Encapsulation of upland cotton, Gossypium hirsutum L., axillary buds as artificial seeds

Objective To provide a new manufacturing method for the artificial seeds of upland cotton, Gossypium hirsutum L., using axillary buds.

Method The axillary buds of upland cotton were used as explants. The explants were embedded by embedding solutions which were composed of different concentrations of sodium alginate and MSB after sterilization, and then immersed in different concentrations of CaCl₂ solutions to solidify and obtain artificial endosperm beads. The artificial seed coat was obtained on the outer synthetic endosperm beads which were immersed in the solution composed of high concentration of sodium alginate and methyl cellulose, and then immersed in CaCl₂ liquid. After added the bacteriostatic agent to the artificial seed coat, the seed germination experiment was done in nonsterile substrate.

Result The axillary buds could be made into artificial seeds after disinfection treatment, and the optimal length of explant was 5 mm. The optimal embedding program was found to be the combination of 3 % sodium alginate+MSB+0.5 mg·L^-1 NAA+0.5 mg·L^-1 IBA, and solidified in 100 mmol·L^-1 CaCl₂ for 20 min. The optimal combination of artificial seed coat was the solution of 4 % sodium alginate+1% methyl cellulose+1.0% sodium benzoate+0.02-0.04 mg·L^-1 penicillin+0.5 mg·L^-1 paclobutrazol, and solidified in 200 mmol·L^-1 CaCl₂ for 20 min. The germination rate of synthetic seed was 95.0 %, the rooting rate was 35.8 %.The artificial seed could germinate and grow into seedling in nonsterile substrate.

Conclusion A new asexual reproduction technology making artificial seed is obtained using upland cotton axillary bud, and the artificial seed can be converted into seedling in nonsterile substrate.