Page 5 - Buia&al2001

Morpho-chronology ofPosidonia oceanica seedlings 603

1.2

F avi g n a n a

1.0

] .sE
UJ 0.8
UJ
Q)
c
-u""
5Q) 0.6

~

Ul

0 .4

0 .2 876 43 a
14 13 12 11 10 9 Scale rank
o
1.2

Ustica

1.0

.Es

UJ 0.8

UJ
Q)

c
-u""
~
Q) 0.6

~

Ul

0.4

b

0.2

20 18 16 14 12 10 8 6 4 2 o

Scale rank

Fig. l - Mean trend of scale thickness in juvenile shoots of P oceanica collected at Favignana (a) and
at Ustica (b).

Andamento della media dello spessore delle scaglie nelle piante giovanili di P. oceanica raccolte a
Favignana (a) e ad Ustica (b).

A common trend in scale thickness was observed in shoots collected at Favignana
and at Ustica, the values of which were mediated and shown in Fig. l. The 1-year-old
shoots at Favignana showed quite constant values, and a clear increase in the last 4-5
scales. The 2-years-old shoots at Ustica showed a more typical cyclic trend with higher
differences between minimum and maximum values. The different pattern between
the two groups of plants can be attributed to shoot age. Scale thickness in younger
plants may be more affected by internai factors, therefore no large thickness variation
was observed. The pattern observed in 2-years-old shoots could be interpreted as the
beginning of the typical annua! cycle, and probably more dependent on environmental
factors.