Influence of inoculation with arbuscular mycorrhizal fungi on stable isotopes of nitrogen in Phaseolus vulgaris

The interactions between Phaseolus vulgaris, Rhizobium spp. strains nodulating P. vulgaris, and arbuscular mycorrhizal (AM) fungi were assessed under greenhouse conditions in a nonsterilized Typic Haplustalf soil from Cauca, Colombia. Our results indicate a specific involvement of AM fungal species in nitrogen acquisition by the legume plants from symbiotic nitrogen fixation and from soil. A significant specific influence of inoculation with Glomus spp. on the ¹⁵N/¹⁴N ratio in plant shoots was dependent on the inoculated rhizobial strain, but AM fungal inoculation had no significant effect on shoot dry weight or nodule occupancy in the two different rhizobial strain treatments. The results imply that in low P soils the effects of an improved mycorrhizal symbiosis may include improved symbiotic N₂ fixation efficiency and/or improved soil N uptake. Received: 11 May 1996     

Maize grain production,plant nutrient concentration and soil chemical properties in response to different residue levels from two previous crops

ABSTRACT

The incorporation of previous crop residues in agricultural management benefits soil fertility, crop production, and environment. However, there is no enough information about maximum residue application level without negative effect over next crop yield. To evaluate maize (Zea mays L.) yield under short-time conservation management with incorporation and/or importation of different residue levels, a biannual rotation experiment was conducted in ash volcanic soil in south-central Chile. The experiment consisted of two previous crops, canola (Brassica napus L.) and bean (Phaseolus vulgaris L.), and four levels of residue incorporation (0%, 50%, 100%, and 200% of generated residue; from 0 to 21.4?Mg?ha^?1 for canola and from 0 to 19.0?Mg?ha^?1 for bean). Previous crop species and residue level affected some nutrients concentrations in grain and plant and some soil chemical properties, without effect in maize yield, which averaged 16.6?Mg?ha^?1. Bean residue increased Ca and reduced S in maize plant, increasing soil P, Ca, Mg and K (P?<?0.05). Maize grain Ca content was positively and proportionally affected by canola residue level and negatively and proportionally affected by bean residue level. All canola residue levels increased soil pH and Mg, but the highest level reduced soil S; soil P concentration increased proportionally with bean residue level. The highest bean residue level increased soil S. Different crop and levels of residue did not affect maize yield but did some plant nutrient concentration, and also affected some soil chemical properties.     

Micronutrient composition of field‐grown dry bean and wheat inoculated with Azospirillum and Trichoderma

Micronutrient deficiency and malnutrition in humans are severe problems in many developing countries, particularly in areas with calcareous soils. There is almost no information on whether inoculation with plant growth–promoting Azospirillum and/or Trichoderma can help to reduce this problem by increasing the mineral concentration of the seeds. Field experiments were conducted in Tokat (Turkey) in 2001–2002 to determine whether inoculation with Azospirillum brasilense, Trichoderma harzianum, sole or in combination, and/or the application of P fertilizers can enhance micronutrient concentrations of field‐grown bean (Phaseolus vulgaris) and wheat (Triticum aestivum). In beans, Azospirillum inoculation combined with P fertilization significantly (p < 0.05) increased seed concentrations of Mn, Zn, and Cu, from 8.8, 22.6, and 7.0 mg kg^–1 in the control to 10.3, 28.3, and 11.0 mg kg^–1, respectively. Trichoderma inoculation alone significantly (p < 0.05) reduced the concentrations of Fe, Mn, Zn, and Cu and the cumulative plant uptake of Fe and Zn in 45‐day‐old bean plants. However, it significantly (p < 0.05) increased bean‐seed Cu content and accumulation. The double inoculation resulted in significantly (p < 0.05) higher micronutrient concentrations than Trichoderma inoculation alone in 45‐day‐old plants. In contrast to beans, the effects of microbial inoculations were less in wheat. However, dual inoculation significantly (p < 0.05) increased Zn content by 45% and Zn accumulation by 40% above the uninoculated control. Inoculation with plant growth–promoting microorganisms appears to be a promising strategy to combat micronutrient deficiencies.     

