GmNMH7基因在大豆成花诱导、花发育和开花逆转过程中的表达

大豆[Glycine max(L．) Merrill]是典型的短日照植物，光周期反应敏感品种在一定的短日一长日条件下可发生开花逆转。本实验室以大豆品种自贡冬豆为材料，将SD(短日)、LD(长日)和SDl3d-LD相结合，建立了大豆光周期反应机制研究的新的实验系统。本研究通过筛选自贡冬豆成熟花的cDNA文库得到MADS-box基因家族的一个成员GmNMH7，采用RNA原位杂交技术分析了不同光周期条件下GmNMH7基因在大豆顶端分生组织分化过程中的表达，并观察了GmNMH7基因在幼叶、幼茎、根瘤等器官中的表达情况。主要结果总结如下：在短日照(SD)条件下，自贡冬豆植株可在较短时间内完成开花诱导、正常开花和结实。GmNMH7基因在可观察到的花芽分化出现之前即开始在大豆顶端分生组织中表达，其表达时间贯穿成花诱导、花芽分化、花器官发育及种子形成的全过程。在长日照(LD)条件下，植株持续进行营养生长，没有任何形式的花器官出现，GmNMH7基因在顶端分生组织中一直不表达。在短日照13天一长日照(SDl3d-LD)条件下，60％以上的植株出现花序逆转和花逆转，另一部分植株顶端出现短花序，开花期比持续短日处理的植株晚。在出现开花逆转的植株中，GmNMH7基因的表达可随长日处理日数的增加和营养器官的出现而减弱。当顶端分生组织完全恢复叶片分化时，GmNMH7基因的表达停止。在出现短花序的植株中，GmNMH7基因一直表达，但表达量低于持续短日处理。对部分时期GmNMH7基因在幼叶、幼茎和根瘤中表达情况的研究未发现明显的规律性。GmNMH7基因在大豆花芽分化启动之前就开始表达的现象为大豆开花诱导提供了早期证据，该基因在顶端分生组织中的表达受光周期调控的事实说明，GmNMH7与大豆光周期反应、成花诱导及花器官发育有密切关系。我们推测，GmNMH7基因在上述过程中可能发挥着类似于分生组织特征基因的作用。实验结果进一步证明，本实验室利用开花(短日处理)、持续营养生长(长日处理)、开花逆转(短日-长日处理)三种发育状态(光照处理)建立的实验系统在大豆(短日植物)光周期反应和个体发育研究中有重要的利用价值。     

Induction of male sterility in wheat using organic ligands with high specificity for binding copper

Summary Because copper is extremely important to the development of normal polllen, an attempt was made to induce male sterility in wheat by applying specific copper-binding ligands to wheat plants. Four different chelates were used at two rates in three methods of application. All four chelates, cupferron, neocuproine, benzotriazole and cuprizone, reduced grain yield at high concentration applied to the soil at sowing but benzotriazole was most effective, even when applied at late tillering to either soil or foliage, and it also reduced yield to a lesser extent when applied at low concentration. At high concentration of benzotriazole (50 mg kg^-1 of dry soil) the percentage of pollen staining with I₂/KI was very low (0–7%) depending on method of chelate application), and this soil treatment resulted in complete male sterility. The appearance of the pollen, anthers, grain, ears and leaves in many cases mimicked that of normal copper deficiency, and also that caused by other recognised gametocides. These results raise the question of whether binding of copper or some other disturbance of copper metabolism may be the mechanism by which andro-gametocidal chemicals work and if so, dictate a theoretical basis for selecting such chemicals for testing.     

Induction of male flowering in gynoecious cucumbers (Cucumis sativus L.) by silver ions

Summary Silvernitrate (AgNO₃) and silverthiosulphate (Ag(S₂O₃)₂ ^3-) effectively induced male flowering in many nodes of 7 gynoecious cucumber genotypes in 3 glasshouse trials. A single spraying of the plants in the first true leaf stage with 3 mM Ag⁺ as Ag(S₂O₃)₂ ^3- or AgNO₃ (500 ppm) yielded many more staminate flowers than GA-3 (1500 ppm) and almost as many as 3 consecutive sprayings of GA-4/7 (50 ppm).Male flowering started about 3 weeks after treatment and lasted for a period of up to 4 weeks thereafter. Plants treated with silver ions did not elongate and grew normally; effective concentrations of AgNO₃ proved phytotoxic only in poor growing conditions, while Ag(S₂O₃)₂ ^3- never gave deleterious side-effects. Even very strongly female lines can be induced to male flowering with silver ions, thus increasing the feasibility of large scale seed production of gynoecious × gynoecious cucumber hybrids.     

