Bicalho E M, Pintó-Marijuan M, Morales M, Müller M, Munné-Bosch S, Garcia Q S
Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Departamento de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
Plant Biol (Stuttg). 2015 Sep;17(5):990-6. doi: 10.1111/plb.12332. Epub 2015 Apr 17.
The hormonal mechanisms involved in palm seed germination are not fully understood. To better understand how germination is regulated in Arecaceae, we used macaw palm (Acrocomia aculeata (Jacq.) Lodd. Ex Mart.) seed as a model. Endogenous hormone concentrations, tocopherol and tocotrienol and lipid peroxidation during germination were studied separately in the embryo and endosperm. Evaluations were performed in dry (D), imbibed (I), germinated (G) and non-germinated (NG) seeds treated (+GA3 ) or not treated (control) with gibberellins (GA). With GA3 treatment, seeds germinated faster and to a higher percentage than control seeds. The +GA3 treatment increased total bioactive GA in the embryo during germination relative to the control. Abscisic acid (ABA) concentrations decreased gradually from D to G in both tissues. Embryos of G seeds had a lower ABA content than NG seeds in both treatments. The GA/ABA ratio in the embryo was significantly higher in G than NG seeds. The +GA3 treatment did not significantly affect the GA/ABA ratio in either treatment. Cytokinin content increased from dry to germinated seeds. Jasmonic acid (JA) increased and 1-aminocyclopropane-1-carboylic acid (ACC) decreased after imbibition. In addition, α-tocopherol and α-tocotrienol decreased, while lipid peroxidation increased in the embryo during germination. We conclude that germination in macaw palm seed involves reductions in ABA content and, consequently, increased GA/ABA in the embryo. Furthermore, the imbibition process generates oxidative stress (as observed by changes in vitamin E and MDA).
棕榈种子萌发所涉及的激素机制尚未完全明确。为了更好地理解棕榈科植物的萌发调控方式，我们以金刚鹦鹉棕榈（Acrocomia aculeata (Jacq.) Lodd. Ex Mart.）种子为模型。分别研究了萌发过程中胚和胚乳内的内源激素浓度、生育酚和生育三烯酚以及脂质过氧化情况。对干燥（D）、吸胀（I）、已萌发（G）和未萌发（NG）的种子进行了评估，这些种子用赤霉素（GA）处理（+GA3）或未处理（对照）。经过GA3处理，种子萌发速度更快，发芽率高于对照种子。与对照相比，+GA3处理使萌发过程中胚内的总生物活性GA增加。在两种组织中，脱落酸（ABA）浓度从D期到G期逐渐降低。在两种处理中，G种子的胚中ABA含量均低于NG种子。G种子胚中的GA/ABA比值显著高于NG种子。+GA3处理在两种处理中均未显著影响GA/ABA比值。细胞分裂素含量从干燥种子到已萌发种子增加。吸胀后茉莉酸（JA）增加，1-氨基环丙烷-1-羧酸（ACC）减少。此外，萌发过程中胚内的α-生育酚和α-生育三烯酚减少，而脂质过氧化增加。我们得出结论，金刚鹦鹉棕榈种子的萌发涉及ABA含量的降低，从而导致胚内GA/ABA比值增加。此外，吸胀过程会产生氧化应激（如通过维生素E和丙二醛的变化观察到）。