中药植物丁香杀虫杀螨活性研究

系统研究了中药植物丁香的杀虫和杀螨活性。采用正己烷、苯、乙醚、甲醇和水对丁香进行顺序提取,分别测定提取物对朱砂叶螨和玉米象等供试生物的活性,结果表明：丁香的正己烷提取物24h和72h对朱砂叶螨的致死中浓度(LC50)分别为1．5333和0．5796g／L;苯的提取物24h和72h对朱砂叶螨的致死中浓度(LC50)分别为4.4393和1．3537g／L;丁香的正己烷提取物熏蒸处理7d,对玉米象的校正死亡率达94．44％。     

干旱胁迫条件下臭柏群落灌丛生长的模糊综合评价分析

在对干旱胁迫环境下臭柏适应性进行研究的过程中，发现存在大量模糊现象和模糊数据，通过适当给出模糊综合评判矩阵和权值，可以运用模糊综合评判方法分析干旱对臭柏群落灌丛生长的影响，结果表明该方法与模拟实验结果一致，并使评价结果更具体、直观。     

应用PAGE梯度电泳技术鉴定西瓜杂交种纯度

应用PAGE梯度电泳技术分析西瓜杂交种苏蜜五号、早抗京欣和抗病苏蜜及其父母本种子的酯酶、过氧化物酶、多酚氧化酶及种子蛋白.结果显示:除早抗京欣发芽5 d时过氧化物酶有一明显谱带特征可以有效区别杂种与亲本外,其他电泳组合谱带虽清晰但无明显差异,表明西瓜遗传基础相对狭窄.蛋白质和同工酶难以发现统一的谱带特征来检测不同西瓜杂交种子的纯度.由于不同杂交种双亲的遗传背景不同,对于亲缘关系相对较远的一些品种可能会出现某些特别的特征以用来鉴别真假杂种.     

松油烯-4-醇对粘虫幼虫体壁结构的影响

用砂地柏精油主要杀虫活性成分松油烯 - 4 -醇熏蒸处理粘虫 6龄中期幼虫后 ,在扫描电镜下观察了不同中毒阶段粘虫体表蜡质颗粒及体壁底膜的变化。结果表明 ,松油烯 - 4 -醇处理可导致粘虫幼虫体表蜡质层颗粒形态和排列形式发生改变 ,颗粒间空隙变大 ,体壁底膜也有一定程度的破坏 ,这些病变可能是导致体表失水的主要原因。     

微波辅助提取夏枯草中熊果酸的工艺

[目的]探索从夏枯草中有效提取熊果酸的有效方法。[方法]以夏枯草为原料,采用乙醇作为提取溶剂,研究在微波辐射下提取夏枯草熊果酸的工艺条件;探讨夏枯草熊果酸的提取条件,对微波功率、溶剂浓度、料液比、提取时间等影响因素进行了研究。[结果]结果表明:微波辅助法从夏枯草中提取熊果酸的适宜工艺条件为夏枯草在90%乙醇溶剂液中,采用功率350 W,提取时间260 s。此条件下夏枯草中熊果酸提取得率为0.54%。[结论]微波法提取熊果酸提取时间短,提取效率较高,具有广阔的应用前景。     

百合及半夏试管繁殖中的污染防治初报

取百合（Ｌｉｌｉｕｍｂｒｏｗｎｖａｒ．ｖｉｒｉｄｕｌｕｍＢａｋｅｒ）鳞片和半夏（Ｐｉｎｅｌｌｉａｔｅｒｎａｔａ（ＴＨ）Ｂｒｉ－ｅｔ．ｖａｒ．ｖｕｌｇａｒｉｓＥｎｇｌ．）块茎作外植体，基本培养基ＭＳ，附加成份有６－ＢＡ与ＫＴ和ＮＡＡ．经试验后进行批量生产时，发现严重的细菌污染，经微生物学鉴定，污染细菌系土壤杆菌属（Ａｇｒｏｂａｃｔｅｒｉｕｍ）的一个种，采用混合配制的灭菌剂Ｄ＿２（升汞加次氯酸纳）防治污染菌，其防除效果可使８０％以上的外植体正常生长而无污染。     

Antinutritional factors in anasazi and other pinto beans (Phaseolus vulgaris L.)

Antinutritional factors of anasazi bean were compared to traditional pinto bean (Phaseolus vulgaris L.). Anasazi beans contained less (p<0.001) soluble and bound condensed tannins compared to pinto beans. No differences (p>0.05) in stachyose and raffinose content were found between the two bean types; verbascose was not detected at all. Significant (p<0.05) differences in lectin content were observed between anasazi and pinto bean. The lectins of anasazi beans were classified as non toxic and those of the pinto beans as toxic types. No differences (p>0.05) in inhibitor activity against human and bovine trypsin and chymotrypsin were found between the two bean types.