烟草黑胫病生物防治的研究进展

随着烟草生产向无公害发展,黑胫病作为烟草生产上的主要病害之一,其生物防治取得了较大的进展。笔者就其育种、生防菌、寻找抗病基因、筛选细胞突变体,诱导抗性和轮作等方面的研究进行综述,以期为烟草黑胫病的生物防治提供参考。     

木塑复合材料成型加工过程中的变色机理及控制研究进展

文章介绍了木塑复合材料的成型方法及发展趋势,主要论述了木塑复合材料成型过程中的变色原因及其控制方法。     

椴木光变色前后碳价态变化初探

利用紫外光照射椴木单板,采用X射线光电子能谱仪（XPS）分析光变色前后碳价态的变化情况。结果表明,C1和C2随着光照时间的增长,呈现出下降的趋势;C3和C4随着光照时间的增长,呈现上升的趋势。     

^60Co-γ射线对不同柑橘品种的辐射效应

以稻叶温州蜜柑（Citrus unshiu var.Inaba）、福橘（C.reticualta var.Fuju）、玫瑰橙（C.sinensis var.Meiguicheng）、华红（C.sinensis var.Huahong Newhall）和早金（C.sinensis var.Earlygold）等5个柑橘品种的接穗为试材,进行^60Co-γ射线照射处理,结合常规压片法,研究^60Co-γ射线对不同柑橘品种接穗的嫁接成活率及细胞有丝分裂行为的影响。结果表明：辐射累积剂量为2000R时,接穗嫁接成活率因品种不同而异,其中稻叶温州蜜柑的嫁接成活率最高（69.89%）,福橘次之,橙类较低（华红最低为32%）;^60Co-γ射线处理可诱发细胞有丝分裂异常,其诱变效应因柑橘品种不同而有所差别,柑类与橘类的有丝分裂异常率明显高于橙类。     

海南橡胶木红变的化学研究

对橡胶木中的变色成分进行甲醇浸提,浸提液浓缩后用极性从小到大的石油醚、氯仿、乙醚、乙酸乙酯和正丁醇萃取。经过化学分析认为橡胶木中产生红变的成分存在于极性较大的乙酸乙酯、正丁醇和水中,变色成分主要是鞣质单宁、酚类及蒽醌类物质。同时进行鞣质单宁引起橡胶木红变的机理试验,结果表明,橡胶木抽提液无论是加酸性还是加碱性溶液都会产生红变,为此采用具有漂白功能的氧化剂和还原剂可以减轻或消除橡胶木抽提液的红变。     

微酸性电解水结合壳聚糖对水蜜桃护色保鲜的效果

为了防止水蜜桃(Prunus persicaL.Batsch)采后的果肉颜色变化而严重影响其商品价值。该研究以南汇水蜜桃为材料,分别利用自制羧甲基壳聚糖复合保鲜剂,以及微酸性电解水对水蜜桃进行护色保鲜处理,并对冷藏条件下(2℃)水蜜桃果肉颜色及与颜色品质变化相关的指标进行了检测,同时还利用核磁共振成像(MRI)合成T2-MAP图研究了冷藏开始和结束后水蜜桃内部变化的规律。结果表明,在贮藏结束后,对照组果肉颜色的L*值、H*值、C*值分别是羧甲基壳聚糖复合保鲜剂和微酸性电解水处理组的85%～91%、85%～93%和114%～122%(p<0.05)。显然,羧甲基壳聚糖复合保鲜剂和微酸性电解水由于可以抑制水果自身乙烯的产生,减少水果的细胞膜透性和T2-MAP图中T2弛豫常数的变化,降低了多酚氧化酶(PPO)活性的增加速度,减少了酚类物质的累积,进而延缓了果肉的变色。另外,与仅用电解水处理相比,结合羧甲基壳聚糖处理具有较好的护色保鲜效果。通过该研究,可以为提高采后南汇水蜜桃的果肉护色保鲜效果提供参考。     

In growing pigs, chlortetracycline induces a reversible green bone discoloration and a persistent increase of bone mineral density dependent of dosing regimen

We studied in growing pigs the effects of exposure to dietary chlortetracycline on bone mineral density (BMD) and bone color. Pigs were randomly allocated to a drug-free diet (n = 48) or a diet fortified with 800 ppm of chlortetracycline, starting either at 28- or 84-d of age, and for either a 28- or 56-d duration (n = 16 pigs/group). The lumbar vertebral discoloration and BMD of randomly chosen pigs were evaluated at 28-d intervals up to 168-d of age. The odds of bone discoloration increased with dosing duration and age at treatment onset, and decreased with the withdrawal time and age at treatment onset interaction (p ? 0.001). The measured trabecular BMD linearly increased with age and squared treatment duration (p ? 0.005). Therefore, TC-induced bone discoloration is reversible, and may be prevented with proper dosing regimen design. Moreover, TC induces a persistent increase on BMD that could be detected with quantitative computed tomography.     

烟草与龙葵细胞杂交和新品系694-L选育的研究

 在烟草生产上尚存在容易感病、品质需要改进等问题。试验选用烟草（革新1号）和药用植物龙葵（野生种）为细胞杂交亲本，它们是茄科不同属的植物，有性杂交不育。用二个亲本的叶肉原生质体经诱导融合、培养、选择和鉴定得到了细胞杂种（TS-28，TS-33）。将其后代在选种圃经二年培育选出了大叶型株系694-L。再将694-L株系在鉴定圃与烟草亲本革新1号及目前黄淮海烟区统一应用的标准品种G140进行二年比较鉴定。结果表明694-L对烟草花叶病和气候斑点病的抗性均比革新1号和G140有所改善。694-L的产量和评吸结果和G140相近，但有些品质还需改进。试验将细胞杂交和有性杂交选育相结合，得到了可供进一步选育的烟草新品系，为应用细胞工程改良作物提供新的例证。     

Production of chips from potato cultivars (Solanum tuberosum L.) with high sugar content using lactic acid fermentation

Summary Tubers of twelve cultivars ofSolanum tuberosum L., with a varying content of reducing sugars (0.49–2.30 g/100 g fresh weight), were sliced and fermented for up to 48 h by lactic acid bacteria in a brine of 1.5% NaCl, prior to frying. The content of reducing sugars decreased by 80 to 100%, depending on the initial sugar level. Colour of chips was measured using the CIE (1976) L^*a^*b^* colour system, where L^* is lightness, a^* is redness and b^* is yellowness of the material and by IBVL colour cards, photographs used for grading the colour of potato chips. L^*-values were the best measurement of chip colour. The scale of the IBVL colour cards was too narrow (scale 1–9) for this study, as chips from eight of the cultivars were scored lighter than IBVL 9 after 48 h of fermentation. Lighter coloured chips significantly correlated with lower contents of reducing sugars. The sugar content decreased as fermentation time increased. Fermentation time can thus be used to control potato chip colour, and all the cultivars tested can be used for production of chips with regard to colour.     

诱发甘蓝型油菜含油量突变的研究

用~(60)coγ射线照射油菜干种子,诱发含油量突变。结果指出:交变体间含油量的极差达6.99％,世代间的相关性达显著或极显著,亲本含油量对后代含油量的突变影响明显,并初步选育出一批比现有推广品种高5％—7％的高油分品系。