烟草简易型直播漂浮式育苗技术研究

研究了烟草的直播漂浮式育苗,包括基质、育苗盘、施肥、剪叶及炼苗等方面的试验。开发出适合中国实际的简易型配套技术。应用该技术可生产出均匀、健壮的烟苗。与传统的营养土两段育苗相比,成本降低78%,劳力节省91.7%,苗床面积减少91.7%。成功地开发出炭化谷壳和炭化玉米德轴两种新质。试验证明,其育苗效果与蛙石、泥炭、白云母、岩棉等相当,且成本低廉,不滋生藻类。育苗盘以200型成苗质量最佳。起始营养增添微量元素并在出苗后20天添加一次营养液。剪叶频率以4天为宜。成苗后控制水肥炼苗,以4~6天较好。      

烤烟湿润育苗技术研究

对以育苗基质和营养液配方的筛选、肥水管理方式的改进和不同育苗方式比较为主要内容的烤烟湿润育苗技术进行了探讨。结果表明,10号育苗基质配方和2号营养液配方所育烟苗综合素质最高,茎高、茎围适中,根系发达,根系活力强,根茎叶干鲜重最重;育苗肥水管理方式由传统的"一段式"改为"前期浅灌、后期浇施"的"二段式",不仅大大降低了烟农的育苗用工,而且解决了肥水单纯采用浇施,导致基质易板结、出苗率较低、生长不整齐等问题;与漂浮育苗相比,该技术不仅保持了漂浮育苗的优势,同时提高了成苗期烟苗的素质,有效地解决了返苗期偏长的问题。     

烤烟漂浮育苗中不同水位炼苗对烟株生长发育及生理特性的影响

为解决烤烟漂浮育苗中的还苗期长、不耐干旱的问题,结合湿润托盘育苗技术,以常规漂浮育苗方,式为对照设置了浅水水位(垫入砖块使漂盘底面刚好与水面接触)和超低水位(垫入砖块使漂盘底面与水面隔开5 cm)等不同程度的水位炼苗试验.结果表明:烟苗生物学性状总体表现为浅水水位较好,超低水位次之,对照较差;烟苗的还苗率、根系活力、硝酸还原酶活性、光合速率和叶绿素含量总体表现为超低水位较好,浅水水位次之.     

光质对立体托盘育苗烟苗生长及叶片光合特性的影响

为揭示光质对立体托盘育苗烟苗叶绿体色素、光响应和根系发育的影响,设置了全白光(对照)和补充红光、蓝光和LED光质4个处理的封闭式室内立体育苗试验。结果表明:补充红蓝光质提高了烟苗叶片光合色素含量,增强了叶片光合能力;补充蓝光条件下烟苗根系发育最好,补充蓝光质显著增加了烟苗根系长度、根系表面积和根系体积,烟苗4叶1心时根系长度达75.45 cm、根系表面积13.49 cm2、根系平均直径0.51 mm和根系体积0.18 cm3;立体育苗中,烟苗干物质积累量与烟苗叶片光合能力和根系发育水平呈显著正相关。补充蓝光光质更适于烤烟立体育苗。     

烟草漂浮育苗系统中培养基质对烟苗生长发育影响的研究

本文研究了烤烟漂浮育苗系统中培养基质对烟苗生长发育的影响。结果表明,1.漂浮育苗基质中有机质材料的比例对烟苗生长发育具有重要作用。在以草炭、蛭石、膨化珍珠岩为原料的培养基中草炭比例以5 0%~70%较为适宜,低于40%或高于80%均影响烟苗根系的发育。2.有机质材料的选择应充分利用当地自然资源条件,因地制宜开发利用。以一定比例的腐熟作物残体代替草炭亦是完全可行的,同样能够培育出根系发达,均匀一致的壮苗。3.基质配比确定后,苗盘中基质容重对烟苗影响较大。试验以美国漂浮育苗商品基质Sunshine Tobacco Mix L 5为材料,证明苗盘装填容重在0.15~0.2 5 g/m L适宜于烟苗的生长发育。4.基质中加入少量的肥料,有利于烟苗前期的发育,肥料浓度超过5 0 mg/L即影响烟苗生长。试验显示营养液中的氮和钙、镁、铜、铁、锰等元素在基质上部富集,可产生肥料盐害。5.漂浮育苗与传统育苗方式相比,烟苗移栽大田后还苗快,生长迅速,增加收获叶片数,促进烟株开片开秸,为烟叶的优质丰产奠定了良好的基础。      

