Key message

Significant differences in phytohormone profiles existed among the normal tree and two sterile mutant trees in interior Douglas-fir. Stem injection of gibberellin A₄ and A₇ induced male cone formation in one of the two genotypes of sterile trees.

Abstract

Two sterile genotypes of interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) were analyzed. The phenotype of these mutant trees is characterized by compact internodes, stunted vegetative growth and an inability to initiate male or female cone buds. Long shoots were sampled at the stage prior to cone bud initiation in both sterile and wild type trees. Multiple phytohormones and their selected metabolites were analyzed using high-performance liquid chromatography–electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Compared with concentrations in wild-type samples, levels of total quantifiable cytokinins were about half (51.9%) in samples of sterile trees. In particular, levels of both trans-zeatin riboside and isopentenyl adenosine were lower. Concentrations of abscisic acid (ABA)-related metabolites, especially ABA-glucose ester, were higher (1.4-fold) in sterile trees. Total quantifiable gibberellins were about one-third (28.3%) lower in the sterile trees: concentrations of GA₃₄ were significantly lower. There were no significant differences in concentrations of indole-3-acetic acid (IAA) or its conjugated form, IAA-aspartate. After stem injection of GA₄₊₇, male cone formation was induced in one of the sterile genotypes. Gibberellin injection also caused the vegetative growth phenotype to change. Branches expanded to approximately five times their previous size in years past and their internodes showed more normal spacing. With their unique phytohormone profiles, these sterile mutants of Douglas-fir could provide a valuable research system for further exploration of molecular and physiological regulations during conifer reproduction.

中文翻译：

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不育花旗松突变体的植物激素谱和对注射茎的赤霉素的反应

关键信息

内部花旗松的正常树和两种不育突变树之间的植物激素谱存在显着差异。赤霉素 A ₄和 A _{7 的}茎注射诱导了两种不育树基因型之一的雄性锥体形成。

抽象的

分析了内部花旗松 ( Pseudotsuga menziesii var. glauca (Beissn.) Franco) 的两种不育基因型。这些突变树的表型的特点是节间紧凑、营养生长发育迟缓和不能产生雄性或雌性锥芽。在不育型和野生型树的锥芽萌生之前的阶段对长芽进行取样。使用高效液相色谱-电喷雾电离串联质谱 (HPLC-ESI-MS/MS) 分析了多种植物激素及其选定的代谢物。与野生型样品中的浓度相比，不育树木样品中可量化的细胞分裂素总量水平约为一半（51.9%）。特别是，这两种反式的水平-玉米素核苷和异戊烯基腺苷较低。不育树中脱落酸 (ABA) 相关代谢物的浓度，尤其是 ABA-葡萄糖酯的浓度更高（1.4 倍）。不育树中可量化的赤霉素总量降低了约三分之一 (28.3%)：GA _{34 的}浓度显着降低。吲哚-3-乙酸 (IAA) 或其共轭形式 IAA-天冬氨酸的浓度没有显着差异。GA ₄₊₇茎注射后，在其中一种不育基因型中诱导雄性锥体形成。赤霉素注射液也引起营养生长表型的改变。分枝扩大到过去几年前大小的大约五倍，并且它们的节间显示出更正常的间距。凭借其独特的植物激素谱，这些花旗松不育突变体可以为进一步探索针叶树繁殖过程中的分子和生理调控提供有价值的研究系统。