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影响无土栽培黄瓜叶片中镁含量的因素研究   总被引:2,自引:0,他引:2  
温室三因素(地温、营养液钾、镁离子浓度)五水平旋转组合设计试验,分析无土栽培黄瓜开花结果前、中、后期叶片中镁含量的影响因素,得到黄瓜叶片中镁含量对3因素的回归数学模型。结果表明:①在本试验条件下,3因素对黄瓜叶片中镁含量的影响顺序是镁离子浓度〉地温〉钾离子浓度;②各因素间存在着交互作用,地温与营养液中镁离子浓度和钾离子均呈正相关,镁离子与钾离子呈负相关;③要使黄瓜叶片中镁的含量最高,相对应的地温、营养液镁离子浓度、钾离子浓度应分别为29.13℃、4mmol/L、4.43mmol/L。试验结果经后续验证,证明构建的模型准确可靠。  相似文献
2.
Marker-exchanged mutants of phoP and phoQ of Erwinia chrysanthemi (Ech) strain 3937 became more sensitive to the cationic antimicrobial peptide (CAMP) magainin II than did the wild type at a low Mg2+ concentration and at either acidic or neutral pH. At high Mg2+ and acidic pH, only the phoQ mutant, but not the phoP mutant, became more sensitive to magainin II than did the wild type; both mutants were more sensitive at neutral pH. The hyperinduction of Pel synthesis in medium containing plant extracts and polygalacturonic acid (PGA) was confirmed in the wild type but not in the mutants at low Mg2+ and neutral pH. However, Pel was hyperinduced at high Mg2+ and neutral pH in these mutants but not in the wild type. Maceration was also greatly reduced by these mutants compared to the wild type when the inoculum was precultured and then resuspended in the medium with low Mg2+ at neutral pH. However, when bacteria were precultured and resuspended in the medium with high Mg2+ at neutral pH, severe maceration was observed in these mutants but not in the wild type. Thus, at low Mg2+, PhoP-PhoQ TCS seems to be stimulated for maceration and the hyperinduction of Pel synthesis. At high Mg2+, however, PhoP-PhoQ TCS may be repressed for these phenotypes, and PhoP may be controlled by a mechanism(s) other than PhoQ regulation.  相似文献
3.
向氨氮废水中投加磷源和镁源可以形成磷酸铵镁(MAP)沉淀。本试验采用轻烧镁粉作为MAP法的镁源。试验对配比、pH、反应时间对氨氮去除率的影响进行了研究。确定了最佳反应条件。实验结果表明:当摩尔比N:Mg:P=1:8:1(将轻烧镁粉看作纯氧化镁计算)、pH=7、反应时间为50min时,氨氮去除率达到92%,剩余磷含量为2mg/L。  相似文献
4.
针对近年来北方日光温室中栽培番茄缺镁普遍发生和日益严重的问题,研究了叶面喷施MgSO、Mg(NO3)2及不同施用量对秋冬茬缺镁番茄K、Ca、Mg吸收和分配的影响,以期为番茄缺镁的矫正提供科学依据.结果表明:(1)随番茄生育进程各处理番茄叶片Mg和K含量呈下降趋势,Ca含量先下降后基本稳定,其中,Mg和Ca以第1穗果膨大期到第2穗果膨大期下降幅度最大,降幅分别为17.8%和39.1%.(2)喷施Mg肥显著提高叶片中Mg的浓度及携出量,喷施含镁0.4%的MgSO4 ·7H2O溶液叶片镁含量及携出量较对照分别提高了1.55和1.78倍,而对根、茎和果实中Mg的浓度及携出量无明显影响;从产量上看,喷施含镁0.2%和0.4% MgSO4·7H2O及0.2%Mg(NO3)2·6H2O溶液与不喷施相比产量分别提高了8.0%、8.9%和5.3%,但差异不显著.(3)土壤交换性K/Mg均大于适宜值,K、Mg养分比例严重失调,而石灰性土壤养分失调后叶面补施Mg肥,Mg从叶片向其他部位的转运有限,必须降低钾肥施用量,使养分平衡供应.  相似文献
5.
