Question

Gas exchange surfaces should have large surface areas, be moist and be thin. How are these conditions met in the leaf?

Accepted Answer

huge number of spongy/palisade mesophyll cells provide a big surface area (for gas absorption);

large number of air spaces in contact with spongy cells;

covered in film of water (from xylem) to dissolve gases;

mesophyll cells have thin cellulosic walls (which are permeable to gases);

Front	Gas exchange surfaces should have large surface areas, be moist and be thin. How are these conditions met in the leaf?
Back	huge number of spongy/palisade mesophyll cells provide a big surface area (for gas absorption); large number of air spaces in contact with spongy cells; covered in film of water (from xylem) to dissolve gases; mesophyll cells have thin cellulosic walls (which are permeable to gases);

Gas Large Surface Number Mesophyll Cells Exchange Areas