Direct differentiation of ears and tassels from cultured shoot apices of maize.
In vitro morphogenesis of inflorescences from the cultured corn seedling shoot tips was obtained on modified Murashige and Skoog (MS) medium in complete darkness. Some shoot tip meristems excised from seedlings of inbred line 515, inbred line 8112 and their filial generations would directly give rise to florets on modified MS medium supplemented with 2.0 mg/L N(6) -bezyladenine (6-BA) in five or six weeks. On the medium with 1.0 mg/L 6-BA and 0.2 mg/L 2, 4-dichlorophenoxy acetic acid (2,4-D), the explants swelled first, and produced multiple shoot clumps, then the culture of the shoot tips from all of the six inbred lines in experiment would ultimately initiate to develop ears and tassels accompanied by multiple shoot clumps developing on the medium with 1.0 mg/L 6-BA and 0.2 mg/L indole-3-butyric acid (IBA). The developmental patterns of the corn inflorescences were similar to the controls of normal plants in the field, but the number of the ears was much more than that of the tassels in vitro. It seemed that proper kinds and concentrations of exogenous hormones were necessary for the initiation and development of the inflorescences. The genotype of explants was responsible for the response to culture conditions. It could be inferred that there were different control mechanisms existing in the vegetative and reproductive developmental processes of maize, because the cultured shoot tips could directly produce the reproductive organs.
Li
X
X
Shandong University, Jinan, China.
Zhang
J
J