Figure 3.

Relationship of stem length to anatomical parameters of sieve elements and their end walls in woody angiosperms with simple end walls (blue circle), woody angiosperms with compound end walls (orange diamond) and woody gymnosperms (grey triangle). (a) Relationship between stem length and total sieve pore area per end wall. (b) Relationship between sieve pore area and number of sieve areas per end wall. (c–g) Relationship between stem length and average sieve pore radius (c), number of pores per end wall (d), number of sieve areas (e), sieve element radius (f) and sieve element length (g). Regression lines were only added in case there was a significant correlation between two parameters. Solid line, strong correlation; dotted line, weak correlation.