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http://indianaquariumhobbyist.com/community/ :: View topic - Why those additional pigments?
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Why those additional pigments?

 
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essabee
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PostPosted: Fri Dec 25, 2009 11:09 am Post subject: Why those additional pigments? Reply with quote

 Why  do  certain  species  of  aquatic  plant  colour  up  under  intense  light?  That  they  do  is  something  we  often  observe  in  all  well  lighted  planted  tanks.  That  this  change  in  colouration  becomes  more  prominent  with  the  intensity  of  light  is  also  a  common  observation.  I  will  concede  that  some  specie  of  aquatic  plants  will  not  show  any  perceptible  change  in  their  colouration  and  some  others  do  not  need  very  intense  light  to  be  other  than  green.
 
 There  are  and  always  had  been  nutritional  factors  which  can  change  the  colouration  of  plants  –  but  those  need  not  be  addressed  here.
 
 As  I  see  it,  when  a  plant  does  change  its  colour  under  lights,  it  does  not  stop  reflecting  the  green  part  of  the  light  spectrum  it  normally  did,  but  is  now  reflecting  an  additional  part  of  the  spectrum,  and  this  causes  the  change  in  colouration.  Conversely  this  means  that  the  plant  is  reducing  the  range  of  the  light  spectrum  it  was  absorbing.  Therefore  it  follows  that  the  plant  is  reducing  its  energy  absorption  from  those  parts  which  are  in  more  intense  light.  Why?
 
 Additional  energy  when  there  is  no  lack  of  nutrients  for  the  plant  to  increase  synthesis  of  its  growth  substances  should  have  been  an  advantage  to  the  plant;  still  the  plant  is  opting  to  reduce  it  energy  absorption.  Nature  never  induces  curtailment  of  any  action  (or  omission)  which  is  of  advantage  to  any  specie;  then  why  is  such  an  advantage  to  the  plant  being  curtailed?  The  answer  must  be  that  behind  the  obvious  advantage  lies  some  hidden  disadvantage.
 
 Reflecting  over  the  question,  it  suddenly  struck  me  the  answer  must  be  oxygen.  Oxygen  is  synonymous  with  life,  as  we  know  it,  but  it  is  a  dangerous  poison.  Man  regularly  uses  oxygen  and  oxidising  agents  to  kill  living  organisms.  The  most  abundant  byproduct  of  photosynthesis  is  oxygen.  Therefore  the  plants  that  change  colour  with  more  intense  light  must  have  a  limited  capacity  to  handle  the  byproduct  oxygen  in  its  photosynthetic  action.  The  change  of  colour  is  a  defensive  mechanism  to  reduce  the  quantum  of  the  byproduct  –  oxygen.
 
 I  am  no  scientist,  but  I  do  like  my  queries  answered.  So  I  put  questions  to  myself  and  try  to  find  logical  answers  to  them,  not  all  my  beliefs  are  true  but  this  time  I  think  I  am  on  the  right  track.
 
 Nature  does  nothing  without  reason.  The  propensity  to  change  colour  must  have  a  purpose,  especially  as  synthesising  those  pigments  need  effort  and  expense  of  nutrient  elements  of  these  plant  specie.  No  plant  would  evolve  such  an  unnecessary  and  costly  (extravagant)  behaviour.  
 
 Genetically  the  threshold  of  different  plants  in  handling  of  oxygen  or  the  mechanism  by  which  different  specie  control  the  threshold  may  differ.  The  explanation  why  some  plants  do  not  change  colour  would  be  there.
 
 The  range  of  the  spectrum  chosen  by  the  plant  would  naturally  be  fixed  by  their  genetic  evolution.  
 
 Even  if  the  trigger  for  additional  pigments  is  linked  to  the  byproduct  oxygen  from  photosynthesis  only;  it  would  explain  nutritional  deficiencies  and/or  availabilities  causing  colour  change  in  plants.  
 
