This study was carried out to clarify the morphological characters of germinating seeds, and determine the optimal concentration of hydrogen-ion, sucrose, NAA and kinetin added to basal medium for seed germination and subsequent growth of seedlings derived from nonsymbiotic culture of Laelia briegeri seeds which-elapsed 240 days after artificial pollination.
The results are as follows.
I. In the early stage of seed culture, cell division and enlargement occurred concurrently within swollen seeds by absorbing water, and then became a protocorm-like body containing chlorophyll in a 4 or 6 weeks of culture. The occurrence of primitive leaf end shoot primordia in the formed protocorm-like body was originated in the cells undergoing periclinal division is 2 or 3-layered epidermis
2. Percentage of seed germination was enhanced by Murashige-Skoog and Knudson C and Hyponex medium in turn. But the subsequent growth of germinated seeds and chlorophyll content were increased in the Knudson C and Hyponex medium.
3. The optimum pH value for satisfactory germination and growth was 5.0 in the Knudson C medium. The pH value of the culture medium dropped from an initial pH value of 4.0∼7.0 to 4.1∼4.6 after 6 months of culture. So initial pH value of culture medium was more critical factor for germination and subsequent growth of seedlings.
4. Percentage cf seed germination was decreased by increasing sucrose concentration from 2 to 4% in the culture medium, whereas chlorophyll content of seedlings and hydrogen-ion concentration of culture medium with time were increased. The optimal concentration of sucrose for the growth of seedlings ranged from 3 to 4%.
5. Supplementation of NAA and kinetin was not effective for seed germination compared with control. But fresh weight of seedling and chlorophyll content were increased most effectively on the culture medium containing 2.0㎎/ℓ NAA, 1.0㎎/ℓ NAA and 0.01㎎/ℓ kinetin in combinations.
6. Seed germination of Laelia briegeri was promoted under light condition.
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