烤烟砂培漂浮育苗的试验与应用

为了降低育苗成本,以砂作为基质研究了烤烟砂培漂浮育苗技术。结果表明:与现行漂浮育苗比较,出苗率高且出苗整齐,大约60 d可以成苗,成苗率和壮苗率较高;在出苗后至大十字期前,烟苗生长缓慢,生育期晚2~3 d;大十字期后,烟苗生长迅速,生育期与现行漂浮育苗一致;烟苗茎粗、茎高、最大叶面积、干物质积累量、总根数以及根系活力、硝酸还原酶活性、叶绿素含量的变化均表现出烟苗生长前期缓慢增长,后期急剧上升;至成苗后期,根系活力、硝酸还原酶活性、叶绿素含量又有所下降。砂培漂浮育苗的烟苗根系发达、生长健壮整体素质好,育苗成本较现行漂浮育苗降低56.58%。     

基于营养液自动循环系统的烟草育苗方式

为解决烟草漂浮育苗中由于营养液静止不动而导致的根系生长受阻及烟苗生长不均匀的问题,对现有育苗设施进行了改造,研发了营养液循环系统,增加自动循环装置,并研究了基于营养液循环系统的烟草育苗方式.结果表明:与常规育苗方式对比,循环系统育苗营养液中的溶解氧浓度增加至2.24mg/L,烟苗根长、根系生物量显著提高,且生长速度加快,成苗期比对照(CK)提早9d,烟苗叶绿素、可溶性蛋白、游离氨基酸含量升高,生理素质提高.因此,营养液循环系统育苗方式有利于烟草壮苗的培育.     

烤烟不同育苗方式的对比试验

为寻求适合贵州烟区烤烟生产实际的育苗新技术,对漂浮育苗、托盘水床育苗和常规育苗3种育苗方式进行了对比试验。结果表明:托盘水床育苗和常规育苗全天苗床温度变化相对较慢,而漂浮育苗系统升、降温迅速。托盘水床育苗的幼苗生长迅速,烟苗株高、叶数合理,茎干粗壮,叶面积较大,烟株根系发达,干物质积累量大;漂浮育苗的烟苗前期生长缓慢而后期生长迅速,成苗素质明显低于托盘水床育苗。托盘水床培育的烟苗光合速率、根系吸收面积明显占优势,根系活力与常规育苗基本一致,但明显高于漂浮育苗。因此,托盘水床育苗技术适宜于贵州烟区应用。     

育苗盘密度对烟苗生长发育及烟叶产质量的影响

为明确适合恩施烟区井窖式小苗移栽的育苗盘密度,采用漂浮育苗的方法,研究了153孔、200孔、288孔和500孔4种育苗盘密度对烟苗生长发育及烟叶产质量的影响。结果表明,153孔、200孔和288孔3种育苗盘育出的烟苗素质较好,均能满足井窖式小苗移栽的要求,但153孔和200孔2种育苗盘育苗成本相对较高;500孔育苗盘育苗成本最低,但育出的烟苗素质最差。总体而言,288孔育苗盘育苗成本相对较低、经济效益最好,明显减工、降本、增效,更符合恩施烟区育苗实际,值得在生产上推广应用。     

不同规格育苗盘对膜下小苗烟苗素质及烟叶产量产值的影响

基于膜下小苗移栽所用烟苗素质比常规移栽烟苗偏弱的实际,试验研究了162孔、392孔和595孔3个规格育苗盘处理对烟苗素质、烟株大田长势及烟叶产量、产值和投入成本、经济产出的影响。结果表明,162孔规格育苗盘所育烟苗素质最好,其成苗率、壮苗率均为最高;392孔次之,595孔相对最弱;但单位面积大田移栽所需烟苗育苗投入和烟农购苗成本则与上述相反,以595孔育苗盘最低。烟株田间长势和烟叶产量、产值以及减去购苗成本后的烟农经济效益则以392孔育苗盘相对最好,162孔次之,595孔最低,其中392孔与595孔育苗盘之间差异显著。综合而言,392孔育苗盘可以推荐为膜下小苗移栽生产育苗使用。      

烤烟大棚漂浮育苗

介绍了烤烟的大棚漂浮育苗技术,包括育苗的材料准备、大棚建造及苗床制作、育苗基质及专用肥配制、播种、苗池施肥和苗床管理等。苗床管理主要有开启通风门窗调节大棚温湿度,小十字期进行间苗和定苗,烟苗5～6片真叶时剪叶,8～10片真叶时锻苗,以及加强苗期病虫害的防治。     

