Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum is a damaging disease of oilseed rape. In order to assess the potential of NPK fertilizers to control SSR, nine field experiments conditions with or without N–fertilizer application, with or without P-fertilizer application and with or without K-fertilizer application were studied using five varieties of rapeseed in Wuxue city, Hubei Province, China, from 2006 to 2009. Compared to control, the results showed that applying N fertilizer increased rapeseed yield and SSR index by 203.7% and 17.7% respectively. Applying P fertilizer, the yield increased by 47.2% and SSR index decreased by 31.0%. Applying K fertilizer, the yield increased by 30.1% and SSR index decreased by 21.9%. These results suggested that: (1) For N-fertilizer application, the pathogen may obtain more nutrients and rapeseed vigorous growth may raise the field humidity, which further increased rapeseed SSR disease. (2) The P-fertilizer application may provide energy for rapeseed to resist infection by S. sclerotiorum. (3) The K-fertilizer application may regulate plant metabolic processes and plant morphology, thus improving resistance to S. sclerotiorum. This study suggests that rational application of NPK fertilizers can control SSR and improve the yield of rapeseed.

对5个油菜品种，设氮肥（对照、施氮），磷肥（对照、施磷）和钾肥（对照、施钾）试验，分析了氮磷钾肥对油菜产量和菌核病发生的影响。结果表明，施氮油菜平均增产203.7%，菌核病病情指数平均增加17.7%；施磷油菜平均增产47.2%，菌核病病情指数平均下降31.0%；施钾油菜平均增产30.1%，菌核病病情指数平均下降21.9%。分析认为，施氮因病原菌获得更多的营养物质，以及油菜枝繁叶茂提高田间阴湿度而致使油菜病害加重；施磷为油菜抗性生理活动提供了物质基础；施钾通过对植株代谢过程的调控和植物形态学的调节提高了油菜对菌核病的抗性。生产上可以通过调控氮肥施用，合理增施磷钾肥，达到既提高油菜产量又有效减轻菌核病危害的目的。    

【Objective】The study was conducted to investigate the effect of strain EDR2 on oilseed rape Sclerotinia stem rot and strain identification.【Method】Inhibitory effects of strain EDR2 on mycelial growth,sclerotia germination,and biocontrol efficacies were evaluated in vitro and in vivo .The strain was identified based on the morphology,physiological and biochemical characteristics and 16S rDNA sequence analysis.【Result】Strain EDR2 could strongly inhibit the growth of mycelial and cause leakage and disintegration of hyphal cytoplasm of mycelial cell from Sclerotinia sclerotiorum .In petri dish,strain EDR2 could inhibit both mycelial growth and sclerotia germination;the inhibitory rate was up to 96.6%.In the greenhouse,the culture filtrates of strain EDR2 displayed effective biocontrol activities in the seedlings and the biocontrol efficacy exceeded 80%.The biocontrol activities were influenced by the spraying time of strain EDR2.The control efficacy was higher when strain EDR2 was applied prior to inoculation of the pathogen than after inoculation.Different dilution factors of fermentation showed different inhibitory effects on S.sclerotiorum .As the increase of dilution factor,the biocontrol efficacies declined.Furthermore,strain EDR2 also showed a broad antifungal spectrum on mycelium growth of numerous important plant pathogenic fungi.According to the morphology,physiological and biochemical characteristics,and 16S rDNA sequence analysis,strain EDR2 was identified as Bacillus subtilis .【Conclusion】Our results suggest that endophyic B.subtilis strain EDR2 is a promising biological control agent for Sclerotinia stem rot.

