Abstract
For the fundamental studies of radiation breeding in edible marine algae, the biological effects on conchospores of Porphyra species by gamma-irradiation were examined. Two varieties, Keun-cham-gim (Porphyra tenera Kjell. form tamatsuensis Miura) and Saga No.5, were chosen for this study, and their conchospores after r-irradiation($5.0{\sim}20.0$ KR) were cultured for 50 days. The results obtained were summarized as follows. 1. Gamma-irradiation in less than the dose of 20KR did not affect germination of conchospores, and almost all spores grew into two cells germ in 24 hours after irradiation, but withering germs were gradually increased in number according to higher exposure within 5 days old culture. 2. High irradiation caused the induction of giant cells, abnormal useless growth of hold-fast, lumpish thalli and callus-like lumpy tissues. 3. The liberation of neutral spores from young germs and carpospores from mature thalli were observed on the frond exposed at $10{\sim}20$ KR irradiation. All spores were normal in division and its size. 4. The best irradiation effect on growth of Keun-cham-gim was observed at 10 KR dose, whose growth-rates were $140\%$ in wet weight and $108\%$ in mean frond area, but only $48\%$ was recorded in wet weight at 20 KR exposure. Saga No.5 were in contrast with Keun-cham-gim, and their most growth-rate was $400\%$ in wet weight ($258\%$ in frond area) at 10 KR irradiation and the worst was $20\%$ at the dose of 20 KR. 5. The withering phenomenon to death by treatment of gamma-ray presented substantial difference between two varieties. Survival rate compared with control in Keun-cham-gim was $70.7\%$ at 20 KR, but that in Saga No.5 recorded $47.0\%$ at same dose. 6. Synthesizing the results of high and low r-irradiation, it was suggested tat high r-irradiation in more than 5.0 KR inhibited conspicuously the growth of germs derived from conchospores, and about half of them withered at 15.0 KR dose or more.
착생 48시간후의 큰참김과 사가 5호의 각포자에 $5.0{\sim}20.0$ KR범위의 고선량 r-선($^{60}-Co$)을 조사한후 1983년 10월 11일부터 11월 30일까지 (50 일간) ESP배지로 배양하면서 그 생장효과와 기타 생물학적 영향을 조사하였다. 1. 배양 24시간후 각포자는 모두 정상적으로 발아하여 2세포체가 되었으나 배양일수가 경과함에 따라 고사수와 생장의 차가 점증하였다. 특히 5 일째 20KR이 조사된 사가 5호의 유아는 평균 약 3세포체에 머물러 있어 타의 $6{\sim}7$세포체에 비해 현저하게 발육이 부진하였다. 2. 생장은 전반적으로 부진하였으나 큰참김은 10.0KR에서 대조대비 생중량으로 $140\%$, 엽면적으로는 $108\%$가 기록되고 사가 5호는 같은 선양에서 $400\%$(생중양)와 $258\%$(엽면적)의 생장효과를 나타내어 품종간에 유의차를 보였다. 그러나 두품종 공히 15.0 KR이상에서는 생장율이 급격히 저하하여 조해현상이 뚜렷하였다. 3. r-선조재로 인한 고사현상은 15.0KR이상에서 현저하여 큰참김에서는 생잔율이 $76\%$(15.0 KR)와 $71\%$(20.0 KR)였고 사가 5호는 각각 $55.0%$ 와 $47.0\%$ 에 불과하였다. 4. r-선에 의해서 유기되는 이상체현상은 거세포의 출현, 부착기의 이상도장, 괴상의 부정형엽체 및 callus 양의 이상증식조직등이었으며 그 발현율은 15.0 KR 이하의 선양에서는 $1.0\%$ 미만이었으나 20.0KR에서는 $5\%$나 되었다. 5. 조사선양에 관계없이 유아체는 정상적으로 중성포자를 형성방출하며 생잔성엽체는 모두 과포자를 생성하였다. 6. 저선양조사실험결과와 연관해 볼때 5.0 KR 이상의 고선양에서는 생장이 억제되고 15.0 KR 이상에서는 조해현상이 심대하며 생육반감선양으르 추정된다.