缺锌与低锌对玉米苗期生长发育的影响

用溶液培养的方法研究了缺锌、低锌和正常供锌对玉米生长发育的影响.结果表明:缺锌和低锌使玉米的株高和茎叶干重均显著降低,低锌比缺锌降低的更多;缺锌和低锌对根干重的影响远小于对地上部的影响,所以,使根冠比增大,缺锌和低锌对玉米生长发育的这种影响与其影响玉米体内的锌含量有关,而且这种影响因玉米的品种不同而有差异.     

荫蔽信号对大豆幼苗生长和光合特性的影响

红光/远红光比值(R/FR)下降是自然界荫蔽发生的重要信号。为探究大豆幼苗对荫蔽信号的应答机制,本文采用室内盆栽试验,以‘南豆12’和‘南032-4’两个大豆品种幼苗为材料,通过正常光照和低R/FR两种光照处理后,对其形态、光合特性以及叶绿素荧光参数进行研究。结果表明:与正常光照相比,低R/FR下,两个大豆材料幼苗均表现出典型的避荫性反应,即株高、叶面积、叶柄长、节间长增加,茎秆变细,其中,‘南豆12’的株高、叶柄长、节间长分别显著增加7.86%、81.48%、26.55%,‘南032-4’分别增加3.95%、76.67%、20.00%;叶片的光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)提高,胞间二氧化碳浓度(Ci)和初始荧光强度(Fo)、最大荧光(Fm)、最大光化学效率(Fv/Fm)、PSⅡ实际光化学效率(ΦPSⅡ)、光化学淬灭系数(q P)等降低,非光化学淬灭系数(q N)升高,总干物质积累量增加,其中,‘南豆12’和‘南032-4’的Pn分别增加37.21%和39.04%、总干物质积累量分别增加12.35%和17.36%、Ci分别降低9.29%和11.72%。然而,不同大豆材料对低R/FR的敏感程度不同。在低R/FR光环境下,‘南豆12’较‘南032-4’表现出较低的株高、节间长、叶柄长,较大的叶面积和茎粗,较高的光能传递转换效率、Pn、Gs以及干物质积累量,体现了对荫蔽较强的适应性。本研究进一步证实了大豆具有感受荫蔽信号(低R/FR)的能力,但其敏感程度因品种不同而不同,在间套作过程中,为提高大豆耐荫性,降低大豆因避荫反应导致的倒伏率,保障大豆产量,应该选择对荫蔽信号不敏感的品种。     

不同浓度砻糠灰浸提液对番茄和黄瓜幼苗生长的影响

以番茄品种“豫艺金粉二号”、黄瓜品种“豫艺201”为试验材料,采用穴盘育苗的方式,以草炭∶蛭石∶珍珠岩=1∶1∶1 (体积比)为栽培基质。通过根施用不同浓度(0、25%、50%、75%、100%)的砻糠灰浸提液,研究其对基质的理化性质、番茄和黄瓜幼苗生长的影响。试验结果显示:与对照相比,根施75%浓度的砻糠灰浸提液显著提高了育苗基质的持水孔隙、通气孔隙,改善了基质的理化特性;随着砻糠灰浸提液浓度的增加,2种育苗基质中微生物数量的变化趋势基本一致,其中细菌和真菌数量均呈下降趋势;与对照相比,根施砻糠灰浸提液可显著提高番茄和黄瓜幼苗株高、茎粗、根冠比和壮苗指数,幼苗叶片叶绿素含量、净光合速率、气孔导度和蒸腾速率也显著提高,以75%砻糠灰浸提液浓度为最佳;此外,根施75%砻糠灰浸提液还可以显著提高幼苗叶片可溶性总糖、蔗糖含量,提高碳水化合物代谢关键酶活性。由此可见,砻糠灰浸提液可以有效改善基质理化性质,促进植株生长和光合作用能力的提高,以提升幼苗碳水化合物的代谢能力,并以75%砻糠灰浸提液浓度的效果最好。     

