玉米叶片胚性愈伤组织诱导及其与内源IAA和ABA关系的初步研究

玉米幼叶愈伤组织的形成能力因其形态学部位的不同而呈显著差异, 从基部向上依次递减, 幼叶外植体的内源IAA和ABA水平亦相应地呈递减趋势。 2, 4-D及与BA组合对基部切段的愈伤组织形成无显著影响, 愈伤组织生长符合Logistic曲线, 单独使用BA不利于愈伤组织形成; 采用2 mg/L 2, 4-D与0.5 mg/L BA的组合最有利于胚性愈伤     

IAA和乙烯与NR基因的表达及相关的生长生理反应

试验以番茄为材料,通过IAA和乙烯对番茄黄化幼苗“三重反应”、植物细胞膜透性、呼吸作用、气孔导度、蒸腾作用和细胞间CO2浓度和NR基因表达的影响,探讨了激素对乙烯信号转导的影响。结果表明：当没有外源乙烯处理时,IAA抑制了乙烯的产生,使NR等受体蛋白基因处于不活跃状态;因而表现出叶片维持稳定的细胞膜透性;植株叶片蒸腾作用、呼吸作用和气孔导度都降低(IAA处理2h后)。在有外源乙烯处理时,乙烯与IAA诱导植株产生的内源乙烯足以诱导乙烯受体蛋白基因NR基因的大量表达,并反过来抑制了乙烯的合成;因而植株代谢表现出与乙烯相拮抗的作用,如高浓度的IAA处理(≥4mg／L)、使番茄黄化幼苗下胚轴迅速伸长,抵消乙烯对幼苗下胚轴生长的抑制作用;IAA押制乙烯引起的植株叶片蒸腾作用、呼吸作用和气孔导度的增高和促进叶片细胞膜透性的增加。因此,NR基因是负调节子。     

不同核背景的玉米CMS系内源激素关系研究

采用两套同核异质系 ,研究了不同核背景和不同孢质内源激素含量与玉米CMS的关系。结果表明 ,不同核背景以及不同孢质的CMS之间内源激素含量有差异 ;较高的ABA和较低GA、IAA含量、特别是较低的GA3 /ABA、IAA/ABA浓度可能是花粉发生败育的一个重要原因 ;不育系中较高的GA3 和IAA含量可能导致育性不稳定     

溶磷菌溶磷和分泌IAA特性及对苜蓿生长的影响

植物根际溶磷菌不仅可以提高植物对土壤磷素的利用率,同时可以促进根瘤菌的结瘤和固氮作用。利用液体培养法对5株溶磷菌的溶磷特性和分泌IAA能力进行研究,并通过盆栽试验研究接种溶磷菌对苜蓿(MedicagosativaL.)生长的影响。结果表明:各供试菌株溶磷能力差异较大,溶磷能力最强的是LM18(300.3 mg/mL);菌株都有分泌IAA特性,最大分泌量为17.95μg/mL(LM12)。接种溶磷菌后苜蓿株高、茎粗、干重、干鲜比和叶茎比都比对照明显增加。因此,溶磷能力和分泌IAA能力较强的菌株(LM12和LM18)可作为研制微生物肥料的优良菌株。     

激素对草本植物种子休眠、萌发的影响

随着我国草产业的快速发展和草种子需求量的不断增加, 草种子的品质差和产量低已成为我国草业发展的瓶颈。研究植物种子休眠和萌发规律是提高种子品质和产量的前提之一, 对于保障草种业的健康发展具有重要意义。植物激素是调节种子休眠、萌发的关键因子, 其与种子休眠、萌发的关系一直是种子生理生化研究的热点。本文旨在综合激素对草本植物种子休眠、萌发影响的研究结果, 为进一步分析各种激素间相互作用的机理、揭示植物种子休眠与萌发的生理机制奠定基础。     

玉米秃尖与内源激素的关系

玉米果穗顶部不能形成种子或部分种子败育而导致秃尖,秃尖受遗传影响较大,并对光合作用的依赖性很强。本文以20个玉米杂交组合雌穗顶部穗轴为材料,对光合作用的"源"和"库"起调控作用的顶部穗轴内源激素与其秃尖长度的关系进行了研究。结果表明,在快速灌浆期,玉米雌穗顶部穗轴GA3I、AA、CTK含量较高,而ABA含量很低;ABA含量与玉米秃尖长度呈极显著的正相关;(GA3+IAA+CTK)/ABA含量与玉米秃尖长度呈极显著的负相关。说明顶部穗轴ABA含量的高低与玉米秃尖长度存在密切关系。     