稻曲病是水稻穗期的一种重要病害,严重影响稻米的产量和品质。稻曲病菌Ustilaginoidea virens在离体培养条件下生长缓慢,严重制约了杀菌剂室内生测试验的观察和高效筛选。本研究以稻曲病菌培养基为研究对象,通过筛选、组合和优化固体培养体系的氮源、碳源、凝固剂以及阳离子浓度,以期构建适合稻曲病菌生长的室内培养体系。结果发现:在5种常见的商品化培养基中,稻曲病菌的生长速率仅为0.7~2.3 mm/d;而在18种配制培养基中,有77%的培养基对稻曲病菌表现出不同程度的生长促进效应,其中蛋白胨蔗糖结冷胶(PSGG)培养基的促进效果最显著(P0.05),生长速率达3.4 mm/d,且其对不同地理分布的稻曲病菌菌株均有生长促进效应。此外,在以结冷胶作为凝固剂的培养基中添加质量分数为0.02%的硫酸镁(Mg~(2+)),可有效提高培养基的凝固程度,且对菌丝体的生长速率无影响。在适合稻曲病菌生长的PSGG培养基中,蛋白胨和蔗糖是合适的氮源和碳源组合,结冷胶是合适的凝固剂。此研究结果可提高室内培养稻曲病菌的生长速率,为进一步理解稻曲病菌在离体条件下的生长机制及提高室内杀菌剂生测试验的效率提供了重要参考。  相似文献
6.
采用室内光照培养法(光温自动控制的光照培养箱),研究沙质土壤中施加燃煤烟气脱硫镁渣(以下简称脱硫镁渣)对沙冬青(Ammopiptanthus mongolicus)种子萌发及幼苗生长的影响。结果表明:脱硫镁渣对种子萌发、幼苗出土和幼苗根系生长有显著的抑制作用;施用脱硫镁渣对幼苗的单株鲜/干重、总生物量及茎生长有显著的促进作用。与对照相比,在种子萌发到幼苗建成的整个过程中,当脱硫镁渣施用量在5~15 g/kg时,种子萌发率和幼苗出土率显著降低,幼苗生物量显著提高;脱硫镁渣施用量小于5 g/kg时,对于种子萌发和幼苗生长均无显著影响;施用量大于15 g/kg,单株干重、鲜重、生物量和幼苗茎生长均极显著增加,种子萌发率和幼苗出苗率极显著降低。  相似文献
7.
Bacterial wilt is a serious problem affecting many important food crops. Recent studies have indicated that treatment with biotic or abiotic stress factors may increase the resistance of plants to bacterial infection. This study investigated the effects of magnesium oxide nanoparticles (MgO NP) on disease resistance in tomato plants against Ralstonia solanacearum, as well as its antibacterial activity. The roots of tomato seedlings were inoculated with R. solanacearum and then immediately treated with MgO NP; the treated plants showed very little inhibition of bacterial wilt. In contrast, when roots were drenched with a MgO NP suspension prior to inoculation with the pathogen, the incidence of disease was significantly reduced. Rapid generation of reactive oxygen species such as O2 radicals was observed in tomato roots treated with MgO NP. Further O2 was rapidly generated when tomato plant extracts or polyphenols were added to the MgO NP suspension, suggesting that the generation of O2 in tomato roots might be due to a reaction between MgO NP and polyphenols present in the roots. Salicylic acid‐inducible PR1, jasmonic acid‐inducible LoxA, ethylene‐inducible Osm, and systemic resistance‐related GluA were up‐regulated in both the roots and hypocotyls of tomato plants after treatment of the plant roots with MgO NP. Histochemical analyses showed that β‐1,3‐glucanase and tyloses accumulated in the xylem and apoplast of pith tissues of the hypocotyls after MgO NP treatment. These results indicate that MgO NP induces systemic resistance in tomato plants against R. solanacearum.  相似文献
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