Ms. Vanpatten et C. Yarish, ALLOCATION OF BLADE SURFACE TO REPRODUCTION IN LAMINARIA-LONGICRURIS OF LONG-ISLAND-SOUND (USA), Hydrobiologia, 261, 1993, pp. 173-181
Sorus formation in the kelp Laminaria longicruris de la Pylaie (Phaeop
hyta) was quantified for a biennial population in Long Island Sound (C
onnecticut, USA), at the southern limit of its biogeographical range i
n the Western Atlantic Ocean. The allocation of blade surface to repro
duction was measured monthly during two years, with additional samples
taken at times of peak growth and reproduction. Sporophytes produced
sori year-round, with the highest percentages of fertile plants (75 to
95 percent) occurring from October to December. The mean percentage o
f sorus area to blade ranged from 1 to 37 percent, remaining low and f
airly constant during the spring and summer, but reaching much higher
levels in the fall (when growth is minimal) and early winter. The comp
aratively low mean annual allocation of blade surface to reproduction
(5 percent), was postulated to be due to temperature stress on these p
lants at the southern limit of distribution, but may instead be typica
l of the species. Such a small allocation of resources to reproduction
nevertheless results in billions of spores per M2 of substrate, makin
g a major contribution of material potentially available to grazing fo
od webs.