﻿514 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  Since 
  the 
  plants 
  rooted 
  in 
  soil 
  have 
  a 
  larger 
  proportion 
  of 
  ash 
  than 
  

   those 
  anchored, 
  it 
  seems 
  evident 
  that 
  the 
  retarded 
  growth 
  of 
  the 
  

   anchored 
  plants 
  was 
  due 
  to 
  insufficient 
  mineral 
  food 
  rather 
  than 
  to 
  

   inhibited 
  photos3"nthesis. 
  The 
  composition 
  of 
  the 
  ash 
  as 
  determined 
  

   in 
  terms 
  of 
  dry 
  weight 
  is 
  as 
  follows: 
  

  

  Plants 
  

   anchored. 
  

  

  Lime 
  (CaO) 
  , 
  per 
  cent. 
  . 
  1. 
  73 
  2. 
  13 
  

  

  Magnesium 
  oxide 
  ( 
  MgO) 
  do 
  .73 
  1.15 
  

  

  Phosphoric 
  acid 
  (PoOs) 
  do 
  .56 
  .31 
  

  

  Potash 
  (KjO) 
  do.... 
  7.97 
  6.40 
  

  

  It 
  will 
  be 
  noticed 
  that 
  the 
  anchored 
  plants 
  have 
  a 
  smaller 
  propor- 
  

   tion 
  of 
  potash 
  and 
  phosphoric 
  acid. 
  This, 
  together 
  with 
  the 
  diminished 
  

   proportion 
  of 
  protein, 
  strongly 
  indicates 
  that 
  a 
  sufficient 
  suppl}^ 
  of 
  

   nitrogen, 
  potash, 
  and 
  phosphoric 
  acid 
  was 
  not 
  appropriated 
  by 
  the 
  

   anchored 
  plants. 
  

  

  It 
  can 
  not 
  be 
  safely 
  concluded 
  from 
  these 
  results 
  that 
  the 
  lake 
  w^ater 
  

   does 
  not 
  contain 
  nitrogen, 
  potash, 
  and 
  phosphoric 
  acid 
  in 
  sufficient 
  

   proportion 
  for 
  the 
  plants 
  anchored 
  in 
  it 
  to 
  make 
  a 
  normal 
  growth. 
  It 
  

   can 
  be 
  said, 
  however, 
  that 
  either 
  these 
  constituents 
  are 
  not 
  present 
  

   in 
  the 
  lake 
  water 
  in 
  sufficient 
  proportion, 
  or, 
  if 
  the}' 
  are, 
  the 
  condition 
  

   of 
  the 
  plants 
  anchored 
  in 
  the 
  lake 
  water 
  is 
  such 
  that 
  these 
  constituents 
  

   can 
  not 
  be 
  absorbed 
  b}' 
  the 
  plant 
  in 
  proper 
  proportions. 
  This 
  ques- 
  

   tion 
  will 
  be 
  considered 
  further 
  in 
  connection 
  with 
  other 
  data. 
  

  

  CORRELATION 
  OF 
  GROWTH 
  AND 
  UNCONSUMED 
  STARCH. 
  

  

  Earl}' 
  in 
  this 
  study 
  of 
  growth 
  under 
  varying 
  conditions 
  of 
  nutrition 
  

   it 
  was 
  discovered 
  that 
  per 
  unit 
  of 
  fresh 
  volume 
  the 
  plants 
  of 
  most 
  

   growth 
  yielded 
  a 
  smaller 
  dry 
  weight 
  than 
  those 
  retarded 
  in 
  growth 
  by 
  

   reason 
  of 
  unfavorable 
  conditions. 
  Microscopic 
  examination 
  revealed 
  

   the 
  fact 
  that 
  the 
  thrift}' 
  plants 
  contained 
  comparatively 
  little 
  starch, 
  

   while 
  those 
  retarded 
  in 
  growth 
  were 
  literally 
  gorged 
  with 
  it. 
  A 
  sim- 
  

   ilar 
  examination 
  at 
  the 
  conclusion 
  of 
  each 
  experiment 
  showed 
  that 
  

   whether 
  in 
  the 
  aquarium 
  experiments 
  or 
  in 
  those 
  with 
  nutrient 
  solu- 
  

   tions, 
  the 
  starch 
  had 
  accumulated 
  in 
  the 
  plants 
  in 
  proportion 
  as 
  growth 
  

   had 
  been 
  retarded; 
  so 
  it 
  may 
  be 
  said 
  that 
  so 
  far 
  as 
  these 
  experiments 
  

   are 
  concerned 
  the 
  amount 
  of 
  unconsumed 
  starch 
  in 
  the 
  tissues 
  of 
  the 
  

   plant 
  varies 
  inversely 
  with 
  the 
  growth. 
  We 
  have 
  thus 
  from 
  direct 
  

   microscopic 
  examination, 
  as 
  well 
  as 
  from 
  chemical 
  analysis, 
  evidence 
  

   that 
  the 
  retarded 
  growth 
  in 
  these 
  cases 
  can 
  not 
  be 
  attributed 
  to 
  condi- 
  

   tions 
  unfavorable 
  to 
  the 
  photosynthetic 
  process. 
  

  

  