Morphological and anatomical observations of adventitious and lateral roots
of sago palms
Youji Nitta, Yusuke Goto, Ken'ichi Kakuda, Hiroshi Ehara, Ho Ando, Tetsushi
Yoshida, Yoshinori Yamamoto,
Toshiaki Matsuda, Foh-Shoon Jong and Abudul Halim Hassan
Plant Production Science 5-2, 139-145 (2002)
Sago palm (Mtroxylon sagu Rottb.), which produces starch in large quantities
in its trunk, could become one of the most important nutrious food resources
in the near future. Although its root functions are thought to be very important
for the enormous shoot growth, the morphological studies are limited, This
study investigates external and internal shoot structures of sago roots with
reference to their functions to distinguish two types or 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 sclerenhyma cells, cortex and stele, with only differences
in their sizes or cell numbers. Both roots had characteristics 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.
Key words: adventious root, lateral root, lysigenous arernchyma, Mtroxylon
sagu Rottb., root primordia, sago palm, schizogenous arenchyma