Effect of a fly ash and gypsum mixture on rice cultivation

Abstract

The salt titration (ST) method was evaluated as a method to determine ZPC in comparison with the potentiometric titration (PT) method for 26 soils with variable charge clays, i.e., Oxisols and Ultisols from Thailand and Andisols from Japan. In addition to the determination of ST-pH₀ as the zero point of charge, a calculation procedure (STPT method) was adopted here in order to acquire more information from the titration curve. Furthermore, for the purpose of cross-checking of ZPC determined by the PT method, the ST procedure was successively applied to the samples analyzed by the PT method (PTST method).

The soil to solution ratios of 1: 10 to 1: 5 gave almost an identical ST-pH₀ value for every soil. The values of both ST-pH₀ and PT-ZPC ranged from 4.7 to 6.3 for the Andisols, while for the Oxisols and Ultisols, they were always below 4.2. The difference between the values of ST-pH₀ and PT-ZPC was only slight for the Andisols, whereas it was sometimes large (0.4 pH unit) for the Oxisols and Ultisols. Nevertheless, it was concluded that the ST method with its modification (STPT) was comparable to or even better than the PT method for the soil characterization work due to its convenience and simplicity.     

A two-year experience on 15N-urea fertilization of a corn field amended with fly ash

Soybean seedlings (Glycine max) were exposed to simulated acid rain containing sulfate ion only or a mixture of sulfate, nitrate and chloride anions, using a continuous rain generating system in a side opened glasshouse. Plants were subjected to acid rain treatment twice a week, for a 1 or 3 hr period at a rate of 2.2 or 5.0 mm hr^?1, respectively. Dry seed yield in plants treated with simulated acid rain at pH 2.0, in the three of 4 experiments conducted over a 3 yr period, was significantly less than that at pH 3.0 or higher. Simulated acid rain treatment at pH 3.0 or higher did not significantly affect yield compared to pH 5.6; however, plants exposed to simulated acid rain at pH 4.0 tended to yield more than those treated with pH 5.6 rain. Based on the current 3 years of research in which results from 4 experiments were combined, rain acidity at current levels in Japan would not directly affect seed production of selected cultivars of soybean.     

Sewage sludge incinerator ash effects on soil chemical properties and growth of lettuce and corn

Abstract

Incineration reduces sewage sludge volume, but management of the resulting ash is an important environmental concern. A laboratory incubation study and greenhouse pot experiments with lettuce (Lactuca sativa L.) and corn (Zea mays L.) were conducted to examine the potential for recycling elements in sewage sludge incinerator ash in agricultural systems. Ash rates in both the laboratory and greenhouse were 0, 0.95, 3.8, 15.2, and 61.0 g/kg soil (Typic Hapludoll). Ash was also compared to equivalent rates of citrate soluble P from superphosphate fertilizer in a soil‐less growth medium. During soil: ash incubation, Olsen P and DTPA extractable copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) increased with incubation time at the higher ash rates. Release rates diminished rapidly, however, and the limited release of these elements after 280 days was associated with decreasing pH. In the greenhouse, ash amendment increased extractable soil P, plant tissue P, and the growth of lettuce and corn. Ash was a less effective P source than superphosphate fertilizer in the soil‐less growth medium and Olsen P levels were more consistent with these differences than Bray P. Ash increased extractable soil levels and plant tissue concentrations of calcium (Ca), magnesium (Mg), sodium (Na), Cu, and Zn, but extractable soil manganese (Mn) and plant tissue Mn decreased. Ash increased soil pH and extractable SO₄‐S. DTPA extractable Cd and Pb increased, but chromium (Cr) and nickel (Ni) decreased. Lettuce accumulated higher amounts of these trace metals than corn, but tissue concentrations were at control levels or below detection limits in both crops.     

