外源激素对速生轻木种子萌发和幼苗生长的影响

Influence of exogenous hormones on seed germination and seedlings growth of fast-growing Ochroma lagopus

关键词:  轻木, 植物激素, 速生树种, 引种栽培, 育苗技术, 根冠比

Key words:  Ochroma lagopus, plant hormone, fast-growing species, introduction and cultivation, breeding techniques, root-crown ratio

摘要:

轻木(Ochroma lagopus)因其生长快、生命周期短、木材密度最小和材质均匀等优良特性备受风电产业和航空工业的青睐,但轻木种子种皮坚硬、休眠期长、自然萌发率低及幼苗异质性大等问题严重限制了其标准化育苗和规模化栽培。为提高轻木种子的萌发率、幼苗的均匀性及了解其生长特性,该研究分别以轻木种子和幼苗为试验材料,采用培养皿萌发法和盆栽控制试验,探索不同浓度外源激素吲哚乙酸(IAA)、6-苄腺嘌呤(6-BA)和赤霉素(GA)对轻木种子萌发和幼苗生长的影响。结果表明:(1)GA促进了种子萌发和胚芽生长,而IAA和6-BA抑制了种子萌发、胚芽和胚根生长及其生物量积累(P<0.05),并且随浓度的增加,抑制作用增强。(2)相反,喷施GA、IAA和6-BA促进了幼苗的生长,且对地径的促进作用大于树高和根长,并随浓度增加效果越显著(P<0.05)。(3)此外,GA和IAA还显著促进了幼苗地下生物量的积累,并提高了根冠比(P<0.01)。该研究揭示了GA通过打破种子休眠促进种子萌发,而GA、IAA和6-BA不仅能促进幼苗的建成,还提高了幼苗的根冠比,这可能会改善幼苗的水分吸收能力和抗旱性,研究结果为轻木育苗技术和栽培管理提供了理论基础和实践参考。

Abstract:

Ochroma lagopus is characterized by its fast growth, short life cycle, minimum wood density and uniform material texture, and is widely used in the wind power industry and the aviation industry. However, challenges such as low natural seed germination rates due to hard seed coat and prolonged seed dormancy, as well as high seedling variability restricted severely standardized breeding and large-scale cultivation. In order to improve the seeds germination, seedlings homogeneity and growth, this study performed dish germination and pot control experiments to evaluate the effects of varying concentrations of indoleacetic acid(IAA), 6-benzyl ademine(6-BA), and gibberellin(GA)on seed germination and seedling growth for O. lagopus. The results were as follows:(1)GA promoted seed germination and embryo growth, while IAA and 6-BA inhibited seed germination, the biomass and length of embryo bud and embryo root(P<0.05), and the inhibitory effect increased with the increasing of concentration.(2)On the contrary, GA, IAA and 6-BA boosted the growth of seedlings, and the promoting effect on ground diameter was greater than that on the height and root length, and the effect enhanced with the increasing concentration(P<0.05).(3)In addition, GA and IAA also significantly increased the below-ground biomass and root-shoot ratio of seedlings(P<0.01). This study concluded that GA enhanced seed germination by breaking seed dormancy, while GA, IAA and 6-BA not only facilitated the performance of seedlings but also increased the root-shoot ratio, ultimately accelerating their water absorption capacity and drought resistance. These findings provided a theoretical basis and practical reference for the seedling raising technology and cultivation management of O. lagopus.