How are the leaves of higher plants adapted to their functions?

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  Broad  and  flattened  lamina;  to  increase  surface  area;  for  absorption  of  light;  thin  blade;  to reduce  distance  for  diffusion  of  gases  and  penetration  of  light  waves;  transparent  epidermis  and cuticle;  to  allow  light  to  penetrate  to  tissues;  cuticle  layer  absent  on  stomata;  to  allow  for  gaseous exchange;  one-cell  thick  epidermal  layer;  to  reduce  the  distance  over  which  sunlight  penetrates; palisade  cells  have  numerous  chloroplasts  containing  chlorophyll;  to  trap  maximum  amounts  of light  energy;  have  stomata  on  the  epidermis;  to  allow  for  gaseous  exchange;  and  control  of  water loss  through  transpiration;  palisade  layer  have  elongated  cells  located  at  right  angles  to  the  leaf surface;  for  maximum  absorption  of  light  energy;  spongy  mesophyll;  consists  of  spherical  and loosely-packed  cells;  to  create  air  spaces;  which  communicate  with  the  atmosphere  through stomata;  for  purposes  of  gaseous  exchange  and  control  of  water  loss;  veins  have  conducting tissues:  xylem;  for  movement  of  water  and  dissolved  mineral  salts;  phloem;  for  translocation  of manufactured  food;  Max.  20  mks 

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