Inhibition of maize primary root elongation by spermidine: Effect on cell shape and mitotic index
✍ Scribed by M. de Agazio; S. Grego; A. Ciofi-Luzzatto; E. Rea; M. L. Zaccaria; R. Federico
- Publisher
- Springer
- Year
- 1995
- Tongue
- English
- Weight
- 846 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0721-7595
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✦ Synopsis
Spermidine applied for 18 h to intact maize seedlings through their roots reduces root growth 70%, and the effect is reversible. Histological observations of longitudinal sections of 0.4-cm root apical segments from 2-day-old maize seedlings grown for 18 h in 0.5 mM CaSO4 solution with or without 1 mM spermidine contribute to the explanation of spermidine-dependent slow root growth. In the meristematic zone a strong reduction of the mitotic index and in the elongation zone an inhibition of cell elongation occur simultaneously. Cell shape analysis along the growth axis of the maize root apex expressed in terms of form factor (FCircle) values substantiates the dual effect of spermidine on mitotic activity and cell elongation.
Polyamines (PA) are organic polycations distributed widely in all living cells. Their involvement in various cell functions such as cell division, growth and differentiation, fruit ripening, senescence inhibition, and embryo formation has been recognized, but their basic mechanism of action has not yet been established (Smith 1985, Altmann 1989). Although high levels of PA are generally related to cell-division and other plant growth and development processes, recently some inhibitory effects of exogenously applied PA have been described. Among them are the reversible inhibition of maize root elongation after PA pretreatment (Gatta et al. 1992, de Agazio et al. 1992), the growth enhancement of soybean roots as a consequence of PA biosynthesis inhibition (Garmanik and Frydman 1991),