Studies on Sterility in Lower Spikelets of Barley : Part IV. Relation between development of spikelets and top-dressing of nitrogen fertilizers at the stage of flag-leaf emergence.

摘要

The authors reported in the previous paper that sterility in the top and lower parts of spikelets of barley is caused by nutritious impedements at the stage of flag-leaf emergence, and top-dressing of nitrogen fertilizers at that stage has good effects upon preventing from sterility. In this paper the effect of nitrogen fertilizer is studied in detail. 1. Development of spikelets, as indicated by the growth of palea and lemma, length of anther, length and wide of ovary, in top and lower parts of ears is later than the mid-ear spikelets capable of ripening: and even at the time of heading the floral organs do not attain the normal stage of growth and consequently impossible to seminating. Whereas, top-dressing of nitrogen at the stage of flag-leaf emergence accelerates growth of spikelets, and those spikelets that are likely to be degenerated can grow at the heading time in the same way as the normal spikelets, so that ripening is assured. 2. Any spikelet capable of ripening has a palea grown more than 8 mm at the heading time. A pistile and stamen of any spikelets having a palea of more than 8 mm, are ovserved to have seminiferous ability. Meanwhile in those spikelets with a palea of less than 8 mm, some abnormalities are seen such as looking of pollen in the anther, underdeveloped pollen, or underdeveloped stigma of pistile. 3. Growth of palea in length corresponds to growth of floral organs. Palea of normal spikelets is more than 8 mm at the heading time, and it was more than 5 mm at the stage of flag-leaf emergence. However Top-dressing of nitrogen at the flag-leaf emergence is effective to accelerated the growth, of underdeveloped spikelets having palea of about 5 mm and the length of palea can reach more than 8 mm when the heading time.