Pollen morphology, in vitro germination and another culture of Coix lachrymal-jobi L cultivars

To identify �the optimal in vitro conditions for pollen germination, anther culture and callus proliferation and differentiation of job’s tear (Coix lachrymal-jobi L) cv, features of pollen microspores at different flowering stages were observed, pollen germination conditions identified and anthers cultured to identify callus-forming and differentiating conditions. Pollen vigor and germination rates were determined and compared. Results showed that the late uni-, diand tri-nucleate pollen grains were coexisting in the early flowering stage; and the pollen grains were homogeneously spherical and the vigor was the highest at the peak flowering stage. Single-tube pollen germination was observed. The optimal conditions for pollen germination was 10~15% sucrose + 0.01% boric solution at 25 for 5~7 hrs. The rates of callus induction from the late uninucleate anthers differed significantly among the cv. Calluses were successfully induced in the Murashige-Skoog medium+ 2, 4-dichlorophenoxyacetate1~2 mg/L + Kinetin1.5 mg/L. And some were differentiated into short cluster buds in the medium of Murashige-Skoog medium + indole-3-acetic acid 0.5 mg/L + Kinetin 2 mg/L. This represents the first report of the morphology, vigor, optimal germination conditions for pollen microspores of C. lachrymal-jobi L of this understudied and underutilized yet economically important food and medicine homologous crop.