抄録
The seedlings from Cannabis saliva L. seeds irradiated with different doses of γ-rays were examined, in order to determine the dose sufficient to kill the young plants naturally, before their hallucinnogenic component increases. The seeds of "Minamioshihara No.1", which were harvested in 1972 in Tochigi Prefecture, were irradiated with eight different doses of 60Coγ-rays on January 17, 1973, and the seedlings were examined sevefal times during subsequent 9 months, from March to November, 1973, and their morphological and histological effect were examined, and the results are summarized as follows : 1) Morphological Effects Samples irradiated with 1500 and 1000 krads developed radicles about 3 mm in length. Samples irradiated with 500, 200, and 50 krads grew into young plants with the first set of leaves, without lateral roots. Samples irradiated with 30 krads grew to about 10 cm high with a few lateral roots, and the epicotyls about 1 cm in length. These young plants from the irradiated seeds stayed in the same condition and then died. Samples irradiated with 15 and 5 krads grew in the same way as control until the stage of flowering. 2) Histological Effects Samples irradiated with 500, 200, 50, and 30 krads showed cell membranes of endodermis and pericycle to be partially lignified and suberized. The degree of changes was related to the dose of γ-rays. Samples irradiated with 30 krads showed withered cells near the end of the lateral nerves on the first and second sets of leaves. 3) Economical dose of 60Co γ-rays for inhibiting young plants from developing into adult ones was a minimum of 30 krads which made the young plants die. Irradiation with 50 krads of γ-rays will be required to kill the young plants completely before they develope hallucinogenic component.
