title: The avoidance and aggregative movements of mesophyll chloroplasts in C(4) monocots in response to blue light and abscisic acid.
abstract: In C(4) plants, mesophyll (M) chloroplasts are randomly distributed along the cell walls, whereas bundle sheath chloroplasts are located in either a centripetal or centrifugal position. It was reported previously that only M chloroplasts aggregatively redistribute to the bundle sheath side in response to extremely strong light or environmental stresses. The aggregative movement of M chloroplasts is also induced in a light-dependent fashion upon incubation with abscisic acid (ABA). The involvement of reactive oxygen species (ROS) and red/blue light in the aggregative movement of M chloroplasts are examined here in two distinct subtypes of C(4) plants, finger millet and maize. Exogenously applied hydrogen peroxide or ROS scavengers could not change the response patterns of M chloroplast movement to light and ABA. Blue light irradiation essentially induced the rearrangement of M chloroplasts along the sides of anticlinal walls, parallel to the direction of the incident light, which is analogous to the avoidance movement of C(3) chloroplasts. In the presence of ABA, most of the M chloroplasts showed the aggregative movement in response to blue light but not red light. Together these results suggest that ROS are not involved in signal transduction for the aggregative movement, and ABA can shift the blue light-induced avoidance movement of C(4)-M chloroplasts to the aggregative movement.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601 Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Maai
authors.forename: Shouu
authors.initials: S
authors.lastname: Shimada
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamada
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Sugiyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyake
authors.forename: Mitsutaka
authors.initials: M
authors.lastname: Taniguchi
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D002736:Chloroplasts / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D031748:Eleusine / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects / Q000648:ultrastructure; D001467:Hordeum / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D008027:Light; D058503:Mesophyll Cells / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D009068:Movement / Q000187:drug effects / Q000528:radiation effects; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000502:physiology / Q000528:radiation effects / Q000648:ultrastructure; D006109:Poaceae / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects* / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D013997:Time Factors; D003313:Zea mays / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects / Q000648:ultrastructure
chemical_list: D010937:Plant Growth Regulators; D017382:Reactive Oxygen Species; D000040:Abscisic Acid; D006861:Hydrogen Peroxide