母本密度对黔油14号制种产量及生育特性的影响     

代文东  黄泽素  杨晓容  王通强  李德珍 《山地农业生物学报》2006,25(6):475-478

对杂交油菜黔油14号母本设置7个移栽密度,研究密度对黔油14号制种产量和母本经济性状及生育特性的影响.结果表明,制种产量随密度的增加而有增加的趋势,产量差异达显著水平.当母本移栽密度为1.6万株·667m-2时,制种产量为最高,达到55.69 kg·667m-2,但结合比较效益,贵阳地区生产黔油14号的母本种植密度以1.0万株·667m-2为宜.母本种植密度对一次有效分枝数、植株分枝高度、单株有效角果数、千粒重的影响较大,相关系数分别为-0.922 16、0.818 56、-0.743 14、0.780 38;母本全生育期为234～236d,播种至现蕾、现蕾至初花、初花至终花、终花至成熟经历的时间分别为85～87d、79～85d、32～40d、29～31d.  相似文献   

Expression of 14-3-3 σ protein in normal and neoplastic canine mammary gland     

Suárez-Bonnet A  Herráez P  Martín de las Mulas J  Rodríguez F  Déniz JM  Espinosa de los Monteros A 《Veterinary journal (London, England : 1997)》2011,(3):345-351

14-3-3 σ protein is a negative cell cycle regulator, with both reduced and elevated levels associated with cancer in humans. This study assessed the expression of this protein in canine mammary tissues using immunohistochemistry and Western blotting. 14-3-3 σ was detected in 97% of the mammary tissue samples examined and was found in both myoepithelial (MECs) and epithelial (ECs) cells. Expression levels were elevated and reduced in neoplastic ECs and MECs, respectively (P < 0.001). Intense expression of 14-3-3 σ was detected in neoplastic ECs infiltrating blood vessels and lymph nodes and suggests a possible role for this protein in the malignant transformation of mammary neoplasms. Moreover, double immunostaining for 14-3-3 σ and the MEC – specific marker p63, confirmed that 14-3-3 σ is a highly sensitive marker of MECs since all p63 – positive cells were also positive for 14-3-3 σ. However, this protein is not exclusive to MECs as ECs also labelled positively.  相似文献   

Variable use of plant- and soil-derived carbon by microorganisms in agricultural soils     

Christiane Kramer 《Soil biology & biochemistry》2006,38(11):3267-3278

In this study we used compound specific ¹³C and ¹⁴C isotopic signatures to determine the degree to which recent plant material and older soil organic matter (SOM) served as carbon substrates for microorganisms in soils. We determined the degree to which plant-derived carbon was used as a substrate by comparison of the ¹³C content of microbial phospholipid fatty acids (PLFA) from soils of two sites that had undergone a vegetation change from C3 to C4 plants in the past 20-30 years. The importance of much older SOM as a substrate was determined by comparison of the radiocarbon content of PLFA from soils of two sites that had different ¹⁴C concentrations of SOM.The ¹³C shift in PLFA from the two sites that had experienced different vegetation history indicated that 40-90% of the PLFA carbon had been fixed since the vegetation change took place. Thus PLFA were more enriched in ¹³C from the new C4 vegetation than it was observed for bulk SOM indicating recent plant material as preferentially used substrate for soil microorganisms. The largest ¹³C shift of PLFA was observed in the soil that had high ¹⁴C concentrations of bulk SOM. These results reinforce that organic carbon in this soil for the most part cycles rapidly. The degree to which SOM is incorporated into microbial PLFA was determined by the difference in ¹⁴C concentration of PLFA derived from two soils one with high ¹⁴C concentrations of bulk SOM and one with low. These results showed that 0-40% of SOM carbon is used as substrate for soil microorganisms. Furthermore a different substrate usage was identified for different microorganisms. Gram-negative bacteria were found to prefer recent plant material as microbial carbon source while Gram-positive bacteria use substantial amounts of SOM carbon. This was indicated by ¹³C as well as ¹⁴C signatures of their PLFA. Our results find evidence to support ‘priming’ in that PLFA indicative of Gram-negative bacteria associated with roots contain both plant- and SOM-derived C. Most interestingly, we find PLFA indicative of archeobacteria (methanothrophs) that may indicate the use of other carbon sources than plant material and SOM to a substantial amount suggesting that inert or slow carbon pools are not essential to explain carbon dynamics in soil.  相似文献   

Effects of nitrogen and intensive mixing on decomposition of C-labelled maize (Zea mays L.) residue in soils of different land use types     

Haiqing Chen  Norbert Billen  Karl Stahr  Yakov Kuzyakov 《Soil & Tillage Research》2007,96(1-2):114-123

This study investigated the effects of mineral-N addition and intensive mixing (analogous to disturbance by plowing) on decomposition of ¹⁴C-labelled maize (Zea mays L.) residue and soil organic matter (SOM). Soils were collected from the upper 5 cm of three land use types at Edelweiler, Germany: plow tillage (PT), reduced tillage (RT), and grassland (GL). Soils were incubated for 112 days at 20 °C, with or without ¹⁴C-labelled maize residue (4 g DM kg⁻¹ soil), with or without nitrogen (100 mg N kg⁻¹ soil as NH₄NO₃) and with or without intensive mixing.

The effect of mineral-N on maize residue decomposition differed depending on the stage of decomposition and land use type. Nitrogen accelerated residue decomposition rates in the first 5 days in RT and GL soils, but not in PT soil, and decreased residue decomposition rate in all three land use types after 11 days. At the end of the incubation, N suppressed ¹⁴CO₂ efflux in RT and PT soils, but not in GL soil. Mineral-N did not increase SOM decomposition independently on the land use types.

