.68-52.25 ug/g，平均为30.10ug/g，最高与最低相差35.58ug/g；锌含量变幅为12.29-33.47 ug/g，平均为21.11ug/g，最高与最低相差21.18ug/g；钙含量变幅为167.53-348.80ug/g，平均为248.59ug/g，最高与最低相差192.59ug/g；铜含量变幅为2.32-5.83 ug/g，平均为2.98ug/g，最高与最低的相差3.61ug/g；钾含量变幅为1822.71-4414.91 ug/g，平均为2617.87ug/g，最高与最低的相差2634.72ug/g；钠含量变幅为10.25-39.82 ug/g，平均为23.05ug/g，最高与最低的相差29.57ug/g。 两年不同小麦品种（系）中矿质元素的含量分析结果表明：铁、铜、钙、钠和钾含量年际变化不明显,说明小麦对铁、铜、钙、钠和钾的吸收较稳定；锌含量变化较大，可能受环境的影响比较大。分析各矿质元素含量与粗蛋白、湿面筋、沉降值及元素之间的相关关系，结果表明，锌含量与粗蛋白含量呈极显著正相关关系，相关系数为0.317，与湿面筋含量之间呈显著正相关，相关系数达到0.246；铁含量与粗蛋白含量呈显著的正相关关系，相关系数是0.262；铜、钙、钠和钾含量与粗蛋白含量、湿面筋和沉降值之间存在正相关，但不显著，其中钠与沉降值之间为负相关。表明施锌或铁对提高小麦粗蛋白和湿面筋有显著效应，其余矿质元素有促进作用但不明显。 利用RAPD分子标记技术对川育23、41058、川育20及其父母本进行分析，力图从分子水平找到小麦矿质元素含量之间的差异性，琼脂糖电泳结果表明不同的小麦品种（系）间扩增出了差异条带。 以上研究结果，将对筛选“微量营养强化型”小麦新材料，选育“微量营养强化型”小麦新品种奠定基础。 62 different wheat cultivars was digested with HNO3 in a tightly closed vessel heated under micro-wave,then contents of zinc，iron,copper，calcium，sodium and potassium were determined by inductively coupled plasma-atomic emission spectroscopy(ICP-AES)．The main indexes of wheat quality such as total protein、wet glu and sedimentation volume were detected by Infratec 1255 Food & Feed Analyzer at the same time.The obtained results showed that variation for all of the mineral elements concentrations among different cultivars were observed .In 2006, the amplitude variation of the iron content was 18.55-58.19 ug/g,the average value was 30.83ug/g,and 39.64ug/g between the highest-content cultivar and the lowest one; the amplitude variation of the zinc content was 5.70-25.8 ug/g,the average value was 15.13ug/g,and 20.10ug/g between the highest-content cultivar and the lowest one.In 2008, the amplitude variation of the iron content was 16.68-52.25 ug/g,the average value was 30.10ug/g,and 35.58ug/g between the highest-content cultivar and the lowest one; the amplitude variation of the zinc content was 12.29-33.47 ug/g,the average value was 21.11ug/g,and 21.18ug/g between the highest-content cultivar and the lowest one; the amplitude variation of the calcium content was 167.53-348.80ug/g,the average value was 248.59ug/g,and 192.59ug/g between the highest-content cultivar and the lowest one; the amplitude variation of the copper content was 2.32-5.83 ug/g,the average value was 2.98ug/g,and 3.61ug/g between the highest-content cultivar and the lowest one; the amplitude variation of the potassium content was 1822.71-4414.91 ug/g,the average value was 2617.87ug/g,and 2634.72ug/g between the highest-content cultivar and the lowest one; the amplitude variation of the sodium content was 10.25-39.82 ug/g,the average value was 23.05ug/g,and 29.57ug/g between the highest-content cultivar and the lowest one. Analysis was made on the annual variation of mineral elements content in different Wheat cultivars ,the result shows:there is no obvious difference of iron ,copper ,sodium、calcium and potassium concentrations in wheat cultivars, suggesting the absorption of the iron, copper, sodium、calcium and potassium by wheat are relatively steady ,but zinc concentrations change obviously ,maybe influenced heavily by environment . The correlation between mineral elements 、mineral elements and total protein、mineral elements and sedimentation volume as well as mineral elements and wet glut were analysed in this paper, the result showed that there was significant positive correlation between zinc content and total protein (the correlation coefficient is 0.317), positive correlation between zinc content and wet glu (the correlation coefficient is 0.246), positive correlation between iron content and total protein (the correlation coefficient is 0.262). there was positive but not obvious correlation between the contents of copper, calcium, sodium or potassium and total protein, wet glut or sedimentation volume,among which was negative correlation between sodium and sedimentation volume.It was indicated zinc or iron fertilization has prominent effects in improving the total protein in wheat, the rest mineral elements have Non- obvious facilitation. The study then forecasted the genetic difference of different wheat by the molecular marker of RAPD in order to find differences in molecular level. Chuanyu23、41058、chuanyu20 as well as their male and female parents were analysed by RAPD markers,Agarose gel electrophoresis of DNA revealed the appearance of differential bands . The above-mentioned results of this study establish the foundation to screening the new materials of wheat of " strengthening type of micro- nutrition ", and to breeding the new wheat cultivars of" strengthening type of micro- nutrition ".