2,4-表油菜素内酯对烟苗幼茎生长及相关基因表达的影响

为研究油菜素内酯（Brassinolide,BR）对烟草主茎生长的影响,利用外源2,4-表油菜素内酯（2,4-Epibrassinolide,EBR）,设置0.5×10^-7 mol/L（T1）、0.5×10^-5mol/L（T2）两个浓度,以蒸馏水（CK）为对照对烟草幼苗进行喷施。分析了不同处理的烟草幼苗株高,节距及解剖结构特征,检测了茎中与细胞分裂和细胞大小调控相关基因以及与油菜素内酯（BR）、生长素（IAA）和赤霉素（GA）合成相关基因的表达量。结果表明,喷施EBR对烟草幼苗节距和株高有显著促进作用,并随处理浓度升高,促进作用增强。观察石蜡切片发现EBR处理后茎皮层薄壁细胞数目增多,单细胞面积减小。EBR处理后,细胞周期调控基因NtCYCD3表达上调,细胞大小调控基因NtARF6、NtARF16表达下调;BR信号受体基因NtBRI1,NtBIN2表达上调,BR转录因子NtBES1T表达下调;BR、IAA和GA的关键生物合成基因NtDWF4、NtYUCCA8、NtGA3ox-2表达量均上调。说明喷施EBR可促进内源BR、IAA和GA的合成基因表达,通过促进节间细胞分裂、抑制细胞大小促进烟草幼苗茎的生长。     

茉莉酸对烤烟烟苗生长的影响

本文研究了茉莉酸对烤烟烟苗生长的影响,结果表明,在5至7叶期喷施茉莉酸(2.8×10-4~4.2×10-4 mol/L)能促使幼苗健壮,提高叶片中过氧化物酶和超歧化物氧化酶活性,从而提高抗逆力。喷施茉莉酸,叶片中细胞分裂素、生长素和赤霉素含量水平有所提高。      

苗期剪叶处理对烤烟生长发育的影响

以NC82为材料进行了苗期剪叶处理对烟草生长影响的研究。剪叶处理对烟草生长的影响与温度条件有很大关系,在低温条件下影响明显,而高温条件下影响较小。低温造成早花的情况下剪叶可以推迟现蕾期20天以上,且剪叶次数越多推迟时间越长。剪叶处理降低了大田早期(50d)的株高,但不会影响最终株高。剪叶处理比不剪叶处理多1片叶。剪叶对花芽分化的显微结构无明显影响。     

5(6)-cFDA 标记乳酸菌细胞的影响因素

选用常规发酵乳菌种,探讨不同溶剂、不同浓度的羧基荧光素二醋酸酯(5-(6)-Carboxyfluorescein diacetate,5(6)-cFDA)标记乳酸菌细胞的影响因素。结果显示：水、PBS 和二甲基亚砜(DMSO)配制的5(6)-cFDA 标记初期,细胞标记率分别为94.8%、95.2% 和99.77%,放置30d 后细胞标记效果分别下降到51.53%、55.6% 和96.7%;每毫升菌悬液加60μL 的5mg/mL 5(6)-cFDA(相当于终浓度为6.52 × 10-7mol/L),其荧光强度与5(6)-cFDA 浓度成正比,且标记效果最理想。实验还证实了1 × 106～1 × 107cells/mL 是流式细胞仪检测细胞活性较适合的浓度,且标记率较高;在pH7.0 的条件下对细胞活性和发光强度影响最小,其标记率达到98.3%。     

Singlet Oxygen Oxidation Rates of ∝-, γ-, and δ-Tocopherols

ABSTRACT:  The reaction rate constants of 5 × 10⁻⁴ M, 10 × 10⁻⁴ M, and 20 × 10⁻⁴ M α-, γ-, and δ-tocopherols with singlet oxygen in methylene chloride containing 1 × 10⁻⁵ M chlorophyll under light at 25 °C for 60 min were studied. The oxidation of tocopherols determined by a spectrophotometric method showed that the losses of 20 × 10⁻⁴ M α-, γ-, and δ-tocopherols after 60 min under light were 21%, 16%, and 9%, respectively. The degradation of α-, γ-, and δ-tocopherols was undetectable in the absence of chlorophyll under light or in the presence of chlorophyll in dark. The losses of tocopherols under light were mainly due to singlet oxygen oxidation. The degradation rates of 20 × 10⁻⁴ M α-, γ-, and δ-tocopherols were 6.6 ×10⁻⁶ M/min, 5.0 × 10⁻⁶ M/min, and 2.9 × 10⁻⁶ M/min, respectively. The reaction rates between α-, γ-, or δ-tocopherol and singlet oxygen were 4.1 ×10⁶/M s, 3.3 × 10⁶/M s, and 1.4 × 10⁶/M s, respectively. The singlet oxygen oxidation rate of δ-tocopherol was significantly lower than α- or γ-tocopherol at α= 0.05. As the electron density in the chromanol ring of tocopherol increased, the singlet oxygen oxidation was increased.     

