An effective method of tulip regeneration via somatic embryogenesis (SE) was developed. Explants, flower stem slices excised from cooled bulbs were incubated in darkness on MS modified media containing auxins alone (2,4-dichlorophenoxyacetic acid—2,4-D, 1-naphthalene acetic acid—NAA and 4-amino-3,5,6-trichloro-2-pyridine carboxylic acid—picloram) or combined with thidiazuron (TDZ) at 0.1 and 0.5 mg L⁻¹. Yellowish-white callus with a granular structure was developed in the presence of all auxins on the cut surface from the tissues of the vascular bundles. From this, lines of embryogenic calli were derived. The addition of TDZ to the medium with auxins significantly stimulated somatic embryo formation. Cyclic and the most intensive proliferation of embryogenic callus as well as embryo formation was obtained in the presence of 2,4-D at 0.1 mg L⁻¹ combined with TDZ at 0.5 mg L⁻¹. Addition of proline enhanced either callus proliferation rate or frequency of embryo formation. The best quality embryos with cotyledons longer than 10 mm able to form bulbs were recorded when TDZ was replaced with 6-benzylaminopurine (BAP) at the concentration of 0.1 mg L⁻¹. Histomorphology showed that the development of somatic embryos could have either external or internal origins. Embryos of external origin were initiated by cell division on the edge of embryogenic calli. Embryos of internal origin resulted from the division of parenchyma cells inside the tissue. Embryonic cells were characterized by their small volume, regular shape, dense cytoplasm and large nuclei. The globular embryos were covered by a distinct layer of periderm. Then, the embryos developed into structures having leaf-shaped cotyledons with a procambial strand and a sideward-orientated meristem of the vegetative apex (stolon). Cotyledon embryos did not show vascular connections with the parent tissue, and they did not develop embryonic roots.

中文翻译：

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通过体细胞胚发生的郁金香的微繁殖

开发了一种通过体细胞胚发生（SE）进行郁金香再生的有效方法。在黑暗中，在仅包含生长素的MS改良培养基（2,4-二氯苯氧基乙酸-2,4-D，1-萘乙酸-NAA和4-氨基-3,5， 6-三氯-2-吡啶羧酸-吡咯烷）或与噻唑隆（TDZ）混合，浓度为0.1和0.5 mg L ^-1。在从血管束组织切下的表面上存在所有生长素的情况下，形成了具有颗粒状结构的黄白色愈伤组织。由此，获得了胚发生愈伤组织。将TDZ添加到具有生长素的培养基中可显着刺激体细胞胚的形成。在0.1 mg L ^-1的2,4-D与0.5 mg L ^-1的TDZ结合存在下，获得了胚性愈伤组织的循环性和最强烈的增殖以及胚胎形成。脯氨酸的添加增强了愈伤组织的增殖速率或胚胎形成的频率。当用浓度为0.1 mg L ^-1的6-苄基氨基嘌呤（BAP）代替TDZ时，记录了子叶长于10 mm且能形成鳞茎的最佳质量胚。。组织形态学表明，体细胞胚的发育可能具有外部或内部起源。外部来源的胚胎是由胚发生愈伤组织边缘的细胞分裂引发的。内部来源的胚胎是由组织内部的薄壁细胞分裂引起的。胚胎细胞的特点是体积小，形状规则，胞质致密，细胞核大。球形胚被一层明显的皮层覆盖。然后，胚胎发育成具有子叶状子叶的结构，该子叶具有原生菌的链和营养性顶点（sto茎）的侧向分生组织。子叶的胚胎与亲本组织没有血管联系，它们没有发育成胚根。