High-voltage electron microscopy of whole, critical-point dried plant cells

Cox, Guy; Hawes, Chris; Lubbe, L. van der; Juniper, B. E.

doi:10.1007/bf01273727

Cited by 19 publications

(5 citation statements)

References 17 publications

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“…At present we have no information about the putative mechanism for anchoring chloroplasts on the P side. Spatial changes in the organization of the microfilaments have been suggested to function in the light-induced anchoring of chloroplasts in Vaucheria , Selaginella (Cox et al 1987), and Adiantum (Kadota and Wada 1992a). In the present material, however, the ability of red light to cause anchoring of chloroplasts on the P side seems to be intact even in the presence of cytochalasin B (Izutani et al 1990;Takagi et al 1991).…”

Section: Discussioncontrasting

confidence: 63%

Regulation of the orientation movement of chloroplasts in epidermal cells of Vallisneria: cooperation of phytochrome with photosynthetic pigment under low-fluence-rate light

Dong

Takagi

1995

Planta

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Abstract. In epidermal cells of the leaves of the aquaticangiosperm Vallisneria gigantea Graebner, the chloroplasts accumulate in the outer periclinal layer of cytoplasm (P side) under light at low fluence rates. The nature of such intracellular orientation of chloroplasts was investigated in a semiquantitative manner. Time-lapse video microscopy revealed that, while irradiation with red light (650 nm, 0.41 W" m-2) rapidly accelerated the migration of chloroplasts, not only from the anticlinal layers of cytoplasm (A sides) to the P side but also from the P side to the A sides, the increased rate of migration in both directions returned to the control rate upon subsequent irradiation with far-red light (746nm, 0.14W.m-2). These effects of red and far-red light could be observed repeatedly, both in the presence and in the absence of inhibitors of photosynthesis, suggesting the involvement of phytochrome as the photoreceptor. After saturating irradiation with red light, the increased rate of migration of chloroplasts from the P side to the A sides declined more rapidly than the increased rate of migration in the opposite direction. This imbalance in the migration of chloroplasts between the two opposing directions resulted in the accumulation of chloroplasts on the P side. The more rapid decline in the rate of migration of chloroplasts from the P side to the A sides than in the opposite direction was not observed in the presence of an inhibitor of photosynthesis. It appears, therefore, that phytochrome and photosynthetic pigment cooperatively regulate the accumulation of chloroplasts on the P side through modulation of the nature of the movement of the chloroplasts.Abbreviations: A side = cytoplasmic layer that faces the anticlinal wall; DCMU = 3-(3,4-dichlorophenyl)-l,l-dimethylurea; Pfr = farred-light-absorbing form of phytochrome; Pr = red-light-absorbing form of phytochrome; P side = cytoplasmic layer that faces the outer periclinal wall Correspondence to: S. Takagi; FAX: 81 (6) 850 5817; Tel: 81 (6) 850 5818

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Section: Discussioncontrasting

confidence: 63%

Regulation of the orientation movement of chloroplasts in epidermal cells of Vallisneria: cooperation of phytochrome with photosynthetic pigment under low-fluence-rate light

Dong

Takagi

1995

Planta

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“…Circular F-actin structures formed around the chloroplast accumulate at their endocellular destination and these structures disappeared in darkness (Kadota and Wada, 1992). Spatial changes in the organization of F-actin was suggested for chloroplast positioning in diverse plant systems (Cox et al, 1987;Grolig and Wagner, 1988;Menzel and Elsner-Menzel, 1989;Kadota and Wada, 1992;Dong et al, 1996). An intriguing possibility is that the actin cytoskeleton is responsible not only for moving of chloroplasts, but also for their clustering and anchoring at distinct subcellular domains, typically at the cell periphery (e.g., Witztum and Parthasarathy, 1985;Dong et al, 1998).…”

Section: Chloroplast Positioning By Lightmentioning

confidence: 99%

Actin cytoskeleton in plants: From transport networks to signaling networks

Volkmann

Baluška

1999

Microsc. Res. Tech.

144

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The plant actin cytoskeleton is characterized by a high diversity in regard to gene families, isoforms, and degree of polymerization. In addition to the most abundant F‐actin assemblies like filaments and their bundles, G‐actin obviously assembles in the form of actin oligomers composed of a few actin molecules which can be extensively cross‐linked into complex dynamic meshworks. The role of the actomyosin complex as a force generating system — based on principles operating as in muscle cells — is clearly established for long‐range mass transport in large algal cells and specialized cell types of higher plants. Extended F‐actin networks, mainly composed of F‐actin bundles, are the structural basis for this cytoplasmic streaming of high velocities On the other hand, evidence is accumulating that delicate meshworks built of short F‐actin oligomers are critical for events occurring at the plasma membrane, e.g., actin interventions into activities of ion channels and hormone carriers, signaling pathways based on phospholipids, and exo‐ and endocytotic processes. These unique F‐actin arrays, constructed by polymerization‐depolymerization processes propelled via synergistic actions of actin‐binding proteins such as profilin and actin depolymerizing factor (ADF)/cofilin are supposed to be engaged in diverse aspects of plant morphogenesis. Finally, rapid rearrangements of F‐actin meshworks interconnecting endocellular membranes turn out to be especially important for perception‐signaling purposes of plant cells, e.g., in association with guard cell movements, mechano‐ and gravity‐sensing, plant host–pathogen interactions, and wound‐healing. Microsc. Res. Tech. 47:135–154, 1999. © 1999 Wiley‐Liss, Inc.

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“…The light-induced spatial reorganization of actin filaments has been shown to occur concomitantly with redistribution of chloroplasts in several species. Specific structures and arrangements of actin appeared in weak/strong light in algae [Vaucheria (Blatt and Briggs, 1980), Caulerpa (Menzel and Elsner-Menzel, 1989) and Mougeotia (Mineyuki et al, 1995)] and ferns [Selaginella (Cox et al, 1987) and Adiantum (Kadota and Wada, 1992)].…”

Section: Introductionmentioning

confidence: 99%