睡蓮體內厚壁細胞之構造、形成和分佈

Abstract

1.睡蓮植株之各器官都有厚壁細胞的存在，其以異型細胞方式單獨嵌滲在薄壁組織間，或是順延著維管束的外圍。 2.存在於各器官之成熟的厚壁細胞，形狀、大小變異頗大。根據形態並考慮其形成的部位與發育的情形，大致分成主要的兩型：一為纖維狀厚壁細胞；另一為分枝狀厚壁細胞，而其再由分枝的情形又區分為四類。 3.成熟的厚壁細胞其次生細胞概厚度均勻且木質化，留有明顯的細胞腔，在其初生細胞以與次生細鮑壁之間堆積結晶狀的物質。此外，細胞中央本體之內壁留有無綠孔，核當仍遺留於細胞之周邊處。 4.厚壁細胞分佈於地下莖之外部皮層、根的內部皮層、葉片的海綿與柵狀組織以及葉柄、花柄、托葉、花托、花萼、花瓣與雄蕊的基本組織。並且其在葉柄、花柄中分佈的數量上，明顯地由上（近葉或花）而下（近地下莖）地減少，並且多芒狀者常順延著通氣管道。各種厚壁細胞在各器官、組織中分佈的位置、及其形態、排列方式與其功能之間均頗有相關性。 5.葉柄、花柄不具特定的中間分生帶而屬於廣泛生長。葉部厚壁細胞均始源自基本薄壁組織，初期可由其核較臨近細胞者為大，且具明顯的核仁而加以辨認。而後配合協同生長、侵人生長與滑動生長於細胞間隙中或向通氣空腔形成分枝，隨即有次生細胞壁的填加。亦即睡蓮葉部厚壁細胞的發育依循著細胞之變大、分枝化與厚壁化三個時期。 6.睡蓮各器官組織中之厚壁細鮑，其始源及發育的順序與其所存在的組織有著一定的關係存在。就葉部而言，以托葉之厚壁細胞最先出現，接著為葉柄與地下莖交接處、葉柄與葉片交接處而後才於葉柄中段出現，約在葉柄之厚壁細胞達到其最終大小時，葉片內海綿組織之厚壁細胞才於中肋向兩邊綠有始源細胞之產生，最後才在柵狀組織形成和發育。

1. Sclereids are present as the form of idioblast in all the organs of Nymphaea tetrgona. Georgi. They are arranged sporadically in the parenchymatous tissue or along the periphery of vascular tissue. 2. Mature sclereids vary quite widely in the shape and size. Based on the shape, location (topography) as well as the developmental pattern, sclereids are classified into two main types, viz: fibrous sclereids and ramified sclereids. The ramified sclereids then are divided into four groups. 3. The secondary wall of a mature sclereid is uniformly thickened and lignified. The cell lumen is obvious in the most of sclereids, and the secondary wall exhibits prominent simple pits near the central part of the cell. Besides, numerous crystalline bodies are imbedded between the primary wall and the secondary wall. As the cell reaches its maximum size, sclereid always retains its nucleus on the periphery of the lumen. 4. Sclereids are distributed in all the tissues such as: the outer cortex of the rhizome, inner cortex of the root, spongy tissue and palisade tissue of the lamina. And the ground tissue of the petiole, peduncle, stipule, receptacle, sepal, petal and stamen also contain sclereids. In both petiole and peduncle, there are great proportion sclereids in the upper part (near leaf or flower). And they decrease in number gradually as observed downward the lower part (near rhizome). The polyarch-asterosclereids always lie along the periphery of the air canal. It shows the fair relationships among the site, the shape, the type of arrangement and the function of sclereids. 5. In petiole and peduncle, the sclereids have no typical intercallary meristem but general growth. The foliar sclereid initial originates from fundamental parenchyma. The first indication of the sclereid initial is the enlargement of nucleus and the nucleolus becomes conspicuous. With symplastic growth, intrusive growth and gliding growth the sclereid primordia undergo ramification in the intercellular spaces or to the air chamber. And then the secondary wall is deposited. The developmental sequences of the foliar sclereids may be described as following three phases: hypertrophic growth, ramification and sclerification. 6. In Nymphaea tetragona, there is an identical relationship between the sclereid initial sequence and the kinds of tissues or organs where they exist. The sclereids originate first in the stipule, then they appear in the joint of petiole and rhizome, the joint of petiole and lamina, and finally in the middle part of the petiole. As soon as the sclereids in the petiole reach their final size, the sclereid initials undergo the process of cell enlargement along the midrib to the leaf margin in the spongy layer. The formation of the sclereid primordia in the palisade tissue always fall behind that of all tissues mentioned above.