赤霉素对‘粉红朱砂’和‘虎丘晚粉’开花的影响

该文研究了不同时间、不同浓度的赤霉素处理对‘粉红朱砂’和‘虎丘晚粉’两种露地栽培梅花的花期、展叶期和落蕾率的影响。结果表明 :2 0 0 0mg L的赤霉素在 10月底至 11月处理可使‘粉红朱砂’的花期提前约 1个月 ,展叶期提前 30～ 4 1d ,但同时出现明显的落蕾效应 ;而 1月处理使‘虎丘晚粉’始花期、末花期均延迟 ,同时开花量增加 ,且观赏期延长。研究还探讨了温度作为梅花开花的主导因子对试验研究的影响。     

Heterochromatic silencing and HP1 localization in Drosophila are dependent on the RNAi machinery

Genes normally resident in euchromatic domains are silenced when packaged into heterochromatin, as exemplified in Drosophila melanogaster by position effect variegation (PEV). Loss-of-function mutations resulting in suppression of PEV have identified critical components of heterochromatin, including proteins HP1, HP2, and histone H3 lysine 9 methyltransferase. Here, we demonstrate that this silencing is dependent on the RNA interference machinery, using tandem mini-white arrays and white transgenes in heterochromatin to show loss of silencing as a result of mutations in piwi, aubergine, or spindle-E (homeless), which encode RNAi components. These mutations result in reduction of H3 Lys9 methylation and delocalization of HP1 and HP2, most dramatically in spindle-E mutants.     

海南兰花病毒病调查及病原检测

2007-2008年,对海南主要兰花种植基地进行病毒病危害情况调查。结果表明,海南兰花病毒病症状复杂,以斑驳花叶型和坏死型最为普遍。凋查还发现,兰花的病毒病发病率与龄期呈正相关,文心兰、石斛兰的发病率显著高于蝴蝶兰。病原血清学检测表明,海南兰花病原病毒主要为建兰花叶病毒、齿兰环斑病毒,以及二者复合感染,检出率分别为29．5％、2．3％、15．9％。其中文心兰和蝴蝶兰带毒率较高,石斛兰带毒率最低,石斛兰上未检出齿兰环斑病毒。     

黔油18号高产综合农艺措施数学模型研究

【目的】为明确影响高原生态区黔油18号油菜产量的关键因子及实现高产高效优化栽培的综合农艺措施。【方法】运用四因素二次回归最优组合设计试验方法,在海拔950￣1200m的高原生态区对优良杂交油菜新品种黔油18号的主要栽培措施施氮量、施磷量、施钾量与油菜产量的量化关系进行系统研究,通过建立数学模型的优化与解析,【结果】结果表明,在4因素中,对黔油18号的影响为氮肥>密度>磷肥>钾肥;【结论】要获得≥2493.46kg/hm2的产量,其最佳栽培措施组合是:保持密度13.60￣14.50万株/hm2,氮肥291.35￣330.00kg/hm2,磷肥92.28￣102.2746kg/hm2,钾肥119.20￣129.20kg/hm2。     

Perchlorate Depositional History as Recorded in North American Ice Cores from the Eclipse Icefield, Canada, and the Upper Fremont Glacier, USA

Temporal depositional rates are important in order to understand the production and occurrence of perchlorate (ClO₄⁻) as limited information exists regarding the impact of anthropogenic production or atmospheric pollution on ClO₄⁻ deposition. Perchlorate concentrations in discrete ice core samples from the Eclipse Icefield (Yukon Territory, Canada) and Upper Fremont Glacier (Wyoming, USA) were analyzed using ion chromatography tandem mass spectrometry to evaluate temporal changes in the deposition of ClO₄ ⁻ in North America. The ice core samples cover a time period from 1726 to 1993 and 1970 to 2002 for the Upper Fremont Glacier (UFG) and Eclipse ice cores, respectively. The average ClO₄ ⁻ concentration in the Eclipse ice core for the time period from 1970 to 1973 was 0.6 ± 0.3 ng L⁻¹, with higher values of 2.3 ± 1.7 and 2.2 ± 2.0 ng L⁻¹ for the periods 1982–1986 and 1999–2002, respectively. All pre-1980 ice core samples from the UFG had ClO₄ ⁻ concentrations <0.2 ng L⁻¹, and the post-1980 samples ranged from <0.2 ng L⁻¹ to a maximum of 2.6 ng L⁻¹ for the year 1992. A significant positive correlation (R = 0.75, N = 15, p < 0.001) of ClO₄⁻ with SO₄²⁻ was found for the annual UFG ice core layers and of ClO₄ ⁻ with SO₄²⁻ and NO₃⁻ in sub-annual Eclipse ice samples (R > 0.3, N = 121, p < 0.002). The estimated yearly ClO₄⁻ depositional flux for the Eclipse ice core ranged from 0.6 (1970) to 4.7 μg m⁻² year⁻¹ (1982) and the UFG from <0.1 (pre-1980) to 1.4 μg m⁻² year⁻¹ (1992). There was no consistent seasonal variation in the ClO₄⁻ depositional flux for the Eclipse ice core, in contrast to a previous study on the Arctic region. The presence of ClO₄⁻ in these ice cores might correspond to an intermittent source such as volcanic eruptions and/or any anthropogenic forcing that may directly or indirectly aid in atmospheric ClO₄⁻ formation.     