杂卤石对玉米生长及养分吸收的影响研究

对杂卤石作为钾肥在玉米上施用的效果进行分析,以期为杂卤石应用于农业生产提供理论依据。通过盆栽试验研究了杂卤石对玉米生长及养分吸收的影响。各杂卤石处理分别较空白对照增产31. 54%～63. 14%,千粒重分别提高23. 80%～47. 15%,且差异均达显著水平。杂卤石处理的玉米产量分别较氯化钾、硫酸钾及硫酸钾镁处理提高22. 17%～29. 51%,千粒重分别提高7. 67%～12. 92%,差异均达显著水平。杂卤石能改善玉米对钾的吸收,各杂卤石处理玉米植株钾含量分别较空白对照增加21. 79%～93. 50%。适量施用杂卤石能促进玉米对钙的吸收,杂卤石用量为100 kg/hm~2的处理玉米植株钙含量较空白对照增加52. 7%,且杂卤石处理的玉米植株钙含量较3种传统钾肥处理提高了30. 59%～50. 37%。杂卤石能促进玉米对硫的吸收,各杂卤石处理玉米植株硫含量分别较空白对照增加了4. 43%～52. 22%。杂卤石用量与玉米植株钾、钙、硫含量及玉米产量均呈显著正相关关系,同时在杂卤石处理中玉米植株钾含量及钙含量与玉米产量均呈显著正相关关系。杂卤石能够提高玉米产量,促进玉米对钾及钙的吸收。     

Lead contents of coal,coal ash and fly ash

Flameless atomic absorption spectrometry is applied for the determination of Pb in coal, coal ash and fly ash. Lead concentrations in coal and coal ash ranging from respectively 7 to 110 µg g^?1 and 120 to 450 µg g^?1 are found. A mean concentration of 1520 µg g^?1 in fly ash corresponding to a concentration of 117 µg m^?3 in the effluent gas suggests the importance of coal combustion as an atmospheric source of Ph. The contribution of coal combustion to the total Pb emissions is conservatively estimated at 6%.     

蚯蚓堆肥浸提液对幼苗生长的影响

蚯蚓堆肥浸提液的育苗试验结果表明,不同浓度蚯蚓堆肥浸提液理化性质呈梯度变化,对幼苗生长发育的影响不同。与纯无机营养液体系相比,蚯蚓堆肥浸提液对番茄、小白菜及水稻幼苗的地上部生长、根系生长和活力、壮苗指数、叶绿素含量、抗氧化酶活性等指标均有不同程度提高。其中,添加浓度为 7.5%蚯蚓堆肥浸提液的应用效果最佳;随着浸提液浓度的增加,盐分浓度相应增加,则抑制了育苗生长。综上,在无机营养液中添加浓度 7.5%的蚯蚓堆肥浸提液能够不同程度促进幼苗的生长,具有良好的壮苗效果,为蚯蚓堆肥浸提液的应用奠定了一定的理论基础。     

Defluoridation of water by adsorption on fly ash

The ability of fly ash to remove fluoride from water and wastewaters has been studied at different concentrations, times, temperatures and pH of the solution. The rate constants of adsorption, intraparticle transport, mass transfer coefficients and thermodynamic parameters have been calculated at 30, 40, and 50 °C. The empirical model has been tested at various concentration for the present system. The removal of fluoride is favorable at low concentration, high temperature and acidic pH.

     

Effect of conservation tillage systems on corn root growth

The effects of conservation tillage on crop production have been widely investigated, but less information is available on root growth with different tillage systems over a range of soils. In this study, we compared corn (Zea mays L.) root length density and distribution with conventional moldboard plowing (MP) and 3 conservation-tillage treatments: chisel plowing (CH); ridge-tillage (RT); no-tillage (NT); for Griswold and Kewaunee silt loam and Plainfield loamy-sand soils. Root length densities were determined for the row (R), non-wheel track (NWT) and wheel track (WT) positions for two growing seasons (1982 and 1983). Conservation-tillage systems had equal or higher root densities than MP for all positions and depths at all 3 sites. Maximum root densities occurred between 10 and 40 cm for all tillage systems at all locations. In most cases, reduced root growth was associated with wheel traffic positions. Wheel traffic reduced root densities in the surface 10 cm by as much as 52% in MP at the Plainfield site.     

