Frond Structure and Growth in Laminaria Hyperborea

Abstract

Age, frond weight, frond area, stipe length and other data have been recorded for plants of Laminaria hyperborea growing off the coast of south-west England and southwest Ireland. The ratio of total frond weight to total frond area (unit frond weight) has been found to be related to age, depth, type of community, and water turbulence. Decrease in unit frond weight appears to result from a decrease in the number of cell layers of the frond, which is most marked at the frond tip. At the frond tip differences between the thickest and thinnest fronds may be fivefold or more.It is concluded that water turbulence, particularly wave-action, is an important factor influencing the changes in frond structure. The importance of submarine irradiance as a factor is not clear from the present evidence. An intrinsic factor affecting frond structure may be the age of plants.

Morphological variations of Macrocystis pyrifera in the Falkland Islands in relation to environment and season

“…Similar effects of wave-exposure on lamina density or thickness and form have been recorded for M. integrifolia in British Columbia by Pace (1972) and Druehl (1978). It is generally found that laminae of laminarian algae are narrower (Sundene 1964, Norton 1969, Palmisano and Sheng 1977 and thicker (Norton 1969, Larkum 1972) in more exposed water. Gerard and Mann (1979) found that broad, thin blades of Laminaria longicruris from sheltered areas were three times greater in surface area per unit weight than blades of plants from an exposed site, and concluded that the "thick, narrow blade form seems to result from severe and continuous environmental stress at the expense of surface area for photosynthesis and nutrient uptake".…”

“…became thinner with greater depth, which disagrees with the findings in this study. Larkum (1972), however, stated that water turbulence and not light was the more important factor determining changes in lamina density. This is supported by the records of Kain (1977) of a L.…”

“…has been studied in relation to environmental factors such as water movement (Sundene 1962, 1964, Larkum 1972, Palmisano and Sheng 1977, Gerard and Mann 1979 and depth (John 1970, Larkum 1972. Pace (1972), Druehl (1978) and Druehl and Kemp (1982) studied the morphology of Macrocystis integrifolia from different locations in British Columbia, Kain (1982) investigated the morphology of M. pyriJera in California and New Zealand, and Jackson et al (1985) described the morphology of fronds of M.…”

Photosynthetic light‐response curves and photoinhibition of the deep‐water laminaria abyssalis and the intertidal laminaria digitata (phaeophyceae)

“…Finally, the similar thallus structure may be related to water turbulence, as wave action and currents influence the structure of macroalgal thalli (Larkum 1972). Laminaria digitata is subjected to tidal and wave action and L. abyssalis is subjected to upwelling currents.…”

Zur Entwicklung und funktionellen Anatomie des Phylloids vonLaminaria hyperborea

“…Die Entwicklung des jungen Phylloids beginnt im Winter unter ungiinstigen Licht-und Temperaturbedingungen; dabei schiebt sich das neue Phylloid zwlschen Cauloid und altes Phylloid und w~ichst bis Ende Juni zu seiner maximaten GrSt~e heran. Das alte Phylloid bleibt mit seinem basalen Tell, der nun als Kragen bezeichnet wird, noch einige Zeit mit dem jungen Phylloid verbunden, wird jedoch durch den Wellenschlag sukzessive yon apikal her dezimiert, bis es schtieglich Ende Mai vSllig erodiert ist (LONING 1971, LARKUM 1972 Zur genaueren Lokalisation des Zentrums der Wachstumszone kann die Bildung der Schleimkan~le herangezogen werden: diese entwickeln sich aus schizogen entstandenen Interzellularen zwischen Meristoderm und Rinde (Abb. 8a), und zwar sowohl oberhalb wie unterhalb der Wachstumszone und differenzieren sich einerseits yon der Wachstumszone aus nach apikal, zum anderen nach basal, so dat3 zwischen dem …”