【目的】明确内生细菌EDR2菌株的分类地位以及对油菜菌核病的防治作用，为该菌株的进一步应用奠定基础。【方法】采用皿内和温室盆栽试验，测定菌株EDR2对油菜菌核病菌菌丝生长和菌核萌发的抑制作用以及对病害的防治效果；并结合菌体形态观察、生理生化特性测定以及16S rDNA序列分析确定该菌株的分类地位。【结果】内生细菌EDR2菌株能够有效抑制油菜菌核病菌的菌丝生长，并可导致菌丝出现畸形、细胞质外渗，同时其还对病菌的菌核萌发具有较强的抑制作用，培养原液的抑制率可达到96.6%。温室盆栽试验结果表明，菌株EDR2的培养原液和无菌培养滤液对苗期油菜菌核病均有良好的防治效果，其防效都在80%以上；菌株EDR2的喷施时间可影响其防治效果，其中以接种病菌前1 d喷施防治效果最好，可达到95.4%；培养原液及不同倍数稀释液对病害的防治效果明显不同，随着稀释度的增加，其生防效果降低。菌株EDR2对供试的16种植物病原菌的菌丝生长均表现出一定的抑制作用，表现出较广的抑菌谱。结合形态和培养特征、生理生化特性及分子生物学鉴定结果认为，内生细菌EDR2属于枯草芽孢杆菌（ Bacillus subtilis ）。【结论】综合皿内及温室盆栽试验结果认为，内生枯草芽孢杆菌EDR2是1株对油菜菌核病具有较好防治潜力和开发前景的生防菌株。

【Objective】 Boron (B) is an essential trace element for plant growth, however, excessive boron in soil may exert toxic effects on plants. In boron-deficiency soil, excessive use or uneven application of boron can easily lead to boron toxicity, if such levels of boron are accompanied by excessive salinity, the consequences can be drastic for plants. Boron toxicity is a significant constraint to cereal production in regions worldwide, including parts of southern Australia. Raising the suitable boron range of crops and reduce the toxicity of excessive boron are technical problems to be solved for agricultural production. An appropriate amount of selenium can improve crop resistance. This paper aims to investigate the effect of appropriate amount of selenium on rapeseed biomass and active oxygen metabolism under the condition of excessive boron, and explain the alleviation mechanism of selenium on boron inhabitation of rape growth. 【Method】In the present study, solution culture experiments were carried out using rape seedlings (Brassica napus L. cv. Xiangnongyou 571) as the test material. The interactive effects of boron and selenium especially with a purpose to test whether selenium application is effective in countering the boron toxicity were tested. Boron fertilizer was applied at two levels (50, 500 µmol?L-1), selenium fertilizer was applied at two levels (0, 1 µmol?L-1). The effects of these treatments on rape seedling growth, boron uptake and accumulation, enzymatic and non-enzymatic antioxidant, stress injury, oxidative damage along with defense mechanisms under boron (500 µmol?L-1) stress were assessed. 【Result】 Whilst boron application alone at 50 µmol?L-1 level was beneficial for the growth, treatment with boron severely inhibited the growth at 500 µmol?L-1 level. Under boron stress conditions, the dry weight of rapeseed seedling shoots and roots decreased significantly, rape seedling shoots and roots dry weight severely decreased by 20.1% and 32.0%, respectively, over 50 µmol?L-1 boron, and a lot of boron took up and accumulated over normal boron concentration (50 µmol?L-1). The enzymatic activity of scavenging reactive oxygen species, including catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) in rape seedling leaves decreased, CAT, POD and APX activity decreased by 19.7%, 11.0% and 15.0%, respectively, compared to normal boron concentration, and the endogenous reactive oxygen substances (glutathione (GSH)) in leaves were significantly reduced, while hydrogen peroxide (H2O2) and malondialdehyde (MDA) increased significantly by 19.0% and 18.5% over 50 µmol?L-1 boron treatment. The boron-treated (500 µmol?L-1) plants supplemented with 1 µmol?L-1 selenium showed increased shoot and root dry weight, it significantly improved by 22.8% and 28.6% over boron-treated (500 µmol?L-1) plants, respectively, it also indicated that an antagonistic interaction between the two elements. Selenium at 1 µmol?L-1 concentration significantly affected the boron uptake and accumulation, it decreased boron content and accumulation in shoot by 38.6% and 31.9% respectively, over 500 µmol?L-1 boron treatment. Oxidative damage due to boron was lowered, which could be related to the reduction of active oxygen metabolism enzyme and endogenous scavengers in seedling leaves caused by boron toxicity were significantly alleviated. The boron-treated (500 µmol?L-1) plants supplemented with 1 µmol?L-1 selenium showed improved CAT, POD and APX activities, they increased by 12.8%, 15.1% and 15.3%, respectively, GSH and ASA contents increased by 9.7% and 21.0% over 500 µmol?L-1 boron treatment, while the accumulation of hydrogen peroxide and the increase of membrane lipid product malondialdehyde were effectively reduced, selenium application at 1µmol?L-1 to boron treated (500 µmol?L-1) plants, H2O2 and MDA content decreased by 25.1% and 22.1% over 500 µmol?L-1 boron treatment, respectively. 【Conclusion】 It was suggested that an appropriate amount of selenium can increase reactive oxygen metabolism of rapeseed and reduce the accumulation of reactive oxygen, thereby significantly decreasing the impact of excessive boron on rapeseed growth and improving the adaptability of rape seedlings to excessive boron.