 Any  nutritional  deficiency  which  affects  the  plants  efficiency  in  handling  the  oxygen  –  or  a  nutritional  excess  of  any  element  that  increases  the  plants  photosynthesis;  can  and  will  cause  a  change  of  the  colour  of  the  plant,  when  the  threshold  is  breached.
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essabee
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PostPosted: Tue Dec 29, 2009 6:53 am Post subject: Re: Why those additional pigments? Reply with quote

 Originally  Posted  by  essabee   
 Why  do  certain  species  of  aquatic  plant  colour  up  under  intense  light?  That  they  do  is  something  we  often  observe  in  all  well  lighted  planted  tanks.  That  this  change  in  colouration  becomes  more  prominent  with  the  intensity  of  light  is  also  a  common  observation.  I  will  concede  that  some  specie  of  aquatic  plants  will  not  show  any  perceptible  change  in  their  colouration  and  some  others  do  not  need  very  intense  light  to  be  other  than  green.

 
 Then  you  will  want  to  be  specific  about  which  plants  you  speak  of,  and  not  generalize.
 
 
 
 As  I  see  it,  when  a  plant  does  change  its  colour  under  lights,  it  does  not  stop  reflecting  the  green  part  of  the  light  spectrum  it  normally  did,  but  is  now  reflecting  an  additional  part  of  the  spectrum,  and  this  causes  the  change  in  colouration.  Conversely  this  means  that  the  plant  is  reducing  the  range  of  the  light  spectrum  it  was  absorbing.  Therefore  it  follows  that  the  plant  is  reducing  its  energy  absorption  from  those  parts  which  are  in  more  intense  light.  Why?  
 The  plant  still  absorbs  the  light  and  different  spectrums,  this  can  be  measured  by  the  reflecting  light  and  spectroradiometer  for  each  nm  wavelength  in  question.
 Absorption  and  our  preceptions  of  light  are  very  different,  you  cannot  make  this  observation  and  use  it  as  support  for  this  conclusion.
 You  must  measure  it.
 
 
 Additional  energy  when  there  is  no  lack  of  nutrients  for  the  plant  to  increase  synthesis  of  its  growth  substances  should  have  been  an  advantage  to  the  plant;  still  the  plant  is  opting  to  reduce  it  energy  absorption.  Nature  never  induces  curtailment  of  any  action  (or  omission)  which  is  of  advantage  to  any  specie;  then  why  is  such  an  advantage  to  the  plant  being  curtailed?  The  answer  must  be  that  behind  the  obvious  advantage  lies  some  hidden  disadvantage.  
 It  may  have  nothing  to  do,  with  this  "dis/advantage",  plants  in  nature  have  to  adapt  to  a  much  wider  range  of  conditions,  light  changes  hour  tpo  hour,  day  to  day,  even  second  to  second  as  light  filters  through  a  forest  canpoy.
 These  flecks  of  light  cause  very  high  levels  and  very  low  levels  to  strike  the  leaf.  Which  set  of  pigments  would  it  use  there  then?
 The  situation  is  both  cases.
 
 Plants  can  and  do  adapt.
 But  they  also  have  mechanisms  for  each  case.  It's  often  not  "either"  "or",  rather.........both  cases  that  we  find.
 
 
 Reflecting  over  the  question,  it  suddenly  struck  me  the  answer  must  be  oxygen.  Oxygen  is  synonymous  with  life,  as  we  know  it,  but  it  is  a  dangerous  poison.  Man  regularly  uses  oxygen  and  oxidising  agents  to  kill  living  organisms.  The  most  abundant  byproduct  of  photosynthesis  is  oxygen.  Therefore  the  plants  that  change  colour  with  more  intense  light  must  have  a  limited  capacity  to  handle  the  byproduct  oxygen  in  its  photosynthetic  action.  The  change  of  colour  is  a  defensive  mechanism  to  reduce  the  quantum  of  the  byproduct  –  oxygen.
 I  am  no  scientist,  but  I  do  like  my  queries  answered.  So  I  put  questions  to  myself  and  try  to  find  logical  answers  to  them,  not  all  my  beliefs  are  true  but  this  time  I  think  I  am  on  the  right  track.  
 So  adding  pure  O2  would  change  the  colors  of  the  plants?
 Have  you  tired  this?  I  have  with  algae,  no  results  at  150%  O2  and  with  any  CO2  combination  relative  to  low  O2(90-100%).
 
