Inhibition of bulb development in Allium wakegi Araki under a high red/far-red photon ratio.

摘要

In spring 1994 and Summer 1995, field experiments were conducted in at Ano, Mie, Honshu, Japan. Plants were covered with 3 types of acrylic resin: (1) a normal clear resin with a piece of white cheesecloth (control); (2) a resin with low transmittance of red light (R); and (3) a resin with low transmittance in the far-red (FR) region. The R:FR (660±5:730±5 nm) photon flux density ratios in the control, R-intercepted, and FR-intercepted devices under natural light were 1.00, 0.53 and 1.73, respectively. In both experiments, the FR-intercepted treatment increased bulb fresh weight, bulb dry matter percentage, and bulbing index (maximum diameter:neck diameter of a bulb). In the summer experiment, the plants in the FR-intercepted treatment did not develop scaly leaves which were formed by all plants in the other treatments. It is suggested that bulb development of A. wakegi was inhibited under the high R:FR photon ratios, and that this effect was more obvious in the summer than in the spring experiments. Plants under low R:FR photon ratios produced bulbs similar to the controls.