红发夫酵母发酵虾青素的研究

红发夫酵母分离于北美西部高山地区和日本一些岛屿上落叶树的渗出液中，因其所产主要色素为在水产养殖、食品和医药工业有广阔应用前景的虾青素而成为研究的热点。本论文对红发夫酵母Phaffia rhodozyma 的生长特性、培养参数与培养基组分对生长和虾青素积累的影响及其优化、虾青素合成的调节控制、虾青素的提取测定及红发夫酵母耐高温菌种的诱变进行了系统的研究。 虾青素是红发夫酵母的胞内色素，要对其进行分析首先要对红发夫酵母进行破壁处理，实验发现二甲亚砜是最有效的破壁溶剂，用氯仿和丙酮可以有效地把类胡萝卜素从二甲亚砜破壁后的红发夫酵母细胞中提取出来。 在固定摇床转速为200 rpm，温度为20 ℃的条件下，当种龄为36 h，以10％的接种量接入装液量为30 mL的250 mL三角瓶，初始pH为5.5时最有利于红发夫酵母的生长及类胡萝卜素的合成。 本实验中红发夫酵母最佳利用碳、氮源分别为蔗糖和蛋白胨，但蛋白胨价格昂贵，不适宜作单一氮源，因此使用硫酸铵和酵母膏作为复合氮源。 本论文采用了BP神经网络结合遗传算法的方法来优化红发夫酵母的发酵培养基，得到红发夫酵母发酵培养基的最佳配比为：蔗糖45.10 g/L、硫酸铵3.00 g/L、硫酸镁0.80 g/L、磷酸二氢钾1.40 g/L、酵母膏3.00 g/L、氯化钙0.50 g/L，使用优化后的培养基发酵类胡萝卜素产量达到8.20 mg/L，干重达到9.47 g/L，类胡萝卜素的产量比起始培养基提高了95.90%，干重提高了89.40%。 从代谢途径出发对红发夫酵母合成虾青素调控调控，选择谷氨酸、乙醇、VB1作为添加剂，通过正交试验设计得出三者添加水平分别为0.2 g/L，0.1% (V/V)，10 mg/L时，类胡萝卜素产量提高了25.73%，达到了10.31mg/L。 通过上述优化培养，本论文中红发夫酵母的虾青素产量从1.33 mg/L提高到9.12 mg/L，产量提高了6.86倍；总类胡萝卜素产量从4.23 mg/L提高到10.31 mg/L，产量提高了2.44倍；细胞干重从5.00 g/L提高到11.35 g/L，提高了2.27倍，总体提高效果显著。 红发夫酵母属于中低温菌，本论文采用紫外复合诱变的方式，通过高温筛选，得到一株能在35 ℃下能生长的突变株，但所产类胡萝卜素中虾青素所占比例很小，可能是诱变改变了红发夫酵母的代谢途径，阻断了虾青素的合成。 Phaffia rhodozyma is a heterobasidiomyceteous yeast that was originally isolated from the slime fluxes of brich tree wounds in mountain regions of northern Japan and southern Alaska. Phaffia rhodozyma produces astaxanthin as its principal carotenoid pigment, which has potential applications in acquaculture, food and pharmaceutical industry. This paper researched ways to break cell, analysis of astaxanthin, characteristics of growth, culture parameters and the effects of components of medium on growth and astaxanthin formation , optimization of culture medium, control of astaxanthin synthesis and mutagenesis of Phaffia rhodozyma. It is necessary to disrupt the yeast cell for extracting astaxanthin considering the yeast accumulating carotenoids in cell. Dimethyisulphoxide was the most effective solvent for breaking the yeast cell; acetone and chloroform were effective to extract carotenoids out of the disrupted cell. The optimum pH for growth and carotenoids synthesis is 5.5, the optimum medium volume is 30 mL (in 250 mL flask), the optimum culture time of inoculum is 36 h, the optimum inoculum concentration is 10%. The research on culture medium showed: sucrose is the best one of 6 carbon sources for growth and astaxanthin