PHYSIOLOGY 



285 



Table VII. Percentage of normal assimilation reattained 



Pelvetia canaliculata 



70-80% 8-9 hours after ist tide; exposed for 11 days 

 previously 

 Fucus spiralis (and F. 49 % 8-9 hours after ist tide; ^4 hours after 



platycarpus) 

 Fucus vesiculosus 



Fucus serratus 

 Laminaria digital a 



3 days' exposure previously 97 % 

 20% 8-9 hours after ist tide; 



3 days' exposure previously 72% 

 Cannot tolerate 3 days' ex- 

 posure 42 % ^ 



Cannot tolerate 1-2 hours' exposure 



flooding; ex- 

 posed 5 hours 

 previously in 

 air dryness 

 10% of max., 

 or 90 % R.H. 



u 



a 



a 



ei 



o 

 o 



s 



u 

 u 



0) 



o 

 o 



to 



- fucui 3Crra.tu.i7 - ciou.d 

 - ' -^unLLSht 



—Fucui /bUitLfCArbus-cLoud. 



— " '■ -Sunligkt 



B 



7 8 g^^o^Rs 



12 

 10 

 8 

 6 

 4 

 2 



~1 

 -3 



A-6&Lm.iLa.tion curoe - Fucm 

 ■Sc rrdfus . /-S, 000 ca.ndU jboocr 



10 



Tern/b. - 

 20 



^e.5>bLrd.iion, curue^ 



30°C 



Fig. 183. A, water loss, and B, assimilation in relation to exposure (drying) on 

 sunny and cloudy days. C, D, effect of temperature on respiration and assimila- 

 tion of Fucus. Investigational period for assimilation, 5 min.; for respiration, 

 18 min. (After Stocker and Holdheide.) 



