Histological features and development dynamics of axillary shoots during direct organogenesis in the maize mature embryo culture

Abstract

Background. The study of the morphogenesis is important for the development of effective technologies for plant regeneration in vitro. The least studied pathway of morphogenesis in the maize embryoculture is direct organogenesis. The purpose of the study is to identify the features of the direct organogenesis in the maize mature embryo culture. Material and methods. The material of the study was a homozygous maize line ATTM (bm, y, wx). Mature embryos were used as the primary explant. Sterile culture was initiated on MS medium without hormones, micropropagation was performed on MS medium supplemented with 0,5 and 2,0 mg/l 6-benzylaminopurine (BAP). Histological features of morphogenesis were studied on preparations of longitudinal sections of explants, which were fixed temporally. Results. The induction of cell division in the intercalary meristems of seedlings and a change in the direction of their differentiation under the influence of BAP was established. Vegetative buds (1-4) are formed in the coleoptilary node and at the base of the higher located phytomers of the seedling. This buds grow into axillary shoots. The dynamics of the axillary shoots development depends on the hormone concentration. Axillary shoots of the first order began to develop on the explant after an average of 10 days, axillary shoots of the second order - after 40 days, and axillary shoots of the third order - after 60 days from the start of cultivation on the medium with 2,0 mg/l BAP. These stages correspond to the following periods on a medium with 0,5 mg/l BAP: 25, 55, 85 days. The revealed patterns should be taken into account when developing effective technologies for clonal micropropagation through direct organogenesis in maize.

Keywords

• clonal micropropagation
• in vitro cultivation
• mature embryo culture
• direct organogenesis
• maize
• zea mays