Yoshida - 1981 - Fundamentals of Rice Crop Science
Yoshida - 1981 - Fundamentals of Rice Crop Science
Yoshida - 1981 - Fundamentals of Rice Crop Science
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MINERAL NUTRITION OF RICE 113<br />
Table 3.1. Direct and indirect evidences for transport <strong>of</strong> molecular oxygen from shoot<br />
to root in plants. a<br />
Measurement or observation<br />
Deposit <strong>of</strong> brown ferric iron<br />
compounds on root surface<br />
Oxidation <strong>of</strong> pigments<br />
thionin<br />
leucomethylene blue<br />
a -napthtylamine<br />
Esculin<br />
Bacterial luminescence on<br />
root surface in dark<br />
Chemiluminescence<br />
Oxygen concentrations in root<br />
tissues as affected by removal<br />
<strong>of</strong> shoot, root cortex and by<br />
oxygen tension in root medium<br />
Polarographic measurement <strong>of</strong><br />
oxygen diffused from roots<br />
Transport <strong>of</strong> isotopic oxygen<br />
from shoot to root<br />
Plant species<br />
<strong>Rice</strong> ( Oryza sativa L.)<br />
Salicornia herbacea L.<br />
Arachis hypogaea<br />
General<br />
<strong>Rice</strong><br />
<strong>Rice</strong><br />
<strong>Rice</strong><br />
<strong>Rice</strong><br />
<strong>Rice</strong><br />
Pumpkin ( Cucurbita spp.)<br />
<strong>Rice</strong><br />
<strong>Rice</strong><br />
Barley ( Hordeum vulgare L.)<br />
Bog plants and rice<br />
12 nonaquatic species<br />
<strong>Rice</strong> and barley<br />
Broad bean ( Vicia faba L.)<br />
<strong>Rice</strong>, corn ( Zea mays L.),<br />
barley<br />
a<br />
<strong>Yoshida</strong> and Tadano (1978).<br />
3.2. ADAPTATION TO SUBMERGED SOILS<br />
3.2.1. Oxygen transport<br />
The most direct evidence for oxygen transport from shoot to root has been obtained<br />
through the use <strong>of</strong> isotope oxygen ( 15 O and 18 O). When isotope oxygen is fed to the<br />
shoot, the same oxygen can be recovered from the root. There is much other direct<br />
and indirect evidence for the transport <strong>of</strong> molecular oxygen in rice and other plant<br />
species (Table 3.1).<br />
Microscopic examinations <strong>of</strong> the rice plant have established the presence <strong>of</strong><br />
well-developed air spaces in leaf blade, leaf sheath, culm, and roots. These air<br />
spaces constitute an efficient air-passage system in rice. The system <strong>of</strong> transporting<br />
oxygen from shoot to root in rice is about 10 times more efficient than that in barley<br />
and 4 times more efficient than that in corn (Jensen et al 1967).<br />
The rice plant develops air spaces in the culm even in upland conditions. The<br />
rice plant grown in submerged soils, however, develops more and larger air spaces<br />
(Table 3.2). Thus, the presence <strong>of</strong> air spaces in rice is controlled by both genetics<br />
and environment. The air spaces may be considered as many small pipes each with<br />
one end connected to the leaf sheaths and the other to the roots.
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