赤霉素对茄子种子发芽的影响

研究了赤霉素对生产上常用的几个茄子品种种子发芽的影响。结果表明:用较低浓度(50～100mg/kg)GA溶液浸种8h,对于破除浅休眠茄子品种的休眠具有良好的效果;对于中度休眠的茄子品种,以500mg/kgGA丙酮溶液处理24h效果最佳。以上方法可用于种子发芽试验和育苗生产。     

赤霉素对邓恩桉嫁接种子园花蕾生长的影响

以邓恩桉嫁接种子园为研究材料,分别以赤霉素0、500、1000、1500 mg·L-1进行叶面喷施,研究赤霉素处理对花蕾直径生长、花蕾保存率,叶片叶绿素、氨基酸、蛋白质、可溶性糖含量的影响。结果表明:赤霉素处理后花蕾保存率、氨基酸含量、可溶性糖含量显著高于对照,花蕾直径生长量第2次观测值显著大于对照,可溶性蛋白质含量第1、2次观测值显著高于对照;随着时间的延长,叶绿素含量呈先升高后下降趋势,氨基酸、可溶性蛋白质含量分别呈极显著、显著下降趋势,可溶性糖含量呈显著上升趋势。表明赤霉素处理对提高花蕾直径生长量、花蕾保存率、叶绿素、氨基酸、可溶性蛋白质、可溶性糖含量效果明显,其中以赤霉素1000 mg·L-1处理效果最好。     

催花期施氮对观赏凤梨激素含量的影响

【研究目的】为了探讨催花期氮素对观赏凤梨成花效果的影响以及为凤梨花期调控提供理论依据,【方法】以‘丹尼斯’凤梨为试材,研究了催花期施氮处理对其内源激素含量及比值的影响。【结果】催花期施氮处理不同程度地降低了植株叶片和生长点玉米素核苷(ZRs)和脱落酸(ABA)含量,提高了赤霉素(GAs)含量,但对叶片和生长点生长素(IAA)含量影响较小,从而引起叶片和生长点ABA/IAA、ABA/GAs、ZRs/GAs和ZRs/IAA比值的显著降低,同时植株成花率下降、花期推迟、成花质量降低。【结论】催花期施氮通过影响植株内源激素含量和比值的动态平衡从而降低植株催花效果。     

Hormonal Control of Dormancy

Abstract

Changes in the equilibrium of almost all known phytohormones are correlated with the onset, maintenance and removal of dormancy in seeds, buds, bulbs and tubers, but the results are often contradictory. At present, there is no consistent theory which would explain the mechanism of hormonal control of dormancy. Also, the molecular regulation of dormancy is poorly understood.     

Pre-maturity α-amylase in wheat: The role of abscisic acid and gibberellins

The occurrence of pre-maturity α-amylase (PMA) is a major cause of poor bread-making quality (low Hagberg Falling Number) in wheat grain. In susceptible genotypes, it involves the excessive accumulation of high isoelectric point (pI) α-amylase in mature grain prior to germination and in the absence of pre-harvest sprouting. Several factors regulate PMA formation in developing grain, including genotype, agronomy, and environmental conditions. In particular, a cold period during mid-grain development has been found to be a major stimulus for PMA induction. Although the factors affecting the PMA occurrence are well known, little is known about the molecular mechanism governing its induction. The plant hormones abscisic acid (ABA) and gibberellins (GAs) influence various aspects of grain development, and it has been suggested that PMA involves changes in the amount of these hormones or the sensitivity of the grain to these hormones. This review summarizes recent studies investigating the role of ABA and GAs in PMA induction and PMA occurrence.     

Effect of elevated nitrogen levels on endogenous gibberellin and jasmonic acid contents of three rice (Oryza sativa L.) cultivars

