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The Role of the Cytoskeleton and Dictyosome Activity in the Pulsatory Growth of Nicotiana tabacum and Petunia hybrida Pollen Tubes
Author(s) -
Geitmann Anja,
Li Yi Qin,
Cresti M.
Publication year - 1996
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1996.tb00549.x
Subject(s) - pollen tube , biology , brefeldin a , tip growth , elongation , pollen , nicotiana tabacum , cytoskeleton , botany , turgor pressure , biophysics , microtubule , microbiology and biotechnology , golgi apparatus , pollination , endoplasmic reticulum , cell , biochemistry , materials science , ultimate tensile strength , gene , metallurgy
Pollen tubes of Nicotiana tabacum and Petunia hybrida show pulsatory growth. Phases of slow growth lasting minutes are interrupted by pulse‐like elongations lasting 10–20 seconds involving an increase of growth rate by up to 24‐fold. Inhibition of dictyosome activity with brefeldin A or monensin did not result in an inhibition of pulsatory growth but eventually stopped pollen tube elongation. In contrast to this the inhibition of the cytoskeletal elements with cytochalasin D and colchicine caused the pollen tubes to abandon the pulse‐like elongations. It was concluded that the activity of the dictyosomes does not have a controlling function in the mechanism of pulsatory growth, even though it is necessary for pollen tube elongation, since cell wall material is provided by secretory vesicles deriving from the Golgi apparatus. In contrast the cytoskeletal elements, actin and microtubules, seem to play an important regulatory role in the pulse‐like elongations. In addition, it was observed that during the experiments several pollen tubes burst upon the completion of a pulse‐like expansion, indicating on the one hand that the internal turgor is the driving force of the pulse‐like expansions. On the other hand, the bursting shows that the pollen tube cell wall is rather weak at the end of a pulse, indicating that at this point of time it is either thinner or less stable than during the slow growth phase or at the beginning of a pulse.