Effects of mycorrhizal fungi on root-hair growth and hormone levels of taproot and lateral roots in trifoliate orange under drought stress

A pot experiment was used to evaluate the effects of an arbuscular mycorrhizal fungus (AMF) Funneliformis mosseae on plant growth performance, root-hair growth, and root hormone levels in trifoliate orange (Poncirus trifoliata) seedlings under well-watered (WW) and drought stress (DS). A 9-week mild DS treatment significantly reduced mycorrhizal colonization of 2nd- and 3rd-order lateral roots. Root mycorrhizal colonization was relatively higher in the 2nd- and 3rd-order lateral roots than in the taproot and the 1st-order lateral root under WW and DS. AMF seedlings exhibited significantly higher root-hair density, length (except for the taproot) and diameter in taproot and 1st-, 2nd-, and 3rd-order lateral roots under WW, and considerably higher root-hair density (except for 1st-order lateral root), length (except for 2nd-order lateral root) and diameter under DS. Mycorrhizal inoculation remarkably increased root abscisic acid (ABA), indole-3-acetic acid (IAA), methyl jasmonate, and brassinosteroids (BRs) concentrations under DS, in company with the decrease in root zeatin riboside and gibberellins levels and root IAA effluxes. Root-hair traits were significantly positively correlated with root colonization and root ABA and BRs levels. It is concluded that mycorrhizal plants possessed better root-hair growth to adapt mild DS, which is associated with mycorrhizal colonization and endogenous hormone changes.     

安徽省油菜磷肥施用效果及土壤有效磷丰缺指标研究

为了解油菜磷肥施用效果及土壤有效磷丰缺指标,选择安徽省典型油菜产区,开展多年多点田间小区试验,设置不施磷和施磷2个处理,研究施用磷肥对安徽省冬油菜产量、增产效果和经济效益的影响,并通过建立油菜籽粒相对产量和土壤有效磷含量的关系,确定土壤有效磷丰缺指标。结果表明,油菜施用磷肥增产增收效果明显。油菜施磷后的产量平均为2 571 kg/hm~2,增产量和增产率分别为672 kg/hm~2和41.5%。施磷每公顷增收2 012元,89.6%的试验点产投比2.0,施磷收益显著。以相对产量60%,60%~75%,75%~90%,90%~95%和95%为标准,将土壤有效磷分成"严重缺乏"、"缺乏"、"轻度缺乏"、"适宜"和"丰富"5级,对应的丰缺指标为6.5、6.5~13.0、13.0~26.5、26.5~34.0和34.0 mg/kg。该研究结果为水稻田冬油菜的磷肥管理提供依据。     

The role of potassium in alleviating detrimental effects of abiotic stresses in plants

Plants exposed to environmental stress factors, such as drought, chilling, high light intensity, heat, and nutrient limitations, suffer from oxidative damage catalyzed by reactive oxygen species (ROS), e.g., superoxide radical (O₂equation/tex2gif-sup-1.gif^–), hydrogen peroxide (H₂O₂) and hydroxyl radical (OHequation/tex2gif-sup-4.gif). Reactive O₂ species are known to be primarily responsible for impairment of cellular function and growth depression under stress conditions. In plants, ROS are predominantly produced during the photosynthetic electron transport and activation of membrane‐bound NAD(P)H oxidases. Increasing evidence suggests that improvement of potassium (K)‐nutritional status of plants can greatly lower the ROS production by reducing activity of NAD(P)H oxidases and maintaining photosynthetic electron transport. Potassium deficiency causes severe reduction in photosynthetic CO₂ fixation and impairment in partitioning and utilization of photosynthates. Such disturbances result in excess of photosynthetically produced electrons and thus stimulation of ROS production by intensified transfer of electrons to O₂. Recently, it was shown that there is an impressive increase in capacity of bean root cells to oxidize NADPH when exposed to K deficiency. An increase in NADPH oxidation was up to 8‐fold higher in plants with low K supply than in K‐sufficient plants. Accordingly, K deficiency also caused an increase in NADPH‐dependent O₂equation/tex2gif-sup-6.gif^– generation in root cells. The results indicate that increases in ROS production during both photosynthetic electron transport and NADPH‐oxidizing enzyme reactions may be involved in membrane damage and chlorophyll degradation in K‐deficient plants. In good agreement with this suggestion, increases in severity of K deficiency were associated with enhanced activity of enzymes involved in detoxification of H₂O₂ (ascorbate peroxidase) and utilization of H₂O₂ in oxidative processes (guaiacol peroxidase). Moreover, K‐deficient plants are highly light‐sensitive and very rapidly become chlorotic and necrotic when exposed to high light intensity. In view of the fact that ROS production by photosynthetic electron transport and NADPH oxidases is especially high when plants are exposed to environmental stress conditions, it seems reasonable to suggest that the improvement of K‐nutritional status of plants might be of great importance for the survival of crop plants under environmental stress conditions, such as drought, chilling, and high light intensity. Several examples are presented here emphasizing the roles of K in alleviating adverse effects of different abiotic stress factors on crop production.     