【目的】硼是植物生长发育所必需的微量元素，但在土壤中过量存在会对植物产生毒害。在干旱半干旱地区硼毒害是限制作物生长的重要因子，此外，硼矿开采以及硼肥用量过大或施用不均匀均会导致硼浓度过高，从而限制作物生长。适量硒能提高作物抗性，减轻作物因逆境产生的伤害，本文旨在通过适量硒处理，研究硒对高硼条件下油菜生物量及油菜活性氧代谢的变化，探讨硒缓解高硼对油菜生长抑制作用的机理，进而提高作物对硼的适宜范围，减轻硼毒害对农业生产的危害。【方法】本文以油菜（湘农油571）为试验材料,设置硼和硒2因素2水平（硼水平为：50、500 μmol•L-1，分别用B50、B500表示，硒水平为：0、1 μmol•L-1，分别用Se0、Se1表示）完全随机试验，共4个处理，通过苗期溶液培养，研究硒对高硼（500 µmol•L-1）胁迫条件下油菜幼苗生长、硼吸收累积和抗氧化酶及非酶系统的影响。【结果】高硼胁迫条件下油菜幼苗地上部和地下部干物质重显著降低，与正常硼（50 μmol•L-1）处理相比分别降低20.1%和32.0%；硼含量和累积量显著增加，与正常硼处理相比分别增加2.95和2.97倍；油菜幼苗因硼毒害导致叶片内抗氧化酶（过氧化氢酶（CAT）、过氧化物酶（POD）和抗坏血酸过氧化物酶（APX））活性和非酶抗氧化物（谷胱甘肽（GSH））含量显著降低，与正常硼处理相比，CAT、POD和APX活性分别降低19.7%、11.0%和15.0%；而过氧化氢（H2O2）和丙二醛（MDA）含量显著增加，比正常硼处理分别增加19.0%和18.5%。高硼条件下，经1 μmol?L-1硒处理，与无硒处理相比，地上部和地下部干物质重分别增加22.8%和28.6%，硼含量和累积量分别降低38.6%和31.9%；油菜幼苗叶片内抗氧化酶活性和非酶抗氧化物含量显著增加，CAT、POD和APX活性分别增加12.8%、15.1%和15.3%，GSH和ASA含量分别增加9.7%和21.0%；而过氧化氢和丙二醛含量分别降低25.1%和21.2%。【结论】适量硒可降低高硼胁迫下油菜幼苗硼的吸收累积，增强抗氧化酶和非酶系统抗氧化作用，降低活性氧累积，减轻细胞质膜因过氧化作用而产生的损伤，从而显著减轻过量硼对油菜生长的影响，提高油菜幼苗对硼过量的适应性。

