The application of growth regulators for the physiological emasculation of rye(secale cereale l.) flowers

The present paper deals with the possibility of using growth regulators for the physiological emasculation of rye flowers and utilizes our knowledge of the higher sensibility of stamens to the auxin level. By means of bioassays it has been found that a relatively low content of auxins and a definite level of gibberellins and inhibitors are characteristic for normal rye spikes at the time of stamen differentiation. The higher level of auxins and expressive inhibitions occur in the later course of pistil differentiation. Two sprayings of plants with mixed solutions of MH and NAA and two further sprayings with a solution of NAA only before the stamen differentiation change slightly the natural character of endogenous regulators in spikes and cause the destruction of mother pollen cells in anthers and the sterility of anthers in the majority of rye florets. The anthers in the basis of spikes sometimes contain pollen grains after treatment, but their fertility is substantially lowered because the spray evidently disturbed the accumulation of reserve substances in pollen grains. The development of pistil was not affected by the exogenous application of growth regulators. Normal kernels arose in the majority of flowers after supplementary pollination. Some accidental effects of exogenous application of growth regulators, as for example reduced stem growth and disorder of lodicule function were lowered to a great extent by adding GA_S to the last two sprayings of NAA.