Silicon stimulates initial growth and chlorophyll a/b ratio in rice seedlings,and alters the concentrations of Ca,B, and Zn in plant tissues

Abstract

Silicon (Si) is considered a beneficial element for plants due to the far-reaching benefits it confers, including enhanced growth, yield, and crop quality, as well as stress resistance. In this study, we evaluated the effect of Si during germination and initial growth (0.0, 0.5, 1.0, or 1.5?mM Si) and during vegetative growth (0, 1, 2, or 3?mM Si) in rice (Oryza sativa) cv. Morelos A-98. Si did not affect germination but stimulated seedling height, root length, number of roots, as well as fresh and dry biomass weight of shoots and roots during initial growth. During vegetative growth, the application of 3?mM Si significantly increased the chlorophyll a/chlorophyll b ratio, but no major changes were observed either in growth or in concentrations of most nutrients, with the exception of Ca (which increased with 3?mM Si), and B and Zn (which decreased in the presence of Si). In conclusion, applying Si had positive effects during the initial stage of growth, increasing seedling height, root length, root number, and fresh and dry biomass weight. Under our experimental conditions, Si did not affect germination and vegetative growth, but increased Ca concentrations and decreased B and Zn concentrations.     

Diversity of cultivable endophytic bacteria associated with halophytes in Xinjiang of China and their plant beneficial traits

Endophytic bacteria from halophytes have a wide range of application prospects in various fields, such as plant growth-promoting, biocontrol activity and stress resistance. The current study aimed to identify cultivable endophytic bacteria associated with halophytes grown in the salt-affected soil in Xinjiang Uygur Autonomous Region, China and to evaluate their plant beneficial traits and enzyme-producing activity. Endophytic bacteria were isolated from Reaumuria soongorica (PalL Maxim.), Artemisia carvifolia (Buch.-Ham. ex Roxb. Hort. Beng.), Peganum harmala L. and Suaeda dendroides (C. A. Mey. Moq.) by using the cultural-dependent method. Then we classified these bacteria based on the difference between their sequences of 16S rRNA (16S ribosomal RNA) gene. Results showed that the isolated bacteria from R. soongorica belonged to the genera Brucella, Bacillus and Variovorax. The bacteria from A. carvifolia belonged to the genera Micromonospora and Brucella. The bacteria from P. harmala belonged to the genera Paramesorhizobium, Bacillus and Peribacillus. The bacteria from S. dendroides belonged to the genus Bacillus. Notably, the genus Bacillus was detected in the three above plants, indicating that Bacillus is a common taxon of endophytic bacteria in halophytes. And, our results found that about 37.50% of the tested strains showed strong protease-producing activity, 6.25% of the tested strains showed strong cellulase-producing activity and 12.50% of the tested strains showed moderate lipase-producing activity. Besides, all isolated strains were positive for IAA (3-Indoleacetic acid) production, 31.25% of isolated strains exhibited a moderate phosphate solubilization activity and 50.00% of isolated strains exhibited a weak siderophore production activity. Our findings suggest that halophytes are valuable resources for identifying microbes with the ability to increase host plant growth and health in salt-affected soils.     

应用红外热像技术检测木材孔洞缺陷

为了提高木材空洞缺陷的红外检测精度,采用空洞模拟手段,以6个含有不同径级的人工孔洞缺陷的色木试样为研究对象,应用人工红外灯和烘干箱法,研究孔径缺陷识别的最佳加热时间和最佳加热温度,探讨热源选择对不同孔径大小的试材检测效果的影响。研究结果表明:随着试样缺陷孔径的不断减小,最佳加热时间和最佳加热温度都逐渐减少;在一定孔径范围内热像图能较为准确的反映木材缺陷的位置及大小情况;随着试样缺陷孔径的不断减小,检测效果越来越不明显。     

不同贮藏方式对辣椒花粉生活力及授粉效果的影响

研究不同贮藏温度、不同含水量处理对辣椒花粉生活力变化及田间授粉效果的影响,以探究不同贮藏条件下辣椒花粉的贮藏能力。结果表明：辣椒花粉生活力随着贮藏时间的延长而降低,贮藏温度和花粉含水量显著影响辣椒花粉贮藏能力,降低贮藏温度能有效延长花粉贮藏时间,干燥处理花粉贮藏能力显著优于未干燥处理。所有处理中,以超低温干燥处理贮藏效果最佳,低温处理优于冷冻处理,冷冻处理优于常温处理,贮藏辣椒花粉有效生活力下限为10%。以花粉生活力下限为标准,常温(20±1) ℃未干燥处理有效贮藏期为3~5 d,常温(20±1) ℃干燥处理有效贮藏期为7~10 d;低温(4±1) ℃未干燥处理有效贮藏期为15~20 d,低温(4±1) ℃干燥处理有效贮藏期为35~40 d;冷冻(-20±1) ℃未干燥处理有效贮藏时间为5 d左右,冷冻(-20±1) ℃干燥处理有效贮藏期为15~20 d;超低温(-196 ℃)干燥处理贮藏1 a仍具有新鲜花粉一半的生活力,但未干燥处理几乎无有效贮藏期。     

