Page 3 - Gambi_Guidetti_1998

, W ~ ~ r u l i i > loof ~P~o~sidonia oceanica .ru<.~llin~s 55 l

Table 1 - Mean values i standard deviations of morphological parameters and leaf biomass
of the analyzed P. oceanica seedlings (N= 20).

Medie Ideviazioni standard del parametri morfologici e dello biomosso fogliore dei
germogli di P oceonico analizzati [N- 20).

I I

Parameters

leaf length (cm) 9.5 I5.9
length of the longest leaf (cm)
leaf width (cm) 48 I
leaf number per shoot
adult leaves (%) 26.1 I 5.5 1
intermediate leaves (%) 6.0 i 2.9 1
young leaves (%) 132.4 i 56.6
leaves with broken apex (%)

I leaves with brown tissue (%)

scales number per shoot
scars number per shoot

1 total number of leaves produced per shoot after germination

II secondary root number
Ieaf biomass (mg d.w. per shoot)

(Cooper, 1979; Caye and Meinesz, 1989; Bedini et al., 1997), and "in situ" (Buia
and Piraino, 1989; Gambi et al., 1996; Piazzi et al., 1996 b). Caye (1989), in
13 months old seedlings cultured in natura1 sea water, observed in June a total
mean production of 22 leaves. This comparison suggests that the seedlings recorded
at Favignana are at least one year old and derived from seeds settled in late spring
or early summer 1994 and produced by a flowering in the autumn-winter of the
previous year. Literature information on the P. ocennica beds of the Western coast
of Sicily (Calvo et a1.,1995) and of the areas around the Egadi Archipelago
(Giaccone and Sortino, 1974). confirm that in these zones flowering and fruiting
are quite regular and diffuse phenomena, and that a conspicuous fruiting has been
recorded just in 1994 (Calvo et al., 1995). Furthermore, a previous record of a
P. oceanica seedling has been observed by Buia and Piraino (1989) in the
Marettimo Island (Egadi), near Favignana. In May 1995 decaying pericarps of P.
oceanica fruits have been observed floating in the harbour of Favignana (Gambi
M.C., pers. observ.), and in June of the same year further P. oceanica seedlings
were found at Cala Rotonda (Badalamenti F., pers. comm.). These findings
demonstrate once more the regular flowering events and a high sexual reproductive
effort of P. oceanica beds occurring in this zone. Following time evolution of
P. oceanica seedlings settled in the area, it should be extremely important to
evaluate the actual sexual reproductive success of the species, and the potential
formation of new meadow patches by its offsprings.

Acknowledgements

We wish to thank Dr Buia M.C. and Dr Acunto S. for the useful advices,
Dr Mazzella L. for the critica1 comments on the manuscript, and Dr Bussotti S.
for help in data collection.