Light-Induced Transformation of Amyloplasts Into Chloroplasts
Plant Physiol. (1984) 75, 142-145
0032-0889/84/75/0 142/04/$01.00/0
Light-Induced Transformation of Amyloplasts into Chloroplasts in Potato Tubers'
Received for publication November 9, 1983 and in revised form January 19, 1984
YU S. ZHU, DENISE L. MERKLE-LEHMAN, SHAIN D. KUNG*
Department of Biological Sciences, University of Maryland Baltimore County, Catonsville,
Maryland 21228
ABSTRACT
The transformation of amyloplast into chloroplasts in potato (Solawum tuberosum L.) tuber tissue can be induced by light. Excised potato tuber discs illuminated with white light of 3000 lux bepgn to synthesize chlorophyll after a lag period of 1 day, and continued to synthesize chlorophyll for 3 weeks. In this paper we present evidence, based on ultracentrifugal sedimentation and immunoprecipitation, that the lightmediated synthesis of Ribulose-1,5-bisphosphate carboxylase began 1 day after illumination with white light. When illuminated the chloroplasts isolated from light-grown potato tuber tissue incorporated I3SImethionine into polypeptides, one of which has been idenified as the large subunit of Ribulose-1,5-bisphosphate carboxylase. These chloroplasts are functional as determined by 02 evolution in the Hill reaction.
A great deal of data is now available on the biochemistry of the development of chloroplasts from etioplasts (6). Much less is known about the development of chloroplasts from amyloplasts, a starch storing organeile, which exists in storage tissue, roots, and some callus. It is well known that potatoes turn green on exposure to light for several days. Not only does the study of the organelle transformation and light-regulated gene expression stimulate theoretical interest, but the greening of potato also has some practical importance, since the greening of the potato is accompanied by the formation of the poisonous alkaloid, solanine (5). The morphological and ultrastructural changes in the development of chloroplasts from
0032-0889/84/75/0 142/04/$01.00/0
Light-Induced Transformation of Amyloplasts into Chloroplasts in Potato Tubers'
Received for publication November 9, 1983 and in revised form January 19, 1984
YU S. ZHU, DENISE L. MERKLE-LEHMAN, SHAIN D. KUNG*
Department of Biological Sciences, University of Maryland Baltimore County, Catonsville,
Maryland 21228
ABSTRACT
The transformation of amyloplast into chloroplasts in potato (Solawum tuberosum L.) tuber tissue can be induced by light. Excised potato tuber discs illuminated with white light of 3000 lux bepgn to synthesize chlorophyll after a lag period of 1 day, and continued to synthesize chlorophyll for 3 weeks. In this paper we present evidence, based on ultracentrifugal sedimentation and immunoprecipitation, that the lightmediated synthesis of Ribulose-1,5-bisphosphate carboxylase began 1 day after illumination with white light. When illuminated the chloroplasts isolated from light-grown potato tuber tissue incorporated I3SImethionine into polypeptides, one of which has been idenified as the large subunit of Ribulose-1,5-bisphosphate carboxylase. These chloroplasts are functional as determined by 02 evolution in the Hill reaction.
A great deal of data is now available on the biochemistry of the development of chloroplasts from etioplasts (6). Much less is known about the development of chloroplasts from amyloplasts, a starch storing organeile, which exists in storage tissue, roots, and some callus. It is well known that potatoes turn green on exposure to light for several days. Not only does the study of the organelle transformation and light-regulated gene expression stimulate theoretical interest, but the greening of potato also has some practical importance, since the greening of the potato is accompanied by the formation of the poisonous alkaloid, solanine (5). The morphological and ultrastructural changes in the development of chloroplasts from