 Since  O2  ppms  are  correlated  with  growth  rates  of  submersed  plants,,  how  can  it  be  due  to  O2  vs  a  general  growth  rate?
 You  can  test  it  by  adding  O2  to  these  same  levels.
 
 
 Nature  does  nothing  without  reason.  
 Then  why  do  you  have  an  appendix?
 Why  do  whales  have  a  hip  bone?
 
 Obviously,  we  do  not  need  them  and  they  impart  no  advantage.
 
 
 The  propensity  to  change  colour  must  have  a  purpose,  especially  as  synthesising  those  pigments  need  effort  and  expense  of  nutrient  elements  of  these  plant  specie.  No  plant  would  evolve  such  an  unnecessary  and  costly  (extravagant)  behaviour.  
 Evolution  in  the  aquarium  or  nature?
 Where  are  we  talking  about?
 
 Very  important  point.
 
 
 Any  nutritional  deficiency  which  affects  the  plants  efficiency  in  handling  the  oxygen  –  or  a  nutritional  excess  of  any  element  that  increases  the  plants  photosynthesis;  can  and  will  cause  a  change  of  the  colour  of  the  plant,  when  the  threshold  is  breached.  
 I  suspect  teasing  apart  growth  rates  and  O2  due  to  color  pigment  change  is  fairly  straight  forward  test.
 But.........you'd  need  to  look  up  how  O2  and  growth  rates  change  things  in  a  steady  light  state  and  with  enriched  CO2.
 
 Growth  is  a  huge  factor  there  and  O2  makes  little  difference  if  the  growth  is  not  also  addressed.
 
 Regards,  
 Tom  Barr  
 www.BarrReport.com
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PostPosted: Tue Dec 29, 2009 6:59 am Post subject: Re: Why those additional pigments? Reply with quote

 Adding  oxygen  to  the  water  will  have  no  effect  as  it  will  not  cause  damage  to  the  plant  tissue  surrounding  the  photosynthetic  area.  Then  again  the  reactions  taking  place  during  photosynthesis  may  be  producing  oxygen  (or  to  a  certain  extent  of  the  oxygen)  in  its  nascent  form  which  causes  the  damage.  
 
 Your  reply  appears  to  be  directed  more  against  me  and  not  the  subject  of  my  post.  Just  look  at  the  arguement  
 
 "Then  why  do  you  have  an  appendix?
 Why  do  whales  have  a  hip  bone?
 
 Obviously,  we  do  not  need  them  and  they  impart  no  advantage."

 
 Any  child,  aware  of  Darwin's  work,  will  tell  you  why  we  have  an  appendix  or  the  whales  have  hip  bones.
 
 My  post  is  not  the  result  of  any  experiment  or  a  scientific  research  but  a  thought  about  what  goes  on  around  us.  Being  an  aquarium  plant  forum  and  the  subject  being  thoughts  about  aquarium  plants,  I  have  shared  it  with  others  having  the  same  interest.  If  such  conversations  are  not  allowed  I  shall  correct  myself  and  refrain  from  speaking  about  my  thoughts  here.
 
 Thank  you  Tom  Barr
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PostPosted: Tue Dec 29, 2009 9:12 am Post subject: Re: Why those additional pigments? Reply with quote

 As  per  my  limited  knowledge  I  don't  I  think  that  plants  change  colours  in  high  light.
 Some  Plants  have  red  pigments  instead  of  green  cholorophyll,  these  red  pigments  are  not  very  efficent  in  photosyenthesis,  and  under  low  light,  plants  start  producing  more  of  green  cholorophyll,  which  are  more  efficient  in  photosyenthesis.
 Hence  under  low  lights  these  red  plants  turn  to  green,  however  as  soon  as  they  receive  high  lights  they  revert  back  to  their  original  pigments.
 A  plant  which  has  only  green  pigments(cholorophyll)  will  not  change  colours  under  very  high  lights.
 Now  as  to  why  these  plants  have  red  pigments  instead  of  regular  green  pigments,  I  have  no  idea,  maybe  GOD  does.  Very Happy
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PostPosted: Tue Dec 29, 2009 4:36 pm Post subject: Re: Why those additional pigments? Reply with quote

 By  Yosef   on  the  TFH  forum  in  rejoinder  to  my  article
 on  Tue  Dec  29,  2009  9:41  am  
 Red  color  in  plants  comes  from  pigments  called  carotenoids  (like  beta  carotene,  which  gives  carrots  their  orange  color),  which  are  photosynthetic  compounds  like  chlorophyll.  They  convert  energy,  like  chlorophyll,  but  are  not  as  efficient  and  must  "transfer"  their  energy  (by  electron  transfer)  to  the  chlorophyll.  Their  main  purpose  is  to  a)  help  in  photosynthesis  by  absorbing  blue  light,  and  b)  block  UV  rays.
 
