2种内生细菌对文冠果幼苗矿质元素吸收的影响

为探究前期筛选的具有溶磷、产铁载体、产IAA能力的内生细菌对文冠果(Xanthoceras sorbifolia Bunge)幼苗矿质元素的影响,选取一株假单胞菌属菌株XSB5和一株约克氏菌属菌株GG10作为试验菌株。用菌液浸泡经过层积催芽的文冠果种子,待植株长出第一片真叶后,用等量的菌液和清水处理文冠果幼苗,4个月后分析文冠果植株的生长状况。结果表明:用XSB5菌液处理后,文冠果植株地上和地下生物量均显著增加(P<0.05);GG10菌液处理后,文冠果地上和地下生物量均有所增加,地下生物量增加达显著水平(P<0.05);两种菌液处理后文冠果植株N、P、Mg积累量较对照显著增加(P<0.05),Fe积累量因处理时间不同而有差异;4种矿质元素的转运系数因不同菌液、不同处理时间而有差异;栽培基质中有效态N、P含量较对照显著增加(XSB5-30处理除外),有效态Mg、Fe含量与对照无显著差异。说明接种这2种内生细菌能影响栽培基质中矿质元素含量的变化,提高文冠果植株对矿质元素的吸收,改变矿质元素向上的运输能力,从而促进文冠果植株的生长。该研究可为文冠果促生菌肥的筛选提供一定的理论基础。     

轻型屋顶绿化中景天属植物栽培基质配比研究

以国产泥炭、椰糠、珍珠岩、陶粒等为原料,进行不同配比的轻型屋顶绿化栽培基质配方研究,依据其理化性质,筛选出2种较适配方。以金叶佛甲草Sedum lineare ‘Aurea’等5种景天属植物为试材,对2种配比基质中扦插植株的生长效果进行比较,以筛选适于景天属植物屋顶绿化栽培基质。结果表明,除松塔景天S. nicaeense在2种栽培基质上生长差异不显著外,其余4种景天属植物均在配比为国产泥炭∶椰糠∶珍珠岩= 2∶3∶1的基质(F3)中生长旺盛,覆盖迅速,地上及地下部分生物量积累较大。因此,初步确定基质F3为适宜景天属植物生长的轻型屋顶绿化基质。     

不同肥料对盆栽苹果花卡特兰生长及开花的影响

以三种不同比例缓释固体肥与三种液体肥组合为苹果花卡特兰施肥,分析不同施肥处理对苹果花卡特兰生长与开花的影响,并对开花植株商品化性状进行评分,探讨营养配方对苹果花卡特兰商品化栽培的影响。结果表明,含N量较高的肥料有利于苹果花卡特兰叶片与假球茎生长,而P、K比例较高的肥料有利于假球茎发育和开花。苗期可使用含N量较高的肥料促进营养生长及抽生假球茎,成株期则施P、K比例较高的肥料促进假鳞茎成熟与花芽分化,使苹果花卡特兰多抽花枝多开花,增加观赏性状,提高苹果花卡特兰商品价值。     

鼎湖山濒危植物紫背天葵的人工栽培

为研究鼎湖山紫背天葵人工栽培适宜的生长基质和气候条件,以组培球茎为材料,比较了自然气候条件下几种混合基质处理对植株生长情况的影响。结果表明：不同配比混合基质的pH值、有机质和铵态氮含量对球茎萌芽和植株的生长均有显著的影响,适合的pH缓冲范围在3．5～4．5之间,表明紫背天葵为喜酸植物。添加黄泥的基质并不适合紫背天葵的生长;泥炭土＋珍珠岩（3：1）混合基质较适宜于紫背天葵的生长,球茎萌芽率达到88％,植株的须根、球茎、叶和株高等指标表现良好。结合栽培物候期分析,球茎的萌芽期在当年11月～次年1月,生长适温在16～25℃之间,相对湿度为90％～95％。     

NaCL胁迫下番茄苗的生长和营养元素积累(简报)

