部份地生蘭和附生蘭葉部之鈣晶體與矽沈澱物和金線連葉部形態發生及其內針束狀晶體之分佈與發育

Abstract

本論文以生長於台灣的7屬9種地生蘭和10屬13種附生蘭植物為材料，觀察其葉部之鈣晶體和矽沈積物的種類、形態與分佈，並探討其與植物之不同生育型間的相關性。另以金線連為主要材料，觀察其葉部生長及葉片中結晶異形細胞發育過程的微細構造變化，並運用無菌組織培養來探討不同鈣離子濃度對金線連葉片內鈣晶體形成的影響。 在所觀察之植物葉片內，均含有針束狀草酸鈣晶體，其單一針晶的切面形態呈六至八邊形。在附生蘭之金草、新竹石斛、黃穗蘭及黃繡球蘭和地生蘭之竹葉根節蘭葉片內，另觀察到晶簇狀草酸鈣晶體的分佈，而在烏來石山桃則另有短柱狀晶體的分佈。就草酸鈣晶體而言，附生蘭葉片內的晶體形態比地生蘭多，然而地生蘭葉片內的晶體密度，較大於附生蘭。附生蘭的葉片中，僅紋星蘭、撬唇蘭和黃繡球蘭並未觀察到矽質體；而地生蘭，僅台灣白及具有矽質體。所觀察的矽質體形態可分為兩型，台灣白及、黃穗蘭和文心蘭為圓錐形矽質體，其餘為球形矽質體。 初步觀察無菌瓶苗、室內種植和套袋種植的金線連，室內種植的金線連植株節間較長，而套袋種植的植株展開葉葉片面積最大。研究室內栽植的金線連，其葉部發育依形態可分為：新月狀葉原(<0.1 mm)、鬥蓬狀葉原(0.1至0.3 mm)、直立狀葉原(0.3至1 mm)、捲葉(1至33 mm)和展開葉時期(16至42 mm)。栽培於不同生長環境的金線連，其葉片結晶異形細胞最早出現時期，均在葉原長約1 mm時期，而晶體大量出現，則在捲葉初期，約2-3.5 mm的捲葉。 其葉內結晶異形細胞發育，可區分為六個階段：(1)結晶細胞發育早期、(2)鈣晶體腔出現期、(3)鈣晶體累積期、(4)內質網膨脹期、(5)黏液質堆積期與(6)結晶細胞成熟期。結晶細胞在整個發育至成熟過程，均具有一個明顯的細胞核與數個核仁。在發育早期，可觀察到油質體分佈，其後則不再出現。結晶細胞的色素體形態不同於一般細胞的色素體，前人研究稱為結晶色素體。其分化狀態於第3至第5期均可觀察到。分化中的結晶色素體其內含不溶性多醣類與蛋白質，而其成熟葉綠體主要含脂質與蛋白質。針束狀晶體形成為液胞內先形成數個晶體腔，其內逐漸累積晶體，在液胞內黏液質堆積後，晶體束外圍及個別針晶之間形成電子緻密的黏液鞘，而成熟的晶體腔周圍具有多層板狀構造圍繞。 於l/8 Ca (0.19 mM)、1/4 Ca (0.37 mM)、1 Ca (l.50 mM)、4 Ca (5.59 mM)和8 Ca (11.97 mM)五種不同鈣濃度培養基種植的金線連，其葉片的鈣晶體密度有明顯差異，隨著培養基內鈣濃度遞增，其葉片內晶體密度依序由2.35士1.6/mm2; 2.4士1.2/mm2; 5.19土2.7/mm2; 8.7士1.4/mm2；15.16土5.9mm2增加。在低鈣栽培的葉片，其葉尖和葉緣的晶體密度較高於葉中，而高鈣(8Ca)培養下，晶體則密佈於整個葉面。

The morphology and distribution of calcium crystals and silica deposition in the leaves of nine species (seven genera) of terrestrial orchids and thirteen species (ten genera) of epiphytic orchids were investigated. All of the studied orchids contain calcium oxalate crystals in the shape of six-eight sided raphides. Dendrobium aurantiacum, D.falconer Dendrochilum uncatum, Pomatocalpa acuminata and Calanthe densiflora have druses in the leaf Pholidota cantonensis has styloids. The results show that there are more types of calcium oxalate crystals in the epiphytic orchids. Nevertheless, the density of raphides in the leaves of the terrestrial orchids is higher than that in the epiphytic orchids. Most of the studied epiphytic orchids have silica body in the bundle sheath cells. However, there is no silica body in the leaves of Bulbophyllum affine, Holcoglossum guasipinifolium, and Pomatocalpa acuminata. Otherwise, the silica body was observed only in the leaves of Bletilla formosana, and not in the other studied terrestrial orchids. Two types of silica bodies were found. In B. formosana, Dendrochilum uncatum, and Oncidium Sweet Sugar the silica bodies are conical in shape and the others are spherical in shape. Besides, the ultrastructural changes of the leaf development and the formation of the calcium oxalate crystal idioblasts in the mesophyll of Anoectochilus formosanus were studied. Effects of calcium concentrations on the leaf development of A. formosanus were studied by tissue culture processes. The leaf morphogenesis of A. formosanus is as follows: crescent-shaped leaf primordium (<0.1 mm). hood-shaped leaf primordium (0.1-0.3 mm), straight leaf primordium (0.3-1 mm), rolled-leaf(l-33 mm). and unfolded mature leaf (16- 42 mm). Crystal initial idioblasts are found in the apex of 1 mm leaf primodium and large number are detected in the 2-3.5 mm rolled-leaves. The development of the raphide crystal idioblast is divided to six stages: (1) crystal idioblast initiation. (2) crystal chamber formation, (3) crystal growth, (4) ER expanded, (5) mucilage accumulation, and (6) crystal idioblast maturation. There are an enlarged nucleus and nucleoli in crystal idioblast of all stages and numerous spherosomes in initiation stage. The vacuoles contain electron- dense amorphous materials, which are association with the crystals and attached to the tonoplast. The morphology of plastids in some crystal idioblast are different from that in normal cells, and early literatures described that in crystal idioblast as the crystalloplatids One to several lobe regions are formed on the periphery of the crystalloplastids. The crystalloplastids contain insoluble polysaccharides and proteins. After the crystal chamber form in the vacuole, the crystal accumulates in these chambers and mucilage fills in the vacuole. There is high electron-dense mucilage sheath packed the raphide. In the mature raphide crystal cells, there are many lamellae sheath between the crystal. There are no distinct effects on the development of the leaves of A. formosanus cultured with different concentrations of calcium ion in the medium: 1/8 Ca (0.19 mM), 1/4Ca (0.374 mM), 1Ca (1.496 mM), 4Ca (5.586 mM), and 8Ca (11.972 mM). However, the density of crystals in leaves is increased with increasing concentrations of calcium ion.