代代花子叶不定芽形态发生的研究

以代代花（ＣｉｔｒｕｓａｕｒａｎｔｉｕｍＬ．ｖａｒ．ａｍａｒａＥｎｇｌ．）的种子胚为外植体，接种在仅含ＢＡ２ｍｇ／ＬＭＳ培养基上，能形成多芽苗，平均每胚２．６个．少数幼苗，还可以从下胚轴处长出许多不定芽．另外还可以从子叶近基部腹面的中央部位以及近基部的边缘长出一些不定芽．接种在附加ＢＡ２ｍｇ／Ｌ＋２，４－Ｄ０．２ｍｇ／Ｌ培养基上的种胚，不能形成幼苗，但能使子叶产生愈伤组织，出愈率达９１．７％．仅附加２，４－Ｄ２ｍｇ／Ｌ的培养基，子叶最后仅形成呈黄色炸裂状的疏松物．将上述幼苗的下胚轴、子叶、上胚轴等切成小段进行培养，可在外植体上直接形成不定芽．对种子胚子叶不定芽的形态发生进行了组织细胞学观察，表明子叶的不定芽是由上表皮下的叶肉细胞分裂分化而来

Study on adventitious bud morphogenesis from cotyledon from Citrus aurantium L. var. amara Engl. in vitro

Explants of mature embryos from Citrus aurantium L. var. amara Engl. were cultured on MS medium with only BA 2 mg/L . Mature embryos could produce multiple shoot buds (average 2.6 per seedling) . Hypocotyle of a few seedlings could also form many adventitious buds. Central part of proximal base of adaxial side and the margin of near basal part of cotyledon could be found some adventitious buds, too. While mature embryos on medium with BA 2 mg/L 2,4 D 0.2 mg/L , explants could not form seedlings at all. Calli were often found on the cotyledon (91.7%). On medium adding only 2,4 D 2 mg/L , cotyledon changed into loose structure which was yellow and explosion shaped When seedling's hypocotyl, cotyledon, and epicotyl were cut into segments and cultured on media respectively. The formation of adventitious buds directly from these explants Histo cytological investigation on adventitious bud morphogenesis revealed the origin of cotyledon adventitious bud from mesophyll cell differentiation under the upper epidermis.