﻿83 
  

  

  ( 
  JAN 
  Z 
  

  

  The 
  Effect 
  of 
  Nitrogen-fixing 
  Organisms 
  and 
  Nucleic 
  Acut~ 
  

  

  Derivatives 
  on 
  Plant 
  Growth. 
  

  

  By 
  W. 
  B. 
  Bottomlet, 
  M.A., 
  Ph.D. 
  

   (Communicated 
  by 
  Prof. 
  F. 
  W. 
  Oliver, 
  F.E.S. 
  Received 
  June 
  6, 
  1919.) 
  

  

  Introduction. 
  

  

  In 
  a 
  previous 
  communication* 
  it 
  has 
  been 
  shown 
  that 
  a 
  water 
  extract 
  of 
  

   bacterised 
  peat 
  has 
  a 
  remarkable 
  effect 
  on 
  the 
  growth 
  of 
  Lemna 
  minor 
  in 
  

   water-culture 
  solution. 
  The 
  experiments 
  there 
  described 
  showed 
  that 
  when 
  

   supplied 
  with 
  inorganic 
  nutrients 
  only, 
  the 
  plants, 
  though 
  increasing 
  in 
  

   number, 
  failed 
  to 
  maintain 
  their 
  normal 
  size 
  and 
  health, 
  and 
  rapidly 
  

   deteriorated, 
  while 
  the 
  addition 
  of 
  a 
  small 
  quantity 
  of 
  the 
  organic 
  material 
  

   resulted 
  in 
  a 
  marked 
  increase 
  in 
  the 
  rate 
  of 
  multiplication, 
  the 
  plants 
  at 
  the 
  

   same 
  time 
  showing 
  improved 
  health 
  and 
  vigour, 
  proof 
  of 
  which 
  was 
  given 
  by 
  

   the 
  increase 
  in 
  the 
  dry 
  weight 
  of 
  the 
  plants 
  so 
  treated. 
  

  

  The 
  author 
  has 
  also 
  shownf 
  that 
  wheat 
  seedlings, 
  when 
  deprived 
  of 
  their 
  

   endosperm 
  at 
  a 
  very 
  early 
  stage, 
  will 
  not 
  grow 
  normally 
  unless 
  supplied 
  with 
  

   organic 
  matter. 
  These 
  experiments 
  led 
  to 
  the 
  conclusion 
  that 
  all 
  plants, 
  as 
  

   well 
  as 
  animals, 
  require 
  a 
  certain 
  amount 
  of 
  organic 
  substance 
  for 
  their 
  proper 
  

   development 
  — 
  a 
  conclusion 
  entirely 
  contrary 
  to 
  the 
  established 
  view 
  that 
  

   plants 
  can 
  be 
  grown 
  in 
  purely 
  inorganic 
  nutrients 
  in 
  water-culture. 
  

  

  In 
  the 
  course 
  of 
  the 
  previous 
  work, 
  however, 
  it 
  was 
  found 
  that 
  the 
  organic 
  

   matter 
  is 
  effective 
  in 
  extremely 
  minute 
  quantities, 
  such 
  as 
  might 
  conceivably 
  

   be 
  supplied 
  by 
  bacterial 
  and 
  algal 
  contamination, 
  though 
  in 
  these 
  preliminary 
  

   stages 
  no 
  attempt 
  was 
  made 
  to 
  determine 
  the 
  nature 
  of 
  the 
  essential 
  

   substances. 
  The 
  water 
  extract 
  of 
  the 
  bacterised 
  peat, 
  which 
  was 
  largely 
  

   used, 
  must 
  be 
  a 
  complex 
  mixture, 
  containing 
  constituents 
  from 
  both 
  the 
  peat 
  

   and 
  the 
  bacteria, 
  as 
  well 
  as 
  the 
  products 
  of 
  their 
  interaction 
  ; 
  and 
  the 
  growth- 
  

   promoting 
  effect 
  may 
  be 
  due 
  to 
  any 
  or 
  all 
  of 
  these 
  substances. 
  The 
  all- 
  

   important 
  bacteria 
  used 
  in 
  the 
  preparation 
  of 
  the 
  bacterised 
  peat 
  are 
  those 
  

   concerned 
  in 
  nitrogen-fixation, 
  and 
  in 
  May, 
  1917, 
  a 
  preliminary 
  experiment 
  

   was 
  carried 
  out 
  with 
  the 
  object 
  of 
  ascertaining 
  how 
  far 
  the 
  effect 
  of 
  the 
  

   bacterised 
  peat 
  extract 
  was 
  due 
  to 
  the 
  products 
  of 
  these 
  bacteria. 
  

  

  * 
  Bottomley, 
  W. 
  B., 
  ' 
  Roy. 
  Soc. 
  Proc.,' 
  B, 
  vol. 
  89, 
  pp. 
  481-507 
  (1917). 
  

   t 
  Bottomley, 
  W. 
  B., 
  ' 
  Annals 
  of 
  Botany,' 
  vol. 
  28, 
  No. 
  Ill, 
  pp. 
  531-540 
  (1914). 
  

   VOL. 
  XCI. 
  — 
  B. 
  G 
  

  

  