To investigate the alleviation effects of selenium (Se) on the cadmium (Cd) toxicity in rape root tips, we investigated the effects of 0.2 mg · L -1 Se on root growth, root morphological characteristics, integrity of membrane, ultrastructure, and programmed cell death (PCD) in the roots tips of rape seedlings. MS (Murashige and Skoog) experiments showed that addition of 0.2 mg · L -1 exogenous Se significantly alleviates the inhibitory effect of 1 mg · L -1 Cd stress on the growth of rape seedlings. Total length, total surface and forks number of root were promoted by 33.28%, 18.81% and 21.66% respectively. The roots with diameter below 1 mm were restored and the total root length increased by 44.73%. Damage of the membrane system caused by Cd deceased, and levels of lipid peroxides and superoxide free radicals (O 2 ·- ) induced by Cd also decreased. The membrane permeability and ultrastructure of root tip were considerably recovered due to the application of Se. However, supplementation of the medium with Se did not reduce the number of cell death in root tip, but reduced the ratio of late period apoptotic cell. Meanwhile, there was no significant role of selenium on the integrity of DNA and other cytogenetic material.

为研究镉胁迫对油菜根尖的毒性效应及硒的添加对该毒性效应的缓解作用,采用MS (Murashige and Skoog)培养基培养的方式,研究了0.2 mg · L -1 硒对1 mg · L -1 镉胁迫下油菜幼苗根系生长、根系构型、根尖膜系统完整性、亚细胞超微结构及细胞凋亡程度的影响.结果表明:镉胁迫下,硒的添加在一定程度上恢复了根系的生长,维持了根系的构型,使得总根长、总表面积和分叉数分别增加了33.28%、18.81%和21.66%;硒对根系形态的恢复作用主要表现在对直径小于1.0 mm的根系的恢复,直径小于1.0 mm的根系总根长提高了44.73%,总表面积提高了37.35%,总体积提高了32.88%;硒能够缓解镉对根尖细胞膜系统完整性的破坏;降低膜脂质过氧化程度,减少自由基的生成量,使得根尖O 2 ·- 含量降低了67.47%;并能维系细胞的形态和细胞器的结构完整性.然而,0.2 mg · L -1 的硒并未显著降低根尖死亡细胞的数量,仅降低了晚期凋亡细胞的比例.

迄今为止,对硒在有机体内的生理生化作用的认识,主要来自于动物研究领域,普遍认为,其主要作用是作为谷胱甘肽过氧化物酶(GSH-Px)和磷脂氢谷胱甘肽过氧化物酶(PHGSH-Px)等含硒酶活性中心的必要组成这一生物活性形式发挥抗氧化作用。薛泰麟等〔1,2〕曾在大豆、油菜、小麦和?..

Selenium is a kind of beneficial minor element for human being, and it is also indispensable in plant growth. The research advances on the kinds of plants rich with selenium and ability of selenium accumulation of plants, the mechanism of absorption, metabolism and accumulation in plant, and application methods of selenium fertilizer are reviewed, so as to provide reference for cultivation management of crops rich with selenium and rich selenium product development in the future.

