【目的】 研究幼化、激素处理对娜塔栎(Quercus texana)嫩枝扦插生根的影响,观察生根过程中插穗不定根的形成过程,探究娜塔栎扦插生根困难的原因,为娜塔栎的扦插繁殖提供理论依据和技术借鉴。【方法】 以幼化(6 年生母树平茬后的苗木)、6 年生母树上剪取的当年生半木质化娜塔栎插条为材料,分别用不同质量浓度的吲哚丁酸(IBA)+萘乙酸(NAA)+间苯三酚(THB)的混合溶液浸泡插穗基部10 min,以清水处理相同时间为对照(CK),于扦插75 d后计算各处理插穗的愈伤率、生根率、根系指数和根系效果指数;同时,以幼化半木质化娜塔栎插条为材料,对不同生根阶段的插穗用FAA标准固定液固定,采用石蜡切片技术对插穗不定根的形成过程进行解剖观察。【结果】 植物激素处理能显著提高娜塔栎扦插的生根效果,幼化及6年生母树插穗的生根率均表现出处理组的生根率高于对照组,其中生根率最高可达43.3%。双因素方差分析表明,幼化处理是影响娜塔栎扦插生根的重要因素,且各指标的综合分析排序发现,幼化插穗生根效果大于6年生母树插穗的。利用石蜡切片法观察娜塔栎生根过程茎部的解剖构造,发现刚剪取的插穗不含有潜伏状根原基,属于诱导根原基生根类型;存在愈伤生根和皮部生根的,属混合生根类型;解剖学观察还发现茎部韧皮部中连续的环状厚壁细胞阻碍了不定根的伸长生长。【结论】 以IBA 500 mg/L+NAA 250 mg/L+THB 50 mg/L的混合溶液处理幼化娜塔栎插穗基部10 min,其扦插生根效果最佳;但是否为最适浓度需进一步验证。插穗属于诱导根原基生根类型;韧皮部存在环状连续的韧皮纤维(厚壁细胞)是导致其生根困难的原因之一。不定根原基发生的方式有两种:一种是愈伤组织内发生不定根原基,另一种是形成层附近的细胞分裂形成根原基。

【Objective】 This study was performed to investigate the effects of rejuvenation and hormone treatment on the rooting of Quercus texana cuttings and obverse the formation process of adventitious roots during the rooting process. This was done to explain the reasons behind the difficulty of rooting Q. texana cuttings to provide a theoretical basis and technical reference for the subsequent cutting propagation of Q. texana.【Method】 Using the rejuvenated (seedlings after the flat stubble of the six-year-old parent stocks) and the annual semi-woody branches cut from the six-year-old seedlings as materials to make cuttings, the bases of the cuttings were treated with the mixed solution of IBA, NAA, THB and soaked for 10 min. Furthermore, cuttings treated with water for the same duration were taken as the control (CK). After cutting for 75 days, we determined the callus rate, rooting rate, root index and root effect index of the cuttings of each treatment. Meanwhile, the formation process of the adventitious roots of cuttings from semi-woody branches of rejuvenated Q. texana was anatomically observed with the paraffin section technique.【Result】 Hormone treatments could significantly improve the rooting effect of Q. texana cuttings, and the results showed that the rooting rates of the treatment groups were higher than that of the control group in both the rejuvenated and six-year-old cuttings, with the highest rooting rate reaching 43.3%. The two-factor analysis indicated that the rejuvenation treatment was a crucial factor affecting the rooting of Q. texana cuttings. Additionally, through the comprehensive analysis and ranking of various indicators, we found that the rooting effect of the rejuvenated cuttings was better than that of the six-year-old cuttings. The anatomical structure of the stem during the rooting process of Q. texana was observed with the paraffin section method, and it was found that the stem of new cuttings did not contain latent primordia, which belonged to the induced root primordium rooting type. Callus and skin rooting existed, which were classified into the mixed rooting type. Moreover, anatomical observation found that the phloem of the stem contained continuous annular thick-walled tissue, which hindered adventitious root elongation.【Conclusion】 The best rooting effect of the cuttings was achieved when the cuttings were made from rejuvenated Q. texana seedlings, with the base part soaked in the IBA (500 mg/L),NAA (250 mg/L) and THB (50 mg/L) mixed solution for 10 min. Anatomical observation of the stem during the rooting process revealed that the stem did not contain latent root primordia, which belonged to the type of induced primordium rooting. The presence of annular continuous phloem fibers (thick-walled tissue) in the phloem is one of the reasons for rooting difficulty. There are two pathways in which adventitious root primordia can occur: one is through the emergence of adventitious root primordia from the callus, and the other is through cells that divide near the cambia to form root primordia.