外源激素对大葱种子萌发、休眠的调控效应

本试验以不同活力水平的大葱种子为材料,用不同浓度的赤霉素、脱落酸处理后进行标准发芽试验,研究了外源激素对不同活力大葱种子发芽与休眠的影响.结果表明:适宜浓度的赤霉素处理可促进大葱种子的萌发,加快发芽速度,提高活力.对于极低活力种子,低浓度(10 μg/L)赤霉素处理效果好于高浓度,25 μg/L赤霉素处理低活力种子效果显著;而对于中高活力种子,60 μg/L赤霉素浸种干燥处理有利于种子活力的提高.对于当年收获的种子,则是40 μg/L赤霉素浸种干燥处理提高种子活力效果明显.适宜浓度(0.5 mg/L)的脱落酸处理抑制种子萌发,降低发芽速度,促进种子休眠.     

硫素对红葱生长发育及品质的影响

采用霍格兰氏完全营养液培养研究不同施硫水平对红葱生长发育及品质的影响。结果表明:在一定范围内,红葱单株产量随着施硫量增加而提高,在生长后期,施硫量的增加对红葱产量无明显影响,葱的分蘖数、叶片数随硫素浓度的升高而增多。不同浓度的硫素处理对红葱维生素C和色素含量影响不大,特别是生长后期;随着施硫量的增多,植株中硝酸盐含量呈增加趋势;红葱丙酮酸含量随生长和供硫水平提高而增强,但是施硫量超过2.1mmol/l,丙酮酸含量差异不大。适合水培红葱生长的硫浓度范围为1.4mmol/l~2.1mmol/l。     

不同营养液配方对红葱生长及品质影响

研究4个营养液配方对红葱生长及营养品质的影响,结果发现:在水培条件下,从栽种开始前40d红葱生长主要是茎叶生长,40d~55d分蘖数急剧增加,茎叶生长量也继续增加;栽种前40d内配方T4较好,红葱产量较高,可溶性糖、可溶性蛋白、Vc含量高,硝酸盐含量最低。生产上可采用配方T4,并及时采收产品。     

配方施肥对柴达木地区洋葱产量的影响

在柴达木地区,对洋葱进行3414配方施肥试验。结果表明:在柴达木地区随着施肥量的增加,洋葱的产量逐渐增加,当施肥量增加到一定程度时,洋葱的产量随着氮肥的增加不断降低,氮对洋葱产量的作用排第一位,其次是磷,再次是钾;氮、磷、钾两两配合后均可提高洋葱产量,磷钾配合对洋葱产量的作用最大,其次是氮钾,再次是氮磷。667 m~2最佳经济效益时的氮、磷、钾最佳配合比例和施用量及洋葱产量分别为纯氮28.3 kg,纯磷22.7 kg,纯钾10.0 kg,此时洋葱产量5783.1 kg。     

氮磷钾平衡施肥对高海拔冷凉区洋葱产量的影响

采用“311-A”拟饱和最优回归设计,研究了氮磷钾平衡施肥对高海拔冷凉区洋葱产量的影响.结果表明:洋葱最高产量施用尿素、过磷酸钙、硫酸钾分别为45.0、110.0、36.7kg/ 667m2,最高产量为7173.96kg/667m2;最佳经济施肥量为尿素、过磷酸钙、硫酸钾分别为38.0、95.8、17.3 kg/667m2,最佳利润为4 768.23元/667m2.     

大葱花芽分化过程中内源激素的变化

为探讨激素与大葱花芽分化的关系, 研究了不同大葱品种花芽分化过程中植株根、假茎及叶片内源激素的变化动态。结果表明, 大葱植株根、假茎及叶片ABA、GA₃、ZR的含量均在花芽分化基本完成时达到高峰, 而IAA则至低谷, 且内源激素出现高峰或低谷的时间, 与不同品种花芽分化完成时间一致, 表明测试激素均与花芽分化有密切关系。但不同器官内源激素含量高低及变化幅度显著不同, 其中叶片ABA、GA₃及根系ZR含量较高, 且变化显著, 而IAA在根系及叶片中的含量及变化幅度差异较小, 但显著高于假茎。大葱叶片ABA / IAA、ABA /GA₃均随花芽分化率的增加而显著升高, 花芽分化完成时达峰值, 之后迅速降低, 说明叶片内源激素间的平衡关系, 在大葱的花芽分化过程中亦起着重要的调控作用。     

辣椒WRKY转录因子候选基因的瞬间表达分析

从辣椒cDNA文库中克隆获得一个推定的WRKY（CaWRKY）转录因子,为分析其功能,分别构建启动子区含有双倍W（2W）盒的报告载体和WRKY置于2x35S启动子控制下的超表达载体,通过基因枪瞬间转化技术将两种载体共转化洋葱表皮。检测共转化细胞中GUS基因的表达情况来分析转录因子与特定顺式作用元件的结合及对其转录的激活效应。结果表明CaWRKY能与W盒结合,表明该基因是WRKY转录因子的编码基因。     

大葱种质资源研究及利用进展

综述了大葱种质资源的研究进展,包括大葱的起源、分布,种质资源的保存和分类,大葱种质资源遗传多样性的研究进展（基于形态学标记、基于细胞学水平、基于蛋白质水平、基于DNA分子水平的大葱种质遗传多样性）,大葱种质资源的利用（产量构成、品质性状、抗病性和品种选育）及中国大葱今后研究重点等。     

葱和韭菜种子发芽试验条件的研究

一前言葱和韭菜是广泛种植于全国各地的2种常用的蔬菜作物,其种子数量虽然不多,种子批量倒不少。据反映葱和韭菜种子一般较难发芽,发芽条件难于掌握和控制,发芽率往往较低,这对于蔬菜种子质量检验及蔬菜生产都会造成不良后果。     

Response of onion (Allium cepa L.) plants to fertilizers, weed competition duration, and planting times in the central Jordan Valley

The competitive ability of onion with weeds and the effects of weeds on onion crop growth and yield were investigated in three field experiments carried out in the central Jordan Valley during the 1997–1998 growing season. Fertilizer application to the onion plants in the presence of weeds significantly lowered the onion yield and reduced the bulb diameter, compared to the unfertilized, weed-infested onion crop. Weed competition and onion yield reduction increased with an increase in the fertilizer rate. All weed-free treatments with or without fertilizer gave a significantly higher onion yield than any of the fertilized, weedy plots. The highest yield of onion was obtained from the weed-free plots with a moderate application of fertilizer. Weed competition reduced the growth, bulb yield, and size of onion in the plots established from bulbs, seedlings, and seeds when compared to the relevant weed-free controls. The effect increased with competition duration and was more pronounced in direct-seeded onion than in the other two types of planting material. However, onion grown from bulbs or seedlings gave better growth, bulb weight, and number and was more competitive than the direct-seeded onion. The results showed that the minimum number of days of weed competition needed for a significant reduction in onion growth was 42 days when propagated from bulbs or seedlings and 21 days after direct-seeding. Onion grown from bulbs tolerated weed competition better and produced a higher bulb yield than that obtained from direct-seeded or transplanted onion, irrespective of the planting dates. December was found to be the best planting time for onion that was grown from bulbs and seedlings, while November was the best planting time for direct-seeded onion, provided the plots were weed-free throughout the growing season.