leaf arrangements on plants

Question 1

how are leaves arranged

Answer 1

in best way to receive maximum amount of light

Question 2

how are leaves arranged in large trees with lots of leaves

Answer 2

the leaves at top may shade those lower down
this is avoided by having leaves divided into leaflets or have jagged edges so light can get in between them
leaves at top arrange themselves so their edges are directed towards the sun
this allows light to pass between them to the leaves lower down
leaves do not overlap one another but are spread out in opposite sides in whorles alternate or subopposite patterns

Question 3

how has the lamina adapted to be of use to the plant

Answer 3

usually broad and flat so this gives it a large surface area to absorb sunlight energy and carbon dioxide
usually thin so this allows sunlight energy and carbon dioxide to reach all the cells
held out flat by veins this maximises its exposure to sunlight
usually lies at 90 degree angle to the sunlight this maximises its exposure to the sunlight