扁柏屬三種植物葉部氣孔之分佈

Stomatal Distribution on Leaves of Three Species of Chamaecyparis

Seedlings of Chamaecyparis formosensis, C. taiwanensis and C. lawsoniana were grown in well-watered nursery conditions. Scale leaves of the three species differed slightly in the general distribution of stomata. ln C. lawsoniana, size and stomatal characteristics of facial scale leaves were similar to lateral leaves, and similar to facial leaves of other species. In the other two species, lateral leaves were larger than facial leaves, with more stomata but lower stomatal frequency and lower estimated coverage by stomatal pores. Scale leaves from natural seed lings were smaller in C. formosensis, and had a lower stomatal frequency in C. taiwanensis. Stomatal pore size was smallest in C. taiwanensis. Coverage by stomatal pores of C. lawsoniana is 0.67% (assuming a 6 p pore width), compared to 0.52 and 0.49% for the species from Taiwan. Compared to other conifers measured, Chamaecyparis is intermediate in its stomatal frequency and coverage by pores, although C. lawsoniana has relatively long stomatal pores. Primary leaves of C. formosensis are much larger than scale leaves, with more stomata; most stomata are on the abaxial surface, which has a stomatal frequency similar to that of facial leaves.