综述富硒植物的种类、富硒能力、植物体内硒的吸收、代谢、积累过程及施硒方法等，为今后富硒作物高效栽培管理及富硒产品开发利用提供参考。

The rape ( Brassica napus L. cv. Xiangnongyou 571) was chosen as the experimental material to undergo solution cultivation at seedling stage to investigate the effects of selenite addition on the selenium (Se) absorption and distribution, root morphology and physiological characteristics of rape seedlings. The results showed that the bioaccumulation ability of Se decreased significantly with increasing the Se application rate, but the Se distribution coefficient remained around 0.9 with no significant influence. The application of 10 μmol·L -1  selenite stimulated the growth of rape seedlings through improving the root physiological characteristics and root morphology significantly, including significantly increasing the production of superoxide radical (O 2 - · ) rate and the activities of superoxide dismutase (SOD), peroxidase (POD) and fungal catalase (CAT) in the root system, which resulted in a reduction of the lipids peroxidation (MDA) content as much as 26.0%, consequently increasing the root activity as much as 17.4%. The promoting degrees of selenite on root morphological parameters were from strong to weak in such a tendency: root volume > total surface area > number of root forks > total root length > number of root tips > average diameter. However, such positive effects had no significant difference with those in treatment with 1 μmol·L -1  selenite, indicating that small amounts (≤10 μmol·L -1 ) of selenite were able to increase the activity of antioxidant enzymes and reduce the content of MDA in root system, which could increase root activity and improve root morphology, hence increased the biomass of rape seedlings.

以甘蓝型油菜(湘农油571)为试验材料，通过溶液培养研究了外源四价硒条件下，油菜幼苗硒吸收分配、生理特性及根系形态的变化.结果表明： 油菜幼苗的硒富集能力随施硒量增加显著降低，而硒分配系数一直稳定在0.9左右，不受硒浓度影响.10 μmol·L -1 硒可以通过显著改善油菜幼苗根系生理指标和根系形态来促进油菜幼苗的生长，其对生理指标的影响主要表现为：显著降低油菜幼苗根系超氧阴离子自由基(O 2 - · )产生速率，并显著提高超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性，从而显著降低根系的膜脂过氧化物质(MDA)含量，降幅达26.0%，进〖JP2〗而显著提高根系活力，增幅达17.4%；其对构型指标促进程度依次为：根体积>总表面积>分根数>总根长>根尖数>平均直径，但这些正效应均与1 μmol·L -1 硒处理无显著差异，表明少量硒(≤10 μmol·L -1 )可以通过提高油菜幼苗根系抗氧化酶活性和降低膜脂过氧化物含量，来提高根系活力和改善根系构型，最终促进油菜幼苗生长.

通过溶液培养,研究不同浓度硒(0.0、0.10、0.25、0.50、1.0mg/L)对水稻幼苗生长和生理特性的影响.结果表明,硒抑制水稻幼苗增高和增重;硒使水稻幼苗叶片MDA含量降低,SOD、POD活性增加,而CAT活性降低;硒处理,提高叶片N.P含量,低浓度硒(0.10mg/L)提高叶片Fe、Zn和Mn含量、对K、Ca、Mg含量无明显影响,而高浓度硒(1.0mg/L)显著降低水稻幼苗叶片Ca、Mg、Fe、Zn、Mn含量.

Effects of selenium on the growth and nutrient absorption in pakchoi(Brassica campestris ssp. chinensis L.)were studied. The results showed that the plant growth was promoted at lower selenite concentration, while it was inhibited at higher selenite concentration. The contents of soluble sugar and reducing sugar in shoots of pakchoi were increased, while those of the sucrose and starch were decreased. The content of cellulose was increased at lower selenite concentrations, but decreased at higher selenite concentrations. The content of protein was decreased at the treatment (Se≤1.0 mg/L ), but it was increased gradually with the increase of selenite concentration in the solution. The content of total free amino acids was higher than control. The contents of N, Ca, Mg, Mn, Zn in shoots of pakchoi treated with selenite were increased, while those of P, K, S were decreased. Compared to the control, the contents of N, S in roots of plant were increased while those of P、Ca、Mg、Fe、Mn、Zn were decreased at the treatment, but the K content was hardly affected . The content of selenium in either shoots or roots of the plant was positively correlated with the selenite concentration in the solution. Most of the selenium form in plant was organic selenium and the organic selenium invert rates were above 80 percent in all treatments.

