More leaves (or spines, or other photosynthesizing organs) means a bigger surface area and more stomata for gaseous exchange. This will result in greater water loss. [Feature] 
Number of leaves
N u m b e r o f l e a v e s
N u m b e r o f s t o m a t a
S i z e o f t h e l e a f
P r e s e n c e o f p l a n t c u t i c l e
L i g h t s u p p l y
T e m p e r a t u r e
R e l a t i v e h u m i d i t y
W i n d
W a t e r s u p p l y