ISSN:
1432-2145
Keywords:
Pollen tube
;
Organelle, vegetative nucleus and generative cell movement
;
Microfilament bundles
;
Cytochalasin effects
;
Iris spp
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Cytochalasins B and D in the concentration range 0.5–10 μg ml−1 produced similar effects on growth, movement and cytoplasmic structure in the pollen tubes of Iris spp. cultured in vitro. Continuous video recording showed that at 5 μg ml−1, CB was capable of stopping organelle circulation in as short a period as 20 s. The usually elongated vegetative nuclei were also arrested, and subsequently contracted irregularly. Generative cells were not radically changed in shape, but occasionally moved erratically before being halted. Detailed examination of CD- and CB-treated tubes regarded as being capable of recovering growth upon transfer to normal medium revealed several characteristic effects on cytoplasmic structure. Fibrils presumed to consist of, or contain, microfilament bundles are readily visible in the older parts of the living tube where they form the pathways of organelle movement; these were either condensed into amorphous columns or fragmented by treatment. In the distal parts of the tube, the cytoplasm had contracted into amorphous masses which continued to show very slow shape changes. With the arrest of extension growth, pectin accumulated over the tube tip and in patches along the flanks. In a medium containing 1 mM ATP, recovery from treatment was achieved in some instances within l min. Organelle circulation in the younger tubes was resumed, and fresh adventive tube tips were formed. The fibrillar system of the older tubes was not restored, however; instead, the cytoplasm in these zones formed aggregates which underwent continuous amoeboid movement, the organelles within moving rapidly in irregular trajectories with no indication of the resumption of the original long-range cyclotic flux. Some possible implications of the results are briefly discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00190116
Permalink