在NaCI胁迫下番茄植株生长速率和营养元素积累均下降，但两品种的根冠比没有改变。不同品种番茄植株的生长和根冠部元素的积累对NaCI胁迫的响应有异。100mol·L（－1）NaCI处理下，K＋积累与植株生长速率呈显著正相关，Ca＋、Mg（2＋）的积累与生长速率相关性不显著。     

NaCl胁迫番茄苗的生长和营养元素积累（简报）

在ＮａＣｌ胁迫下番茄植株生长速率和营养元素积累均下降,但两品种的花冠比没有改变。不同品种番茄植株的生长和根冠部元素的积累对ＮａＣｌ胁迫的响应在异。１００ｍｏｌ·Ｌ＾－１ＮａＣｌ处理下,Ｋ＾＋积累与植株生长速率呈显著正相关,Ｃａ＾２＋、Ｍｇ＾２＋的积累与生长速率相关性不显著。     

水分和盐分胁迫对番茄植株生长和木质部水力特性的影响

木质部是植株体内水分传输的主要通路,其水力特性的变化会影响植株的水分关系和果实的水分积累。目前关于番茄植株木质部解剖结构和水力特性对水分和盐分胁迫的响应及其与植株生长和果实含水量之间的关系尚不明确。本研究通过日光温室番茄盆栽试验,设置3个处理:对照,土壤含水量(θ)为75%～95%田间持水量(FC),初始电导率(EC)为0.398 dS·m^-1;水分胁迫,开花前θ为75%～95% FC,开花后至成熟期θ为45%～65% FC,EC为0.398 dS·m^-1;盐分胁迫,θ为75%～95% FC,EC为1.680 dS·m^-1,研究了樱桃型番茄(红宝石)和中果型番茄(北番501)植株在水分和盐分胁迫下的植株生长、果实含水量以及木质部水力特性的变化。结果表明: 与对照相比,水分和盐分胁迫下茎秆横截面积和木质部导管直径分别减小了22.0%～40.7%和10.0%～18.3%,茎秆比导水率和桁架柄比导水率分别降低了8.8%～41.1%和12.9%～28.4%,抑制了植株生长,减少了地上部鲜重、果实大小、果实鲜重和含水量,且与樱桃型番茄相比,中果型番茄的降幅更大。此外,果实含水量分别与茎秆和桁架柄比导水率呈显著正相关。综上,番茄植株在水分和盐分胁迫下木质部水力特性指标减小,生长被抑制,果实鲜重显著降低,最终导致产量降低。其中,中果型番茄相较于樱桃型番茄对水分和盐分胁迫更敏感。     

不同栽培措施对不同品种彩色马蹄莲高生长的影响

通过栽培基质、肥料浓度和N、P、K元素浓度配比试验,对8个彩色马蹄莲(Zantedeschia Spreng．hybrids)品种的株高生长进行了比较。结果表明,栽培基质变化对大部分品种的高生长影响较小,只有‘Parfait’和‘Rubylite Rose’2个品种的高生长受栽培基质的影响较大。就‘Crystal Blush’和‘Parfait’2个品种而言,不同浓度的肥料处理,在生长后期各处理间无显著差异;而不同N、P、K营养元素配比处理显示,N元素变化对高生长影响较小,而P、K含量的提高有利于彩色马蹄莲的株高生长。     

消毒、伴生和微生物菌对连作基质性质及黄瓜生长发育的影响

以连续种植2茬的连作基质为对象,采用室内盆栽试验,设置连作基质太阳能消毒、热水消毒、多菌灵消毒、大蒜伴生栽培和施入微生物菌处理以及新基质对照,在种植黄瓜后观测基质理化性质、养分含量、酚类物质含量、相关酶活性的变化以及黄瓜结果期生长发育、光合作用和果实产量的变化,探究不同处理对连作基质栽培黄瓜生长发育影响的机制,以期在生产上为废旧基质重复利用提供新的思路和方法。结果表明:在连作基质栽培黄瓜后,太阳能消毒和热水消毒处理均能显著提高连作基质的pH,同时降低电导率;施入微生物菌处理的基质EC值、速效氮、速效磷、速效钾和总酚含量均显著低于连作基质,而其基质磷酸酶活性和过氧化氢酶活性显著高于连作基质。热水消毒还显著降低连作基质的总酚含量和复合态酚含量。黄瓜生长至结果期,太阳能消毒、热水消毒、多菌灵消毒、大蒜伴生栽培和施入微生物菌均显著增强黄瓜的根系活力和株高;其中热水消毒和施入微生物菌处理的产量增加最为显著,分别比连作基质栽培提高了16.56%和18.40%。可见,连作基质进行热水消毒处理和施入微生物菌处理均能降低基质盐分积累,减少总酚含量,进而显著提高黄瓜的根系活力和光合作用,从而增加产量。     