Three rice (Oryza sativa L.) cultivars ( cv. Daesanbyeo, cv. Dongjinbyeo, cv. Junambyeo) were analyzed for endogenous gibberellin (GA) and jasmonic acid (JA) contents and their changes in response to elevated nitrogen (N) levels. The N fertilizer was applied in the form of urea [(NH₂)₂CO] at three rates (0, 36.8, 73.6 kg N ha^–1). Plant growth (height and dry weight) was enhanced by the first N rate but not further enhanced by the highest rate. The endogenous GA contents were analyzed through high‐performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry–selected ion monitoring (GC‐MS‐SIM) while that of JA with GC‐MS‐SIM. They were analyzed one week after N application and were significantly increased with elevated N levels in all rice cultivars. The bioactive GA₁ markedly increased, but its concentration differed in different rice cultivars. Similar fluctuations were observed for endogenous GA₈, GA₁₂, GA₁₉, GA₂₀, and GA₅₃ in response to elevated N levels, showing that the rates of biosynthesis of GAs were differently affected by elevated N levels within different rice cultivars. The level of GA₂₀, a precursor of GA₁ biosynthesis, was not significantly increased, though GA₁₉, a precursor of GA₂₀, was found to be the most abundant GA type in all rice cultivars. Jasmonic acid content in the plants increased with the basic urea application (36.8 kg N ha^–1), but significantly decreased with the double urea level (73.6 kg N ha^–1). The results demonstrate that GA and JA are differentially affected in response to elevated N application in rice.     

赤霉素处理促进白菜开花的效应分析

研究了赤霉素处理对白菜开花的影响,结果表明,赤霉素促进白菜的开花。测定植株叶片相关物质的含量,可溶性糖和可溶性蛋白质含量均升高,总的C/N升高。在激素方面,赤霉素处理不仅提高了植物体内GA的含量,而且也使IAA的含量升高,而ABA含量呈先下降后上升的趋势。比较三种激素的比值,GA/ABA、GA/IAA和IAA/ABA值均升高。     

针叶树G ID1同源基因分离鉴定与功能预测

GID1作为赤霉素(GA)受体蛋白,是GA信号通路的重要组成部分,其编码基因GID1在被子植物中已经被广泛克隆,但在针叶树种中的研究十分滞后。为了分离针叶树GA受体GID1基因并推测其功能,本研究以拟南芥GID1s序列为探针,在油松高质量参考转录组内筛选并鉴别出了油松GID1直系同源基因;基于该基因序列同源克隆了樟子松、白皮松、赤松GID1基因,通过BLAST获得了日本落叶松、火炬松、白云杉与挪威云杉的GID1-like基因;对针叶树GID1基因进行序列保守性、蛋白结构和组织表达活性分析。结果表明:针叶树种很可能只含有一个GID1基因,该基因在针叶树中具有很高的保守性;虽然与被子植物GID1之间的序列一致性较低,但其保持GA亲和活性所必需的氨基酸残基十分保守,与其下游DELLA蛋白相互作用的功能域与结构同样十分保守,推测其在针叶树GA信号转导中具有受体功能;表达分析显示GID1在挪威云杉不同组织和油松雌雄球花不同发育阶段间表达较为稳定,表明GID1可能广泛参与这些组织的发育过程,针叶树GA信号调控通路中GA受体的转录调控可能并不是核心调控机制。研究结果为GID1基因在针叶树生长发育过程中的分子调控机制研究奠定了基础。      

Seed cone abortion and full seed production in an indoor seed orchard with potted grafts of Picea abies

Abortion of seed cones and production of full seeds have been recorded in an indoor‐potted Norway spruce (Picea abies (L.) Karst.) seed orchard at Biri nursery in Norway. Seed cone buds aborted their normal development at much higher frequencies (22–45%) inside isolation bags than in an open‐air (4–12%) greenhouse environment. The grafts had been induced to flower the year prior to seed cone development. Treatment with gibberellin A_4/7 in conjunction with heat reduced the proportion of aborted, isolated flowers (13%) compared to treatment with heat alone (22%) in a clonally balanced material. The production of full seeds per cone increased from 3 in 1987 to 50 in 1991. The full seed production is discussed in relation to methods and timing of pollen forcing. It is anticipated that 1 kg of seeds could be produced annually in a 1250 m² greenhouse.     

外源GA3对非洲菊舌状花着色的影响

以红色非洲菊品种‘红地毯’为试材,在花朵发育的P1时期喷施赤霉素,浓度分别为0、50、100、200、400、800 mg/L,研究外源GA3处理对非洲菊舌状花着色的影响。结果表明：随着外源赤霉素浓度的增加,花瓣内花青素含量逐渐升高,促进花青素的合成;当外源赤霉素浓度在100~200 mg/L时,最有利于类黄酮的合成和可溶性糖的积累;但是赤霉素浓度大于200 mg/L时才能提高苯丙氨酸解氨酶的活性,因此赤霉素浓度为200 mg/L左右时能促进非洲菊舌状花着色。