Köhler D, Willert K V, Lüttge U
Botanisches Institut der Technischen Hochschule Darmstadt, Darmstadt, Deutschland.
Planta. 1968 Mar;83(1):35-48. doi: 10.1007/BF00385133.
Inhibition of internodial growth of pea seedlings by light is compensated for by increased growth of leaves. At a given time the sum of fresh weight of internodes plus the product of fresh weight of leaves times a certain factor is constant in darkness or with different periods of light. This correlation may reflect a competition of internodes and leaves for materials delivered at a lightindependent rate from the cotyledons. This hypothesis was tested by immersing roots of pea seedlings into (86)Rb labelled K-solutions for one day in darkness, removing the plants from the solutions, exposing the seedlings to near or far red light and measuring the radioactivity and fresh weights of leaves and internodes separately. Radioactivity and fresh-weight were both dependent on phytochrome; i.e. inhibition of ion uptake and of growth in internodes and promotion of both processes in leaves by near red light as compared to dark or far red controls are mediated by phytochrome.Short time experiments of ion uptake by the roots show that K transport into the shoot organs is promoted by light after a lag phase of somewhat more than one hour. This interval corresponds well to the lag phase of the light induced growth inhibition of internodes.Seedlings deprived of cotyledons and roots grow well in water but exhibit no difference in growth rate of leaves and internodes in light and darkness. Light dependence is restored if the seedlings are submersed in approximately 3% sucrose solutions. This result seems to indicate that the influence of light on growth rates of leaves and internodes is dependent on the uptake of material by the cell. It seems possible that in the etiolated pea seedling light promotes growth of leaves by promoting uptake and hampers growth of internodes by inhibiting uptake of essential growth material delivered from the cotyledons.
光照对豌豆幼苗节间生长的抑制作用可通过叶片生长的增加得到补偿。在给定时间，黑暗中或不同光照时长下，节间鲜重与叶片鲜重乘以某一因子的乘积之和是恒定的。这种相关性可能反映了节间和叶片对来自子叶的以与光照无关的速率输送的物质的竞争。通过将豌豆幼苗的根浸入含（86）Rb的钾溶液中黑暗处理一天，然后将植株从溶液中取出，将幼苗置于近红光或远红光下，并分别测量叶片和节间的放射性及鲜重，对这一假设进行了检验。放射性和鲜重均依赖于光敏色素；即与黑暗或远红光对照相比，近红光对离子吸收以及节间生长的抑制作用和对叶片中这两个过程的促进作用均由光敏色素介导。根部离子吸收的短期实验表明，在略超过一小时的延迟期后，光照促进钾向地上器官的运输。这一间隔与光照诱导的节间生长抑制的延迟期非常吻合。去除子叶和根的幼苗在水中生长良好，但在光照和黑暗条件下叶片和节间的生长速率没有差异。如果将幼苗浸入约3%的蔗糖溶液中，则恢复了对光照的依赖性。这一结果似乎表明，光照对叶片和节间生长速率的影响取决于细胞对物质的吸收。在黄化豌豆幼苗中，光照似乎通过促进吸收来促进叶片生长，并通过抑制从子叶输送的必需生长物质的吸收来阻碍节间生长。