Floral induction (FI) in longan (Dimocarpus longan, Lour.) trees. III: Effect of shading the trees on potassium chlorate induced FI and resulting hormonal changes in leaves and shoots

Previous experiments demonstrated that treatment of longan trees with potassium chlorate (KClO₃) induces “off season floral induction” (FI) even in the absence of the naturally required cool temperature [Manochai, P., Sruamsiri, P., Wiriya-alongkorn, W., Naphrom, D., Hegele, M., Bangerth, F., 2005. Year around off season flower induction in longan (Dimocarpus longan, Lour.) trees by KClO₃ applications: potentials and problems. Sci. Hortic. 104, 379–390]. Potassium chlorate, however, cannot replace the presence of functional mature leaves and sufficient light intensity. Here we examined in more detail the effect of shade (about 10% of natural sunlight) on KClO₃ affected hormone concentrations/transport of leaves and shoot apical buds (SAB) and their interactions with FI.     

栽培花生Aux/IAA家族鉴定与生物信息学分析

Aux/IAA(Auxin/Indole-3-Acetic Acid)家族是生长素(Auxin)信号的早期响应基因家族之一,广泛参与调控植物的生长发育。然而目前对于栽培花生(Arachis hypogaea)Aux/IAA家族的研究还未见相关报道。本研究在栽培花生中共鉴定到了34个Aux/IAA基因,分布在15条不同的染色上。多重序列比对分析发现花生Aux/IAAs具有4个保守结构域,分别为Ⅰ-Ⅳ。聚类分析将花生Aux/IAAs分为Ⅰ-Ⅷ,8个亚家族。各个亚家族内部基因具有相似的保守基序,而基因之间的内含子/外显子结构存在差异。基于基因表达模式分析将栽培花生分为A和B两组基因,A组基因在花生各个组织的表达量都相对较高,而B组基因的表达具有组织特异性。基于以上结果,本研究将为进一步对Aux/IAA家族的基因功能研究提供科学依据。     

Growth and Metabolic Changes of Cowpea Plants as Affected by Water Deficiency and Indole-3-Yl-Acetic Acid

Cowpea plants ( Vigna sinensis Savi.) were grown in pots for two successive years. These plants were daily maintained water holding capacities (15, 25, 45, 65 %).
The foliage of plants grown at every level of soil moisture was sprayed till dripping with IAA solutions (0, 10, 50, 100 mg/l) three times after 3, 6 and 9 weeks from sowing. Samples were taken at the two physiological stages before flowering and during flowering for growth measurements and determinations of nitrogen fractions.
Water shortage led to retardation of stem length, number of internodes, number of leaves and dry weight shoots. IAA increasing the same parameters only when applied at concentrations of 10 and 50mg/1 at moisture level 65 %, 45 % and 25 % of W.H.C.
Water stress decreased total-N and protein-N contents of cowpea shoots. On the other hand total soluble- N content was increased under the same conditions. IAA increased total-N and protein-N content of cowpea shoots. Meanwhile, the same growth regulator decreased total soluble-N when applied at 45% 25 % and 15 % W.H.C. levels.     

Refinement of shed-microspore culture protocol to increase normal embryos production in hot pepper (Capsicum annuum L.)

A low percentage of normal-looking embryos (20%) is still a problem in an efficient shed-microspore culture of hot pepper (Capsicum annuum L.) and it is more a serious problem in other androgenesic culture systems of pepper. Therefore, several factors were investigated to refine the protocol in order to increase the percentage of normal-looking embryos. The most important factors which improved the protocol and resulted in a significantly higher percentage of normal-looking embryos produces (>50%), were delayed enrichment of the liquid upper layer medium with 2.5 μM Zeatin and 5 μM IAA, and reduced incubation temperature from 28 °C to 21 °C, both after 3 weeks of culture. Addition of 1% activated charcoal in the solid lower layer of the medium enhanced the total embryo yield only, while an application of abscisic acid and increased osmolality medium had a detrimental effect on embryo production. The use of doubled haploid lines as anther donor plants has clearly decreased the variability and improved the statistical analysis of treatment effects. A higher percentage of normal embryos are produced with this refined protocol, and is therefore more suitable for implementation in the breeding programs of hot pepper.