以小白菜为材料 ,研究了硒对植株生长和养分吸收的影响。结果表明 ,当营养液中加入低浓度硒 (Se≤ 1.0mg L)时促进了小白菜的生长 ,增加了产量 ;加高浓度硒 (Se≥ 2 .5mg L)时则抑制了小白菜的生长。加硒后增加了小白菜地上部可溶性总糖、还原糖含量 ;降低了蔗糖和淀粉的含量 ;低浓度硒增加了粗纤维含量 ,而高浓度硒则降低了其含量 ;Se≤ 1.0mg L的硒处理降低了植株地上部总蛋白质的含量 ,但随着硒浓度的进一步增加 (Se >1.0mg L)植株体内的总蛋白质含量逐渐升高 ,并大于对照。加硒后增加了小白菜地上部游离氨基酸总量和N、Ca、Mg、Mn、Zn含量 ,降低了P、K、S元素的含量 ;与对照相比 ,加硒后增加了小白菜地下部N、S元素的含量 ,降低了P、Ca、Mg、Fe、Mn、Zn元素的含量 ,但对K元素的影响不大。无论是小白菜地上部还是地下部 ,体内硒的含量均与营养液中硒的浓度呈显著的正相关。植物地上部硒的含量以有机态硒为主 ,有机硒转化率均在 80 %以上。

本文通过土培试验，研究了硒粉、硒矿、亚硒酸钠和硒酸钠四种硒源对小麦和油菜生长及硒累积的影响，旨在通过评价四种硒源在作物上的应用效果，为不同硒源的合理利用提供技术支撑。主要结果如下:　　 1、不同硒源对小麦和油菜生长的影响。　　 施用不同硒肥对小麦和油菜生长的影响存在显著差异。硒粉对小麦和油菜生长没有显著影响;硒矿在研究浓度范围内(2-15 mg/kg)均表现为促进小麦和油菜的生长，小麦产量增加1.34％-16.30％，油菜产量增加4.09％-2.12％;硒酸钠和亚硒酸钠对小麦和油菜生长的影响最为显著，表现为适宜浓度促进生长，小麦产量增加7.77％-1...

以我国北方常见的生菜为材料,采用无土基质栽培方式,进行不同梯度水平的施硒试验,研究生菜富硒效果以及硒对生菜体内叶绿素、Vc含量的影响,为富硒蔬菜无土基质栽培提供参考依据。结果表明,基质施硒可以有效地提高生菜中有机硒的含量,改善生菜的品质。

Under field plot experiment condition, the different application methods and application periods of selenium(Se)fertilizer were explored to make sure the absorption and accumulation of Se in plants and grains of rice. The results showed there were significant differences in the early and exuberant periods of rice for Se absorption and accumulation. Compared with the control, three kinds of application methods could significantly improve Se value of rice. From the effect of Se enrichment, the content of Se was in the range of 0.163～0.207 mg·kg -1 which increased by 5.8～7.6 times, within the safe range. From the way of Se enrichment, the order of better effect was: spraying Se at flowering stage treatment>application Se in soil>spraying Se at breeding period>CK. From the foliar application period of Se, the order of Se enrichment effect was spraying Se at flowering stage>breeding period>grain filling period>full heading period>CK. Exogenous inorganic and organic Se fertilizer could significantly promote the accumulation of Se in rice. Foliar spray in rice seedling and flowering stage could increase the Se containing of rice grain but not reduce the yield of rice.

