高等植物花发育的基因调控

以拟南芥为例,阐述了开花过程中基因调控方面的最新进展。     

Gibberellin-mediated suppression of floral initiation in the long-day plant Rhododendron cv. Hatsugiri

In a number of woody perennial species a decrease in gibberellins concentrations in the apical meristems is required for floral initiation to occur. In Rhododendron, applied gibberellins inhibit flowering and gibberellin biosynthesis inhibitors promote flowering. However, unlike previous reports on other Rhododendron cultivars, Rhododendron cv. Hatsugiri is a faculatitive LDP. It was therefore unknown how gibberellins regulate flowering in this cultivar and if non-inductive short daylengths stimulate the productions of endogenous gibberellins to suppress flowering. By inhibiting floral initiation while not stimulating vegetative growth we found applications of GA₅ to best match the natural response of Rhododendron cv. Hatsugiri under short-day regimes. GA₅-mediated effects on flowering have previously been reported to be due to conversion to GA₆, however, GA₅ was found to be present in tissue samples at up to 0.57 ng g⁻¹ FW, while GA₆ was never found. In addition, foliar applications of [¹⁴C] GA₅ were not found to have metabolised to GA₆. In line with the hypothesis that gibberellins inhibit floral initiation in short days in Rhododendron cv. Hatsugiri, the concentration of GA₂₀, a precursor to many bioactive gibberellins, was higher in leaf tissues from plants in short days, compared to those in permissive long days when analysed using GC–MS.     

豫北钢板平房仓隔热控温储存大豆应用试验

严格按照施工工艺要求,通过对钢板仓内表面喷涂5cm厚的聚氨酯发泡储存大豆试验,夏季仓温相比砖混高大平房仓要低1～2.8℃,豆堆上层粮温低0.8～3.0℃,大豆储存品质也较砖混高大平房仓效果要好,证明了豫北地区钢板平房仓隔热控温储存大豆的可行性。     

白菜型无花瓣油菜突变体的花器官形态特征

在我国白菜型油菜地方品种余井花籽和国外白菜型油菜品种Am032中同时发现了无花瓣突变体。通过对白菜型油菜无花瓣突变体与甘蓝型无花瓣油菜及正常油菜器官形态的鉴定和比较，认为白菜型油菜无花瓣突变体的花瓣缺失突变机制与甘蓝型油菜不同，白菜型油菜无花瓣突变体有花瓣转变成雄蕊的现象，推测白菜型油菜花瓣缺失突变可能与花器官同源异型基因突变有关。     

Processing of microcellular nanocomposite foams by using a supercritical fluid

Polystyrene/layered silicate nanocomposites were prepared by melt intercalation. To examine the distribution of the clay in polymer matrix, small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) were used. Intercalated nanocomposites were obtained and their rheological properties were investigated. Microcellular nanocomposite foams were produced by using a supercritical fluid. As clay contents increased, the cell size decreased and the cell density increased. It was found that layered silicates could operate as heterogeneous nucleation sites. As the saturation pressure increased and the saturation temperature decreased, the cell size decreased and the cell density increased. Microcellular foams have different morphology depending upon the dispersion state of nanoclays.     

A new method for studying clay soils using unaltered soil blocks

The purpose of this paper is to outline a procedure for soil block extraction, which is highly appropriate for clay soils. The method described here is rapid and cheap and has been used successfully by us in clay soils in southern Spain for the last six years. A wooden box is used to shape the soil block in situ and protect it during its transport from the field to the laboratory. Polyurethane foam was selected as the bonding agent, between the wooden framework and the soil block in order to avoid any possible alterations of the soil. This type of foam is used because it is strong, durable and non-toxic. The polyurethane foam is applied to the soil block as a permanent coating. This technique allows us to extract the clay soil solution in the laboratory.     

野败型不育系水稻畸形籽粒形成原因的探讨

 野败型不育系水稻的开闭颖时间长，不闭颖率高，由不闭颖颖花发育而成的颖果由于受到阳光的直接照射，果皮的生长和胚乳细胞的分裂都受到抑制，籽粒含水量过早降低，引起早衰。这不仅使粒重降低，空瘪率增加，而且使这些颖果都长成畸形的尖头米。如给不闭颖颖花套上锡箔纸袋遮光保湿，能使颖果发育良好，米粒长出颖壳，粒重增加一倍。     

花香基因工程研究进展

综述了花香物质生物合成途径及其相关酶和基因的研究进展;探讨了基因工程调控及改良植物花香的策略;同时简要评述了花香基因工程研究中存在的问题并展望了其应用前景.     

脂肪酸二乙醇酰胺类表面活性剂合成研究

以十四酸、十六酸、硬脂酸和二乙醇胺为原料,NaOH为催化剂,经酯化和水解二步法合成C14、C16、C18脂肪酸二乙醇酰胺类非离子表面活性剂,研究了各类脂肪酸二乙醇酰胺合成条件。测定了产物表面张力并确定了3种产物的临界胶团浓度(cmc),考察了无机盐对系列产物表面张力的影响,并测试了产物的起泡能力。结果表明,C14、C16、C18脂肪酸二乙醇酰胺形成临界胶团的浓度(cmc)分别为10、5、1mg/L,对应的表面张力分别为28.91、27.57、26.15mN/m。无机电解质浓度越高,产物水溶液的表面张力降低得越多,阳离子价态数的高低对产物表面张力影响不大。合成产物的起泡能力不强,但其消泡速率比较小,在0.37～0.6ml/min之间,说明合成产物的稳泡性能较好。     

多胺与板栗花性别分化的关系

研究了板栗花性别分化期内源多胺含量变化以及外源多胺对板栗花性别分化的影响。结果表明,在板栗雄花分化期,抽生结果枝的芽内源腐胺和亚精胺含量高于抽生营养枝的芽;在板栗雌花分化期,抽生结果枝的芽和抽生营养枝的芽内源多胺含量变化基本一致,内源腐胺含量在萌芽前降至最低后到萌芽时升至较高水平,内源亚精胺和精胺含量在萌芽前均略有上升,到萌芽时迅速升至较高水平;在雄花分化期和雌花分化期,抽生结果枝的芽均以亚精胺含量变化幅度最大,腐胺次之,精胺最小。板栗雌花分化期施用外源多胺,外源腐胺对花芽分化(尤其是雌花分化)有显著抑制作用,亚精胺对雌花分化有促进作用。