Morphological and anatomical observations of adventitious and lateral roots of sago palms
Morphological and anatomical observations of adventitious and lateral roots of sago palms
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DOI：
10.1626/pps.5.139
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发表时间：
2002-06-01
影响因子：
2.5
通讯作者：
Hassan, AH
中科院分区：
文献类型：
--
作者：
Nitta, Y;Goto, Y;Hassan, AH
西米棕榈在树干中大量产生淀粉，在不久的将来可能成为最重要的营养食物资源之一。虽然它的根功能被认为对巨大的枝条生长非常重要，但对其形态和解剖学的研究有限。本研究对西米根的外部和内部结构进行了研究，以区分每株植物中的两种根：大根(直径约6-11 mm)和小根(直径约4-6 mm)。大根是指不定根，其原基就在茎的表皮内形成，从树干表面长出，向下生长到土壤中。小根是指侧根，其原基是在水平伸展的大根或其他小根上形成的，不仅在深层泥炭和矿物土壤中向下倾斜生长，而且在深层泥炭土壤中也在正上方生长。解剖观察表明，大根和小根具有相同的内部结构，包括表皮、外胚层、硬壁组织细胞、皮层和中柱，只是大小或细胞数量不同。两种根均具有裂生或裂生组织发育的特点，但似乎具有不同的功能。整个树干连续形成根原基。下部树干根原基直径较大，上部树干单位树干表面积的根原基密度较高。
Sago palm (Metroxylon sagu Rottb.), which produces starch in large quantities in its trunk, could become one of the most important nutritious food resources in the near future. Although its root functions are thought to be very important for the enormous shoot growth, the morphological and anatomical studies are limited. This study investigates external and internal structures of sago roots with reference to their functions to distinguish two types of roots in each plant; i.e., large (about 6-11 mm diameter) and small (about 4-6 mm diameter) roots. Large roots were adventitious roots whose primordia were formed just inside the epidermis in the stem, emerged from the trunk surface and grew downward into the soil. Small roots were lateral roots whose primordia were formed on large roots running horizontally or on other small roots, grew not only downward and obliquely in both deep peat and mineral soils, but also right above in deep peat soils. Anatomical observations revealed that both large and small roots had the same internal structures containing epidermis, exodermis, suberized sclerenchyma cells, cortex and stele, with only differences in their sizes or cell numbers. Both roots had characteristic development of schizogenous or lysigenous aerenchyma, but seem to have different functions. Root primordia were formed successively throughout the trunk. Root primordia in the lower trunk had a large diameter, while density of root primordia per unit trunk surface area was high in the upper trunk.