县级测土配方施肥指标体系建立研究—以江苏省江都市水稻为例

以江苏省江都市水稻为例,基于地力差减法预测氮肥用量、 养分丰缺指标法预测磷钾肥用量,构建县域测土配方施肥指标体系,研究分析20052011年测土配方施肥田间试验示范。结果表明,当种植水稻预测目标产量为6825~9270 kg/hm2（平均为8145 kg/hm2）,氮肥推荐用量为146.42~57.4 kg/hm2（平均为207.5~ kg/hm2）。磷钾肥施用标准: 当有效磷含量高于21 mg/kg,不推荐施用磷肥;当有效磷含量在17~21 mg/kg时,推荐施磷（P2O5）量为40.5 kg/hm2;当有效磷含量在10~17 mg/kg时,推荐施磷（P2O5）量为 48 kg/hm2;当有效磷含量低于10 mg/kg 时,推荐施磷（P2O5）量为64.5 kg/hm2。当速效钾含量高于140 mg/kg,不推荐施用钾肥;当速效钾含量在115~140 mg/kg时,推荐施钾（K2O）量为 22.5 kg/hm2;当速效钾含量在60~115 mg/kg时,推荐施钾（K2O）量为40.5 kg/hm2;当速效钾含量低于60 mg/kg 时,推荐施钾（K2O）量为 82.5 kg/hm2。同时对施肥指标体系建立进行校验分析,结果表明基于试验建立施肥指标体系是可行的,从而为构建县域测土配方施肥指标体系提供了方法,达到因土施肥的目的。     

冀东平原水稻大田生产营养元素限制因子研究

通过冀东平原水稻土壤氮、磷、钾、锌、硼等大量和微量元素对水稻产量的影响进行研究,阐明了养分限制因子,提出了增产措施。按照NY/T 497—2002《肥料效应鉴定田间试验技术规程》,采用田间小区肥料试验方法,对氮、磷、钾、铜、铁、锰、锌、硼、钼九种营养元素进行缺素对比,找出限制因子。施用氮肥比对照增产明显,产量差异极显著,说明氮肥是影响水稻产量的主要限制因子;除氮肥外,其他肥料作用与全素比较差异不显著,说明还不是限制因子;缺氮处理与对照比产量差异不显著,说明在氮素缺失情况下,其他肥料综合作用不明显。通过对水稻营养元素限制因子的研究,初步了解了水稻生产中各种营养元素对产量的影响,为今后水稻科学施肥奠定了基础。     

Ammonium‐driven nitrification plays a key role in increasing Mn availability in calcareous soils

Background : Manganese deficiency often becomes a yield limiting factor, particularly on calcareous soils, even though the total soil manganese content is usually sufficient. Although it is known that acidifying N fertilizers can improve Mn availability, the reason of this effect is still unknown. Aim : Our aim was to investigate the effect of stabilized ammonium fertilizers as a tool to distinguish between physiological‐ and nitrification‐induced acidification. Method : Two pot experiments with Triticum aestivum L. and one soil incubation experiment using different nitrogen forms (CN = calcium nitrate, AN = ammonium nitrate, AS = ammonium sulfate, ATS = ammonium thiosulfate) with and without addition of nitrification inhibitors (DCD, Nitrapyrin, Piadin, DMPP) were conducted to examine the effect on Mn availability in the soil and Mn uptake by the plants at different development stages (EC 31 und 39). Results : With increasing fertilizer ${\mathrm{NH}}_4^{+}$ content a higher Mn concentration was detected: CN: 32 µg Mn g^?1 DM, AN: 39 µg Mn g^?1 DW, AS: 55 µg Mn g^?1 DM, ATS: 109 µg Mn g^?1 DM. The addition of a nitrification inhibitor resulted in a significantly lower rhizosphere pH compared to the non‐stabilized fertilizer. Surprisingly, the use of different nitrification inhibitors led to unchanged (CN, AN) or lower Mn concentrations of wheat. Especially in the ${\mathrm{NH}}_4^{+}$ treatments (AS and ATS), this negative effect was very evident (AS+DCD: 42 µg Mn g^?1 DM; ATS+DCD: 55 µg Mn g^?1 DM). Conclusions : Mn availability was enhanced by ongoing nitrification process rather than physiological acidification. Compared to other N forms, ammonium thiosulfate led to the highest Mn availability in bulk soil.     