有机物料对黄河三角洲滨海盐土的根际效应：Ⅱ.盐分效应

采用根际袋法研究腐熟有机物料对滨海盐土水稻淹水层及土壤的盐分和植株元素吸收的影响．结果表明,在不排水条件下,施用有机物料使淹水层盐分上升,土壤盐分也高于对照,但其根际富集程度降低;植株Ｋ吸收增强,Ｎａ则明显下降,Ｃａ、Ｍｇ含量略增,但变化没有１价元素明显．     

Changes in chemical compositions of substrates before and after <Emphasis Type="Italic">Ganoderma lucidum</Emphasis> cultivation

After the commercial cultivation of Ganoderma lucidum, that is becoming increasingly popular because of its valuable medicinal effects, a large amount of Ganoderma spent substrate (GSS) remains as a residual material. It is important to identify differences in the chemical compositions among GSS to indicate their suitability. This study was carried out to characterize and evaluate the substrates and GSS for the some chemical contents such as; pH, EC, organic carbon (C), total nitrogen (N), macro and micro elements and C:N ratios. The substrates were prepared by the mixtures of hornbeam and oak sawdust supplemented with wheat bran in a ratio of 20% (20WB) and tea manufacture waste in different ratios (10, 15, 20 and 25%). Organic C, C:N and pH values decreased in GSS, while N, P, K, Mg, Fe, Mn and Zn contents increased. EC and pH values of GSS varied between 1.13 and 2.33 dS m⁻¹, and 5.14 and 5.69, respectively. GSS was found rich in all investigated mineral nutrients. The highest increases in all nutrient contents were generally determined in hornbeam sawdust with 20TW spent substrate. Initial mineral composition of the wastes influenced the mineral composition of the substrates and spent substrates.     

Continuous microbial leaching of a pyritic concentrate by Leptospirillum-like bacteria

Summary Continuous leaching of a pyritic flotation concentrate by mixed cultures of acidophilic bacteria was studied in a laboratory scale airlift reactor. Enrichment cultures adapted to the flotation concentrate contained Thiobacillus ferrooxidans and Thiobacillus thiooxidans. During the late stationary growth phase of these thiobacilli growth of Leptospirillum-like bacteria was observed, too. In discontinuous cultivation no significant influence of Leptospirillum-like bacteria on leaching rates could be detected. During continuous leaching at pH 1.5 Leptospirillum-like bacteria displaced Thiobacillus ferrooxidans. The iron leaching rate achieved by Leptospirillum-rich cultures was found to be up to 3.9 times higher than that by Leptospirillum-free cultures.     

不同种植年限有机土基质的变化及其对温室黄瓜生长的影响

研究了不同种植年限有机土基质的理化性质变化及其对黄瓜生长的影响.结果表明：随着种植年限的增加,有机土栽培基质的理化性质变差,表现为容重增大、总孔隙度减小、土壤酸碱度降低、有效养分含量下降;有机土微生物区系中细菌、放线菌数量下降,真菌数量增多.随有机土种植年限的增加,黄瓜的生长受到一定影响,表现为株高、叶面积减小,光合功能衰退,黄瓜产量和品质下降,有必要对连续种植3年的有机土基质进行地力恢复.
     

