Leaf structure and photosynthetic properties in rosetting and bolting Eustoma plants

Leaf structure and photosynthetic properties of an individual leaf and a whole plant were compared between rosetting and bolting plants in Eustoma grandiflorum (Raf.) Shinn. Leaves on bolting plants (BP) were thinner, had smaller mesophyll cells, and lower chlorophyll content compared to the leaves on rosetting plants (RP). The photosynthetic capacity of upper leaves on a leaf area basis was lower in BP than in RP. On a leaf area basis, the amount of ¹³C incorporated into upper leaves of BP was less than RP, but that into lower leaves of BP was significantly larger than RP. On a dry weight basis, the total amount of ¹³C incorporated into BP, similar to the relative growth rate, was 1.6 times larger than that fixed on RP. These results indicate that rapid growth in BP does not depend on changes in the photosynthetic capacity of leaves, but on the increase in leaf area and improvement of light-intercepting characteristics of the whole plant.