在田间小区的试验条件下研究不同硒(Se)肥的施用方法及施用时期对水稻植株和籽粒中Se的吸收与富集的影响。研究表明:水稻在生长前期和旺盛时期对Se的吸收和积累有很大差异。与对照相比,苗床施Se、土壤施Se和叶面喷Se 3种方式均能明显提高各生育期水稻植株和籽粒中Se的含量,富Se效果达到差异极显著水平。从稻米富Se效果看,富Se含量在0.163～0.207 mg·kg -1 之间,Se含量增加了5.8～7.6倍,且都在安全范围内。从水稻富Se的方式上,不同施Se方式富Se效果依次为水稻扬花期喷Se>土壤施Se>育苗期喷Se>对照。从叶面喷施Se的时间上,稻米富Se效果依次是扬花期喷Se>育苗期喷Se>灌浆期喷Se>齐穗期喷Se>对照。从水稻富Se类型上看,外源无机Se和有机Se都能明显促进水稻对Se的积累。水稻育苗期和扬花期叶面喷Se在提高水稻稻米中含Se量的同时,并没有降低水稻产量。因此水稻叶面喷Se是一条安全、简单、易操作的途径。

In order to understand the effect of selenium on the yield of garlic and its absorption and transformation , the experiment was carried out through three different ways , namely leaf absorption , seed soaking and soil application. It was found that the ability to absorb selenium varied among the four garlic varieties , the highest of which was ‘Yingxian’garlic , and followed by ‘Xinzhou’, ‘Yuci’and ‘Taigu’. Under the range of selenium concentration in this experiment , with the rise of selenium concentration , the yield of garlic increased and then dropped , whereas the total content of selnium in garlic increased steadily with the decrease of the ratio of inorganic Se to organic Se.

以土壤施硒(0. 1 g·m -2 ) 研究大蒜对硒的吸收、转化及硒对大蒜产量的影响。结果表明, 4 个大蒜品种吸收硒的能力为: 应县大蒜> 忻州大蒜> 榆次大蒜和太谷大蒜。以土壤施硒(0. 01、0. 1、1、10 g·m -2 ) 、叶面施硒(10、100、1 000 mg·kg -1 ) 和硒浸种10、 100 mg·kg -1 ) 3 种方式处理应县大蒜, 结果随着硒处理浓度的提高, 大蒜的产量先升后降,大蒜含硒量随着硒处理浓度的提高而提高, 但无机硒转化成有机硒的比率下降。

Selenium is a necessary element for plant growth. This study employed the method of pot experiments to investigate the effect of exogenous selenium concentration on the growth of annual seedlings and chlorophyll fluorescence parameters of Apocynum venetum L. The results showed that annual A. venetum L. seedling growth and chlorophyll fluorescence parameters had significant correlation under root applied Selenium (R) or spray Selenium of A. venetum L. Within a certain range of concentration （0-1.5 mg·kg -1 ），stem dry weight，weight，plant height，stem diameter，the number of leaves of A. venetum L. on the stem and branches increased significantly with the increase of selenium concentration. Fv/Fm，Fv/Fo，Ψo，φEo，PIABS also increased with the increase of selenium concentrations while V K ，V J ，V I gradually decreased. However，the growth and chlorophyll fluorescence parameters of Apocynum venetum L. reduced with the excessive supply of selenium. Selenium promoted the growth of Apocynum，particularly the function of the root system，which reinforced the nutrient absorption ability of the plant. Although high concentration （3-5 mg·kg -1 ） of selenium put stresses on the aboveground parts of the plant，it could still boost the growth of the root. There might be two reasons why the root can grow fast under the high concentration. On the one hand，the root might have a better tolerance to selenium toxicity than the rest parts of the plant. On the other hand，it was possible that A. venetum L. had had developed an adaptive response to selenium poisoning. A. venetum L. could change the growth strategy to let more photosynthetic product and nutrients being allocated to roots，to increase root cap ratio and to improve the absorbing ability to maintain the normal growth. A certain concentration of selenium can improve the activity of PSII and increase the PSII reaction central open degree，and then improve the utilization rate of light energy，so as to effectively promote the growth of A. venetum L.. The suitability range of selenium concentration was not obvious. The concentration below 1 mg·kg -1 had no significant influence on the growth of A. venetum L. but the concentration greater than 3 mg·kg -1 would significantly inhibit the growth of the plant. Therefore，concentration of selenium should be strictly controlled within 1-3 mg·kg -1 to avoid the accumulation of selenium in the soil. Leaf spray might be a better harmless way to improve the growth of the plant.