Effect of soyasaponins-rich extract from soybean on acute alcohol-induced hepatotoxicity in mice

The protective effects of soyasaponins-rich extract (SRE) from soybean against acute alcohol-induced hepatotoxicity were first investigated in the Institute of Cancer Research mice. Administration of SRE prior to alcohol significantly prevented the increases in serum aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase caused by alcohol, as well as hepatic triglyceride, total cholesterol, and malondialdehyde levels. Mice treated with SRE showed a better profile of the antioxidant system with normal superoxide dismutase, glutathione S-transferase, and glutathione peroxidase activities, which were associated with the increase of hepatic glutathione levels relative to the acute alcohol-treated group. Supplement of SRE prevented alcohol-induced hepatic steatosis necrosis, inflammation, and swelling, as indicated by liver histopathological studies. All of these findings demonstrate that SRE has protective effects on acute alcohol-induced liver damage.     

分根区垂向交替供水对玉米生长影响的研究

为探索1种新的节水灌溉技术-分根区垂向交替供水的节水增产效应，选用3种不同灌水方式（ 表面灌、下部灌、交替灌）和不同灌水周期（3d、5d、7d）及不同灌水方式下的相同灌水量组合进行了盆栽玉米对比试验研究。结果表明，垂向交替供水是可行的，相同灌水量条件下交替供水对作物根系的生长有明显促进作用，使根系在土壤垂直剖面分布更为均匀。同时根系活力和吸收功能明显增强，整株作物长势呈现出苗壮根旺的特点。此外5d的交替灌与3d的表面灌相比，作物长势明显改善，且节水26％以上；7d的交替灌与5d的表面灌相比，作物长势无明显差异，但节水20％以上，而5d的灌水周期是试验范围内交替灌应用时较为成功的方式。     

铜对不同苹果砧木实生苗生长的影响差异研究

在网室采用盆栽的方法研究了当年生八棱海棠、平邑甜茶 (M .hupehensis Rehd .)、莱芜难咽及海棠果 4种苹果砧木实生苗在外源铜 0、75、15 0mg kg处理下对植株相对株高、胸径、生物量 ,细胞膜透性及根茎叶中的铜、钙、铁矿质元素含量等的影响。结果表明 ,海棠果比平邑甜茶、莱芜难咽和八棱海棠等 3种砧木实生苗具有较强的抗铜毒害能力。     

稀土镧对镉胁迫下玉米幼苗生长的影响

以水培法研究了重金属Cd对玉米幼苗的胁迫伤害及稀土La对Cd伤害的缓解作用。结果表明,在Cd胁迫伤害下,玉米幼苗生长受到抑制,主要表现为株高、主根长下降,叶面积锐减,茎叶、根的鲜重以及干重明显下降,随着Cd胁迫浓度的增加,玉米幼苗受伤害程度趋向严重。在玉米幼苗上喷施适量浓度LaCl3(20mg/L),能缓解Cd对玉米幼苗生长造成的伤害。     

分根区垂向交替供水对玉米生长影响的研究

为探索1种新的节水灌溉技术——分根区垂向交替供水的节水增产效应，选用3种不同灌水方式(表面灌、下部灌、交替灌)和不同灌水周期(3 d、5 d、7 d)及不同灌水方式下的相同灌水量组合进行了盆栽玉米对比试验研究。结果表明，垂向交替供水是可行的，相同灌水量条件下交替供水对作物根系的生长有明显促进作用，使根系在土壤垂直剖面分布更为均匀。同时根系活力和吸收功能明显增强，整株作物长势呈现出苗壮根旺的特点。此外5 d的交替灌与3 d的表面灌相比，作物长势明显改善，且节水26%以上；7 d的交替灌与5 d的表面灌相比，作物长势无明显差异，但节水20%以上，而5 d的灌水周期是试验范围内交替灌应用时较为成功的方式。     

