GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A light-dependent current associated with chloroplast aggregation in the alga Vaucheria sessilis (1981)
    Springer
    Planta 152 (1981), S. 513-526 
    Details
    ISSN: 1432-2048
    Keywords: Actin ; Blue light ; Chloroplast aggregation ; Electrical current ; Protons ; Vaucheria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Local irradiation of the alga Vaucheria sessilis (Vauch.) D.C. with blue light, which stimulates cortical fiber reticulation and chloroplast aggregation (M.R. Blatt and W.R. Briggs, 1980, Planta 147, 355–362), also induces an outward-directed current from the irradiated region of the cell. This current appears in conjunction with cortical fiber reticulation and precedes chloroplast aggregation. The current is not photosynthetic in origin, as indicated by experiments with 3(3,4-dichlorophenyl)-1,1-dimethyl urea and carbonyl-cyanide-m-chlorophenylhydrazone (CCCP). It shows a wavelength-dependence similar to that of chloroplast aggregation and reaches a maximum of 500 nA cm-2 with saturating light intensities. The current is not dependent upon the presence of Na+, K+, or Cl- in a test medium containing only Na+, K+, Ca2+, and Cl-, but is inhibited, apparently nonspecifically, in the absence of external calcium. Both the light-induced current and chloroplast aggregation are stimulated by increases in the external KCl concentration and are inhibited by sub-micromolar concentrations of CCCP or by external pHs below approximately 5.5. We suggest that blue light stimulates the local extrusion of cations, possibly of protons, at the plasma membrane, an event which may act to destabilize the cortical fibers in Vaucheria, disrupt cytoplasmic streaming, and eventually lead to organelle aggregation in the light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380822
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Blue light promotes ionic current influx at the growing apex ofVaucheria terrestris (1988)
    Springer
    Planta 173 (1988), S. 490-499 
    Details
    ISSN: 1432-2048
    Keywords: Blue light ; Ionic current ; Light-growth response ; Phototropism (Vaucheria) ; Vaucheria ; Vibrating probe ; Xanthophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Irradiation of the growing apex of the algaVaucheria terrestris Götz var.terrestris with blue light (BL), which causes a transient acceleration of growth, also causes a large transient increase in inwardly directed current, which was monitored with a vibrating probe. The growing apex is normally the site of an inward current, and the surface of the non-growing, basal part of the coenocytic cell the site of an outward current. Irradiation of the apex causes only a slight increase in current efflux at the basal part of the cell. The BL-promoted current influx at the apex (BLCI) usually starts within 10 s after the onset of irradiation, preceding the light-growth response. With BL pulses shorter than 3 min, the BLCI reaches a maximum in about 3 min, and then declines to its original value over the next 3 min. If the BL pulse is longer than 3 min, the BLCI continues until the light is turned off. The threshold energy of the BLCI with broad-band BL is 2–5 J·m-2, i.e. smaller than for both the light-growth response and phototropic response. The maximum BLCI reaches a value of approx. 5 μA·cm-2, equivalent to an influx of 50 pmol·cm-2·s-1 of monovalent cations. The effect of red light (RL) is completely different from that of BL: it either causes increases in the inward current of less than 0.3 μA·cm-2, or a transient decrease of current. Furthermore, the direction of the RL-induced change is always the same at the apex and trunk, indicating the participation of photosynthesis. Our results indicate that the BLCI is kinetically and spatially related to the light-growth response and the phototropic bending ofVaucheria. It seems to be a necessary step for the phototropic bending.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00958962
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...