 They  absorb  in  the  blue-green  region  (the  sun's  biggest  output)  and  reflect  UV/violet/orange  red,  giving  them  a  pinkish  violet.  You  know  how  leaves  turn  red  in  the  fall?  This  is  (partly)  because  the  more  delicate  chlorophyll  molecules  begin  to  break  down,  leaving  the  carotenoids  to  make  the  leaves  a  beautiful  bright  red  color.
 
 So,  with  either  increased  sunlight  exposure  or  increased  rate  of  photosynthesis,  plants  adjust  their  level  of  carotenoids  to  block  UV  rays  or  to  keep  up  with  increased  growth  demands.  An  interesting  example  is  a  Japanese  maple  I  have  in  my  yard,  which  has  half  of  its  leaves  in  full  sunlight,  giving  them  a  deep  red  color.  However,  the  other  half  are  growing  under  the  shade  of  our  carport,  giving  them  a  bright  green  color  that  usually  is  not  present  in  Japanese  maples.  The  leaves  in  the  sunlight  have  to  adjust  to  the  sunlight  by  producing  carotenoids  that  color  them  red.
 
 The  same  occurs  when  conditions  are  more  favorable  for  photosynthesis,  like  increased  nutrients  or  CO2.  In  keeping  up  with  the  demands  of  increased  growth,  the  plant  produces  more  pigments  to  increase  light  absorption  and  therefore  sugar  production.  This  is  why  red  plants  require  high  lighting  and  CO2  to  increase  growth  rates  and  maintain  their  red  color.
 
 There's  my  biochemistry  nerd  rant,  hope  it  helps!
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essabee
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PostPosted: Wed Dec 30, 2009 7:07 am Post subject: Re: Why those additional pigments? Reply with quote

 Originally  Posted  by  essabee   
 Adding  oxygen  to  the  water  will  have  no  effect  as  it  will  not  cause  damage  to  the  plant  tissue  surrounding  the  photosynthetic  area.  Then  again  the  reactions  taking  place  during  photosynthesis  may  be  producing  oxygen  (or  to  a  certain  extent  of  the  oxygen)  in  its  nascent  form  which  causes  the  damage.  
 
 Your  reply  appears  to  be  directed  more  against  me  and  not  the  subject  of  my  post.  Just  look  at  the  arguement  
 
 "Then  why  do  you  have  an  appendix?
 Why  do  whales  have  a  hip  bone?
 
 Obviously,  we  do  not  need  them  and  they  impart  no  advantage."
 
 Any  child,  aware  of  Darwin's  work,  will  tell  you  why  we  have  an  appendix  or  the  whales  have  hip  bones.
 
 My  post  is  not  the  result  of  any  experiment  or  a  scientific  research  but  a  thought  about  what  goes  on  around  us.  Being  an  aquarium  plant  forum  and  the  subject  being  thoughts  about  aquarium  plants,  I  have  shared  it  with  others  having  the  same  interest.  If  such  conversations  are  not  allowed  I  shall  correct  myself  and  refrain  from  speaking  about  my  thoughts  here.
 
 Thank  you  Tom  Barr

 
 There  is  a  difference  between  an  idea  and  a  person.
 Debating  what  the  merits  of  an  idea  are/are  not  is  vastly  different  from  personal  gibberish,  assumptions  about  others  and  their  intent  and  actions.
 I  can  make  statements  of  ideas  that  are  without  merit,  or  show  I  have  not  done  my  homework.  However,  it  does  not  imply  anything  about  myself/you  personally.
 I  go  after  the  idea,  never  person,  that  is  an  assumption  you  made,  if  it  was  not  clear  .........simply  ask.
 In  person,  these  types  of  exchanges  virtually  never  occur,  over  the  web,  many  folks  obsess  and  read  into  things  much  more  than  they  really  should.  
 Take  things  with  a  grain  of  salt  in  otherwords.  
 
 http://www.littlersworks.net/reprints/Littler1979a.pdf
 
 See  fig's  1-3,  clearly  O2  concentration  has  a  strong  affect.
 