CHANGES IN SIZE OF GAS CELLS IN DOUGH AND BREAD DURING BREADMAKING AND CALCULATION OF CRITICAL SIZE OF GAS CELLS THAT EXPAND

Microscopic observation showed that a group of small air cells entrained during the early stage of mixing is the original cause of cell structure of bread. At the beginning of fermentation, about 3 × 10⁸/m² gas cells with diameters between 3 × 10⁻⁶ and 8 × 10⁻⁴ m were entrained in the dough. The distribution curve of cell size was approximately normal on a logarithmic scale. During fermentation and proofing, a great portion of carbon dioxide was released into cells larger than about 10⁻⁴ m in diameter that was equivalent to a few percentages of total number of gas cells. After baking, gas cells smaller than 10⁻⁴ m in diameter were not observed and the total number of cells in baked bread reduced to about 10⁶/m² with diameters between 10⁻⁴ and about 5 × 10⁻³ m. The critical cell size to expand generally agreed with the calculated value using an equation, rc'= 3s/E (re': critical radius to expand, s: surface tension, E: elasticity), and cited value of s and E.     

Quenching Mechanisms and Kinetics of α-Tocopherol and β-Carotene on the Photosensitizing Effect of Synthetic Food Colorant FD&C Red No. 3

ABSTRACT: Effects of FD&C Red No. 40, Red No. 3, Yellow No. 5, Yellow No. 6, Green No. 3, Blue No. 1 and Blue No. 2 on 0.03M soybean oil oxidation in acetone at 25 °C under light were studied by measuring headspace oxygen depletion. As Red No. 3 increased from 0 to 5, 20, 100 and 200 ppm, the headspace oxygen was reduced by 2 to 70, 73, 77 and 77%, respectively, for 4 h. Only Red No. 3 acted as a photosensitizer to produce singlet oxygen in the oil. The quenching rates of α-tocopherol and β-carotene for the singlet oxygen by Red No.3 were 4.1 × 10⁷ M⁻¹s⁻¹ and 7.3 × 10⁹ M⁻¹s⁻¹, respectively. When β-carotene was below 1.86 × 10⁻⁶ M, β-carotene quenched singlet oxygen, but it quenched both singlet oxygen and Red No. 3 at or above 3.72 × 10⁻⁶ M. However, α-tocopherol quenched singlet oxygen only.     

The Effectiveness of Sanitizer Treatments in Inactivation of Salmonella spp. from Bell Pepper, Cucumber, and Strawberry

ABSTRACT: Four different postharvest treatments for removal of Salmonella from bell pepper and cucumber were examined, including washes with chlorinated water (HOCl; 200 ppm), acidified sodium chlorite (ASC; 1200 ppm), and peroxyacetic acid (PAA; 75 ppm), and treatment with gaseous chlorine dioxide (ClO₂; total 100 mg). Only ClO₂ gas was evaluated for decontamination of strawberries. Each produce was inoculated with approximately 1.0 × 10⁷ colony-forming units (CFU) of a 5-serovar cocktail of Salmonella on artificially created wounds, smooth surfaces, and stem scar tissue. For tests involving smooth surface inoculation, ASC and PAA treatments decreased contamination to undetectable levels on bell pepper and cucumber, while the chlorine treatment of bell pepper reduced contamination by approximately 2-logs. For stem scar contamination on bell pepper, ASC and PAA treatments both showed >2-log unit reductions, and chlorine treatment showed a <1-log unit reduction. For puncture wounds on bell pepper, HOCl, ASC, and PAA treatments reduced bacterial levels approximately 2-, 3-, and 1-log units, respectively, indicating that HOCl and ASC were more effective than PAA. These aqueous treatments of cucumber with puncture wounds reduced bacterial levels approximately 1-, 2-, and 2-log units, respectively. ClO₂ treatment decreased counts to undetectable levels on all inoculation sites on cucumber and on strawberry smooth surfaces, but failed to completely eliminate Salmonella from bell pepper and from the stem scar and the puncture wounds of strawberry. ASC treatment of bell pepper and ClO₂ gas treatments of cucumber showed the best efficiency for inactivation of Salmonella. ClO₂ treatments effectively reduced Salmonella cells inoculated on the smooth surface and stem scar of strawberries compared with unsanitized control.