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Previous experiments demonstrated that treatment of longan trees with potassium chlorate (KClO3) induces “off season floral induction” (FI) even in the absence of the naturally required cool temperature [Manochai, P., Sruamsiri, P., Wiriya-alongkorn, W., Naphrom, D., Hegele, M., Bangerth, F., 2005. Year around off season flower induction in longan (Dimocarpus longan, Lour.) trees by KClO3 applications: potentials and problems. Sci. Hortic. 104, 379–390]. Potassium chlorate, however, cannot replace the presence of functional mature leaves and sufficient light intensity. Here we examined in more detail the effect of shade (about 10% of natural sunlight) on KClO3 affected hormone concentrations/transport of leaves and shoot apical buds (SAB) and their interactions with FI. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(21):2757-2773
The effectiveness of lime-ammonium-nitrate (LAN) as a nitrogen (N) fertilizer in weathered soils depends on the respective selectivity for ammonium (NH4) and calcium (Ca) by the soils. The study assessed Ca2+/NH4+ exchange selectivity of two benchmark soils from Botswana and examined the soil fertility management implications. Surface horizons (0–20 cm) of Pellustert and Haplustalf were equilibrated with 50 ml stock solution containing variable concentrations of Ca2+ and NH4+. The Ca2+/NH4+ exchange data were fitted into the Vanselow (KV), Gaines and Thomas (KGT), Davies (KD), and the regular solution (KRS) equations. The selectivity coefficients for the Ca2+/NH4+ exchange reactions varied widely with the soil exchanger composition except for the relatively stable KRS. The selectivity coefficients indicated strong preference for NH4+ to Ca2+. The thermodynamic exchange constant, Kex, was 5.75 ± 1.24 in the Pellustert, indicating preferential adsorption of NH4+, but not in the Haplustalf with Kex = 0.92 ± 0.27. The free energy for Ca2+/NH4+ exchange (ΔG°ex) was negative (?4.26 ± 0.59 kJ mol?1) in the Pellustert but slightly positive in the Haplustalf (0.34 ± 0.87 kJ mol?1). In conclusion, the soil-NH4 complex was more stable than soil-Ca complex in the Pellustert, indicating LAN as a N fertilizer would have greater potential effectiveness in the Pellustert than in the Haplustalf. 相似文献
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为了明确O157:H7(ΔhlyΔstxΔtoxB)口服能否减少亲本株O157:H7在山羊体内的定殖。选用3月龄山羊,首先口服接种O157:H7(ΔhlyΔstxΔtoxB),分别于第7,14天再次口服接种亲本株O157:H7,监测亲本株O157:H7的排菌持续时间和排菌量。结果表明:O157:H7(ΔhlyΔstxΔtoxB)口服后第7天攻击亲本株O157:H7,第4天检测不到亲本株O157:H7的排菌;第14天攻击亲本株O157:H7,第9天检测不到亲本株O157:H7的排菌。直接口服亲本株O157:H7,排菌一直持续到第25天。口服O157:H7(ΔhlyΔstxΔtoxB)能够减少O157:H7在山羊体内的定殖,为研制EHECO157:H7基因缺失疫苗奠定了基础。 相似文献
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【目的】验证少根根霉△6-脂肪酸脱氢酶基因在转基因油菜中的表达情况,为进一步基因工程化生产γ-亚麻酸打下基础。【方法】将少根根霉△6-脂肪酸脱氢酶基因和植物表达载体pCPN2301连接,构建重组表达质粒pCPNRAD6,采用农杆菌介导的油菜子叶节转化法,将该基因导入甘蓝型油菜H165,获得转基因植株,最后通过气相色谱检测基因的表达情况。【结果】PCR、GUS组织化学染色和Southern杂交分析结果表明,目的基因已经整合到油菜基因组中,Northern杂交分析进一步表明目的基因在RNA水平获得表达,气相色谱分析检测到转基因油菜叶片中γ-亚麻酸和十八碳四烯酸生成,证明目的基因获得功能表达。同样,用改变少根根霉Δ6-脂肪酸脱氢酶基因的转译起始密码子周边序列的基因RAD6-1所构建的转基因酵母中,也得到类似的结果,而且各种目的脂肪酸的含量均有提高。【结论】初步建立了少根根霉△6-脂肪酸脱氢酶基因在转基因油菜中的表达体系。 相似文献
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Forests cover one-third of the Earth’s land surface and account for 30-40% of soil carbon (C). Despite numerous studies, questions still remain about the factors controlling forest soil C turnover. Present understanding of global C cycle is limited by considerable uncertainty over the potential response of soil C dynamics to rapid nitrogen (N) enrichment of ecosystems, mainly from fuel combustion and fertilizer application. Here, we present a 15-year-long field study and show an average increase of 14.6% in soil C concentration in the 0-5 cm mineral soil layer in N fertilized (defined as N+ hereafter) sub-plots of a second-rotation Pinus radiata plantation in New Zealand compared to control sub-plots. The results of 14C and lignin analyses of soil C indicate that N additions significantly accelerate decomposition of labile and recalcitrant soil C. Using an annual-time step model, we estimated the soil C turnover time. In the N+ sub-plots, soil C in the light (a density < 1.70 g cm−3) and heavy fractions had the mean residence times of 23 and 67 yr, respectively, which are lower than those in the control sub-plots (36 and 133 yr in the light and heavy fractions, respectively). The commonly used lignin oxidation indices (vanillic acid to vanillin and syringic acid to syringaldehyde ratios) were significantly greater in the N+ sub-plots than in the control sub-plots, suggesting increased lignin decomposition due to fertilization. The estimation of C inputs to forest floor and δ13C analysis of soil C fractions indicate that the observed buildup of surface soil C concentrations in the N+ sub-plots can be attributed to increased inputs of C mass from forest debris. We conclude that long-term N additions in productive forests may increase C storage in both living tree biomass and soils despite elevated decomposition of soil organic matter. 相似文献
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This study aimed at investigating the effects of amylose content (AC) of 0.12–19.00% w/w on dry basis, cooling rate (1, 3, 5, and 9 °C/min), and aging time (24, 48, and 72 h) on structure, physical properties and sensory attributes of rice starch-based puffed products. They had an influence upon the crystalline type, and the relative crystallinity (RC). The thermal and physical properties of starch gels were also determined. Amorphism was found for starch gels with 0.12% AC. The polymorphisms (B and V) and differential scanning calorimetric endotherms were found for those with AC ≥4.00%. The RC, retrogradation enthalpy (ΔHr) and gel hardness increased with AC and aging time. The cooling rate did not affect RC, but increased ΔHr and gel hardness. The higher AC and aging time resulted in higher hardness, fracturability, crispiness and bulk density, but lower expansion ratio and less oiliness of the puffed products. The hardness, fracturability, crispiness and bulk density of puffed products were well correlated with the RC of starch gel. 相似文献