臺灣地區小唇蘭與三葯細筆蘭花部形態發育研究

Floral ontogeny of Erythrodes blumei (Lindl.) Schltr. and E. triantherae C. L. Yeh et C. S. Leou (Orchidaceae) in Taiwan

本研究以具1枚孕性花葯的小唇蘭（Erythrodes blumei）與具3枚孕性花葯的三葯細筆蘭（E. triantherae）花始原以石蠟切片及掃描式電子顯微鏡進行花部形態發育觀察，瞭解物種間花部發育順序並提供兩物種在蘭科花部形態演化上的證據。小唇蘭的花部發育過程，依序為：苞片（B）、近軸面的花萼（S_2, S_3）、唇瓣（L）、遠軸面的花瓣（P_1, P_2）、遠軸面背萼片（S_1）、外輪遠軸面中間孕性花葯（A_1）、內輪遠軸面兩側退化花葯（a_1,a_2）與遠軸面心皮（mc）、兩個近軸面心皮（lc）、外輪側生退化花葯（A_2, A_3）與蕊柱合生成附屬物。三葯細筆蘭的花部發育依序為：苞片（B）、近軸面的花萼（S_2, S_3）、唇瓣（L）、遠軸面的花瓣（P_1, P_2）、遠軸面背萼片（S_1）、外輪遠軸面中間孕性花葯（A_1）、內輪遠軸面兩側退化花葯（a_1, a_2）與遠軸面心皮（mc）、外輪側生孕性花葯（A_2, A_3）、兩個近軸面心皮（lc）發育。具有三枚孕性花葯的三葯細筆蘭花部發育順序明顯與最原始的擬蘭亞科三蕊蘭屬不同。三葯細筆蘭與小唇蘭最大的差異在於，外輪側生花葯較近軸面心皮先發育，且會發育成孕性花葯，此兩物種的花部發育仍與單蕊柱蘭科植物最相似。本研究並提出小唇蘭與三葯細筆蘭的花輪花式圖，研究結果亦支持蘭科花輪學說，花葯之花輪確由2輪構成。

The research focuses on Erythrodes blumei and E. triantherae, which bear only one fertile stamen and three fertile stamens respectively. Floral ontogeny was observed by using paraffin section and scanning electron microscope (SEM). The aims was to investigate the sequences of floral development of these two species and provide evidence of evolution in floral development. Floral developmental stages of E. blume are as follows: bract (B), two adaxial sepals (S_2, S_3), labellum (L), two abaxial lateral petals (P_1, P_2), abaxial median sepal (S_1), abaxial outer-whorl median fertile stamen (A_1), two abaxial inner-whorl lateral staminodes (a_1, a_2), abaxial median carpel (mc), two adaxial lateral carpels (lc), and two outer-whorl lateral staminodes (A_2, A_3) form to lateral gynostemium appendages. Floral developmental stages of E. triantherae are as follows: bract (B), two adaxial sepals (S_2, S_3), labellum (L), two abaxial lateral petals (P_1, P_2), abaxial median sepal (S_1), abaxial outer-whorl median fertile anther (A_1), two abaxial inner-whorl lateral staminodes (a_1, a_2), abaxial median carpel (mc), two outer-whorl lateral fertile stamens (A_2, A_3), and two adaxial lateral carpels (lc). The developmental pattern of the floral organs of E. triantherae, which bears three fertile stamens, is different from that of the Neuwiedia of Apostasioideae. The major distinction of floral development between E. blumei and E. triantherae is that two outer-whorl lateral fertile stamens of E. triantherae develop earlier than two adaxial lateral carpels. However, the floral developmental stages of E. blumei and E. triantherae are similar to those of simple gynostemium orchids. The floral diagrams of E. blumei and E. triantherae are provided according to the results. This research also supports the fact that orchids have two-whorl stamens.