Effect of planting date and tillage system on soybean root growth

Soil erosion and moisture retention are major concerns of soybean growers. Conservation tillage provides residue cover to reduce soil loss and water evaporation. This study was conducted on a Tiptonville silt loam near Portageville, MO, USA. to determine the effect of tillage system and planting date on soybean [Glycine max (L.) Merrill] root growth and distribution. Tillage systems were conventional (clean) tillage, ridge tillage, and no‐tillage. ‘Essex’ soybean was planted on 14 May, 15 June, and 7 July in 1992 and 12 May, 2 June, and 21 June in 1993. Roots were observed 30 and 60 days after emergence (DAE) using a minirhizotron system. Stand density was not affected by tillage in either year or by planting date in 1992. Tillage did not effect rooting depth in either year. In 1992, rooting depth 30 DAE was greater for the 14 May planting date than for either of the other two planting dates. No other planting date effects on rooting depth were found. Among soil depths, root length density (RLD) was greatest for the 14 to 26 cm depth in 1992 and for the 0 to 13 cm depth in 1993. Neither tillage system nor planting date affected RLD in either year and there was no interaction between these main effects and soil depths. The largest changes in RLD (CRLD) were observed in the 14 to 26 cm and 27 to 39 cm depths in 1992 and the 0 to 13 cm depth in 1993. Tillage did not planting date in 1992 and the 12 May and 2 June planting dates in 1993 produced the highest yields. Tillage did not affect yield and there was no interaction between tillage and planting date.     

盐胁迫对玉米发芽和苗期生长的影响

通过室内培养及盆栽试验，研究了不同浓度NaCl胁迫对玉米种子发芽和幼苗生长的影响。结果表明，≤0．5g／L NaCl处理有利于提高玉米种子萌发率、发芽率和根、芽的伸长及根数的增加。随盐胁迫浓度的增大，玉米种子萌发率、发芽率急剧下降，根芽伸长及根数极受抑制，0．5g／L NaCl可能是影响玉米种子发芽的临界浓度。用≥0．5g／L NaCl的盐溶液长期灌溉会因土壤中盐分累积而使玉米生长受阻，成活率下降，幼苗在形态上表现出盐害效应。用自来水（0．1g／L NaCl）处理的玉米幼苗在植株干重、根系干重、含水量等5个指标都较其它处理达显著水平，说明用低盐浓度（0．1g／L NaCl）灌溉可促进玉米生长发育，提高产量。     

脉冲电场对渗透胁迫下玉米幼苗自发光子辐射的影响

为了揭示极低频脉冲电场(extremely low frequency pulsed electric field,ELF-PEF)对作物幼苗抗旱性的影响及其机理,采用渗透势为-0.1MPa的PEG-6000溶液对玉米幼苗形成生理干旱,研究了1Hz脉冲电场对渗透胁迫下玉米幼苗生长和自发光子辐射的变化。结果表明,在-0.1 MPa的渗透胁迫下玉米幼苗根系和叶片鲜质量缓慢增长,玉米幼苗种胚的自发光子辐射表现出先增加后减小的趋势,幼苗根系和叶片的自发光子辐射也呈现出波动性的增长趋势;经过脉冲电场处理的玉米幼苗根系和叶片鲜质量始终高于(P0.05)未经过脉冲电场处理的对照组,玉米种胚的自发光子辐射峰值出现的时间比对照组早(P0.01),峰值辐射强度也比对照高(P0.01),玉米幼苗根系和叶片的自发光子辐射都有所增强(P0.05),在渗透胁迫初期脉冲电场处理对玉米幼苗叶片自发光子辐射的增强效应非常显著(P0.01)。研究结果为揭示极低频脉冲电场对作物幼苗抗旱性的影响机理提供参考。