八角莲组织培养的器官发生途径研究

Organogenesis approaches in tissue culture of Dysosma versipellis

关键词:  八角莲, 不定芽, 不定根, 组培苗, 石蜡切片

Key words:  Dysosma versipellis, adventitious bud, adventitious root, tissue culture seedling, paraffin section

摘要:

为探究小檗科植物八角莲组织培养的器官发生方式,该研究以八角莲离体叶片、叶柄在MS培养基上诱导产生的愈伤组织、不定芽、不定根为对象,用连续石蜡切片技术分析八角莲组织培养的器官发生途径。结果表明:八角莲愈伤组织形成的解剖学特征是靠近表皮的薄壁细胞经激素刺激恢复分裂能力,继续培养形成拟分生组织。拟分生组织可形成许多分化中心。通过对八角莲组织培养产生的不定芽细胞组织学观察发现芽原基起源于愈伤组织外侧的几层薄壁细胞,芽原基背离愈伤组织中央生长形成不定芽,故八角莲脱分化形成的芽起源方式为外起源。而八角莲的根原基起源于组织深处髓部薄壁细胞和部分维管形成层细胞,进而形成类似球形或楔形并朝韧皮部突起的根原基轮廓,根原基继续发育会突破表皮生成不定根,起源方式为内起源。八角莲离体再生途径为器官发生型,在组培苗生长过程中先诱导形成不定芽,再诱导形成不定根,在愈伤组织上形成维管组织将不定芽和不定根连接成完整植株。

Abstract:

To study the organic regeneration pathway of tissue culture of Dysosma versipellis, we used callus, adventitious buds and roots induced from in vitro leaves and petioles of D. versipellis on MS medium to analyze it, based on the technique of serial paraffin slices. The results showed that the parenchyma cells which were near the epidermis recovered cell division ability through the hormone stimulation. Originally cells of the stationary state altered cell metabolism after they were stimulated, and cell division became active. The parenchyma cells were continued to culture and formed meristemoid with cells division potential of totipotency of plant cell, which could form a lot of differentiation centers. Histological observation of D. versipellis proved that the bud primodium derived from the subsurface layers of callus and grew away from the middle of callus, so the buds which produced by dedifferentiation originated in exogenous way, formed the adventitious buds. Furthermore, the root primodium originated from parenchyma cells in the pith and partial vascular cambium cells in the depth of tissue, which raised towards the phloem liked spherical or wedge. It would continue growing and break epidermis, then adventitious buds were formed. This way was endogenous. Organogenesis type was the conventional way for D. versipellis to regenerate in vitro. Adventitious buds were induced at first during the growth process of tissue culture seedling, which was followed by the formation of adventitious roots. Because of vascular bundle of adventitious roots being originated from callus must link vascular bundle of stem and branch, it played an important role in supporting small plant development. At last, the vascular bundle formed from callus would connect the two into a complete plant. The research result has important guiding significance for scale planting cultivation of D. versipellis while protecting of germplasm resources.