Studies on the Morphogenesis of Crop Plants under Different Growing Conditions : II. The Formation of Lateral Buds in Rice and Wheat Plants

These experiments were carried out to examine the formation of lateral buds in rice and wheat plants, and also to find its relationships to the leaf development on the main stem. In rice plants, when the base of a leaf margin grows as far as the opposite side of the shoot apex, the lateral bud primordium first appears at its outer position. The primordium is recognized by the repeated periclinal divisions of the inner cells. The bud primordium thus formed remains in the same state until the adjacent upper leaf begins to emerge from the adjacent lower leaf sheath, when the bud primordium suddenly grows up and forms a prophyll. In wheat plants, the same phenomena were observed, in spite of the conspicuous changes in the number of leaf primordia involved in the apical bud. All these phenomena were found in every leaf bases observed except in the first and the second leaf bases of rice plants. At the first leaf base, the lateral bud primordium is first observed, but it does not grow any more and degenerates. At the second leaf base, the primordium develops, but sometimes it fails to form a prophyll and becomes a parenchymatous protuberance. In rice plants, neither the amounts of nitrogen fertilizer applied nor the plant spacings were effective on the formation of lateral buds mentioned above