synthesis. Peptone is the best nitrogen source for growth and astaxanthin synthesis. Uniform Design was used for trial design of the formula medium components, then back-propagation neural network was established to modeling the relationships between the carotenoid yield and the concentration of medium components. Genetic algorithm (GA) was used for global optimization of the model. The optimum combination of the medium was obtained: sucrose 45.10 g/L, ammonium sulfate 3.00 g/L, magnesium sulfate 0.80 g/L, potassium dihydrogen phosphate 1.40 g/L, yeast extract 3.00 g/L, calcium chloride 0.50 g/L. The yield of carotenoid reached 8.20 mg/L, which was 95.90% higher than that of the original medium. Glu, VB1 and ethanol were selected as fermentation addictives, after Orthogonal Test, the carotenoid contents increased by 25.73% when adding 0.16 g/L Glu, VB1 10 mg/L and ethanol 0.1% (V/V). After the above optimization, the astaxanthin content increased 6.86 folds, which is 9.12 mg/L. The carotenoids content increased 2.44 folds, which is 10.31 mg/L. The biomass increased 2.27 folds, which is 11.35 g/L. Phaffia rhodozyma grows in the mild temperature range of 0 to 27 ℃, in this work, a thermotolerant mutant was selected through UV-irradiation. It can grows at 35 ℃, and showed increased carotenoid content. The optimal growth temperature for this mutant is 30 ℃. But the mutant can only produce carotenoids with little astaxanthin accumulation.

CO selective oxidation in a microchannel reactor for PEM fuel cell

It is indispensable to remove CO at the level of less than 50ppm in H-2-rich feed gas for the proton exchange membrane (PEM) fuel cells. In this paper, catalyst with high activity and selectivity, and a microchannel reactor for CO preferential oxidation (PROX) have been developed. The results indicated that potassium on supported Rh metal catalysts had a promoting effect in the CO selective catalytic oxidation under H-2-rich stream, and microchannel reactor has an excellent ability to use in on-board hydrogen generation system. CO conversion keeps at high levels even at a very high GHSV as 500 000 h(-1), so, miniaturization of hydrogen generation system can be achieved by using the microchannel reactor. (C) 2004 Elsevier B.V. All rights reserved.

