TY - JOUR
T1 - Morphological and histological differences among three types of component roots and their differential contribution to water uptake in the rice root system
AU - Watanabe, Yumika
AU - Kabuki, Takuya
AU - Kakehashi, Takahiro
AU - Kano-Nakata, Mana
AU - Mitsuya, Shiro
AU - Yamauchi, Akira
PY - 2020/4/2
Y1 - 2020/4/2
N2 - The rice root system consists of three types of roots; main root, L-type and S-type lateral root (LR). These component roots are morphologically and histologically different, which is termed as heterorhizy. Root system hydraulic architecture is related to the unique features of component roots. We hypothesized that each component root contributes in different degrees to water uptake of the whole root system. Rice varieties IRAT 109 and Taichung 65 were grown in pots filled with soil under continuous waterlogged (CWL) and drought (CD) conditions until two weeks after heading. Morphology and histological structures of roots, which may regulate radial water movement, were compared among the three component roots. Moreover, hydraulic conductivity (Lpr) of the root system, which represents the water uptake ability, were measured with a pressure chamber. Based on a model that Lpr of the whole root system is a product of Lpr of each of the component roots and their surface areas, we found that the differences in Lpr between the two varieties and the plants grown under different soil water conditions for any of the component roots did not support the corresponding differences in the measured Lpr of the whole root system. In contrast, a significant and positive correlation was found between Lpr of the whole root system and the percentage of surface area of S-type LR but not for the other component roots. These results indicate S-type LR might have a higher contribution to Lpr of the whole root system than the other component roots.
AB - The rice root system consists of three types of roots; main root, L-type and S-type lateral root (LR). These component roots are morphologically and histologically different, which is termed as heterorhizy. Root system hydraulic architecture is related to the unique features of component roots. We hypothesized that each component root contributes in different degrees to water uptake of the whole root system. Rice varieties IRAT 109 and Taichung 65 were grown in pots filled with soil under continuous waterlogged (CWL) and drought (CD) conditions until two weeks after heading. Morphology and histological structures of roots, which may regulate radial water movement, were compared among the three component roots. Moreover, hydraulic conductivity (Lpr) of the root system, which represents the water uptake ability, were measured with a pressure chamber. Based on a model that Lpr of the whole root system is a product of Lpr of each of the component roots and their surface areas, we found that the differences in Lpr between the two varieties and the plants grown under different soil water conditions for any of the component roots did not support the corresponding differences in the measured Lpr of the whole root system. In contrast, a significant and positive correlation was found between Lpr of the whole root system and the percentage of surface area of S-type LR but not for the other component roots. These results indicate S-type LR might have a higher contribution to Lpr of the whole root system than the other component roots.
KW - heterorhizy
KW - lateral root
KW - rice (Oryza sativa L.)
KW - Root hydraulic architecture
KW - root hydraulic conductance
KW - root hydraulic conductivity
KW - water uptake
UR - http://www.scopus.com/inward/record.url?scp=85084720306&partnerID=8YFLogxK
U2 - 10.1080/1343943X.2020.1730701
DO - 10.1080/1343943X.2020.1730701
M3 - Article
AN - SCOPUS:85084720306
SN - 1343-943X
VL - 23
SP - 191
EP - 201
JO - Plant Production Science
JF - Plant Production Science
IS - 2
ER -