Sago, a monocot and a sucker-producing plant, can be propagated by suckers, or by seeds. Suckers with unopened buds are the best planting materials.
Recently, however, a shortage of planting materials prompted the increased use of seeds for planting. The problem with seeds is its generally poor germination due to the presence of pericarp and sarcotesta, which restrict water absorption and leach out endogenous germination inhibitors.
What farmers usually do to hasten germination was to soak the seeds in water with a temperature of 30°C, but the researchers said here had been no research findings reported as to its success.
Thus, Ibisate and Abayon tried to evaluate the regeneration capacity of sago through embryogenesis, or embryo rescue, which promotes the development of an immature or weak embryo into a viable plant.
The process first involved seed sterilization wherein pre-mature fruits of different sizes were washed with detergent solution for an hour. re-sterilized inside the inoculating chamber in a bleach solution for 30 minutes, and finally washed thrice with sterilized distilled water.
Embryos were then obtained from sterilized sago seeds and cultured into basal MS medium supplemented with Benzylaminopurine (BAP) until the shoot developed.
The newly-cultured tissues were finally exposed to daily light illumination for eight hours a day, with daily temperature of 26°C to 28°C in the growing chamber.
Actually, the study which the University funded aimed to evaluate the regeneration capacity of sago palm through in vitro technique by, determining the optimum level of BAP supplement in the medium in terms of percentage of browning of the resulting embryo, percentage of embryo survival, and the number of shoots per culture.
The researchers found that the MS culture medium supplemented with 5 ppm (parts per million) BAP had the highest percentage of survival (83.33 percent) compared to those added with 3 and 7 ppm which had a comparable survival’ rate of 50 percent with the control.
Results also showed that the medium added with 5 ppm BAP concentration had resulted in less degree of browning of the newly excised embryo. Browning is a frequently encountered difficulty in palm in vitro culture and is generally_ believed to be a response to wounding.
In terms of the number of shoot produced, embryos cultured in MS medium added with 5 ppm BAP developed two shoots per embryo while those without BAP developed only one shoot per embryo. Media supplemented with 3 and 7 ppm BAP levels did not produce shoot.
The researchers also determined the best seed size for in vitro culture in MS medium supplemented with 5 ppm BAP level. Results revealed that immature fruits whose sizes range from 0.99 to 1.99 mm produced 2.11 shoots and 2.11 roots per embryo at 60 days of culture.