 For  plants,  and  the  issue  with  Darwin............all  plants  use  Rubsico  to  fix  CO2  from  the  external  environment.  O2  comes  in  and  is  also  fixed  and  these  two  processes  are  in  fact  concentrationally  dependent.
 Rubsico  is  an  old  enzyme  back  when  the  air  was  richer  in  CO2  and  low  in  O2,  this  has  changed  over  time.
 
 In  response,  plants  and  algae  both  have  developed  ways  to  deal  with  O2  toxicity  both  internally  and  externally.  Photorespiration  is  a  strong  inhibiting  factor  in  many  species  including  macrophytes.
 In  response  to  this,  C4  plants  developed.  Corn  etc..........many  if  not  most  of  the  crops  are  C4  plants  that  concentrate  the  CO2  around  the  Rubsico  to  advoid  PR.
 
 But............not  all  plants  do  this,  and  the  same  is  true  for  aquatic  plants.
 Algae  use  another  method  to  address  it,  but  not  all  algae  do  this  either.
 
 http://www.plantphysiol.org/cgi/reprint/58/6/761.pdf
 http://www.plantphysiol.org/cgi/reprint/73/2/488
 
 Both  are  excellent  papers  to  think  about  for  PR  and  O2/CO2  issues.
 
 I  think  you  would  get  much  farther  by  looking  things  up,  and  seeing  what  is  out  there.
 Such  research  and  papers  will  offer  much  more  support  and  guide  you  better  on  how  to  develop  your  own  test  so  you  may  answer  things  and  share  such  results  with  others.
 
 Do  not  get  distracted  with  personal  stuff.  Stick  to  the  topic.
 If  you  have  an  interest  in  this  and  other  topics,  ask  and  I'll  provide  some  good  papers  to  review.
 
 http://www.plantphysiol.org/cgi/cont...tract/73/2/488
 
 Dr  Bowes  is  excellent  for  the  O2/CO2  issue  with  aquatic  plants  and  algae,  he  discovered  PR  and  was  an  old  past  professor  of  mine.  I  know  this  topic  somewhat  well.
 
 A  google  scholar  look  shows  for  macrophytes  AND  PR:
 
 http://scholar.google.com/scholar?hl..._ylo=&as_vis=0
 
 You  will  find  plants  that  have  no  effect  with  increased  O2,  others  will,  same  for  algae.
 
 
 
 
 
 If  personal  gibberish  is  what  you  want,  go  to  a  social  networking  site.
 
 www.BarrReport.com
 
 
 ^  this  answer  is  greatly  appreciated  by  me.  This  what  I  was  looking  from  you  at  the  first  instant  (sans  the  very  natural  anger  at  my  coment  ofcourse).  
 essabee
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essabee
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PostPosted: Wed Dec 30, 2009 7:57 am Post subject: Re: Why those additional pigments? Reply with quote

 My  rejoinder  to  Yosef  in  the  TFH  forum
 
 on  Tue  Dec  29,  2009  10:29  am  
 
 yosef  wrote:
 They  absorb  in  the  blue-green  region  (the  sun's  biggest  output)  and  reflect  UV/violet/orange  red,  giving  them  a  pinkish  violet.  
 
 Now  use  a  little  maths  instead  of  biochemistry  -  you  have  lesser  portion  of  the  spectrum  absorbed.  These  are  but  different  ways  of  looking  at  things  -  the  half  empty/half  full  glass.
 
 yosef  wrote:
 Red  color  in  plants  comes  from  pigments  called  carotenoids  (like  beta  carotene,  which  gives  carrots  their  orange  color),  which  are  photosynthetic  compounds  like  chlorophyll.  They  convert  energy,  like  chlorophyll,  but  are  not  as  efficient  and  must  "transfer"  their  energy  (by  electron  transfer)  to  the  chlorophyll.  Their  main  purpose  is  to  a)  help  in  photosynthesis  by  absorbing  blue  light,  and  b)  block  UV  rays.
 
