﻿40 
  

  

  INTRODUCTION 
  TO 
  BOTANY 
  

  

  Often 
  green 
  plants 
  make 
  more 
  food 
  than 
  they 
  use 
  at 
  the 
  

   time, 
  and 
  this 
  surplus 
  food 
  may 
  be 
  stored 
  or 
  reserved 
  in 
  some 
  

   way. 
  Stored 
  food 
  may 
  or 
  may 
  not 
  be 
  used 
  later 
  by 
  the 
  plant, 
  

   and 
  may 
  oftentimes 
  become 
  the 
  food 
  of 
  other 
  plants, 
  of 
  ani- 
  

   mals, 
  or 
  of 
  men. 
  

  

  38. 
  Food 
  transported 
  by 
  the 
  plant. 
  In 
  all 
  except 
  the 
  sim- 
  

   plest 
  plants 
  the 
  reserve 
  food 
  is 
  carried 
  from 
  the 
  cells 
  in 
  which 
  

   it 
  was 
  manufactured, 
  into 
  other 
  cells. 
  In 
  plants 
  with 
  fleshy 
  

   leaves, 
  like 
  the 
  houseleek, 
  the 
  century 
  plant, 
  the 
  common 
  purs- 
  

   lane, 
  and 
  many 
  others, 
  the 
  greater 
  

   part 
  of 
  the 
  stored 
  starch 
  and 
  other 
  

   nutritive 
  materials 
  has 
  only 
  been 
  car- 
  

   ried 
  to 
  the 
  leaf 
  interior 
  from 
  the 
  outer 
  

   portions 
  of 
  the 
  leaf, 
  where 
  photosyn- 
  

   thesis 
  and 
  other 
  manufacturing 
  proc- 
  

   esses 
  go 
  on. 
  The 
  distance 
  traversed 
  

   may 
  be 
  only 
  a 
  small 
  fraction 
  of 
  an 
  

   inch, 
  but 
  in 
  case 
  much 
  of 
  the 
  food 
  is 
  

   stored 
  in 
  underground 
  parts 
  of 
  the 
  

  

  plant, 
  it 
  mav 
  have 
  been 
  carried 
  for 
  

   FIG. 
  28. 
  Starch 
  from 
  root- 
  

   long 
  distances 
  - 
  - 
  in 
  large 
  trees, 
  some- 
  

   times 
  more 
  than 
  a 
  hundred 
  feet 
  before 
  

   it 
  reaches 
  the 
  root 
  at 
  all. 
  

  

  39. 
  Form 
  in 
  which 
  food 
  is 
  transported. 
  As 
  already 
  stated, 
  

   one 
  of 
  the 
  products 
  of 
  photosynthesis 
  in 
  most 
  plants 
  is 
  starch. 
  

   This 
  is 
  deposited 
  in 
  or 
  about 
  the 
  chloroplasts, 
  during 
  their 
  

   exposure 
  to 
  daylight, 
  in 
  very 
  minute 
  grains. 
  In 
  the 
  course 
  

   of 
  the 
  night 
  these 
  disappear, 
  so 
  that 
  testing 
  a 
  leaf 
  with 
  

   iodine 
  1 
  shortly 
  before 
  daylight 
  usually 
  gives 
  no 
  result. 
  A 
  

   leaf 
  cut 
  off 
  from 
  the 
  stem 
  before 
  nightfall, 
  however, 
  responds 
  

   readily 
  to 
  the 
  iodine 
  test 
  for 
  starch 
  in 
  the 
  morning. 
  This, 
  of 
  

   course, 
  shows 
  that 
  the 
  starch 
  made 
  during 
  the 
  day 
  remained 
  

   in 
  the 
  leaf 
  cells, 
  where 
  it 
  was 
  formed. 
  It 
  is 
  very 
  generally 
  

   true 
  that 
  starch 
  carried 
  from 
  any 
  part 
  of 
  the 
  plant 
  to 
  an- 
  

   other 
  part 
  is 
  first 
  changed 
  to 
  sugar 
  and 
  travels 
  in 
  the 
  form 
  

  

  1 
  This 
  turns 
  starch 
  grains 
  blue 
  or 
  almost 
  black. 
  

  

  stock 
  of 
  canna 
  

   Magnified 
  300 
  diameters 
  

  

  