Bioconversion of starch processing waste to Phellinus linteus mycelium in solid-state cultivation

The objective of the experiment was to use starch processing waste as an alternative growth medium for cultivation of mycelia of the mushroom Phellinus linteus and to find an optimum condition under solid-state cultivation. Response surface analysis along with a central composite design was successfully applied to approximate the simultaneous effects of the substrate concentration (16-36 g l(-1)), pH (4.5-6.5), and temperature (25-35 degrees C) on the mycelial growth rate. In the model, pH and temperature significantly affected the mycelial growth but substrate concentration did not. The optimal substrate concentration, pH, and temperature for maximizing growth rate of P. linteus mycelia were found to be 16.5 g l(-1), pH 6.0, and 29.7 degrees C, respectively. Subsequent verification of these levels agreed with model predictions and the maximum mycelial growth rate at these conditions was 6.1 +/- 0.8 mm day(-1). Therefore, the results of the experiments suggest that starch processing waste could be utilized as a growth substrate for the cultivation of the mushroom mycelia of P. linteus, enhancing the usefulness of this byproduct of the starch manufacturing industry. This approach is likely to be useful for establishing similar parameters for the cultivation of other fungi.     

Expression of xyloglucan endotransglycosylases of Gerbera hybrida and Betula pendula in Pichia pastoris

The plant enzyme xyloglucan endotransglycosylase (XET; EC 2.4.1.207, xyloglucan:xyloglucosyl transferase) participates in selective modification of plant cell walls during cell growth. XETs are potential catalysts in various applications. Here, sequences encoding two XETs from Gerbera hybrida and Betula pendula are reported. The encoded proteins, which are 51% identical at the amino acid level, were expressed in the yeast Pichia pastoris in secreted form with the aid of mating factor alpha signal sequence. XET production in shake flask cultivations was better at 22 degrees C than at 30 degrees C. Both the yield of protein of expected molecular mass and the XET activity improved at the lower temperature. Under all cultivation conditions studied, higher amounts of XET from B. pendula (BXET) were expressed than XET from G. hybrida (GXET). Both XET enzymes were produced in 16l fed-batch bioreactor cultures. GXET was produced in methanol-limited fed-batch cultivation in minimal medium, and BXET in temperature-limited fed-batch (TLFB) in minimal or complex medium. Production was highest in TLFB in complex medium. BXET was purified from the culture filtrate and characterized. Based on the specific activity of the purified protein, 60-70 mg l(-1) BXET was produced in the TLFB in complex medium.     

The effect of pH on the cooperative behavior of aspartate transcarbamylase from Escherichia coli.

Saturation curves of activity versus concentration were determined for aspartate transcarbamylase from Escherichia coli (EC 2.1.3.2) for the substrate L-aspartate at saturating carbamyl phosphate (4.8 mM) in buffered solution at pH values from 6.0 to 12.0. Hill coefficients were obtained from the sigmoidal curves. At pH values from 7.8 to 9.1, where substrate inhibition causes difficulties in the Hill approximation, our kinetic scheme includes substrate inhibition and residual activity in the abortive enzyme-substrate complex. The plot of Hill coefficient versus pH has pKalpha values of 7.4 and 9.8 at the half-maximum positions of the curve which has a plateau from pH 8.1 to 9.1. These pKalpha values may be associated with functional groups involved in the allosteric transition which activates the enzyme. A plot of [S]0.5 versus pH shows a pKalpha of 8.5, which may belong to a residue either at or near the aspartate binding site. At 50 mM aspartate concentration the pH-rate profile shows maxima at pH values of 8.8 and 10.0 (cf. Weitzman, P.D.J., and Wilson, I.B.(1966)J. Biol. Chem. 2418 5481-5488, who used 100 mM aspartate). However, when the pH-dependent substrate inhibition is included, the calculated Vmax--H curve is bell-shaped like that of the isolated catalytic subunit.     