 If  the  purpose  of  the  extra  pigments  was  only  to  block  out  the  UV  -  then  it  can  easily  be  tested  by  having  UV  filters  over  the  light  source/s  and  the  plant  would  have  no  need  then  to  colour  up.  I  hope  someone  tries  that  experiment  it  would  give  us  a  better  understanding  of  exactly  what  is  going  on.
 
 You  know  yosef,  there  are  so  many  wonderful  phenomenons  that  we  observe  but  don't  understand.  If  only  we  could  have  a  better  understanding  of  the  things  around  us.  Let  us  try...................
 
 My  path  is  one  way  and  there  are  several  others.

 
   This  is  Wolfenrook's  rejoinder:-
 
 Already  done  essabee.  As  is  well  known,  acrylic  absorbs  a  LOT  of  UV  light.  I  used  to  have  acrylic  covers  between  my  overtank  lighting  and  my  aquarium,  upon  removal  of  this  cover  reds  increased  to  a  certain  depth  (UV  is  one  of  the  first  parts  of  the  spectrum  absorbed  by  water),  so  I  upped  the  UV  going  into  my  aquarium  by  swapping  2  865  6,500  K  tubes  for  2  BiVital  tubes  which  are  5,900k  and  have  an  added  UV  component  to  the  spectrum.  I  did  this  with  care,  as  a  lot  of  sources  claim  that  increased  UV  will  lead  to  increase  algae  growth,  I  however  did  not  find  this.  I  did  however  find  that  plant  colours  deepened,  especially  in  red  plants.
 
 What  I  am  saying  here  is  that  all  other  factors  been  equal,  the  presence  of  increased  levels  of  UV  light  reaching  the  leaves  will  increase  reds.  However  this  process  also  requires  certain  nutrients  (most  folks  find  that  increasing  iron  dosing  helps  reds,  which  suggests  that  iron  is  needed  in  the  production  of  flavonoids.  There  is  also  quite  a  lot  of  research  suggesting  that  these  same  flavenoids  (which  can  cause  both  red  and  purple  colours  in  plants)  are  also  produced  as  a  stress  response  by  plants,  which  would  be  why  techniques  such  as  nitrate  starvation  helps  to  improve  the  reds  in  plants.  Given  this,  it's  going  to  be  VERY  difficult  to  say  whether  these  flavenoids  are  produced  to  protect  against  increased  UV  or  just  too  bright  lighting  stressing  the  plants.
 
 As  to  your  assertion  essabee  that  less  of  the  spectrum  is  absorbed,  you  are  going  to  find  this  VERY  difficult  to  prove.  Less  light  of  a  particular  spectrum  may  reach  the  pigments  in  the  leaf  responsible  for  photosynthesis,  but  this  does  not  mean  that  the  plant  is  using  less.  It  could  just  as  easily  be  that  the  plant  becomes  stressed  due  to  increasing  light  because  it's  usage  rate  of  nutrients  is  outstripping  the  quantity  of  nutrients  available  to  the  plant  to  use,  thus  once  again  causing  nitrate  starvation  for  example,  which  would  mean  that  increasing  the  lighting  is  actually  having  the  exact  same  effect  as  reducing  the  nitrogen  available  to  the  plant.  A  far  more  logical  explanation.
 
 I  am  also  willing  to  bed  that  you  get  much  better  reds  in  the  plants  you  have  in  tanks  with  indirect  sunlight  lighting  them.  Artificial  lighting  producing  far  lower  quantities  of  UV  than  the  sun,  meaning  that  there  is  more  UV  from  the  sun  to  penetrate  to  the  plant  leaves  than  there  would  be  from  artificial  lighting.
 
 Ade
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essabee
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PostPosted: Thu Apr 18, 2013 10:14 am Post subject: Re: Why those additional pigments? Reply with quote

 I  had  started  this  post  with  a  speculative  thought  -  But  it  appears  to  have  been  a  thought  in  the  right  direction  from  what  I  recently  read:-
 
 
 
http://www.sciencedaily.com/releases/2013/04/130404142455.htm
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