寻常型银屑病不同证型蛋白组学表达的比较研究

目的 对寻常型银屑病（血热证、血瘀证、血虚证）患者与正常人差异蛋白进行分析,探求三证之间差异性表达蛋白,从蛋白质组学角度揭示三证之间的差异。方法 取寻常型银屑病血瘀证、血虚证、血热证患者的血清,应用蛋白提取、定量、双向电泳技术、质谱鉴定和数据库检索,寻找出三证之间的差异蛋白和共有蛋白,并将这些蛋白进行组间比较。结果 发现了15种显著性差异蛋白（P<0.05）,其中补体C3、凝聚素、血清转铁蛋白、间-α-胰蛋白酶抑制剂H4重链（片段）、载脂蛋白E、补体C4-B、甘露糖结合蛋白C及富亮氨酸-α-2-糖蛋白在血虚型银屑病患者血清表达水平高于血热型和血瘀型（P<0.05）。纤维蛋白原β链、血液接合素、纤维蛋白原γ链、HPX蛋白、α-抗胰蛋白酶、甲状腺素转运蛋白及载脂蛋白Ⅳ在血热型银屑病患者血清中的表达水平高于血瘀型患者（P<0.05）。共同蛋白有5种（P<0.05）,分别为血液结合素、纤维蛋白原γ链、HPX蛋白、α-抗胰蛋白酶、载脂蛋白A-Ⅳ。结论 寻常型银屑病（血热证、血瘀证、血虚证）血清中存在表达差异性蛋白质,可能与寻常型银屑病的发病机制和银屑病不同证型的物质基础有关。     

青海省贵德县耕层土壤农化指标分析

[目的]评价贵德县耕层土壤养分状况。[方法]采用常规方法,分析贵德县499个耕层土壤8项农化指标。[结果]贵德县耕层土壤平均有机质19.71 g/kg,全氮1.54 g/kg,全磷1.70 g/kg,碱解氮111 mg/kg,有效磷41 mg/kg,速效钾249 mg/kg,缓效钾1 029 mg/kg,pH 7.97。碱解氮、速效钾、缓效钾总体含量水平高;有效磷、有机质含量与丰缺指标比较,结果为中等水平。[结论]该研究可为耕地地力评价和测土配方施肥提供基础数据。     

全自动换血治疗G-6-PD缺陷症并发急性溶血的疗效观察

目的 :观察全自动换血治疗危重G 6 PD缺陷症并发急性溶血的疗效。方法 :对 1 0例危重G 6 PD缺陷症并发急性溶血采用全自动换血治疗。结果 :总胆红素由换血前 (5 33.1 4± 1 1 5 .6 5 ) μmol/L下降至换血后 (2 95 .5 0± 88.5 1 )μmol/L ,换出率是 4 4 .5 7% ,血红蛋白增加 34.1 2 % ,红细胞增加 4 3.30 % ,换血过程无明显不良反应。结论 :全自动换血是抢救危重G 6 PD缺陷症并发急性溶血的简单、实用、安全、有效的方法     

放牧羊钴缺乏症的防治

选某牧场患有慢性钴缺乏病症状的羊120只(5～6月龄)，随机分为4组，每组30只。采用3种方法对其进行治疗。结果表明：3种方法均可防治本牧场羊钴缺乏。口服硫酸钴对提高羊的生产性能(增重)效果最好；钴丸组对增强缺钴羊机体免疫力及其造血、糖代谢等生理功能上效果最佳；施钴肥的效果稍逊色于其他方法，但因其方便、实用，也可作为本牧场防治钴缺乏的一种方法。