Activity and kinetic characteristics of glutathione reductase in vitro in reverse micellar waterpool

The enzyme activity of glutathione reductase (NAD(P)H:oxidized-glutathione oxidoreductase, EC 1.6.4.2) incorporated in CTAB/H2O/CHCl3-isooctane (1:1, v/v) reverse micelles has been investigated. Enzyme follows the Michaelis-Menten kinetics within a specified concentration range. Effects of pH, waterpool (W0), and surfactant concentration on the activity of glutathione reductase have been studied in detail. Optimum pH for the maximum enzyme activity was found to be dependent on the size of the waterpool. Further, a substrate inhibition was observed when concentration of one of the substrates was present in large excess over the other substrate. Km values for the substrate, oxidized glutathione (GSSG) and NADPH in CTAB/H2O/CHCl3-isooctane (1:1, v/v) were determined at W0 values of 14.4, 20.0, 25.5 and 29.7, at pH 8.0. These values are close to those obtained in aqueous solution, whereas the kcat values vary with W0 values of 8.8 to 32.3. Studies on the storage stability in the reverse micelle at W0 29.7 and pH 8.0 showed that glutathione reductase retained about 80% of its activity even after a month. The enzyme showed a higher stability at high waterpool. Oxidized glutathione (GSSG) provides protection to glutathione reductase against denaturation on storage in reverse micellar solution. Apparently, the enzyme is able to acquire a suitable native conformation at waterpool 29.7 and pH 8.0 and thereby exhibits an activity and stability inside the micellar cavity that are almost equivalent to that in aqueous solution.     

Oxidation kinetics and chemostat growth kinetics of Thiobacillus ferrooxidans on tetrathionate and thiosulfate.

Growth of Thiobacillus ferrooxidans in batch culture on 10 mM potassium tetrathionate was optimal at pH 2.5 (specific growth rate, 0.092 h-1). Oxygen electrode studies on resting cell suspensions showed that the apparent Km for tetrathionate oxidation (0.13 to 8.33 mM) was pH dependent, suggesting higher substrate affinity at higher pH. Conversely, oxidation rates were greatest at low pH. High substrate concentrations (7.7 to 77 mM) did not affect maximum oxidation rates at pH 3.0, but produced substrate inhibition at other pH values. Tetrathionate-grown cell suspensions also oxidized thiosulfate at pH 2.0 to 4.0. Apparent Km values (1.2 to 25 mM) were of the same order as for tetrathionate, but kinetics were complex. Continuous culture on growth-limiting tetrathionate at pH 2.5, followed by continuous culture on growth-limiting thiosulfate at pH 2.5, indicated true growth yield values (grams [dry weight] per gram-molecule of substrate) of 12.2 and 7.5, and maintenance coefficient values (millimoles of substrate per gram [dry weight) of organisms per hour) of 1.01 and 0.97 for tetrathionate and thiosulfate, respectively. Yield was increased on both media at low dilution rates by increase in CO2 supply. The apparent maintenance coefficient was lowered without affecting YG, suggesting better energy coupling in CO2-rich environments. Prolonged continuous cultivation on tetrathionate or thiosulfate did not affect the ability of the organism to grow subsequently in ferrous iron medium.     

Response of tomatoes (Lycopersicon esculentum) to an unequal distribution of nutrients in the root environment

Tomato (Lycopersicon esculentum Mill.) plants were grown in a split root system. The plants were rooted in two separate cubes of rockwool, which were subsequently irrigated with nutrient solution of equal (control) or different EC values. Besides optimal values, too low and too high values for maximal production were included.The yield was determined by the EC value considered optimal for plant nutrition if present in one of both rockwool cubes. The quality of the fruits was primarily determined by standard EC values available in part of the root environment. Water was preferably taken up from the low EC compartment, nutrients from the high EC compartment. Samples of leaves and fruits were analyzed to get information about uptake and translocation of nutrients in the plant.     

Change in growth kinetics of hybridoma cells entrapped in collagen gel affected by alkaline supply

The growth yields for glucose and glutamine of murine hybridoma cells entrapped in collagen gel particles were examined during the growth phase. The immobilized hybridoma cells were cultivated in a fluidized bed fermenter where the medium was circulating to supply oxygen separately. Procedures to supply an alkaline solution for adjusting the pH level strongly affected the growth yields. A direct supply of the alkaline solution to the cultivation system reduced both the growth yields for glucose and glutamine, probably due to a local increase in pH level. On the other hand, when fresh medium in which the pH was adjusted to around 8.5 was added to the cultivation system, the growth yields were unchanged even at the same pH level as when direct alkaline supply was used. These results suggest that an indirect alkaline supply could be recommended to ajust the pH level when using medium-circulating-fermenters.