Intensive mixing stimulated decomposition of both plant residue and SOM in all three land use types. However, effects were smaller in GL soil than in RT or PT soil, presumably because stronger soil aggregates in GL would have been less affected by mixing and allowed greater protection of SOM and plant residue against decomposition.  相似文献   

大麦光合产物的分配、再分配与产量形成的关系     

张怀渝  王化新  郭大智  李尧权 《核农学报》1995,9(3):0-0

本试验以二棱形和六棱型两个大麦品种为材料,应用＾１４Ｃ示踪技术,对大麦各生育期＾１４Ｃ光合产物在各器官中的分配、财分配及其干物质积螺的关系进行了研究。试验表明：１．不同生育期光合产物的根本与再分配方式不同,分蘖和拔节期光合产物主要用于根系、茎叶的生长,只有１３．５％,８．９５％分配到籽粒中,抽穗和灌浆期光合产物主要用于籽粒育实和灌浆,分别有４７．２％和４８．１％,７２．１％和８８．１％分配到籽粒。  相似文献   

越冬期间小麦的光合作用及其对生长发育的影响   总被引：1，自引：1，他引：1  

王志芬  宋良增  范仲学  张凤云  刘益同  王守瑰  朱连先  朱伯良  徐明振  高华强  王周文 《核农学报》2001,15(4):243-246

利用14 C同位素示踪技术研究了冬小麦越冬期间的光合特性及其对冬小麦生长发育的影响。结果表明 ,越冬期间的冬小麦能够吸收、同化14 CO2 ,并进行转运 ;其同化产物的 60 %用于越冬期的呼吸消耗 ,约 40 %用于返青后的生长发育 ,其中少量的光合产物参与了穗部产量的形成。  相似文献   

小麦根系物质流示踪研究     

巫建华  龚荐  罗时石 《核农学报》1992,6(3):147-152

在小麦生育进程各主要叶龄期分别用~(32)P和~(14)C标记各根层和叶层,研究根系营养物质流与地上部光合同化物质流的动态变化及兵在产量形成上的相互关联作用。研究表明,小麦各层次生根的最大功能同主茎叶龄进程基本上保持同步关系,即n/0叶龄发生的根至n+3/0叶龄发挥显著吸收功能。小麦某一叶龄期的功能叶和功能根在同化物质和营养物质输配上表现出互相依赖、相互促进的关系。  相似文献   

Short and long-term effects of elevated CO₂ on Lolium perenne rhizodeposition and its consequences on soil organic matter turnover and plant N yield     

V. Allard  C. Robin  M. Lieffering 《Soil biology & biochemistry》2006,38(6):1178-1187

It is still unclear whether elevated CO₂ increases plant root exudation and consequently affects the soil microbial biomass. The effects of elevated CO₂ on the fate of the C and nitrogen (N) contained in old soil organic matter pools is also unclear. In this study the short and long-term effects of elevated CO₂ on C and N pools and fluxes were assessed by growing isolated plants of ryegrass (Lolium perenne) in glasshouses at elevated and ambient atmospheric CO₂ and using soil from the New Zealand FACE site that had >4 years exposure to CO₂ enrichment. Using ¹⁴CO₂ pulse labelling, the effects of elevated CO₂ on C allocation within the plant-soil system were studied. Under elevated CO₂ more root derived C was found in the soil and in the microbial biomass 48 h after labelling. The increased availability of substrate significantly stimulated soil microbial growth and acted as priming effect, enhancing native soil organic matter decomposition regardless of the mineral N supply. Despite indications of faster N cycling in soil under elevated CO₂, N availability to plants stayed unchanged. Soil previously exposed to elevated CO₂ exhibited a higher N cycling rate but again there was no effect on plant N uptake. With respect to the difficulties of extrapolating glasshouse experiment results to the field, we concluded that the accumulation of coarse organic matter observed in the field under elevated CO₂ was probably not created by an imbalance between C and N but was likely to be due to more complex phenomena involving soil mesofauna and/or other nutrients limitations.  相似文献   

Do same-aged but different height Norway spruce (Picea abies) clones affect soil microbial community?     

Tiina Korkama  Hannu Fritze  Oili Kiikkilä  Taina Pennanen 《Soil biology & biochemistry》2007,39(9):2420-2423

The influence of individual trees in monocrop forests on soil microbial communities is poorly understood. We measured basal respiration, substrate-induced respiration and phospholipid fatty acids (PLFA), bacterial growth rate with the ³H-thymidine incorporation technique and fungal growth rate as ¹⁴C-acetate incorporation into ergosterol to investigate whether slow- and fast-growing 12-year-old Norway spruce (Picea abies) clones have affected differently on their associated soil microbial communities. Understorey vegetation, soil chemical properties and elemental concentrations of needles were also determined. The slow- and fast-growing spruce clones differed in PLFA profiles, understorey vegetation and elemental concentrations in needles suggesting that spruce clones have directly or indirectly affected soil microbes.  相似文献   

国审玉米郑单14播期、密度与高产机理研究     

张新  王振华 《玉米科学》2004,12(Z2):76-78

对郑单14的密度、播期及生理特点等一系列研究表明,郑单14的最适播种密度为52 500～60 000株/hm2;理想播期为5月25日至6月5日,不宜在6月10日以后播种.其表现高产稳产的主要生理原因是①叶面积指数变化合理,叶片持绿时间长,衰老慢,叶绿体中的光合色素、蛋白质和可溶性糖含量高;②过氧化物酶活性高,丙二醛积累少,光合效率高;③子粒体积大,灌浆时间长,千粒重高.  相似文献