Inheritance and cross-resistance of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> insecticidal crystal protein Cry1Ac resistance in cotton bollworm <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> Hubner population from Tamil Nadu,India

Cotton bollworm, Helicoverpa armigera Hubner selected for five generations with Bacillus thuringiensis insecticidal crystal protein Cry1Ac in the laboratory developed 12.98-fold resistance. Resistance and susceptible populations were mass crossed to study the dominance of resistance. The Cry1Ac—selected (BCR) population showed 5.8-fold resistance to Cry1Aa and 5.04-fold resistance to Cry1Ab. The degree of dominance (D) was 0.34 and 0.40 for the R × S and S × R hybrids, respectively, which indicates incomplete recessive character of Cry1Ac resistance in the population. The estimated realized heritability (h ²) and response quotient (Q) of resistance for Cry1Ac were 0.52 and 0.15, respectively. This indicated the lower phenotypic variation in the selected population. The resistance risk assessment based on h ² indicated that the resistance would increased tenfold after <9 generations for Cry1Ac in the resistant population. The results show the ability of H. armigera to develop resistance against Cry1Ac and cross-resistance to Cry1Aa and Cry1Ab.     

New icetexane diterpenes with intestinal α-glucosidase inhibitory and free-radical scavenging activity isolated from Premna tomentosa roots

New icetexane diterpenes (1-2); 8, 11, 13-icetexatriene-10-hydroxy, 11, 12, 16-tri acetoxyl (1) and 8, 11, 13-icetexatriene-7, 10, 11-dihydroxy-12, 13-dihydrofuran (2) along with six known compounds namely acetoxy syranzaldehyde (3), syranzaldehyde (4), coniferaldehyde (5), lupeol (6), betulin (7), and 4-(4-methoxy phenyl)-2-butanone (8) were isolated from the roots of Premna tomentosa. The structures of compounds 1 and 2 were established by detailed spectral analysis using UV, IR, ¹H NMR, ¹³C NMR, 1D, 2D and Mass. The newly isolated compounds were screened for rat intestinal α-glucosidase inhibitory and free radical (DPPH) scavenging potentiality. The new icetexane diterpenes (1, 2) and compound 3 were found to have significant α-glucosidase inhibitory and also free radical scavenging (DPPH) activities.     

Plant regeneration from encapsulated nodal segments of Sterculia urens roxb., an endangered gum-yielding tree

The present study is an attempt to prepare synthetic seeds using alginate encapsulation of nodal explants of Sterculia urens. Regeneration potential of encapsulated nodal segments was tested on MS basal, MS + BA (3.0 mg L^?1), MS + TDZ (0.2 mg L^?1), and MS + BA (0.5 mg L^?1) + NAA (2.0 mg L^?1). The regeneration potential was maximum (73.33 ± 1.33) on MS + TDZ (0.2 mg L^?1) followed by (69.33 ± 1.76) on MS + BA (3 mg L^?1) even after 6 months of storage at 4°C, whereas controls did not show any regeneration potential after 1 week. These findings suggest synthetic seed technology as an alternative method for micropropagation and germplasm conservation of Sterculia urens an endangered species.     

Comparison of maize,wheat and triticale in broiler diets

1. Wheat, triticale 131 or triticale 72‐S could replace up to half the maize in broiler diets without affecting performance. Replacing more of the maize on either an equal nitrogen basis or a weight basis adversely affected performance.

2. Triticale 72‐S appeared to be superior to triticale 131 as a direct replacement for maize, but both grains were inferior to maize as energy sources.