Study of an electroosmotic pump for liquid delivery and its application in capillary column liquid chromatography

A packed-bed electroosmotic pump (EOP) was constructed and evaluated. The EOP consisted of three capillary columns packed in parallel, a gas-releasing device, Pt electrodes and a high-voltage power supply. The EOP could generate output pressure above 5.0 MPa and constant flow rate in the range of nl/min to a few mul/min for pure water, pure methanol, 2 mM potassium dihydrogenphosphate buffer, the buffer-methanol mixture and the pure water-methanol mixture at applied potentials less than 20 W The composition of solvent before/after pumping was quantitatively determined by using a gas chromatograph equipped with both flame ionization detector and thermal conductivity detector. It was found that there were no apparent changes in composition and relative concentrations after pumping process for a methanol-ethanol-acetonitrile mixture and a methanol-water mixture. Theoretical aspect of the EOP was discussed in detail. An capillary HPLC system consisting of the EOP, an injection valve, a 15 cm x 320 mum i.d., 5 mum Spherigel C(18) stainless steel analytical column, and an on-column UV detector was connected to evaluate the performance of the EOP. A comparative study was also carried out with a mechanical capillary HPLC pump on the same system. The results demonstrated that the reproducibility of flow rate and the pulsation-free flow property of the EOP are superior to that of mechanical pump in capillary HPLC application. (C) 2004 Elsevier B.V. All rights reserved.

聚丙烯酰胺防治水土流失的效果

Field plots observations indicate that applying polyacrylamide to soil can reduce surface runoff by 18 4%～46 8%,decrease soil erosion by 13%～55%,and increase soil organic matter,alkali-hydrolyzable nitrogen,available phosphate,available potassium in different degrees compared with not application.In addition,applying polyacrylamide can also increase corn yield by 540 5kg·ha -1 ,and net income by 240 5ha.

Calibration of standard seawater in electrical conductivity

The procedure adopted by the Standard Seawater Service for the calibration of Standard Seawater in electrical conductivity relative to a defined potassium chloride solution is described

膜荚黄芪氮磷钾优化施肥模式研究

采用氮、磷、钾三因素二次D-饱和最优设计,通过田间试验建立了氮、磷、钾的施肥量编码值与膜荚黄芪根产量、多糖含量的效应函数。结果表明,氮、磷、钾肥对膜荚黄芪根产量的增产作用大小依次为氮肥>钾肥>磷肥;氮、磷、钾肥对黄芪多糖含量的作用大小依次为钾肥>磷肥>氮肥,其中钾肥为负效应,氮肥、磷肥为正效应。寻优结果表明,膜荚黄芪目标产量在6000～7000 kg/hm~2之间,95%置信区间的优化施肥量为N 66.85～102.92 kg/hm~2、P_2O_5 64.64～94.95 kg/hm~2、K_2O 119.78～166.48kg/hm~2;膜荚黄芪多糖含量在13%～14%之间,95%置信区间的优化施肥量为N 66.85～102.92kg/hm~2、P_2O_5 64.64～94.95kg/hm~2、K_2O 119.78～166.48 kg/hm~2;膜荚黄芪高产优质高效栽培优化施肥量为N 99.52～102.92kg/hm~2、P_2O_5 94.20～94.95kg/hm~2、K_2O 119.78～166.48kg/hm~2,N、P_2O_5、K_2O的最佳比例为1:0.92～0.95:1.16～1....

施钾水平对烟叶含钾量的影响

通过盆栽试验 ,采用定位叶片的方法 ,进行不同钾肥用量试验 ,研究了增施钾肥对石灰性土壤上烤烟吸钾和土壤供钾的影响及提高石灰性土壤上烤烟含钾量的可能途径。结果表明 ,增施钾肥可以显著提高烟叶含钾量 ;而当施钾量达一定水平时 ,只有大幅度增加钾肥施用量 ,烟叶含钾量才显著增加 ,但对烟叶产量影响不大。施钾对烟叶含钾量的提高作用在生育后期最为显著。保证生育后期充足的钾素供应对提高烟叶含钾量可能具有重要意义