Alteration of methylation profiles in distinct cell lineages of the layers during vegetative propagation in carnations (Dianthus caryophyllus)

In vegetatively propagated plants, branches of periclinal chimera give rise to bud mutants, or “sports”, which have been used to breed new cultivars. Here, we have examined DNA methylation profiles in the cells of the L1 and L2+3 layers from single plants of vegetatively propagated carnations. The band patterns of methylation-sensitive amplified fragment polymorphism (M-AFLP) of the genomic DNAs in the L1 and L2+3 layers of the carnation cultivar, “White Sim”, vegetatively propagated over the past 50 years, were completely different. The bud mutant, “White Mind”, obtained from “White Sim” about 25 years ago, also had very different M-AFLP patterns to the parental “White Sim” line. The cultivar, “Red”, which was separated from “Satisfaction” as a bud mutant two years ago, showed similar patterns to “Satisfaction” in each corresponding layer. However, we were able to detect minor, but significantly different M-AFLP patterns between the cultivars, “Red” and “Satisfaction”. The number of bands that differed between these cultivars was larger in the L2+3 layers than in the L1 layers. The results indicate that the DNA methylation profiles differ between each cell layer derived from distinct cell lineages of vegetatively propagated plants, and that changes in these profiles occur frequently and accumulate in the cells of the L2+3 layers, rather than in the L1 layer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Plant regeneration from callus culture in potato

Summary A procedure for plant regeneration from callus culture of potato, Solanum tuberosum L. is described. Calli were induced from 1–2 mm long shoot apices of potato cultivars Cara and A25/19 on half-strength Murashige and Skoog's medium (half-MS) supplemented with 3.2 mg IAA (indole-3-acetic acid), 1.0 mg kinetin (6-furfurylamino)purine], and 0.5 mg 2,4-D [2,4-dichlorophenoxy)acetic acid]/1. Sixty percent explants produced nodular calli on this medium within 30 days. Calli differentiated into shoot-primordia when subcultured on half-MS medium supplemented with 0.5 mg 2,4-D and 1.0 mg zeatin [6-(4-hydroxy-3-methybut-2 enylamino)amino purine]/1. Differentiated calli on half-MS medium without growth hormones produced complete plantlets which were cloned on the same medium and transferred into soil.     

An improved in vitro technique for isolated microspore culture of barley

A detailed procedure for isolated microspore culture of barley is presented along with examples of response across genotypes. Over 30 genotypes, including winter and spring growth habit and 2-row and 6-row genotypes, have shown an essentially genotype independent response, averaging about 10,000 embryos per 5 cm petri culture plate. The regeneration frequency, checked on samples of 500 embryos per plate ranged from 36 to 97% with most genotypes being in the range of 70 to 90%. About 70 to 80% of the plants regenerated have been completely fertile doubled haploids, thus eliminating the need to double the chromosome number of plants. Many little details are critical to success of the microspore procedure and while it saves much time compared to anther culture, greater attention to details and cleanliness is essential. This revised version was published online in August 2006 with corrections to the Cover Date.     

迷你岩桐组织培养及植株再生体系建立

以迷你岩桐(Sinningia hybrida‘Isa’s Murmur’)带柄叶片为外植体,探讨了外植体的灭菌方法、不同基本培养基以及外源激素(6-BA、NAA、IBA)对愈伤组织和不定芽的诱导及增殖、生根等的影响,成功建立了迷你岩桐组织培养植株再生体系。结果表明:迷你岩桐带柄叶片在75%乙醇灭菌10 s,0.1%升汞灭菌300 s时,污染率较低(15.56%)而启动率较高(85.56%)。在MS培养基中添加2.0 mg·L^-16-BA和0.1 mg·L^-1 NAA时,愈伤组织诱导率最高(91.11%)。在1/2 MS培养基中添加2.0 mg·L^-16-BA和0.05 mg·L^-1 NAA时,不定芽诱导率为88.89%。在MS培养基中同时添加2.0 mg·L^-16-BA和0.1 mg·L^-1 NAA时,不定芽增殖效果最好,增殖倍数为2.38。1/2 MS+0.10 mg·L^-1 IBA培养基有利于生根,生根率为87.78%。腐殖土∶泥炭土∶河沙以体积比为1∶2∶2的混合基质为移栽基质时,瓶苗移栽成活率可达96.67%。本研究结果可为迷你岩桐的遗传转化体系的构建及规模化生产提供一定的理论基础和技术支撑。     

罗布泊"耳纹"成因与电磁感应电导仪测量值相关性初探

应用EM38电磁感应电导仪测量法调查了罗布泊“耳纹”地区盐壳电导值，对干盐湖沉积物采取不同尺度和不同空间分辨率的取样与测量。研究结果表明，盐壳土壤EM38电导的各特征参数值均表现出明显的空间变异性，“耳纹”的形成和电磁感应电导所表征的物理量存在较好相关性：“耳纹”黑色区域电导值较高，白色区域电导值较低。