Palm “wood”
Palm “wood”
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棕榈“木”
DOI：
10.1007/bf00350831
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发表时间：
1976
影响因子：
3.4
通讯作者：
L. Klotz
中科院分区：
文献类型：
--
作者：
M. V. Parthasarathy;L. Klotz
对棕榈树分化和成熟的筛管分子、气管分子和纤维的精细结构进行了研究。筛子的精细结构总体上类似于被子植物中筛子的精细结构，只是并非所有棕榈树种都含有 P 蛋白。在采取预防措施以尽量减少韧皮部压力突然释放后检查的材料表明，筛板孔在完整的筛元件中可能没有堵塞。茎基部的筛元件估计有几十年的历史，保持其结构完整性，并且在棕榈的整个生命周期中显然都保持功能。区分木质部元素的特征是存在具有电子致密颗粒基质的变形虫质体。通常存在于分生组织细胞中的所有细胞器也存在于分化的气管元件中。此类元件中通常存在微丝束。气管元件成熟时发生的结构变化与在其他被子植物的气管元件中观察到的结构变化相当。木质部薄壁细胞没有所谓的“保护壁层”。根纤维分化中最显着的超微结构特征是质膜的深度内陷，几乎横穿细胞的整个宽度。纤维的次生壁特征是多层的。
The fine structure of differentiating and mature sieve elements, tracheary elements and fibers of palms has been studied. The fine structure of sieve elements in general resembles that of the sieve elements in angiosperms except that not all the species of palms have P-protein. Material examined after taking precautions to minimize sudden release of pressure in the phloem indicate that the sieve-plate pores may be free of occlusions in intact sieve elements. Sieve elements in the basal parts of the stem estimated to be several decades old maintain their structural integrity and apparently remain functional throughout the life of the palm. Differentiating xylem elements are characterized by the presence of amoeboid plastids with electron-dense granular stroma. All the organelles normally present in meristematic cells are also present in differentiating tracheary elements. Bundles of microfilaments are often present in such elements. Structural changes that occur as the tracheary element matures are comparable to those observed in tracheary elements of other angiosperms. Xylem parenchymatous cells do not have the so called “protective wall layer.” The most striking ultrastructural feature in differentiating fibers of the root is the deep invagination of plasmalemma that traverses almost the entire width of the cell. The secondary wall of the fibers is characteristically multilayered.