A Method of Increasing the Rate of Seed Germination of Taraxacum Kok-saghyz.

The germination of kok-saghyz seed is a gradual process, the first seedlings pushing through in a few days, the rest appearing successively during a period of several weeks. Obviously, surface soil moisture must be maintained high throughout this period if a good stand is to be established, especially since the seeds are small and have to be sown very shallow. Since such ideal conditions seldom prevail, and since the long drawn out germination period is highly conducive to damping off, poor stands are frequently obtained. Some means of speeding up the process of germination is therefore desirable. In view of the rapid appearance of the first few seedlings, and in the absence of hard seed coats, a plausible explanation of the tardiness of the remaining seeds is that they are not fully mature, i.e., their physiological and perhaps morphological development was not completed when they were harvested. The aim of this investigation was to find some way to mature these seeds before sowing them. This should be possible by increasing the moisture content of the seeds sufficiently to permit the necessary physiological changes, but insufficiently to permit germination. It should then be possible to dry the seeds so that they can be sown in the usual way. The two recommended methods (presoaking and vernalization) wittingly or unwittingly make use of this principle. The former, however, permits some germination, and in both cases the seeds are sown wet. Consequently injury sometimes results. Furthermore, it is difficult to obtain uniformity in water uptake by these methods. Some better procedure must therefore be sought. In the following investigation, unless otherwise stated, each value for germination is an average of three Petri plates containing 100 seeds per plate. The seeds were sown on a piece of filter paper which covered the bottom of the plate, and were supplied with 5 ml. of water. Since temperature was not controlled (except when stated), individual experiments cannot be compared directly with each other. The amount of water absorbed by the seeds can be accurately controlled by permitting the seeds to come to equilibrium with a solution of known concentration. Seeds were therefore soaked in dextrose solutions of different concentrations, rinsed with water, dried for about 8 hours, and sown. The stimulation was distinct and none of the seeds were injured by the treatment 1 The seeds used in this investigation were obtained from the U.S.D.A.