Pii: S0031-9422(96)00869-2

-Short-chain saturated fatty acids (SCSFA), ranging from pentanoic (C5) to decanoic acid (C~0), when added at micromolar concentrations to the germination medium of chick-pea seeds, did not significantly affect radicle emergence, although fresh weight diminished. Only heptanoic acid (C7) and octanoic acid (Cs) stimulated ethylene production and free spermidine and spermine content, whereas putrescine reached a maximum with nonanoic acid (C9). All the SCSFA tested increased the polyamines (PAs) bound to substances of low Mr; however, only hexanoic acid (C6) and C9 acid induced a strong appearance of PAs bound to substances of high Mr. Proline synthesis was stimulated in the presence of C7 acid and C9 acid, but values lower than control were obtained with the other SCSFA studied. (C 1997 Elsevier Science Ltd. All rights reserved I N T R O D U C T I O N Short-chain saturated fatty acids (SCSFA) ranging in chain length from 6 to 10 are known to be synthesized during senescence in some plants by the acetate pathway [1]. For example, in petunia and carnation flowers, these acids are synthesized in the styles [1, 2]. In the columns and perianths of orchid flowers, SCSFA increased following pollination, the C8 acid being the main SCSFA found [3]. In addition, such acids have been detected in the endosperm, cotyledons and embryonic axes of some dry [4], or in the hull and pericarp during maturation of some dormant seeds [5, 6]. The mechanism of action of SCSFA is still unknown, but little doubt remains that they contribute to membrane fluidity and permeability [7, 8]; in addition, the sensitivity of various plant tissues of ethylene increases as a result of SCSFA incorporation into the lipid bilayer of cell membranes and subsequent alteration of the lipid order [3, 9, 10]. We have found that the phytohormone, ethylene, is involved in controlling the germination of Cicer arietinum seeds by accelerating radicle emergence [11, 12]. Thermoinhibition in this seed is alleviated by exogenous ethylene [13], inhibition ofpolyamine (PA) biosynthesis [14] and exogenous putrescine (Put) [15]. * Author to whom correspondence should be addressed. 61 Since ethylene and polyamines (PAs) arise from the same precursor, S-adenosyl methionine (SAM), it has been suggested that ethylene and aliphatic PA formation impose competitive demands on this precursor and that allocation of SAM to either pathway may constitute a regulation point in ethylene and PA biosynthesis [16]. The mechanism by which PAs influence growth and development, however, is not yet known [16, 17]. In the present paper, we describe the changes in the levels of free and bound PAs, osmoregulating proline and ethylene production in embryonic axes of chickpea seeds induced to grow in the presence of SCSFA