Effects of High Dietary Levels of Fresh or Oxidised Fish Oil on Performance and Blood Parameters in Female Mink (Mustela vison) During the Winter,Reproduction, Lactation and Early Growth Periods

The effects of high dietary levels of fresh or moderately oxidised fish oil on performance and blood parameters in mink females were investigated during the winter, reproduction, and lactation periods. Furthermore, the effects of the diets on kit performance were investigated during the lactation and early growth periods. The investigation was carried out with a total of 292 females distributed in five experimental groups fed fresh fish oil stored frozen, fresh fish oil ensiled, oxidised fish oil stored frozen, oxidised fish oil ensiled, and soya oil, respectively. The females were weighed three times during the winter period, and the females and the kits were weighed at parturition and 2, 4, and 7 weeks post partum. Blood samples were collected from the females and the kits 6 and 8 weeks post partum, respectively. The results show that high dietary levels of fresh or moderately oxidised fish oil could be used for mink females during the winter and reproduction periods without any negative effects on performance, health and reproduction results. However, high levels of fish oil resulted in lower kit weights at weaning. These negative effects on kit growth were related to the dietary composition fed during the lactation and early growth periods and not to the diet used during the preceding winter and pregnancy periods. A high intake of polyunsaturated fatty acids resulted in a decreased number of blood platelets for both mink females and their kits.     

Impact of four turf management regimes on arthropod abundance in lawns

BACKGROUND: Turfgrass management practices, especially the use of chemical pesticides, may be detrimental to beneficial arthropods such as predators and decomposers. However, little is known about the impact of other practices or pest control products on these beneficials. The impact of four different management regimes, consisting of synthetic pesticide cover sprays or combinations of more targeted applications of natural pesticides, on selected groups of non‐targeted arthropods in lawns of different age was studied over 3 years. The short‐term effect of diazinon and carbaryl on Carabidae and Collembola was also evaluated. RESULTS: Formicidae and Araneae were the most abundant taxa at both sites, representing 74–80% of total captures. With a few short‐term exceptions, no persistent and significant difference between turfgrass management regimes on arthropod abundance was observed over the 3 year study. Diazinon and carbaryl significantly reduced Carabidae abundance, but only one year out of three, while Collembola abundance was only transiently affected by carbaryl application in 2003. CONCLUSION: The study showed that practices and products used in the four management regimes did not disrupt the populations of specific groups of arthropods. These results provide useful information to professionals for the development of ecological turf practices to maintain beneficial arthropod abundance and diversity in urban landscapes. Copyright © 2012 Society of Chemical Industry     

汽车碰撞模型参数变化对计算结果的影响分析

应用矩阵理论建立了汽车碰撞模型中参数变化影响计算结果的分析方法.实例分析表明：应用该方法能够准确地分析参数变化对计算结果的影响.     

植物生长调节剂在油松育苗上的应用

研究了不同植物生长调节剂对北方常用造林树种油松育苗的影响,以GGR6号、GGR8号、ABT3号、绿风-95、喷施宝为研究对象,田间设计采用随机区组法,通过浸种和喷施的方法,连续3a应用不同植物生长调节剂在油松育苗上进行对比试验,测定幼苗出苗率、苗木生长量和质量等,结果表明:用GGR6号浸种能显著加快种子出苗速度,出苗率达到92%,与对照(清水)相比出苗期提前2～3d,出苗率比对照提高10%～30%,且出苗集中整齐.不同植物生长调节剂对油松苗木生长的促进作用具有显著差异性,以GGR6号效果最佳.     

氯虫苯甲酰胺对稻纵卷叶螟的防效及对稻田有益节肢动物的安全性评价

研究了20%氯虫苯甲酰胺悬浮剂对稻纵卷叶螟的防效及对稻田常见有益节肢动物的安全性。室内毒力测定结果显示：将20%氯虫苯甲酰胺悬浮剂稀释3 000、6 000倍浸渍水稻叶片,接稻纵卷叶螟幼虫24 h死亡率在40%左右, 96 h死亡率达100%。稻田小区和大面积示范试验结果显示：药后14 d,氯虫苯甲酰胺对稻纵卷叶螟的防效分别为90.59%、97.07%,高于药后4、7 d的防效。其防效好于氟虫腈、虫酰肼+辛硫磷。田间与施药前相比,药后14 d球腹蛛显著增加,微蛛、狼蛛的数量及蜘蛛总量无显著差别。室内测定,氯虫苯甲酰胺处理后,黑肩绿盲蝽及稻虱缨小蜂的死亡率在0~6.67%。上述结果表明：氯虫苯甲酰胺对稻纵卷叶螟有很好的防效,且对稻田有益节肢动物安全。     

试管开花植物研究现状及展望

概括国内外目前的试管开花植物科种以及目前试管开花的研究思路,着重介绍依靠其中一种普遍的研究思路（即外界因素对试管开花的影响）所取得的成果,并对目前存在的问题进行讨论。