陕北中部丘陵区土壤肥力现状及提高土地生产力的途径

调查分析了延安宝塔区和安塞县 7个乡镇近三年来的粮食生产 ,肥料投入以及各土地类型的土壤肥力状况 ,表明 :投入的化肥中 ,氮肥以低浓度养分的碳铵为主 ,平均占肥料总量的 38.3% ,从施入土壤的 N、P、K养分来看 ,K比例很小 ,结构不合理。土壤肥力总体水平低 ,且不同土地类型差异大 ;由于各乡镇自然和经济状况的差异 ,土地投入量不同 ,从而导致粮食产量相差悬殊 ,并且年际波动大。提高土地生产力的有效途径是培肥土壤和大力推广农作物高产栽培技术

宁夏黄土区不同植物群落土地利用方式对土壤质量的影响

本文研究了宁夏南部山区典型植物群落土地不同利用方式下土壤质量的变化。结果表明:(1)典型长芒草群落土地,开垦地比封禁地土壤有机质、全氮、全磷、速效氮、速效磷、速效钾养分含量明显降低,降低幅度分别为19.5%、20.1%、17.6%1、3.0%、77.8%和47.5%。脲酶活性为开垦地>封禁地,蔗糖酶则表现为封禁地>开垦地,中性磷酸酶差异不明显。(2)铁杆蒿群落土地三种利用方式下:放牧地土壤有机质、全氮、全磷、速效钾等养分含量较封禁地与开垦地有一定幅度的增加;放牧地的土壤脲酶、蔗糖酶和中性磷酸酶活性均高于封禁和开垦的同土层土壤,封禁地的脲酶和蔗糖酶次之,开垦地的脲酶和蔗糖酶活性最小,开垦地的中性磷酸酶活性高于封禁地。脲酶活性在土层之间变化较小,最高为放牧地表层177.6 mg/(kg.h),最低为开垦地表下层114.5 mg/(kg.h),蔗糖酶活性层次之间变化明显,其中放牧地表层为表下层的3倍左右。长芒草群落土壤表层各级微团聚体表现为封禁地远大于开垦地,铁杆蒿群落土地不同利用方式下各级微团聚体表现不同,结构系数表现为表层>表下层,保持率则为表层<表下层。结构系数与保持率均表现为封禁地>放牧地>开垦地。(3)在...

有机酸对茄子生长发育及产量的影响

采用盆栽试验,研究了2种含钾土壤条件下不同有机酸对茄子产量和生长发育的影响。结果表明:通过叶面喷施有机酸可提高茄子单果重,改善植株的生长发育状况。其中,有机酸钾、甲酸、柠檬酸、乙酰丙酸与对照之间有显著差异;高钾土壤高于低钾土壤产量,且差异显著。有机酸的增产效果依次为有机酸钾>甲酸>柠檬酸>乙酰丙酸>草酸>丙酸>乙酸。

原子吸收光谱法测定膜荚黄芪不同器官矿质元素含量

应用混合酸HNO3-HClO4(4∶1)在常压微沸条件下对膜荚黄芪根系及茎叶样品进行消解,采用原子吸收光谱法测定了膜荚黄芪不同器官即根及茎叶中五种人体必需矿质元素K,Fe,Zn,Mn和Cu含量,并对结果进行了统计分析与比较。该方法标准曲线相关系数为0.997 3~0.999 9,加标回收率为92.88%~109.25%,相对标准偏差(RSD,n=5)为0.393 5%~3.175 2%。方法简单,结果可靠。结果显示,膜荚黄芪根及茎叶中5种矿质元素含量顺序均为K>Fe>Zn>Mn>Cu。膜荚黄芪不同器官矿质元素含量不同,根中富含Fe,Zn,Cu元素,根内Fe含量是茎叶的1.54倍。茎叶中也含有丰富的矿质元素,特别是K和Mn元素。茎叶中K含量是根的1.63倍,这与黄芪的药效相符合。试验结果将为研究矿质元素在黄芪植株中的分布以及矿质元素含量与黄芪药效相关性提供理论依据。