Yoshida - 1981 - Fundamentals of Rice Crop Science

PHOTOSYNTHESIS AND RESPIRATION 209
Table 5.5. Values characterizing the conversion of glucose into the main chemical
fractions of plant dry matter in darkness. Each fraction consists of a natural mixture
of different molecules. a Yield Oxygen Carbon
(g product/ consumed dioxide Source of
Chemical fraction g glucose) (g/g glucose) produced nitrogen
(g/g glucose)
Nitrogenous compounds 0.616 0.137 0.256 + NH 3
(consisting of amino
acids, proteins and
nucleic acids) 0.404 0.174 0.673 + NO 3
Carbohydrates 0.826 0.082 0.102
Lipids 0.330 0.116 0.530
Lignin 0.465 0.116 0.292
Organic acids 1.104 0.298 -0.050
a Penning de Vries (1975b).
–
also possible to calculate how many grams of substrates are required for biosynthesis
of 1.00 g dry matter (Table 5.6). For the biosynthesis of 1.00 g leaf dry
matter, 1.36 g mixed organic substrate is required:
(1.055 g sucrose + 0.305 g amino acids) = 1.36 g substrate
The conversion efficiency in the above example leads to:
Leaf dry matter =
Total substrate
l.00 g = 0.74 g/g.
1.36 g
(5.20)
This value agrees with 0.75 ( = 1 – 0.25) in equation 5.18.
To produce 1.00 g rice seeds, 1.20 g mixed organic substrate is required, and
2.16 g substrate is necessary to produce 1.00 g peanut seeds.
Table 5.6. Requirements for the biosynthesis of 1.00 g dry matter of tissues with
different chemical compositions. a Amino CO 2 O 2
Nature of Sucrose acids produced consumed
biomass Composition b (g) (g) (g) (g)
Leaves 25; 66.5; 2.5; 4; 2 1.055 0.305 0.333 0.150
Non-woody stem 12.5; 74; 2.5; 8; 2 1.153 0.153 0.278 0.135
Woody stem 5; 45; 5; 40; 5 1.515 0.061 0.426 0.176
Bean seeds 35; 55; 5; 2; 3 1.011 0.427 0.420 0.170
Rice seeds 5; 90; 2; 1; 2 1.135 0.061 0.186 0.110
Peanut seeds 20; 21; 50; 6; 3 1.915 0.245 1.017 0.266
Bacteria 60; 25; 5; 2; 8 0.804 0.732 0.573 0.208
a Penning de Vries (1975b). b Refers to percentages of nitrogenous compounds, carbohydrates,
lipids, lignin, and minerals, respectively.