changes affecting germination when compared to our earlier results (8). Methods used were described previously (8), with the exception that the seeds were planted in 125-ml flasks containing a disc of 5.5 cm, Whatman No. 2 filter paper, and 1.5 ml water. Germination cabinets were held at + 1°C of the indicated temperature. Flasks were sealed with rubber serum stoppers through which an amount of ethylene in I ml of a stock preparation could be injected to achieve the desired concentration. Venting of the flask (to release ethylene) was accomplished by a brief aeration and substitution of a loose-fitting aluminum sheet over the flask mouth in place of the rubber stopper. Typically, seeds were imbibed in darkness for 3 days at 25°C, exposed to unfiltered fluorescent light (60 ,uE m-2 s-') for 12 h in a growth chamber held at 25°C, and germinated in darkness at 25°C for an additional 5 days. Light-proof plywood boxes provided darkness. All manipulations during an experiment were done in a 20°C darkroom provided with a dim-green safelight. An experimental treatment consisted of two flasks of 100 seeds each. Each experiment was repeated one or more times. Germination means of all experiments ± SE are presented. RESULTSThe Pfr-stimulated germination of P. norvegica seeds was reduced about one-half by 0.2 pl/l ethylene supplied continuously from planting (Fig.

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As already reported in the previous papersl. ~~ , the germination of seed in Eragrostis ferruginea is induced by the sequence of inductive dark followed by inductive light treatments, and moreover it is inhibited or promoted by the red light applied at different stages in germination process. In experiments preliminarily made by the present authors, it was observed that the germination of seed is also affected by kinetin (6-f urf uryl-aminopurine). According to other workers3' 4) , the presence of kinetin remarkably enhanced the germination of some light-sensitive seeds when they were subjected to short exposure to red light, the exposure alone being insufficient for the promotion of germination. Thus, it is surmized that kinetin would have some additional effects on the action of red light for germination of Eragrostis seed. In plant physiological sense, no profound role of kinetin has been shown inn detail, and hence, interdependence between kinetin and red light in seed germinationn remains quite obscure. The present experiment has been planned in order to throw some light on this interesting problem by the use of several Purine and pyrimidine derivatives in germination of Eragrostis seeds.