硒是植物生长发育的必需元素，能促进植物生长。采用盆栽试验的方法，研究了施用不同浓度的外源硒对一年生罗布麻幼苗生长及叶绿素荧光参数的影响。研究结果表明：根施（R）和叶面喷施（L）两种施硒方式下，硒浓度与罗布麻一年生幼苗生长及叶绿素荧光参数有极显著相关性，表现为，一定浓度范围内（0～1.5 mg·kg -1 ），随着硒浓度的增加，罗布麻茎干重、叶干重、株高、茎粗、主叶对数和侧枝数均有有不同程度的上升； Fv/Fm、Fv/Fo、Ψo、φEo、PIABS 、均随着施硒浓度的增加而增加； V K 、V J 、V I 均随着施硒浓度的增加而逐渐下降， S m 逐渐上升；说明施硒促进了罗布麻叶PSII的活性，提高了PSII反应中心的开放程度，增大其光能利用率。但随着供应浓度的进一步提高，各项生长及荧光指标有所降低，因此过量的硒供应对于罗布麻生长不利，而且有益与有害之间的范围很小，具体罗布麻栽培中要严格控制硒用量在1～3 mg·kg -1 范围内。搜索 #SrsZzqBAngjSTips { Z-INDEX: 999999999; POSITION: absolute; WIDTH: 56px; HEIGHT: 24px; LEFT: 1342177.27em } #SrsZzqBAngjSTips A { POSITION: relative; LINE-HEIGHT: 24px; MARGIN: -32px 0px 0px; PADDING-LEFT: 23px; WIDTH: auto; DISPLAY: block; BACKGROUND: url(http://mat1.gtimg.com/www/sogou/sogou_tips_v1.png) no-repeat 0px 0px; HEIGHT: 24px; COLOR: #000; FONT-SIZE: 12px; TEXT-DECORATION: none } #SrsZzqBAngjSTips A:hover { BACKGROUND-POSITION: 0px -34px; COLOR: #45a1ea }

Pot and field experiments were carried out to study the effect of low Se concentration on soybean chloroplast ultra-structure and on Mg, Fe, Mn and contents in soybean leaves under continuous cropping stress. The results showed that Se could certainly increase the contents of Mg, Fe and Mn in soybean leaves when the application rate of Se was below 0.50mg穔g -1 in pot experiment, and below 300g穐m -2 in field experiment.In pot experiment, Se concentration positively correlated with Mg and Fe contents in soybean leaves, but the relationship between Mn and Se was hardly to be quantified.Transmission electron microscopic observation indicated that under continuous cropping stress, application of Se could hold the soybean chloroplast membrane structure in good condition.When Se was not applied,the chloroplast swelled, and its grana disappeared, and even,transformed into etioplast.These experiments indicated that application of low Se could alleviate peroxidative stress resulting from continuous cropping, and keep the soybean grow normally.

采用盆栽试验和田间小区试验方法,研究了低浓度施Se对重茬胁迫下大豆叶绿体超微结构及大豆叶片中Mg、Fe、Mn含量的影响.结果表明,当盆栽试验施Se量小于0.50mg·kg -1 ,田间小区试验施Se量小于300g·hm -2 时,施Se都不同程度地提高了大豆叶片的Mg、Fe和Mn含量.在盆栽试验中,施Se量与大豆叶片中Mg、Fe的含量呈正比,而施Se量与大豆叶片中Mn含量之间的关系很难确定.同时,透射电镜照片显示,盆栽试验中重茬胁迫下,施Se可使大豆叶绿体膜结构保持完好,而不施Se对照的叶绿体发生膨胀,基粒消失,甚至转化成了黄化体.可以认为,低浓度施Se能缓解大豆重茬胁迫所造成的过氧化损伤,使大豆生长较为正常.