Varis Saila, Klimaszewska Krystyna, Aronen Tuija
Natural Resources Institute Finland (Luke), Savonlinna, Finland.
Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Quebec, QC, Canada.
Front Plant Sci. 2018 Oct 24;9:1551. doi: 10.3389/fpls.2018.01551. eCollection 2018.
The recalcitrance of adult conifer tissues has prevented vegetative propagation of trees with known and desired characteristics. Somatic embryogenesis (SE) initiation protocol, recently developed for white spruce (, Klimaszewska et al., 2011), was applied in order to examine the feasibility, frequency and timing of SE induction from primordial shoots (PS) of Norway spruce ). In total, 39 genotypes were screened from 2015 to 2017 using 4-6 years old trees of SE origin as explant donors. Two genotypes responded: 11Pa3794 produced six proliferating embryonal mass (EM) sublines and 11Pa4066 produced 23 EM sublines. SE initiations occurred at the beginning of April, when the temperature sum (d.d.) started to accumulate, and at the end of October or beginning of November when the chilling unit (ch.u.) sum was over 500. EM sublines from both genotypes contained numerous early somatic embryos as detected by acetocarmine staining. The sublines of 11Pa4066 produced the mean of 78.6 ± 12.8 cotyledonary somatic embryos /g FW, but 11Pa3794 produced only a few cotyledonary somatic embryos that were able to germinate. The original EM lines (from which the trees were regenerated) had produced the same number of somatic embryos in 2011 maturations, which was approximately 120 somatic embryos /g FW. Microsatellite analyses conducted with both responsive genotypes confirmed the genetic stability of the EM sublines compared with the donor trees growing in the field. SE protocol developed for white spruce PS explants was also suitable for PS of Norway spruce if the explants were in the responsive developmental stage.
成年针叶树组织的顽拗性阻碍了具有已知和所需特性树木的营养繁殖。为了研究从挪威云杉的原始芽（PS）诱导体细胞胚胎发生（SE）的可行性、频率和时机，应用了最近为白云杉开发的体细胞胚胎发生起始方案（Klimaszewska等人，2011年）。从2015年至2017年，总共筛选了39个基因型，使用4至6年生的体细胞胚胎发生起源的树木作为外植体供体。有两个基因型做出了反应：11Pa3794产生了6个增殖胚性团（EM）亚系，11Pa4066产生了23个EM亚系。体细胞胚胎发生起始发生在4月初，此时积温（日度）开始积累，以及10月底或11月初，此时冷温单位（冷温）总和超过500。通过醋酸洋红染色检测，来自两种基因型的胚性团亚系都含有大量早期体细胞胚胎。11Pa4066的亚系平均产生78.6±12.8个具子叶的体细胞胚胎/克鲜重，但11Pa3794只产生了少数能够萌发的具子叶体细胞胚胎。原始的胚性团系（从中再生出树木）在2011年成熟时产生了相同数量的体细胞胚胎，约为120个体细胞胚胎/克鲜重。对两种有反应的基因型进行的微卫星分析证实，与田间生长的供体树木相比，胚性团亚系具有遗传稳定性。如果外植体处于反应性发育阶段，为白云杉PS外植体开发的体细胞胚胎发生方案也适用于挪威云杉的PS。
