杜鹃兰体胚发生细胞学观察和生理生化差异OA

The study was to establish a stable somatic embryogenesis and regeneration system for Cremastra appendiculata,promote the conservation of germplasm resources and large-scale propagation of this rare medicinal plant,and provide a basis for its genetic transformation.Immature embryos of C.appendiculata were used as explants to induce callus formation.The effects of plant growth regulators at various concentrations and ratios(combinations of IBA and 6-BA)on callus proliferation were systematically investigated.Morphological and physiological-biochemical differences among various callus types were analyzed,including assays of soluble sugars,soluble proteins,and antioxidant enzyme activities.Furthermore,stereomicroscopic observation and paraffin sectioning techniques were employed to examine the origin and developmental process of somatic embryos in detail.Seeds of C.appendiculata could induce pale-yellow callus on 1/2 MS medium.The optimal medium for callus proliferation was MS supplemented with IBA(0.5 mg/L,1 mg/L)combined with 6-BA(2 mg/L,3 mg/L).Embryogenic callus formed under these conditions could regenerate plants on 1/2 MS medium containing 0.2 mg/L IBA.Observations via stereomicroscopy and tissue sections revealed that C.appendiculata somatic embryos developed through globular,pear-shaped,cotyledonary and mature embryo stages,similar to the development of zygotic embryos.Significant differences in soluble sugar,soluble protein content and antioxidant enzyme activities were observed among callus types.Type Ⅰ callus exhibited the highest embryoid potential,whereas Types Ⅰ and Ⅲ callus showed the strongest stress resistance.This study successfully established a somatic embryogenesis and plant regeneration system for C.appendiculata and identified key medium formulations for induction,proliferation and regeneration.The results reveal the physiological and biochemical characteristics of different callus types and their correlation with embryoid potential and stress tolerance,and confirm the similarity between the developmental processes of somatic and zygotic embryos in C.appendiculata.